All language subtitles for [SubtitleTools.com] Carl Sagan Tribute Series (2024 Edition) _ Cosmology Documentary

Our ancestors understood

origins by extrapolating from

their own experience.

How else could they have done it?

So, the universe was hatched

from a cosmic egg,

or conceived in the sexual

congress of a mother god and

a father god,

or was a kind of product of

the creator's workshop,

perhaps the latest of many

flawed attempts.

And the universe was not much

bigger than we see,

and not much older than our

written or oral records,

and nowhere very different

from places that we know.

We've tended in our

cosmologies to make things familiar.

Despite all our best efforts,

we've not been very inventive.

In the West, heaven is placid

and fluffy,

and hell is like the inside

of a volcano.

In many stories, both realms

are governed by dominance hierarchies,

headed by gods or devils.

Monotheists talked about the

king of kings.

things. In every culture, we

imagined something like our

own political system running

the universe.

Few found the similarity suspicious.

Then science came along and

taught us that

we are not the measure of

all things, that there are

wonders unimagined, that the universe

is not obliged to conform to

what was considered comfortable

or plausible.

And again, if we

are not important, not

central, not the apple of

God's eye, what is implied

for our theologically

based moral codes.

The discovery of our true

bearings in the cosmos was resisted

for so long and to such a

degree that many traces of

the debate remain,

sometimes with the motives of

the geocentrists laid bare.

So what do we

really want from philosophy

and religion?

Palliatives?

Therapy? Comfort? Do we want

reassuring fables or an

understanding of our

actual circumstances?

Dismay that the

universe does not conform to

our preferences seems childish.

You might think that grown-ups

would be ashamed to put such

disappointments into print.

The fashionable way of doing

this is not to blame the

universe, which seems truly pointless,

but rather to blame the means

by which we know the

universe, namely science.

Science has taught us that

because we have a talent for

deceiving ourselves, subjectivity

may not freely reign.

Its conclusions derive from

the interrogation of nature,

and are not in all cases pre-designed

to satisfy our wants.

We recognize that even revered

religious leaders, the products

of their time, as we are of ours,

may have made mistakes.

Religions contradict one another.

On small matters, such as

whether we should put on a

hat or take one off on entering a

house of worship, or whether

we should eat beef and eschew

pork or the other way around,

all the way to the most

central issues such as whether

there are no gods, one god,

or many gods.

If you lived two or three

millennia ago, there was no

shame in holding that the universe

was made for us.

It was an appealing thesis

consistent with everything we knew.

It was what the most learned

among us taught without qualification.

But we've found out much since then.

Defending such a position

today amounts to willful

disregard of the evidence and

a flight from self-knowledge.

We long to be here for a

purpose, even though, despite

much self-deception, none is evident.

Our time is burdened under

the cumulative weight of

successive debunkings of our conceits.

We are Johnny-come-latelys.

We live in the cosmic boondocks.

We emerged from microbes and muck.

Apes are our cousins.

Our thoughts and feelings are

not fully under our own control.

There may be much smarter and

very different beings

elsewhere, and on top of all this,

we are making a mess of our

planet and becoming a danger

to ourselves.

The trapdoor beneath our feet

swings open.

We find ourselves in

bottomless freefall.

We are lost in a great

darkness, and there's no one

to send out a search party.

Given so harsh a reality, of

course we're tempted to shut

our eyes and pretend that

we're safe and snug at home,

that the fall is only a bad dream.

Once we overcome our fear of

being tiny,

We find ourselves on the

threshold of a vast and

awesome universe that utterly

dwarfs, in time, in space,

and in potential, the tidy

anthropocentric

proscenium of our ancestors.

We gaze across billions of

light-years of space

to view the universe shortly

after the Big Bang and plumb

the fine structure of matter.

We peer down into the

core of our planet and the

blazing interior of our star.

We read the genetic

language in which is written

the diverse skills and propensities

of every being on Earth.

We uncover hidden chapters in

the record of our own origins.

We invent and refine

agriculture, without which

almost all of us would starve to death.

We create medicines and

vaccines that save the lives

of billions.

We communicate at the speed

of light and whip around the

Earth in an hour and a half.

We have sent dozens of ships

to more than

seventy worlds and four

spacecraft to the stars.

To our ancestors, there was

much in nature to be afraid

of—lightning, storms, Earthquakes,

volcanoes, plagues, drought,

long winters.

Religions arose in part as

attempts to propitiate and

control, if not much to understand, the

disorderly aspect of nature.

How much more satisfying had

we been placed in a garden

custom-made for us, its other

occupants put there for us to

use as we saw fit?

There is a celebrated story

in the Western tradition like

this, except that not quite

everything was there for us.

There was one particular tree

of which we were not to

partake, a tree of knowledge.

Knowledge and understanding and

wisdom were forbidden to us

in this story.

We were to be kept ignorant.

But we couldn't help ourselves.

We were starving for

knowledge, created hungry, you

might say.

This was the origin of all

our troubles.

In particular, it's why we no

longer live in a garden.

We found out too much.

So long as we were incurious

and obedient, I imagine, we

could console ourselves with

our importance and centrality,

and tell ourselves that we

were the reason the universe was made.

As we began to indulge our

curiosity, though, to explore,

to learn how the universe really

is, we expelled ourselves from Eden.

Angels with a flaming sword

were set as sentries at the

gates of paradise to bar our return.

The gardeners became exiles

and wanderers.

Occasionally we mourn that

lost world, but that, it

seems to me, is maudlin

and sentimental.

We could not happily have

remained ignorant forever.

However, there is in this

universe much of what seems

to be design, but instead we repeatedly

discover that natural

processes, collisional selection

of worlds, say, or natural selection

of gene pools, or even the

convection pattern in a pot

of boiling water, can extract order

out of chaos and deceive us

into deducing purpose where

there is none.

The significance of our lives

and our fragile planet is

then determined only by our own

wisdom and courage.

We are the custodians of

life's meaning.

We long for a parent to care

for us, to forgive us our

errors, to save us from our

childish mistakes.

But knowledge is preferable

to ignorance.

Better by far to embrace the

hard truth than a reassuring fail.

If we crave some cosmic

purpose, then let us find

ourselves a worthy goal.

Consider again that pale blue

dot we've been talking about.

Imagine that you take a good

long look at it.

Imagine you're staring at the

dot for any length of time,

and then try to convince yourself

that God created the whole

universe for one of the ten

million or so species of

life that inhabit that speck of dust.

Now take it a step further.

Imagine that

everything was made just for

a single shade of that

species, or gender, or ethnic

or religious subdivision.

If this doesn't strike you as

unlikely, pick another dot.

it. Imagine it to be inhabited by

a different form of intelligent life.

They, too, cherish

the notion of a God who has

created everything for their benefit.

How seriously do you take their claim?

Our ancestors lived out of doors.

They were as familiar with

the night sky as

most of us are with our

favorite television programs.

The Sun, the Moon, the stars, and

the planets all rose in the

east and set in the west,

traversing the sky overhead in

the interim.

The motion of the heavenly

bodies was not merely a diversion.

For hunters and gatherers, as

well as for agricultural

peoples, knowing about the sky

was a matter

of life and death.

How lucky for us that the

Sun, the Moon, the planets,

and the stars are part of

some elegantly

configured cosmic clockwork.

It seemed to be no accident.

They were put here for a purpose,

for our benefit.

Who else makes use of them?

What else are they good for?

And if the lights

in the sky rise and set

around us, isn't it evident

that we're at the center of

the universe?

These celestial bodies,
so

clearly suffused with unEarthly

powers, especially the Sun,

on which we depend for light

and heat circle us like

courtiers fawning on a king.

Even if we had not already

guessed, the most elementary

examination of the

heavens reveals that we are special.

The universe seems designed

for human beings.

It's difficult to contemplate

these circumstances without

experiencing

stirrings of pride and reassurance.

The entire universe made for us.

We must really be something.

This satisfying demonstration

of our importance, buttressed

by daily observations of the heavens,

made the geocentrist conceit a

transcultural truth, taught in

the schools, built into

the language, part and parcel

of great literature and

sacred scripture.

Dissenters were discouraged,

sometimes with torture and death.

It is no wonder that for the

vast bulk of human history no

one questioned it.

Aristotle, Plato, St. Augustine, St.

Thomas Aquinas,

and almost all the great philosophers

and scientists of all cultures

over the three thousand years

ending in the seventeenth century

bought into this delusion.

in.

Some busied themselves figuring

out how the Sun, the Moon,

the stars, and the planets

could be cunningly attached to

perfectly transparent,

crystalline spheres that would

explain the

complex motions of the

celestial bodies so

meticulously chronicled by

generations of astronomers.

Never mind how many kings,

popes, philosophers, scientists,

and poets insisted on the contrary.

The Earth, through those

millennia, stubbornly persisted

in orbiting the Sun.

You might imagine an

uncharitable extraterrestrial

observer looking down on our

species over

all that time, with us

excitedly chattering, the

universe created for us, we're at the

center, everything pays homage

to us, and concluding that

our pretensions are amusing,

our aspirations pathetic, that

this must be the planet of the idiots.

But such a

judgment is too harsh.

We did the best we could.

There was an unlucky coincidence

between everyday appearances

and our secret hopes. We tend not to be

especially critical when

presented with evidence that

seems to confirm our prejudices.

Philosophy and religion

cautioned that the gods, or

God, were far

more powerful than we, jealous

of their prerogatives, and

quick to mete out justice for

insufferable arrogance.

At the same time, these

disciplines had not a clue

that their own teaching of

how the universe is ordered

was a conceit and a delusion.

Every other proposal, and

their number is legion, to

displace us from cosmic center

stage has also been resisted,

in part for similar reasons.

We seem to crave privilege,

merited not by our works but

by our birth, by the mere fact

that, say, we are humans and

born on Earth.

We might call it the

anthropocentric, the

human-centered conceit.

This conceit is brought close

to culmination in the notion

that we are created in God's image.

The creator and ruler of the

entire universe looks just like me.

My, what a coincidence!

How convenient and satisfying!

The 6th century B.C.

Greek philosopher Xenophanes

understood

the arrogance of this perspective.

Here's what he said.

The Ethiopians make their gods

black and snub-nosed.

The Thracians say theirs have

blue eyes and red hair.

Yes, and if oxen

and horses or lions had

hands, and could paint with

their hands, and produce works of art

as men do, horses would paint

the forms of the gods like

horses, and oxen like oxen.

The immense distances to the

stars and the galaxies mean

that we see everything in space

in the past.

Some, as they were before the

Earth came to be, telescopes

are time machines.

Long ago, when an early

galaxy began to pour light

out into the surrounding darkness, no

witness could have known that

billions of years later some

remote clumps of rock and

metal, ice and organic

molecules, would fall together

to make a place called Earth, or

that life would arise and

thinking beings evolve, who

would one day capture a little

of that galactic light and

try to puzzle out what had

sent it on its way.

And after the Earth dies some

five million years from now,

after it is burned to a crisp

or even swallowed by the Sun,

there will be other worlds

and stars and galaxies coming

into being, and they will

know nothing of a place once

called Earth.

Those worlds in space are as

countless as all the grains

of sand on all the beaches

of the Earth.

Each of those worlds is as

real as ours.

In every one of them there's

a succession of incidents,

events, occurrences, which

influence its future.

Countless worlds, numberless

moments, an immensity of space

and time.

And our small planet, at this

moment, here we face a

critical branch point in history.

What we do with our world,

right now, will propagate down

through the centuries and

powerfully affect the destiny

of our descendants.

It is well within our power

to destroy our civilization

and perhaps our species as well.

If we capitulate to

superstition or greed or stupidity,

we can plunge our world into

a darkness deeper than the

time between the collapse of

classical civilization and the

Italian Renaissance.

But we are also capable of

using our compassion and our

intelligence,

our technology and our wealth,

to make an abundant and

meaningful life for every inhabitant

of this planet, to enhance

enormously our understanding of

the universe, and to carry

us to the stars.

We were wanderers from the beginning.

We knew every stand of tree

for a hundred miles.

When the fruits or nuts were

ripe, we were there.

there. We followed the herds

in their annual migrations.

We rejoiced in fresh meat. Through

stealth, feint, ambush, and

main-force assault, a few of

us cooperating accomplished what

many of us, each hunting

alone, could not.

We depended on one another.

Making it on our

own was as ludicrous to

imagine as was settling down.

For 99.9 percent of the time since our

species came to be, we were

hunters and foragers, wanderers

on the savannas and the steppes.

The frontier was everywhere.

We were bounded only by the

Earth and the ocean and the sky.

In the last 10,000 years, an

instant in our long history,

we've abandoned the nomadic life.

For all its material

advantages, the sedentary life

has left us edgy, unfulfilled.

The open road still softly

calls, like a nearly forgotten

song of childhood.

We invest far off places with

a certain romance.

The appeal, I suspect, has

been meticulously crafted by

natural selection as an essential

element in our survival.

all. Long summers, mild winters,

rich harvests, plentiful

game—none of them lasts forever.

It is beyond our powers to

predict the future.

Catastrophic events have a way

of sneaking

up on us, of catching us unaware.

Your own life, or your

band's, or even your species'

These might be owed to a

restless few, drawn by a

craving they can hardly articulate or

understand to undiscovered

lands and new worlds.

To the ancient Greeks and

Romans, the known world

comprised Europe and an attenuated Asia

and Africa, all surrounded by

an impassable world ocean.

them.

Travelers might encounter

inferior beings called

barbarians or superior beings called

gods, but there were not very

many gods, at least at first,

perhaps only a few dozen.

They lived on mountains, under

the Earth, in the sea, or up

there in the sky.

They sent messages to people,

intervened in human affairs,

and interbred with us.

As time passed, as the human

exploratory capacity hit its

stride, there were surprises.

Barbarians could be fully as

clever as Greeks and Romans.

Africa and Asia were larger

than anyone had guessed.

The world ocean was not impassable.

Three new continents existed,

had been settled by Asians in

ages past, and the news had

never reached Europe.

ship. Also, the gods were

disappointingly hard to find.

Since we first emerged a few

million years ago in East

Africa, we've meandered our

way around the planet. There are now

people on every continent and

the remotest islands, from

pole to pole, from Mount Everest

to the Dead Sea, on the

ocean bottoms, and even,

occasionally, in residence 200

miles up.

Humans, like the gods of old,

living in the sky.

These days, there seems to be nowhere

left to explore.

Victims of their very success,

the explorers now pretty much

stay home.

Vast migrations of people,

some voluntary, most not, have

shaped the human condition.

More of us flee from war,

oppression and famine today

than at any other time in

human history.

As the Earth's climate changes

in the coming decades, there

are likely to be far greater

numbers of environmental refugees.

Better places will always call to us.

Tides of people will continue

to ebb and flow across the planet.

But the lands we run to now

have already been settled.

world. Other people, often

unsympathetic to our plight,

are there before us. Maybe it's

a little early, maybe the

time is not quite yet, but

those are the worlds promising

untold opportunities beckon.

In the last few decades, the

United States

and the former Soviet Union

have accomplished something

stunning and historic. The close-up

examination of all those

points of light from Mercury

to Saturn that moved our ancestors

to wonder and to science.

Since the advent of successful

interplanetary flight in 1962,

our machines have flown by

or orbited or landed on more

than seventy new worlds.

We have wandered among the wanderers.

We have found vast volcanic

eminences that dwarf the

highest mountain on Earth, ancient

river valleys on two planets,

enigmatically one too cold and

the other too hot for running

water, a giant planet with an

interior of liquid metallic

hydrogen into which a thousand

Earths would fit, whole moons

that have melted, a

cloud-covered place with an

atmosphere of

Corrosive acids, where even

the high plateaus are above

the melting point of lead.

Ancient surfaces, on which a

faithful record of the violent

formation of the solar system

is engraved.

Refugee ice worlds from the

trans-Plutonian depths.

Exquisitely patterned ring

systems, marking the subtle

harmonies of gravity.

and a world surrounded by

clouds of complex organic

molecules like those that in

the earliest

history of our planet led to

the origin of life.

Silently, they orbit the Sun, waiting.

We have uncovered wonders

undreamt by our ancestors who

first speculated on the nature

of those wandering lights in

the night sky.

We have proved the origins of

our planet and ourselves.

By discovering what else is

possible, by coming face to

face with alternative fates of worlds

more or less like our own,

we have begun to better

understand the Earth.

Every one of those worlds is

lovely and instructive, but so

far as we know, they are also, every

one of them, desolate and barren.

Out there, there are no better places.

So far, at least.

During the Viking robotic

missions, beginning in July

1976, in a certain sense, I spent

a year on Mars.

I examined the boulders and

sand dunes, the sky red even

at high noon, the ancient river

valleys, the soaring volcanic

mountains, the fierce wind

erosion, the laminated

polar terrain, the two dark

potato-shaped moons.

But there was no life. Not a

cricket, or a blade of grass,

or even, so far as we can

tell for sure, a microbe.

Life is a comparative rarity.

You can survey dozens of

worlds and find that

only one of them does life

arise and evolve and persist.

Neptune lies a million times

further from Earth than New

York City is from the banks

of the River Bug.

But there are no distant

relatives, no humans, and

apparently no life waiting for

us on those other worlds.

No letters conveyed by recent

émigrés help us to understand

the new land.

Only digital data, transmitted

at the speed of light by

unfeeling, precise robot emissaries.

They tell us that these new

worlds are not much like home.

But we continue to search

for inhabitants.

We can't help it.

Life looks for life.

No one on Earth, not the

richest among us, can afford

the passage.

So we can't pick up and

leave for Mars or Titan on a whim,

or because we're bored, or

out of work, or drafted into

the army, or oppressed,

or because justly or unjustly

we've been accused of a crime.

There does not seem to be

sufficient short-term profit to

motivate private industry.

If we humans ever go to

those worlds, then it will be

because a nation or a consortium

of them believes it to be to

its advantage, or to the

advantage of the human species.

Just now, there are a great

many matters that are pressing

in on us, that compete for the

money it takes to send people

to other worlds.

Should we solve those problems

first, or are they a reason for going?

Even if the call of the open

road is muted in our time, a

central element of the human

future lies far beyond the Earth.

It's a sultry night in July.

You've fallen asleep in the armchair.

Abruptly, you startle

awake disoriented.

The television set is on, but

not the sound.

You strain to understand what

you are seeing.

Two ghostly white figures in

coveralls and helmets are

softly dancing under a pitch-black sky.

They make strange little

skipping motions, which propel

them upward amid barely perceptible

clouds of dust.

But something
is wrong.

They take too long to come down.

Encumbered as they are, they

seem to be flying—a little.

You rub your eyes, but the

dreamlike tableau persists.

Of all the events surrounding

Apollo 11's landing on the

Moon on July 20, 1969, my

most vivid recollection is its

unreal quality.

Neil Armstrong and Buzz Aldrin

shuffled along the gray, dusty

lunar surface, the Earth looming

large in their sky, while

Michael Collins, now the

moon's own moon, orbited above them

in lonely vigil.

Yes it was an astonishing

technological achievement and a

triumph for the United States.

Yes, the astronauts displayed

death-defying courage.

Yes, as Armstrong said as he

first alighted, this was a

historic step for the human species.

But if you turned off the

bi-play between mission control

and the Sea of Tranquility

and stared into that

black-and-white television

monitor, you could glimpse

that we humans

had entered the realm of myth

and legend.

We knew the Moon from our

earliest days.

It was there when our

ancestors descended from the

trees into the savannas,

when we learned to walk upright,

when we first devised stone tools,

when we domesticated fire,

when we invented agriculture

and built cities

and set out to subdue the Earth.

Folklore and popular songs

celebrate a mysterious connection

between the Moon and love.

Its waxing and waning from

crescent to full to crescent

to new was widely understood

as a celestial metaphor of

death and rebirth.

Walking on the Moon would

have seemed a screwball idea.

It made more sense to

imagine somehow climbing up

into the sky on a ladder or

on the back of a giant

bird, grabbing the Moon and

bringing it down to Earth.

Nobody ever succeeded, although

there were myths aplenty about

heroes who had tried.

Not until a few centuries ago

did the idea of the Moon as

a place a quarter million miles

away gain wide currency.

And in that brief flicker of

time, we've gone from the

earliest steps in understanding the

nature, to walking and

joyriding on its surface.

We calculated how objects move

in space, liquefied oxygen

from the air, invented big

rockets, telemetry, reliable

electronics, inertial guidance,

and much else.

And then we sailed out into the

In the late Roman Empire,

pagan philosophers had attacked

Christian doctrine on the ascension

to heaven of the body of

Christ and on the promised

bodily resurrection of the dead.

Saint Augustine rejoined in

these words, If human skill

can by some contrivance fabricate

vessels that float out of

metals which sink.

How much more credible is it

that God, by some hidden mode

of operation, should even

more certainly effect that

these Earthly masses be

emancipated from the chains

that bind them to Earth?

That humans should one day

discover such a mode of

operation was beyond imagining.

1,500 years later, we

emancipated ourselves.

Once upon a time, we soared

into the solar system for a few years.

Then we hurried back.

Why?

What happened?

What was Apollo really about?

The scope and audacity of

John Kennedy's May 25, 1961

message to a joint session of Congress

on urgent national needs, it

dazzled me.

We would use rockets not yet

designed, and alloys not yet

conceived, navigation and docking

schemes not yet devised, in

order to send a man to an

unknown world, a world not yet

explored, not even in a

preliminary way, not even by robots.

And we would bring him safely

back, and we would do it

before the decade was over.

This confident pronouncement

was made before any American

had even achieved Earth orbit.

I actually thought that all

this had something centrally

to do with science.

Suddenly, I understood.

Sending people to orbit the

Earth, or robots to orbit the

Sun, requires rockets.

Big, reliable, powerful rockets.

Those same rockets can be

used for nuclear war.

The same technology that

transports a man to the Moon

can carry nuclear warheads

halfway around the world.

The same technology that puts

an astronomer in a telescope

in Earth orbit

It can also put up a laser

battle station.

A case can be made, then,

that Apollo served another

purpose, to move the U.S.-Soviet space

competition from a military to

a civilian arena.

Apollo was not mainly about science.

It was not even mainly about space.

Apollo was about ideological

confrontation and nuclear war, but more

important than any of this,

Apollo provided an aegis, an

umbrella,
under

which brilliantly engineered

robot spacecraft were

dispatched throughout

the solar system, making that

preliminary reconnaissance of

dozens of worlds. The

Offspring of Apollo have now

reached the planetary frontiers.

Apollo conveyed a confidence,

energy, and breadth of vision

that did capture the

imagination of the world.

That, too, was part of its purpose.

It inspired an optimism about

technology,

and enthusiasm for the future.

The Apollo astronauts on their

way to and from the Moon

photographed their home planet.

It was a natural thing to do,

but it had consequences that

few foresaw.

For the first time,

the inhabitants of Earth could

see their world from above.

The whole Earth.

The Earth in color.

The Earth, as an exquisite

spinning white and blue ball,

set against the vast darkness of space.

Those images helped awaken our

slumbering planetary consciousness.

They provide incontestable

evidence that we all share

the same vulnerable planet.

They remind us of what's

important and what's not.

We may have found that

perspective just in time, just

as our technology threatens the

habitability of our world.

Whatever the reason we first

mustered the Apollo program,

however mired it was in Cold

War nationalism and the

instruments of death, the

inescapable recognition of the

unity and

The fragility of the Earth is

its clear and luminous

dividend, the unexpected final

gift of Apollo.

What began in deadly

competition has helped us to

see that global cooperation is

the essential

precondition for our survival.

Travel is broadening.

it's time to hit the road again.

The sky calls to us.

If we do not destroy

ourselves we will one

day venture to the stars.

There was a time when the

stars seemed an impenetrable mystery.

Today

we have begun to understand them.

In our personal lives also we

journey from ignorance to knowledge.

our individual growth reflects

the advancement of the species.

The exploration of the cosmos

is a voyage of self-discovery.

Every one of us begins life

with an open mind, a driving

curiosity, a sense of wonder.

Sometimes I think how lucky

we are to live in this time,

the first moment in human

history when we are, in fact,

visiting other worlds and

engaging in a deep

reconnaissance of the cosmos. But if

we had been born in a much

earlier age, no matter how

great our dedication, we

could not have understood what

the stars and planets are.

We would not have known

that there were other suns

and other worlds.

This is one of the great secrets

wrested from nature through a

million years of patient

observation and courageous thinking.

The ǃKung Bushmen of the

Kalahari Desert in the

Republic of Botswana

have an explanation of the Milky Way.

At their latitude,

it's often overhead. They call

it the backbone of night.

They believe it holds the sky up.

They believe that if not

for the Milky Way, pieces of

sky would come crashing down

at our feet. So the Milky Way

in their view as some

practical value, a backbone of night.

Later on, metaphors about

campfires, or backbones,

or holes through which the

flame could be seen

were replaced in most human

communities by another idea.

The powerful beings in the

sky were promoted to gods.

They were given names and

relatives and special

responsibilities for the cosmic

services they were expected to perform.

There was a god for every

human concern.

Gods ran nature.

Nothing happened without the direct

intervention of some god.

If the gods were happy, there

was plenty of food and humans

were happy.

But if something displeased

the gods, and it didn't take

much, the consequences were awesome.

Droughts, floods, storms, wars,

Earthquakes, volcanic

eruptions, epidemics.

The gods had

to be propitiated, and a vast

industry of priests arose to

make the gods less angry.

But because the gods were

capricious, you couldn't be

sure what they would do.

Nature was a mystery.

It was hard to understand the world.

Our ancestors groped in

darkness to make sense of

their surroundings.

Powerless before nature, they

invented rituals and myths.

some desperate, cruel, others

imaginative, benign.

The ancient Greeks explained

that diffuse band of

brightness in the night sky

as the milk of the goddess

Hera, squirted from her breast

across the heavens.

We still call it
the Milky Way.

What do you do when you're

faced with several different

gods, each claiming the same territory?

The Babylonian Marduk and the

Greek Zeus were each

considered king of the gods,

master of the sky.

You might decide, since they

otherwise had rather different

attributes, that one of them

was merely invented by the priests.

But if one, why not both?

And so it was here that the

great idea arose, the

realization that there might

be a way to know the world

without the God hypothesis,

that there might be

principles, forces, laws of

nature, through which the

world might be understood

without attributing the fall

of every sparrow to the

direct intervention of Zeus.

Where are we? Who are we?

We find that we live on an

insignificant planet of a

humdrum star lost in a galaxy tucked

away in some forgotten corner

of a universe in which there

are far more galaxies than people.

We make our world significant

by the courage of our

questions and by the depth of

our answers.

We embarked on our journey to

the stars with a question

first framed in the

childhood of our species, and

in each generation asked anew

with undiminished

wonder, what are the stars?

And the answer is that the

stars are mighty

suns light-years away in the

depths of instellar space.

And around those suns

are there other planets.

And on those other worlds are

there beings who wonder

as we do. Think of how many stars and

planets and kinds of life there may be

in this vast and awesome universe.

Exploration is in our nature.

We began as wanderers and we

are wanderers still.

We have lingered long enough

on the shores of the cosmic ocean.

We are ready at last to set

sail for the stars.

There is one experience that

every human shares, of every

language and culture, the

experience of birth.

Our recollections of birth are

hazy at best.

They have the feel and aura,

not so much of memories as

of mystical transfigurations.

It would be astonishing if

this profound early experience

did not influence our myths and

religions, our philosophy, and

our science.

The birth of a child evokes the mystery

of other origins, the

beginnings and ends of worlds,

infinity and eternity. How did

the universe arise?

What was around before that?

Might there have been no

beginning could the universe

be infinitely old?

The current scientific

story of the origin of the

universe begins with an

explosion which made

space itself expand.

About 15 billion years ago

all the matter and energy that

today make up the observable

universe were concentrated into

a space smaller

than the head of a pin.

The cosmos blew apart in one

inconceivably colossal

explosion, the Big Bang, and

the stuff of the universe

together with the fabric of

space itself began expanding

in all directions as they do today.

The early

cosmos was everywhere white

hot, but as time passed the

radiation expanded and

cooled and in ordinary visible

light space became dark as it is today.

But
then little pockets of gas

began to grow.

Tendrils of gossamer clouds formed.

Colonies of great, lumbering,

slowly spinning things,

steadily brightening, each a kind of

beast composed of a hundred

billion shining points.

The largest recognizable structures

in the universe had formed.

We see them today.

We ourselves inhabit some lost

corner of one.

We call them the galaxies.

We inhabit a universe of galaxies.

There are unstructured blobs,

the irregular galaxies,

globular or elliptical galaxies

and the graceful

blue arms of spiral galaxies.

We've been investigating the

galaxies, their

origins, evolution and motions

for less than a century.

These studies extend our

understanding to the farthest

reaches of the universe.

We view the cosmos on the

grandest of scales, the

majesty of the galaxies is

revealed by science.

The galaxies reveal a

universal order, beauty, but

also violence on a scale

never before imagined.

The universe seems neither

benign nor hostile, merely

indifferent to the concerns of such

creatures as we.

If the general picture,

however, of a Big Bang

followed by an expanding

universe is correct,

what happened before that?

Was the universe devoid of

all matter, and then the matter

suddenly, somehow, created?

How did that happen?

In many cultures, the

customary
answer is that

a god or gods created the

universe out of nothing.

But if we wish to pursue

this question courageously,

We must, of course, ask the

next question.

Where did God come from?

If we decide that this is an

unanswerable question,

why not save a step and

conclude that the origin of

the universe is an

unanswerable question?

Or, if we say that God always existed,

why not save a step and

conclude that the universe

always existed?

There's no need for a

creation, it was always here.

These are not easy questions.

Cosmology brings us face to

face with the deepest

mysteries, questions that were once

treated only in religion.

Every human generation has

asked about the origin and

fate of the cosmos.

Ours is the first generation

with a real chance of finding

some of the answers.

One way or another, we are

poised of forever.

In the 17th century, there

was still some hope that,

even if the Earth was not the center

of the universe, it might be

the only world.

After millennia of

philosophical debate, the issue

was settled decisively in favor of what

was called the plurality of worlds.

They might be profoundly

different from our planet.

None of them might be as

congenial for life, but the

Earth was hardly the only one.

This was the next in the

series of great demotions,

downlifting experiences,

demonstrations of our apparent

insignificance, wounds that science has

delivered to human pride.

Well, some hoped, even if the

Earth isn't at the

center of the universe, the Sun is.

The Sun is our Sun, so the Earth is

approximately at the center of

the universe.

But by the 19th century,

Observational astronomy had

made it clear that the Sun

is but one lonely star in a great

self-gravitating assemblage of

suns called the Milky Way galaxy.

Far from being at the center

of the galaxy, our Sun, with

its entourage of dim and tiny

planets, lies in an

undistinguished sector of an

obscure spiral arm.

we are 30,000 light-years from

the center.

Well, our Milky Way is the only galaxy.

The Milky Way galaxy is in

fact one of billions,

perhaps hundreds of billions,

of galaxies notable

neither in mass, nor in

brightness, nor in how

its stars are configured and arrayed.

Some modern

deep-sky photographs show more

galaxies beyond the Milky Way

than stars within the Milky Way.

Every one of them is an island universe

containing perhaps a hundred

billion suns.

Such an image is a profound

sermon on humility.

Well then, at least our

galaxy is at the center of

the universe.

Nope, this is wrong too.

When the expansion of the

universe was first

discovered, many people

naturally gravitated to the

notion that the Milky

way was at the center of the

expansion, and all the other

galaxies running away from us.

We now recognize that

astronomers on any galaxy

would see all the others

running away from

them unless they were very careful.

They would all conclude that

they were at the center

of the universe.

There is in fact no center

to the expansion, no point of

origin of the Big Bang.

Well, even if there are

hundreds of billions of

galaxies, each with hundreds

of billions of stars, no

other star has planets.

If there are no other planets

beyond our solar system,

perhaps there is no other

life in the universe.

Our uniqueness might then be saved.

Today we have firm evidence

for at least three planets

orbiting an extremely dense star,

and we found for more than

half the stars with masses

like the Sun's, that early in

their careers, they're

surrounded by great disks of

gas and dust, out of which planets

seem to form.

Other planetary systems now

look to be a cosmic

commonplace, maybe even

worlds something like the Earth.

Well, if our position in

space doesn't reveal our

special role, our position in

time does.

We've been in the universe

since the beginning,

Give or take a few days,

we've been given special

responsibilities by the Creator.

The radioactive dating of

rocks, the abundance of impact

craters on many worlds, the evolution

of the stars, and the

expansion of the universe each

provides compelling and

independent evidence

that our universe is many

billions of years old.

Despite the confident

assertions of revered

theologians that a world so

old directly contradicts

the word of God, and that at

any rate information on the

antiquity of the world is inaccessible

except to faith.

These lines of evidence as

well would have to be

manufactured by a deceptive

and malicious

deity unless the world is

much older than the literalists in the

Judeo-Christian-Islamic

religion suppose.

Ages rolled by before the Earth began.

More ages will run their

course before it is destroyed.

A distinction needs to be

drawn between how old the

Earth is and how old the universe is.

The immense interval of time

between the origin of the

universe and our epoch was two-thirds

over before the Earth came to be.

Some stars and planetary

systems are billions of years

younger, others billions of

years older.

But in Genesis chapter 1

verse 1, the universe and the

Earth are created on the same day.

As for humans, we're latecomers.

We appear in the last instant

of cosmic time.

The history of the universe

till now was 99.998% over,

before our species arrived on

the scene.

In that vast sweep of eons,

we could not have assumed any

special responsibilities

for our planet or life or

anything else.

We were not here.

Our common sense intuitions

can be mistaken.

Our preferences don't count. We

do not live in a privileged

reference frame.

Well, even if our position, our

epoch, our motion, and our

world are not unique, maybe we are.

We're different from

the other animals.

We're specially created.

The particular devotion of the

creator of the universe is

evident in us.

This position was passionately

defended on religious and

other grounds, but in the middle

19th century Charles Darwin

showed convincingly how one

species can evolve into another by

entirely natural processes

which come down to the

heartless business of nature saving

the heredities that work and

rejecting those that don't.

Man, in his arrogance, thinks

himself a great work, worthy

of the interposition of a deity.

More humble, and I think

truer, to consider him created

from animals.

The profound and intimate

connections of humans with the

other life-forms on Earth has been

compellingly demonstrated in

the late twentieth century by

the new science of molecular biology."

Well, even if we're closely

related to some of the other

animals, we're different.

Not just in degree, but in kind.

On what really matters,

reasoning, self-consciousness,

tool-making, ethics, altruism,

religion,

language, nobility of character.

Human uniqueness has been

exaggerated, sometimes grossly so.

Chimps reason, are

self-conscious, make tools,

show devotion, and so on.

Chimps and humans have 99.6%

of their active genes in common.

Okay, maybe we're not much.

Maybe we're humiliatingly

related to apes.

But at least we're the best there is.

God and angels aside, we're

the only intelligent beings in

the universe.

But the simple fact is that

we have not yet found

extraterrestrial life.

We're in the earliest stages

of looking.

The question is wide open.

If I had to guess, especially

considering our long sequence

of failed chauvinisms, I'd

guess that the universe is

filled with beings far more

intelligent, far more advanced

than we are.

But, of course, I might be wrong.

Such a conclusion is at best

based on a plausibility

argument, derived from the

numbers of planets,

the ubiquity of organic

matter, the immense time

scales available for evolution,

and so on.

It's not a scientific demonstration.

The question is among the

most fascinating in all of science.

We are just developing the

tools to treat it seriously.

What about the related matter

of whether we are capable of

creating intelligences smarter

than ourselves.

Computers routinely do

mathematics that no unaided

human can manage, outperform

world champions in checkers

and grandmasters in chess,

speak and understand English and

other languages, write

presentable short stories and

musical compositions, learn from

their mistakes, and competently

pilot ships, airplanes, and spacecraft.

Their abilities steadily improve.

They're
getting smaller, faster, and cheaper.

Every year the tide of

scientific advance laps a

little further ashore on the

island of human and collectual

uniqueness

with its embattled castaways.

The long-standing view, as

summarized by the philosopher Immanuel

Kant, that without man the

whole of creation would be a

mere wilderness, a thing in vain,

and have no final end is

revealed to be self-indulgent folly.

A principle of

mediocrity seems to apply to

all our circumstances.

We would not have known

beforehand that the evidence

would be so repeatedly and

thoroughly incompatible

with the proposition that

human beings are at center

stage in the universe. But

Most of the debates have now

been settled decisively

in favor of a position that,

however painful,

can be encapsulated in a

single sentence.

We have not been given the

lead in the cosmic drama.

Perhaps someone else has.

Perhaps no one else has.

In either case, we have good

reason for humility.

When my grandparents were children,

The electric light, the

automobile, the airplane, and

the radio were stupefying technological

advances, the wonders of the age.

But in that same time, around

the turn of the last century,

there were two men who foresaw

other far more ambitious

inventions, Konstantin

Tsiolkovsky and Robert Goddard.

They dreamt of using rockets

to journey to the planets and

the stars.

Step by step, they worked out

the fundamental physics and

many of the details.

Gradually, their machines took shape.

Ultimately, their dream

proved infectious.

A generation later, inspired

by Tsiolkovsky and Goddard,

Werner von Braun was constructing

the first rocket capable of

reaching the edge of space, the V-2.

But in one of those ironies

with which the twentieth

century is replete, von Braun was

building it for the Nazis.

as an instrument of

indiscriminate slaughter of

civilians, as a vengeance

weapon for Hitler.

The rocket factories staffed

with slave labor, untold human

suffering exacted in the construction

of every booster.

Another generation later,

building on the work of

Tsiolkovsky and Goddard, extending

Using von Braun's technological

genius, we were up there in

space, silently circumnavigating

the Earth, treading the

ancient and desolate lunar surface.

Our machines, increasingly

competent and autonomous, were

spreading through the solar

system, discovering

discovering new worlds,

examining them closely,

searching for life, comparing

them with Earth.

This is one reason that in

the long astronomical

perspective there is something

truly epical about now.

And there's a second reason.

This is the first moment in

the history of our planet

when any species by its own voluntary

actions has become a danger to itself.

We've been burning fossil fuels for

hundreds of thousands of years.

By the 1960s there were so

many of us burning

wood, coal, oil and natural

gas on so large a scale that

scientists began to

worry about the increasing

greenhouse effect.

The dangers of global warming

began slowly slipping into

public consciousness.

Nuclear weapons were

invented in 1945.

It took until 1983 before the

global consequences of

thermonuclear war were understood.

Biological warfare has been with us for

centuries, but it's deadly

mating with molecular biology

has occurred only lately.

We humans have already

precipitated extinctions of

species on a

scale unprecedented since the

end of the Cretaceous period,

but only in the last

decade has the magnitude of

these extinctions become clear and the

possibility raised that in our

ignorance of the interrelations

of life on Earth

we may be endangering our own future.

In the littered field of

discredited, self-congratulatory

chauvinisms, there is only one

that seems

to hold up, one sense in

which we are special, due to

our own actions or inactions, and the

misuse of our technology, we

live at an extraordinary

moment for the Earth, at

least the first

time that a species has been

able to wipe itself out.

But this is also, we may note,

the first time that a species

has become able to journey to

the planets and the stars.

The two times, brought about

by the same technology, coincide.

It might be a familiar progression,

Transpiring on many worlds, a

planet, newly formed, placidly

revolves around its star.

Life slowly forms.

A kaleidoscopic procession of

creatures evolves.

Intelligence emerges, which, at

least up to a point, confers

enormous survival value.

And then, technology is invented.

It dawns on them that there

are such things as laws of

nature, that these laws can be

revealed by experiment, and

that knowledge of these laws

can be made both to save and

to take lives, both on

unprecedented scales.

Science they recognize grants

immense powers.

In a flash, they create

world-altering contrivances.

Some planetary civilizations

see their way through, place

limits on what may and what

must not be done,

and safely pass through the

time of perils.

Others, not so lucky or so

prudent, perish.

Since, in the long run, every

planetary society will be

endangered by impacts from space,

Every surviving civilization is

obliged to become spacefaring.

Not because of exploratory or

romantic zeal,

but for the most practical

reason imaginable.

Staying alive.

And once you're out there in

space for centuries,

for millennia,

moving little worlds around,

engineering planets,

Your species has been pried

loose from its cradle.

If they exist, many other

civilizations will eventually

venture far from home.

Of course we must keep our

planet habitable, not on a

leisurely timescale of centuries

or millennia, but urgently on

a timescale of decades or even years.

This will involve changes in

government, in industry, in

ethics, in economics and in religion.

We've never done such a thing

before, certainly not on a

global scale.

It may well be too difficult for us.

Dangerous technologies may be

too widespread.

Corruption may be too pervasive.

Too many leaders may be

focused on the short term

rather than the long.

There may be too many

quarreling ethnic groups,

nation-states, and ideologies

for the right

kind of global change to be instituted.

We may be too foolish to

perceive even what the real

dangers are, or that much of what

we hear about them is

determined by those with a

vested interest in minimizing

fundamental change.

However, we humans also have

a history of making

long-lasting social change that nearly

everyone thought was impossible.

Since our earliest days, we've

worked not just for our

own advantage, but for our

children and our grandchildren.

The newly recognized dangers

threaten all of us equally.

No one can say how it will

turn out down here.

The moon was where the tree

of immortality grew in ancient

Chinese myth.

The tree of longevity indeed

grows on other worlds.

If we were up there among

the planets, if there were

self-sufficient human

communities on many

worlds, our species would be

insulated from catastrophe.

A cataclysmic impact on

one world would likely leave

the others untouched.

The more of us beyond the

Earth, the greater the

diversity of worlds we

inhabit, the more varied the

planetary engineering, the

greater the range of societal

standards and values,

then the safer the human

species will be.

This strategy, breaking up into many

smaller self-propagating groups,

each with somewhat different

strengths and

concerns but all marked by

local pride has been widely

employed in the

evolution of life on Earth

and by our own ancestors in particular.

It may in

fact be key to understanding

why we humans are the way we are.

If our long

term survival is at stake we

have a basic responsibility to

our species to

venture to other worlds.

Sailors on a becalmed sea, we

sense the stirring of a breeze.

As children, we fear the dark.

Anything might be out there.

The unknown troubles us. Ironically,

Maybe it's our fate to live

in the dark.

This unexpected finding of

science is only about three

centuries old.

Head out from the Earth in

any direction you choose, and

after an initial flash of blue

and a longer wait while the

Sun fades, you are surrounded

by blackness, punctuated only

here and there by the faint

and distant stars.

Even after we're grown, the

darkness retains its power to

frighten us.

And so there are those who

say we should not inquire too closely

into who else might be living

in that darkness.

Better not to know, they say.

There are 400 billion stars

in the Milky Way galaxy.

Of this immense multitude,

could it be that our humdrum sun

is the only one with an

inhabited planet?

Maybe. Maybe the origin of life, or

intelligence, is

exceedingly improbable.

Or, maybe, civilizations arise all the

time, but wipe themselves out

as soon as they are able.

Or, here and there, peppered

across space, orbiting other

suns, maybe there are worlds

something like our own, on which

other beings gaze up and

wonder as we do about who

else lives in the dark.

Could the Milky Way be

rippling with life and

intelligence, worlds calling

out to worlds,

while we on Earth are alive

at the critical moment when

we first decide to

listen, our species has

discovered a way to

communicate through the dark, to

transcend immense distances.

No means of communication is

faster or cheaper or

reaches out farther. It's called radio.

After billions of years of biological

evolution on their planet and

ours, an alien civilization

cannot be in

technological lockstep with us.

There have been humans for

more than 20,000

centuries, but we've had radio

only for about one century. If alien

civilizations are behind us,

they're likely to be too far

behind to have radio.

And if they're ahead of us,

they're likely to be far ahead of us.

Think of

the technical advances in our

world over just the last few centuries.

What is for

us technologically difficult

or impossible?

What might seem to us like

magic might for them be trivially easy.

They might use other very

advanced means

to communicate with their

peers, but they would know

about radio as an approach to

newly emerging civilizations.

Even with no more than our

level of technology at the

transmitting and receiving ends, we

could communicate today across

much of the galaxy.

They should be able to do much better.

If they exist.

But our fear of the dark rebels.

The idea of alien beings troubles us.

We conjure up objections.

It's too expensive, some of us say.

But in its fullest modern

technological expression,

it costs less than one attack

helicopter a year.

We'll never understand what

they're saying,

some of us say.

But because the message is

transmitted by radio, we and they must

have radio physics, radio

astronomy, and radio technology

in common.

The laws of

nature are the same

everywhere, so science itself

provides a means and

language of communication, even

between very different kinds

of beings, provided

they both have science.

Figuring out the message, if

we're fortunate enough to

receive one, may be much

easier than acquiring it.

It would be demoralizing

to learn that our science is

primitive, some say.

But by the standards of the

next few centuries, at least

some of our present science

will be considered

primitive, extraterrestrials or

no extraterrestrials.

Incidentally, so will

some of our present politics,

ethics, economics, and religion.

To go beyond present science

is one of the chief goals of science.

The debate is, for the moment, moot.

We are now on an unprecedented scale,

listening for radio signals

from possible other civilizations

in the depths of space.

Alive today

is the first generation of scientists

to interrogate the darkness.

Conceivably, it might also be

the last generation

before contact is made.

And this the last moment

before we discover that someone

in the darkness is calling out to us.

Let's permit ourselves though a moment

of extravagant speculation.

Then we can estimate from how

little time we've

spent watching each piece of

the sky, how many such

transmitters there are in the

entire Milky Way?

The answer is something

approaching a million.

If randomly strewn through space,

the nearest of them would be

a few hundred light years away.

Too far for them to have

picked up our own TV or

radar signals yet.

They would not know for

another few centuries

that a technical civilization

had emerged on Earth.

The galaxy would be pulsing

with life and intelligence,

but unless they're busily

exploring huge numbers of

obscure star systems,

they'd be wholly oblivious of

what's been happening down here lately.

A few centuries from now,

after they do hear from us,

things might get very interesting.

Elsewhere, there may be

engineering on a scale that

dwarfs our proudest achievements.

Imagine the energy crisis of

a really advanced

planetary civilization.

They've used up all their

fuels, they depend on solar

power, but their growth is still

severely limited by the

energy available.

An enormous amount of energy

is generated by the local

star, but most of the star's

light doesn't fall on their planet.

So perhaps they would build a

shell to surround their star

and harvest every photon of sunlight.

Such beings, such civilizations

would bear little resemblance

to anything we know.

Perhaps someday there will be

an entry in the Encyclopedia

Galactica for our planet.

Or perhaps even now there

exists somewhere a planetary

dossier garnered from our television

broadcasts or from some

discrete survey mission.

They might summon up the

index of blue worlds

in our province of the Milky

Way until they came to the

listing for Earth. What would

they know about us?

What would they think of us?

We have always watched the stars and

mused about whether there are

other beings who think and

wonder in a cosmic setting vast

and old, beyond ordinary

human understanding.

We are a little lonely.

In the deepest sense,

the search for extraterrestrial

intelligence is a search.

The spacecraft was a long way

from home, beyond the orbit

of the outermost planet and high above

the ecliptic plane.

The ship was speeding away

from the Sun at 40,000 miles an hour.

But in early February of

1990, it was overtaken by an

urgent message from Earth.

Obediently, it turned its cameras

back toward the now distant

planets, slewing

its scan platform from one spot in

the sky to another.

It snapped 60 pictures

and stored them in digital form

on its tape recorder.

Then, slowly, in

March, April, and May,

it radioed the data back to Earth.

The spacecraft was 3.7

billion miles away from Earth,

so far away that it took

each pixel five and a half hours

traveling at the speed of

light to reach us.

The two Voyager robots have

explored four planets

and nearly 60 moons.

They are triumphs of human engineering

and one of the glories of

the American space program.

They will be in the history books

when much else about our time

is forgotten.

The Voyagers were guaranteed

to work only until the

Saturn encounter.

I thought it might be a good

idea, just after Saturn, to

have them take one last

glance homeward.

From Saturn, I knew, the

Earth would appear too small

for Voyager to make out any detail.

Our planet would be just a

point of light, a lonely pixel.

Hardly distinguishable from the

many other points of light

Voyager would see,

nearby planets, far-off suns.

But precisely because of the

obscurity of our world thus

revealed, such a picture might

be worth having.

Mariners had painstakingly

mapped the coastlines of

the continents.

Geographers had translated

these findings into charts and globes.

Photographs of tiny patches of

the Earth had been obtained

first by balloons and aircraft,

then by rockets in brief

ballistic flight, and at last

by orbiting spacecraft, giving

a perspective like the one

you achieve by positioning

your eyeball about an inch above

a large globe.

While almost everyone has

taught that the Earth is a

sphere, with all of us somehow

glued to it by gravity, the

reality of our circumstance

did not really begin to sink

begin, until the famous

frame-filling Apollo photograph

of the whole Earth, the one taken

by the Apollo 17 astronauts

on the last journey of humans

to the Moon.

It has become a kind of icon

of our age.

You can make out the blue of

the ocean, the yellow-red of

the Sahara and the Arabian desert,

the brown-green of forest

and grassland.

And yet, there is no sign of

humans in this picture.

Not our reworking of the

Earth's surface, not our

machines, not ourselves.

We are too small, and our

statecraft is too feeble to

be seen by a spacecraft between

the Earth and the Moon.

From this vantage point, our

obsession with nationalism is

nowhere in evidence.

The Apollo pictures of the

whole Earth, conveyed to

multitudes, something well

known to astronomers,

on the scale of worlds, to

say nothing of stars or

galaxies, humans are inconsequential,

a thin film of life on an

obscure and solitary lump of

rock and metal.

It seemed to me that another

picture of the Earth, this

one taken from a hundred thousand

times farther away, might help

in the continuing process of

revealing to ourselves our true

circumstance and condition.

It had been well understood

by the scientists and

philosophers of classical

antiquity that

the Earth was a mere point

in a vast, encompassing cosmos.

But no one had ever seen it as such.

Here was our first chance,

and perhaps also our last,

for decades to come.

At last, the time came.

A mosaic of squares laid down

on top of the planets

and
a background smattering of

more distant stars.

We were able to photograph

not only the Earth

but also five other of the

Sun's nine known planets.

This is how the planets would

look to an alien spaceship

approaching the solar system

after a long interstellar voyage.

From this distance, the

planets seem only points of

light, smeared or unsmeared, even

through the high-resolution

telescope aboard Voyager.

They are like the planets seen with

the naked eye from the

surface of the Earth, luminous

dots, brighter than most of the stars.

You cannot tell merely by

looking at one of these dots

what it's like, what's on it,

what its past has been, and

whether, in this particular

epoch, anyone lives there.

Because of the reflection of

sunlight off the spacecraft,

the Earth seems to be sitting

in a beam of light,

as if there were some special

significance to this small world.

But it's just an accident of

geometry and optics.

The Sun emits its radiation

equitably in all directions.

Had the picture been taken a

little earlier, or a little later,

there would have been no

sunbeam highlighting the Earth.

And why that cerulean color?

We can explain the wan

blueness of this little world

because we know it well.

Whether an alien scientist

newly arrived at the outskirts

of our solar system could reliably

deduce oceans and clouds in a

thickish atmosphere is less certain.

From this distant vantage

point, the Earth might not

seem of any particular interest.

But for us, it's different.

Consider again that dot. That's here.

That's home. That's us.

On it, everyone you love,

everyone you know, everyone

you ever heard of, every human being

who ever was, lived out their lives.

The aggregate of our joy and

suffering, thousands of

confident religions, ideologies,

and economic

doctrines, every hunter and

forager, every hero and

coward, every creator and destroyer

of civilization, every king

and peasant, every young

couple in love, every mother

and father,

father, hopeful child, inventor

and explorer, every teacher of

morals, every corrupt politician,

every superstar, every supreme

leader, every saint and sinner

in the history of our species

lived there, on the mote of

dust, suspended in a sunbeam.

The Earth is a very small

stage in a vast cosmic arena.

Think of the rivers of blood

spilled by all those generals

and emperors, so that in glory

and triumph they could become

the momentary masters of a

fraction of a dot.

Think of the endless cruelties

visited by the inhabitants of

one corner of this pixel

on the scarcely distinguishable

inhabitants of some other corner.

How frequent their

misunderstandings, how eager

they are to kill one another,

how fervent

their hatreds, our posturings,

our imagined self-importance,

the delusion that we have

some privileged position in

the universe are challenged by

this point of pale light.

Our planet is a lonely speck

in the great enveloping cosmic dark.

In our obscurity, in all this

vastness, there is no hint

that help will come from elsewhere

to save us from ourselves.

The Earth is the only world

known so far to harbor life.

There is nowhere else, at

least in the near future, to

which our species could migrate.

Visit?

Yes.

Settle? Not yet.

Like it or not, for the

moment, the Earth is where we

make our stand.

It has been said that

astronomy is a humbling and

character-building experience.

There is perhaps no better

demonstration of the folly of

human conceits than this distant

image of our tiny world.

To me, it underscores our

responsibility to deal more

kindly with one another and to

preserve and cherish the pale

blue dot, the only home we've

ever known.

We have considered the

destruction of worlds and the

end of civilizations, but there is

another perspective by which

to measure human endeavors.

Let me tell you a story

about the beginning.

Some 15 billion years ago,

our universe began with the

mightiest explosion of all time.

The universe expanded, cooled,

and darkened.

Energy condensed

into matter, mostly hydrogen

atoms, and these atoms

cumulated into vast clouds,

rushing away from each other that would

one day become the galaxies.

Within these galaxies, the

first generation of stars was

born, kindling

the energy hidden in matter,

flooding the cosmos with light.

Hydrogen atoms had made

suns and starlight.

There were in those times no

planets to receive the light

and no living

creatures to admire the

radiance of the heavens.

But deep in the stellar

furnaces, nuclear

fusion was creating the

heavier atoms, carbon and

oxygen, silicon and iron.

These elements,

the ash left by hydrogen,

were the raw materials from

which planets and life would

later arise.

At first, the heavy elements

were trapped in the hearts of

the stars.

But massive stars soon

exhausted their fuel, and in

their death throes, returned

most of their substance back

into space.

Interstellar gas became

enriched in heavy elements.

In the Milky Way galaxy, the

matter of the cosmos was

recycled into new generations of stars,

now rich in heavy atoms, a

legacy from their stellar ancestors.

And in the cold of interstellar space,

great turbulent clouds were

gathered by gravity and

stirred by starlight.

In their depths, the heavy

atoms condensed into grains of

rocky dust and ice

and complex carbon-based molecules.

In accordance with the laws

of physics and chemistry,

hydrogen atoms had brought

forth the stuff of life.

In other clouds, more

massive aggregates of gas and

dust formed later generations of stars.

As new

stars were formed, tiny

condensations of matter

accreted near them, inconspicuous

motes of rock and metal, ice

and gas, that would become the planets.

And on

these worlds, as in

interstellar clouds, organic

molecules formed, made of atoms

that had been cooked inside the stars.

In the tide pools and oceans

of many worlds,

molecules were destroyed by

sunlight and assembled by chemistry.

One day, among these natural

experiments, a molecule arose

that quite by accident was

able to make crude copies of itself.

As time passed,

self-replication became more accurate.

Those molecules that copied

better, produced more copies.

Natural selection was underway.

Elaborate molecular machines

had evolved.

Slowly, imperceptibly, life had begun.

Collectives of organic

molecules evolved

into one-celled organisms.

These produced multi-celled colonies.

Their various parts

became specialized organs.

Some colonies attached

themselves to the sea floor.

Others swam freely.

Eyes evolved, and now the

cosmos could see.

Living things moved on

to colonize the land.

The reptiles held sway for a

time, but they gave way to

small warm-blooded creatures

with bigger brains who

developed dexterity and

curiosity about their environment.

They learned to use tools and fire and

language, star stuff, the ash

of stellar alchemy, had

emerged into consciousness.

We are a way for the cosmos

to know itself.

We are creatures of the

cosmos and have always

hungered to know our origins,

to understand

our connection with the universe.

How did everything come to be?

Every culture on the planet

has devised its own response

to the riddle posed by the universe.

Every culture celebrates the

cycles of life and nature.

There are many different ways

of being human.

But an extraterrestrial

visitor, examining the

differences among human societies,

would find those differences

trivial compared to the similarities.

We are one species.

We are starstuff harvesting starlight.

Our lives, our past

and our future are tied to the Sun,

the Moon and the stars.

Our ancestors knew that their

survival depended on

understanding the heavens.

They built observatories and

computers to predict the

changing of the seasons by the

motions in the skies.

The discovery that there is

order in the universe, that

there are laws

of nature is the foundation

on which science builds today.

Science is a collective

enterprise that embraces many

cultures and spans the generations.

In every age, and sometimes

in the most unlikely places,

there are those who wish with a great

passion to understand the world.

There is no way of knowing

where the next discovery will

come from.

What dream of the mind's eye

will remake the world?

These dreams begin as impossibilities.

Once, even to see a planet through a

telescope was an astonishment,

but we studied these worlds

and figured out how

they moved in their orbits,

and soon we were planning

voyages of discovery

beyond the Earth, and sending

robot explorers to the planets

and the stars.

We humans long to be

connected with our origins, so

we create rituals.

Science is another way
to

express this longing.

It also connects us with our

origins, and it too has its

rituals and its commandments.

Its only sacred truth is that

there are no sacred truths.

All assumptions must be

critically examined.

Arguments from authority are worthless.

Whatever is inconsistent with

the facts, no matter how fond

of it we are, must be

discarded or revised.

Science is not perfect.

It's often misused. It's only a tool.

But it's the best tool we have.

Self-correcting, ever-changing,

applicable to everything.

With this tool, we vanquish

the impossible.

With the methods of science,

we have begun to explore the cosmos.

For the first time, scientific

discoveries are widely accessible.

Our machines, the products of

our science, are now beyond

the orbit of Saturn.

A preliminary spacecraft

reconnaissance has been made

of 20 new worlds.

We have learned to value

careful observations, to

respect the facts even when

they are disquieting

and they seem to contradict

conventional wisdom.

We humans have seen the atoms

which constitute all of matter

and the forces that sculpt this

world and others.

We have found that the

molecules of life are easily

formed under conditions common

throughout the cosmos.

We have mapped the molecular

machines at the heart of life.

We have discovered a microcosm

in a drop of water.

We have peered into the

bloodstream and down on our

stormy planet

to see the Earth as a single organism.

We have found volcanoes on

other worlds and explosions on the Sun,

studied comets from the depths

of space,

traced their origins and destinies,

Listened to pulsars and

searched for other civilizations.

We humans have set foot on

another world, in a place

called the Sea of Tranquility,

an astonishing achievement for

creatures such as we, whose

earliest footsteps, three and

a half million years old, are

preserved in the volcanic ash

of East Africa.

These are some of the things

that hydrogen atoms do, given

15 billion years of cosmic evolution.

It has the sound of epic

myth, but it's simply a

description of the evolution

of the cosmos as revealed by

science in our time.

And we, we who embody the

local eyes and ears and

thoughts and feelings of the cosmos,

We've begun, at last, to

wonder about our origins.

Star stuff, contemplating the stars.

Organized collections of ten

billion, billion, billion atoms,

contemplating the evolution of matter,

tracing that long path by

which it arrived at consciousness

here on the planet Earth and,

perhaps, throughout the cosmos.

Our loyalties are to the

species and the planet.

We speak for Earth.

Our obligation to survive and

flourish is owed not just to

ourselves, but also to that

cosmos, ancient and vast, from

which we spring.

In the vision of a dream, I

once imagined myself searching

for other civilizations

in the cosmos.

Among a hundred billion

galaxies and a billion

trillion stars, life and

intelligence should

have arisen on many worlds.

Some worlds are barren and desolate.

On them, life never began, or

may have been extinguished in

some cosmic catastrophe.

There may be worlds rich in

life, but not yet evolved to

intelligence and high technology.

There may be civilizations

that achieve technology and

then promptly use it to

destroy themselves.

And perhaps there are also

beings who learn to live with

their technology and themselves

beings who endure and become

citizens of the cosmos.

Immersed in these thoughts, I

found myself approaching a

world that was clearly inhabited,

a world I had visited before.

I saw a planet encompassed by

light and recognized the

signature of intelligence, but suddenly

darkness, total and absolute.

Their world society had

failed, they had made the

ultimate mistake.

I felt a longing to return to Earth.

The television transmissions of

Earth rushed past me,

expanding away from our planet at

at the speed of light.

There can be no whitewash at

the White House.

A series of record oil company profits...

If the serious course of

events continue,

foreign ministers are at this moment...

Oh, please stand by. Stand by.

Then, suddenly, silence.

Total and absolute.

Had we destroyed our home?

What had we done to the Earth?

There had been many ways for

life to perish at our hands.

We had poisoned the air and water.

We had ravaged the land.

Perhaps we had changed the climate.

Could it have been a plague?

Or nuclear war?

So it was nuclear war, a

full nuclear exchange.

There would be no more big

questions, no more answers.

Never again a love or a child.

No descendants to remember us

and be proud.

No more voyages to the stars.

No more songs from the Earth.

I saw East Africa and

thought, a few million years

ago, we humans took our first

steps there.

Our brains grew and changed.

The old parts began to be

guided by the new parts.

And this made us human, with

compassion, foresight, and reason.

But instead, we listened to

that reptilian voice within us,

counseling fear,

territoriality, aggression.

We accepted the products of science.

We rejected its methods.

Maybe the reptiles will evolve

intelligence once more.

Perhaps one day, there will

be civilizations again on Earth.

There will be life.

There will be intelligence.

But there will be no more humans.

Two megatons.

Coventry and Rotterdam, Dresden

and Tokyo, all the death that

reigned from the skies

between 1939 and 1945, 100,000

blockbusters, two megatons.

Today, two megatons is the

equivalent of a single

thermonuclear bomb,

one bomb with the destructive

force of the Second World War.

But there are tens of

thousands of nuclear weapons.

No place on the planet is safe.

The energy contained in these weapons,

Genies of death patiently

awaiting the rubbing of the lamps.

Totals far more than 10,000 megatons,

but with the destruction

concentrated efficiently.

Not over six years, but over

a few hours.

A blockbuster for every family

on the planet.

A World War II every second

for the length of a lazy afternoon.

The bomb dropped on Hiroshima

killed 70,000 people.

In a full nuclear exchange,

in the paroxysm of global death,

the equivalent of a million

Hiroshima bombs

would be dropped all over the world.

But in such an exchange, not

everyone would be killed

by the blast and the

firestorm and the immediate radiation.

There would be other agonies,

the loss of loved ones,

the legions of the burned and

blinded and mutilated,

the absence of medical care,

in military endeavors.

How would we explain all this

to a dispassionate

extraterrestrial observer?

What account would we give of

our stewardship of the planet Earth?

From an extraterrestrial

perspective, our global

civilization is clearly on the edge

of failure in the most

important task it faces,

preserving the lives and

well-being of its

citizens and the future

habitability of the planet.

But if we're willing to live

with the growing likelihood of

nuclear war, shouldn't we also

be willing to explore

vigorously every possible means

to prevent nuclear war?

shouldn't we consider in every nation

major changes in the

traditional ways of doing things,

a fundamental restructuring of

economic,

political, social, and

religious institutions?

We've reached a point where

there can be

no more special interests or

special cases.

Nuclear arms threaten every

person on the Earth.

Fundamental changes in society

are sometimes labeled

of impractical or contrary to

human nature,

as if nuclear war were

practical or as if there were

only one human nature.

But fundamental changes can

clearly be made.

We're surrounded by them.

In the last two centuries,

abject slavery,

which was with us for

thousands of years,

has almost entirely been

eliminated in a stirring

worldwide revolution.

Women, systematically mistreated

for millennia,

are gradually gaining the

political
and economic power

traditionally denied to them.

The old appeals to racial,

sexual, and religious chauvinism

and to rabid nationalist fervor

are beginning not to work.

A new consciousness is developing

which sees the Earth as a

single organism

and recognizes that an

organism at war with itself is doomed.

We are one planet.

We who cannot even put our

own planetary home in order,

riven with rivalries and hatreds,

are we to venture out into space?

By the time we're ready to

settle even the nearest other

planetary systems,

we will have changed.

The simple passage of so many

generations will have changed us.

necessity will have changed us.

We're an adaptable species.

It will not be we who

reach Alpha Centauri and the

other nearby stars.

It will be a species very

like us, but with more of

our strengths and fewer of

our weaknesses.

More

confident, far-seeing, capable

and prudent.

For all our failings, despite our

limitations and fallibilities,

we humans are capable of greatness.

What new

wonders undreamt of in our

time will we have wrought in

another generation and another?

How far will our nomadic

species have wandered by the

end of the next

century and the next millennium?

Our remote descendants safely

arrayed on many

worlds through the solar

system and beyond, will be unified.

By their common heritage, by

their regard for their home

planet, and by the knowledge

that whatever other life may

be, the only humans in all

the universe come from Earth,

they will gaze up and strain

to find the blue dot in their skies.

They will marvel at how

vulnerable the repository of

all our potential once was,

how perilous

our infancy, how humble our

beginnings, how many rivers we

had to cross before we found our way.

If I could travel back into

time, this is the place I

would visit, the Library of Alexandria

at its height 2,000 years ago.

Here, in an important sense, began

the intellectual adventure

which has led us into space.

All the knowledge in the ancient world

was once within these marble walls.

This library was a citadel of

human consciousness,

a beacon on our journey to the stars.

And what did they study?

They studied everything, the

entire cosmos.

But the treasure of the

library, consecrated to the

god Serapis,

built in the city of

Alexander, was its collection of books.

Accurate numbers are difficult

to come by,

but it seems that the library

contained at its peak nearly

one million scrolls.

What happened to all those books?

Well, the classical

civilization that created them

disintegrated, the library

itself was destroyed.

Only a small fraction of the

works survived.

And as for the rest, we are

left only with pathetic,

scattered fragments.

Let me tell you about The End.

It's a story about the last

scientist to work in this place.

a mathematician, astronomer,

physicist, and head of the

School of Neoplatonic

Philosophy in Alexandria.

That's an extraordinary range

of accomplishments for any

individual in any age.

Her name was Hypatia.

She was born in this city in

the year 370 A.D.

This was a time when women

had essentially no options.

they were considered property.

Nevertheless, Hypatia was able

to move freely, unselfconsciously,

through traditional male domains.

By all accounts, she was a

great beauty.

And although she had

many suitors, she had no

interest in marriage.

The Alexandria of Hypatia's

time, by then long under

Roman rule, was a city in

grave conflict.

Slavery, the cancer of the

ancient world, had sapped classical

civilization of its vitality.

The growing Christian Church

was consolidating its

power and attempting to

eradicate pagan influence and culture.

Hypatia stood at

the focus, the epicenter of

mighty social forces.

Cyril, the bishop of

Alexandria, despised her, in

part because of her close

friendship with the Roman

governor, but also because she

was symbolized, she was a

symbol of learning and

science, which were largely

identified by the early church

with paganism.

In great personal danger,

Hypatia continued to teach and

to publish until, in the year

415 A.D., on her way to work,

she was set upon by a

fanatical mob of Cyril's followers.

They dragged her from a

chariot, tore off her clothes,

and flayed her flesh from her

bones with abalone shells.

Her remains were burned,
her

works obliterated,

her name forgotten.

Cyril was made a saint.

The last remains of the

library were destroyed within

a year of Hypatia's death.

It's as if an entire

civilization had undergone a

sort of self-inflicted radical

brain surgery,

so that most of its memories,

discoveries, ideas, and

passions were irrevocably wiped out.

History is full of people

who, out of fear or ignorance

or a lust for power, have destroyed

treasures of immeasurable value

which truly belong to all of us.

We must not let it happen again.

We were, at long last,

beginning to find our true

bearings in the cosmos.

The scientists of antiquity

took the first and most

important steps in that direction

before their civilization fell apart.

But after the Dark Ages, it

was by and large the

rediscovery of the works of

these scholars

done here that made the

Renaissance possible and

thereby powerfully influenced

our own culture.

When in the 15th century

Europe was at last ready to

awaken from its long sleep,

it picked up some of the

tools, the books and the

concepts laid down here more

than a thousand years before.

By 1600, the long-forgotten

ideas of Aristarchus had

been rediscovered.

Johannes Kepler constructed

elaborate models to understand

the motion and arrangement of

the planets,

the clockwork of the heavens.

His principal scientific tools

were the mathematics of the

Alexandrian library

and an unswerving respect for

the facts,

however disquieting they might be.

Seventy years later,

the Sun-centered universe of

Aristarchus and Copernicus

was widely accepted in the

Europe of the Enlightenment.

The idea arose that the

planets were worlds, governed

by laws of nature,

and scientific speculation

turned to the motions of the stars.

The clockwork in the heavens

was imitated by the

watchmakers of Earth.

Precise timekeeping permitted

great sailing ship voyages of

exploration and discovery,

which bound up the Earth.

This was a time when free

inquiry was valued once again.

250 years later, the Earth

was all explored.

New adventurers now looked to

the planets and the stars.

Galaxies were recognized as

great aggregates of stars,

island universes, millions of

light years away.

In the 1920s, astronomers had

begun to measure the speeds

of distant galaxies.

They found that the galaxies

were flying away from one another.

To the astonishment of

everyone, the entire universe

was expanding.

We had begun to plumb the

true depths of time and space.

The long collective enterprise

of science has revealed a

universe some 15 billion years old.

We on Earth have just

awakened to the great oceans

of space and time from which

we have emerged.

We are the legacy of 15

billion years of cosmic evolution.

We have a choice.

We can enhance life and come

to know the universe that

made us, or we can squander

our 15 billion

year heritage in

meaningless self-destruction.

What happens in the first

second of the next cosmic

year depends on what we do here and

now with our intelligence and

our knowledge of the cosmos.

This is the age of planetary

exploration, when our ships

have begun to sail the heavens.

In those heavens there are

some worlds much like hell.

Our planet is, in comparison,

much like a heaven.

But the gates of heaven and

hell are adjacent and unmarked.

We've evolved on the planet

Earth, and so we find it a

congenial place.

But just next door is Venus,

until recently enveloped in mystery.

It has almost the same size

and mass as the Earth.

Might our sister world be a

balmy summer planet,

A little warmer than the

Earth because it's a little

closer to the Sun?

Are there craters, volcanoes,

mountains, oceans, life?

From a distance, our sister

planet seems serene and

peaceful, its clouds motionless.

These clouds are near the top

of a great ocean of air,

about a hundred kilometers

thick, composed

mainly of carbon dioxide.

There's some nitrogen, a

little water vapor and other

gases, but only the merest

trace of hydrocarbons.

And the clouds turn out to

be not water, but a

concentrated solution

of sulfuric acid.

Even in the high clouds,

Venus is a thoroughly nasty place.

The clouds

are stained yellow by sulfur.

There are great lightning storms.

As we descend, there are

increasing
amounts of the

noxious gas sulfur dioxide.

The pressures become so high that

The early Venera spacecraft

were crushed like old tin

cans by the weight of the

surrounding atmosphere.

Beneath the clouds, in the

dense, clear air, it's about

as bright as on an overcast day

on Earth, but the atmosphere

is so thick that the ground

seems to ripple and distort.

The atmospheric pressure down

here is 90 times that on Earth.

The temperature is 380 degrees

centigrade, 900 Fahrenheit,

hotter than the hottest household oven.

This is a world marked by

searing heat, crushing

pressures, sulfurous gases in

a desolate, reddish landscape.

Far from the balmy paradise

imagined by some early

scientists, Venus is the one

place in the solar system

most like hell.

But today, as in ancient

tradition, there are travelers

who will dare a visit to

the underworld.

Venera 9 was the first

spacecraft in human history to

return a photograph from the

surface of Venus.

It found the rocks curiously

eroded, perhaps by the

corrosive gases, perhaps because the

temperature is so high that

the rocks are partly molten

and sluggishly flow.

The Soviet Venera spacecraft,

their electronics long ago

fried, are slowly corroding on the

surface of Venus.

They are the first spaceships

from Earth ever to land on

another planet.

The reason Venus is like hell

seems to be what's called the

greenhouse effect.

Ordinary visible sunlight

penetrates the clouds and

heats the surface, but the

dense atmosphere

blankets the surface and

prevents it from cooling off

into space.

An atmosphere 90 times as

dense as ours, made of carbon

dioxide, water vapor and other gases,

lets in visible light from

the Sun, but will not let

out the infrared light

radiated by the surface.

So the temperature rises until

the infrared radiation

trickling out to space just balances

the Sunlight reaching the surface.

The greenhouse effect can make

an Earth-like world into a

planetary inferno.

In this cauldron, there is

not likely to be anything

alive, even creatures very

different from us.

Organic and other conceivable

biological molecules would

simply fall to pieces.

The hell of Venus is in

stark contrast with the

comparative heaven of its

neighboring world,

our little planetary home, the Earth.

Here, the atmosphere is 90

times thinner.

Here, the carbon dioxide and

water vapor make a modest

greenhouse effect, which heats the

ground above the freezing

point of water.

Without it, our oceans would

be frozen solid.

A little greenhouse effect is

a good thing.

But Venus is an ominous

reminder that on a world

rather like the Earth, things

can go wrong.

There is no guarantee that

our planet will always be

so hospitable.

To maintain this clement

world, we must understand it

and appreciate it.

The Earth is a place to our

eyes more beautiful than any

other that we know.

The destruction of trees and

grasslands makes the surface

of the Earth brighter.

It reflects more sunlight back

to space and cools our planet.

But after we discovered fire,

we began to incinerate forests

intentionally to clear

the land by a process called

slash-and-burn agriculture.

And today, forests and

grasslands are being destroyed

frivolously, carelessly, by humans

who are heedless of the

beauty of our cousins, the

trees, and ignorant of the

possible climatic

catastrophes which large-scale

burning of forests may bring.

The indiscriminate destruction

of vegetation may alter the

global climate in ways that

no scientist can yet predict.

It has already deadened large

patches of the Earth's

life-supporting skin.

And yet we ravage the Earth

at an accelerated pace, as if

it belonged to this one generation,

as if it were ours to do

with as we please.

The Earth has mechanisms to

cleanse itself,

to neutralize the toxic

substances in its system.

But these mechanisms work only

up to a point.

Beyond some critical threshold,

they break down.

The damage becomes irreversible.

Our generation must choose.

Which do we value more,

short-term profits

or the long-term habitability

of our planetary home?

The world is divided

politically, but ecologically

it is tightly interwoven.

There are no useless threads

in the fabric of the ecosystem.

If you cut any one of them,

you will unravel many others.

We have uncovered other worlds

with choking atmospheres and

deadly surfaces.

Shall we then recreate these

hells on Earth?

We have encountered desolate

moons and barren asteroids.

Shall we then scar and crater

this blooming world in their likeness?

Natural catastrophes are rare,

but they come often enough.

We need not force the hand of nature.

If we ruin the Earth, there

is no place else to go.

This is not a disposable

world, and we are not yet

able to re-engineer the planets.

The cruelest desert on Earth

is far more hospitable than

any place on Mars.

The bright sandy surface and

dusty atmosphere of Mars

reflect enough sunlight back

to space to cool the planet,

freezing out all its water,

locking it in a perpetual ice age.

Human activities brighten our

landscape and our atmosphere.

Might this ultimately make an

ice age here?

At the same time, we are

releasing vast quantities of

carbon dioxide, increasing the

greenhouse effect.

The Earth need not resemble

Venus very closely for it to

become barren and lifeless.

It may not take much to

destabilize the Earth's climate,

to convert this heaven, our

only home in the cosmos, into

a kind of hell.

The study of the global

climate, the Sun's influence,

the comparison of the Earth

with other worlds, these are

subjects in their

earliest stages of development.

They are funded poorly and

grudgingly, and

meanwhile we continue to load

the Earth's atmosphere with

materials about

whose long-term influence we

are almost entirely ignorant.

There are worlds that

began with as much apparent

promise as Earth, but

something went wrong. Knowing

that worlds can die alerts us

to our danger.

If a visitor arrived from

another world, what

account would we give of our

stewardship of the planet Earth?

Spaceflight speaks to something

deep inside us, many of us, if not all.

An emerging cosmic

perspective, an improved

understanding of our place in

the universe, a highly visible

program affecting our view of

ourselves, might clarify the

fragility of our planetary environment

and the common peril and

responsibility of all the

nations and peoples of Earth.

And human missions to Mars

would provide hopeful

prospects, rich in adventure,

for the wanderers

among us, especially the young.

Even vicarious exploration has

social utility.

It's no accident that whatever

their human flaws, and however

moribund the human space

program has become, astronauts

and cosmonauts are still

widely regarded as heroes of

our species.

A scientific colleague tells

me about a recent trip to

the New Guinea highlands, where she

visited a Stone Age culture

hardly contacted by

Western civilization.

They were ignorant of

wristwatches, soft drinks,

frozen food, but they knew

about Apollo 11.

They knew that humans had

walked on the Moon.

They knew the names of

Armstrong and Aldrin and Collins.

They wanted to know who was

visiting the Moon these days.

Winning a foothold on other

worlds whispers in our ears

that we're more than Picts,

or Serbs, or Tongans. We're humans.

Exploratory spaceflight puts

scientific ideas, scientific

thinking, and scientific

vocabulary in the public eye.

It elevates the general level

of intellectual inquiry.

The idea that we've now

understood something never

grasped by anybody who ever

lived before,

that exhilaration, especially

intense for the scientists

involved but perceptible to

nearly everybody, propagates

through the society, bounces

off walls, and comes back at us.

It encourages us to address

problems in other fields that

have also never been solved.

It increases the general sense

of optimism in the society.

It gives currency to critical

thinking of the sort urgently

needed if we're going to

solve hitherto intractable

social issues.

It helps stimulate a new

generation of scientists.

The more science in the

media, the healthier, I

believe, the society is.

Just people everywhere, hunger

to understand.

When I was a child, my most

exultant dreams were about flying.

Not in some machine, but all by myself.

I'd be skipping or hopping,

and slowly I could pull my

trajectory higher.

It would take longer to fall

back to the ground.

and soon I'd be on such a

high arc that I wouldn't come

down at all.

I would alight like a

gargoyle
in a niche near the

pinnacle of a skyscraper, or I'd

gently settle down on a cloud.

In the dream, which I must

have had in its many

variations at least a hundred times,

achieving flight required a

certain cast of mind.

It's impossible to describe it

in words, but I can remember

what it was like, to this day.

You did something inside your

head and at the pit of your

stomach, and then you could lift

yourself up by an effort of

will alone, your limbs hanging

limply, off you'd soar.

I know many people have had

similar dreams, maybe most

people, maybe everyone.

Perhaps it goes back 10

million years or more, when

our ancestors were gracefully

flinging themselves from branch

to branch in the primeval forest.

A wish to soar like the

birds motivated many of the

pioneers of flight, including

Leonardo da Vinci and the

Wright brothers.

Maybe that's part of the

appeal of spaceflight too.

In orbit around any world, or

in interplanetary flight,

you're literally weightless.

You can propel yourself to

the spacecraft ceiling with a

slight push off the floor.

You can go tumbling through

the air down the long axis

of the spacecraft.

Humans experience weightlessness

as joy.

This has been reported by

almost every astronaut and cosmonaut.

But because spacecraft are

still so small, and because

space walks have been done with

extreme caution, no human has

yet enjoyed this wonder and

glory, propelling yourself

by an almost imperceptible

push, with no machinery

driving you, untethered,

eventually with no

spacecraft in sight, high up

into the sky, into the

blackness of interplanetary space.

You become a living satellite

of the Earth, or a human

planet of the Sun.

Planetary exploration satisfies

our inclination for great

enterprises and wanderings and quests

that has been with us since

our days as hunters and

gatherers on the East African savannas

a million years ago. By chance.

It is possible, I say, to

imagine many skeins of historical

causality in which this would

not have transpired.

In our age, we're able to begin again.

Exploring

other worlds employs precisely

the same qualities of daring,

planning, cooperative enterprise,

and valor that mark the

finest in the military tradition.

Never mind the night launch of

Apollo spacecraft bound for

another world, that makes the

conclusion foregone.

Witness mere F-14s taking off

from adjacent flight decks,

gracefully canting left and

right after burners flaming,

and there's something that

sweeps you away, or at least

it does me.

And no amount of knowledge of

the potential abuses of

carrier task forces can affect the

depth of that feeling.

It simply speaks to another part of me.

It doesn't want recriminations

or politics.

It just wants to fly.

The philosopher Bertrand

Russell, in 1959, wrote as follows.

The future possibilities of

space travel, which are now

left mainly to unfounded fantasy,

could be more soberly treated,

without ceasing to be

interesting, and could show to even

the most adventurous of the

young that a world without

war need not be a world without

adventurous and hazardous glory.

To this kind of contest there

is no limit.

Each victory is only a

prelude to another, and no

boundaries can be set to rational hope.

Russell's phrase is noteworthy,

adventurous and hazardous glory.

Even if we could make human

spaceflight risk-free, and of

course we can't, it might

be counterproductive.

The hazard is an inseparable

component of the glory.

In the meantime, the most

important step we can take

toward Mars is to make significant

progress on Earth.

Even modest improvements in

the social, economic, and

political problems that our

global civilization now faces

could release enormous

resources, both material and

human, for other goals.

There's plenty of housework to

be done down here on Earth,

and our commitment to it must

be steadfast.

But we're the kind of species

that needs a frontier,

for fundamental biological reasons.

Every time humanity stretches

itself and

turns a new corner, it

receives a jolt of productive

vitality that can carry it

for centuries.

There's a new world next door

and we know how to get there.

The Voyager spacecraft are

bound for the stars.

They're on escape trajectories from

the solar system barreling

along at almost a million miles a day.

The gravitational fields of

Jupiter, Saturn, Uranus and

Neptune have flung them at such

high speeds that they've

broken the bonds that once

tied them to the Sun.

Have they left the solar system yet?

The answer depends very much

on how you define the

boundary of the Sun's realm.

If you define the outer

limits of the solar system as

the heliopause, where the

interplanetary

particles and magnetic fields

are replaced by their

interstellar counterparts, then neither

voyager has yet left the

solar system, although they

may do so in the next few decades.

But if your definition of the

edge of the solar system is

the distance at which our

stark and no longer hold

worlds in orbit around it,

then the Voyagers will not leave

the solar system for hundreds

of centuries.

Weakly grasped by the Sun's

gravity in every

direction in the sky is that

immense horde of a trillion

comets or more, the Oort Cloud.

The two Voyager spacecraft

will finish their passage

through the Oort Cloud in another

20,000 years or so.

Then at last, completing their

long goodbye to the

solar system, broken free of

the gravitational shackles that

once bound

them to the Sun, the Voyagers

will make for the open sea

of interstellar space.

Only then will phase two of

their mission begin.

Their radio transmitters

long dead, the spacecraft will

wander for ages in the calm,

cold, interstellar blackness,

where there is almost nothing

to erode them.

Once out of the solar system,

they will remain

intact for a billion years or

more, as they circumnavigate

the center of the Milky Way galaxy.

We do not know whether there

are other spacefaring

civilizations in the Milky Way.

If they do exist, we don't

know how abundant they

are, much less where they are.

But there is at least a

chance that sometime in

the remote future, one of the

Voyagers will be intercepted

and examined by an alien craft.

Accordingly, as each Voyager

left Earth for the planets and the

stars, it carried with it a

golden phonograph record,

encased in a golden mirrored jacket,

containing, among other things,

greetings in 59 human

languages, and one whale language,

a 12-minute sound essay,

including a kiss, a baby's

cry, and an EEG record of

the meditations

of a young woman in love.

116 encoded pictures on our

science, our civilization,

and ourselves.

And 90 minutes of the Earth's

greatest hits.

Eastern and

Western, classical and folk,

including a Navajo night

chant, a Japanese shakuhachi

piece, a pygmy girl's

initiation song, a Peruvian

wedding song, a 3,000 year old

composition for the chin

called Flowing Streams, Bach,

Beethoven, Mozart,

Stravinsky, Louis Armstrong,

Blind Willie Johnson, and

Chuck Berry's Johnny B.

Goode. Space is nearly empty.

There's virtually no chance

that one of the Voyagers will

ever enter another solar system.

And this is true even if

every star in the sky is

accompanied by planets.

The instructions on the record

jackets, written in what we believe

to be readily comprehensible

scientific hieroglyphics, can

be read and the contents of

the records understood.

Only if alien beings somewhere

in the remote future find

Voyager in the depths

of interstellar space.

Since both Voyagers will

circle the center of the

Milky Way galaxy essentially forever.

There's plenty of time for

the records to be found, if

there's anyone

out there to do the finding.

We can't know how much of

the records they would understand.

Surely the greetings would be

incomprehensible, but their

intent may not be. We thought it

would be impolite not to say hello.

The hypothetical aliens are

bound to be very different from

us, since they're independently

evolved in another world, are

we really sure they

can understand anything at all

of our message? Every time I feel these

concerns

stirring though, I reassure myself.

Whatever the

incomprehensibilities of the

Voyager record, any alien ship

that finds it will have

another standard by

which to judge us, because

each Voyager is itself a message.

In their exploratory intent,

in the lofty ambition of

their objectives, in their

utter lack of intent to do harm,

and in the brilliance of

their design and performance,

these robots speak eloquently for us.

But being much more advanced

scientists and engineers than we,

otherwise they'd never be able

to find and retrieve the small, silent

spacecraft in interstellar space.

Perhaps
the aliens would have no

difficulty understanding what

is encoded on these golden records.

Perhaps they

would recognize the

tentativeness of our society,

the mismatch between our

technology and our wisdom.

Had we destroyed ourselves

since launching Voyager, they

might wonder, or have we gone

on to greater things?

Or perhaps the records will

never be intercepted.

Perhaps no one in five

billion years will ever come upon them.

Five billion years is a long time.

In five billion years, all

humans will have become

extinct or evolved into other beings.

None of our artifacts will

have survived on Earth.

The continents will have

become unrecognizably altered

or destroyed,

and the evolution of the Sun

will have burned the Earth to a crisp,

or reduced it to a world of adults.

and far from home, untouched

by these remote events, the

voyagers, bearing the

memories of a world that is

no more, will fly on.

The Sun is the nearest star, a

glowing sphere of gas, shining

because of its heat, like a

red-hot poker.

The
surface we see in ordinary

visible light is at 6,000

degrees centigrade, but in its

hidden interior, in the

nuclear furnace where sunlight

is ultimately generated, its

temperature

is 20 million degrees.

All this churning power is

driven by the Sun's interior, which is

converting 400 million tons of

hydrogen into helium every second.

The Sun is a great fusion

reactor into which a million

Earths would fit.

Luckily for us it's safely

placed 150 million kilometers away.

It is the destiny of stars

to collapse but on

their ways to their separate

fates all stars experience a

premonition of death.

Before the final gravitational

collapse, the star shudders,

briefly swells into some grotesque

parody of itself.

With its last gasp, it

becomes a red giant.

Some five billion years from

now, there will be a last

perfect day on Earth.

Then, the Sun will slowly

change, and the Earth will die.

There is only so much

hydrogen fuel in the Sun,

when it's almost all converted

to helium,

the solar interior will

continue its original collapse,

the higher temperatures in its core

will make the outside of the

Sun expand, and the Earth

will become slowly warmer.

Eventually, life will be

extinguished, the oceans will

evaporate and boil, and our atmosphere

will gush away to space.

The Sun will become a bloated

red giant star, filling the

sky, enveloping and devouring

the planets Mercury and Venus,

and probably the Earth as well.

The inner solar system will

reside inside the Sun, but

perhaps by then our descendants

will have ventured somewhere else.

In its final agonies, the Sun

will slowly pulsate.

By then, its core will have

become so hot that it

temporarily converts helium

into carbon.

The ash from today's nuclear

fusion will become the fuel

to power the Sun near the end of

its life, in its red giant stage.

Then the Sun will lose great

shells of its outer atmosphere

to space, filling the solar

system with eerily glowing

gas, the ghost of a star outward bound.

Perhaps half the mass of the

Sun will be lost in this way.

Viewed from elsewhere, our system

will then resemble the Ring

Nebula in Lyra, the atmosphere

of the Sun expanding outward

like a soap bubble.

And at the very center will

be a white dwarf, the hot

exposed core of the Sun, its

nuclear fuel now exhausted,

slowly cooling to become a

cold, dead star. Such is the life of an

ordinary star, born in a gas cloud,

maturing as a yellow sun,

decaying as a red giant, and

dying as a white dwarf

enveloped in its shroud of gas.

The cosmos was originally all

hydrogen and helium.

Heavier elements were made in

red giants and supernovas

and then blown off to space,

where they were available for

subsequent generations

of stars and planets.

Our Sun is probably a third

generation star.

Except for hydrogen and helium,

every atom in the Sun and the Earth

was synthesized in other stars.

The silicon in the rocks, the

oxygen in the air, the carbon

in our DNA, the gold in our

banks, the uranium in our

arsenals, were all made

thousands of light years away

and billions

of years ago.

Our planet, our society, and

we ourselves are built of star stuff.

The lives and deaths of the

stars seem impossibly remote

from human experience, and yet we're

related in the most intimate

way to their life cycles.

The very matter that makes us

up was generated

long ago and far away in red

giant stars.

A blade of grass, as Walt Whitman said,

is the journey work of the stars.

The formation of the solar

system may have been triggered

by a nearby supernova explosion.

After the Sun turned on its

ultraviolet light

poured into our atmosphere,

its warmth generated lightning,

and these energy sources

sparked the origin of life.

Plants harvest sunlight,

converting solar into chemical energy.

We and the other animals are

parasites on the plants, so

we are, all of us, solar-powered.

The evolution of life is

driven by mutations, their

cause partly by natural radioactivity

and cosmic rays, but they are

both generated in the

spectacular deaths of massive stars

thousands of light-years distant.

Think of the Sun's heat on

your upturned face on a

cloudless summer's day.

From 150 million kilometers

away, we recognize its power.

What would we

feel on its seething

self-luminous surface or

immerse in its heart of nuclear fire?

And
And yet, the Sun is an

ordinary, even a mediocre star.

Our ancestors worshipped the

Sun and they were far from foolish.

It makes good sense to revere

the Sun and the stars,

because we are their children.

We have witnessed the life

cycles of the stars.

They are born, they mature,

and then they die.

As time goes on, there are

more white dwarfs, more

neutron stars, more black holes.

The remains of the stars

accumulate as the eons pass.

But interstellar space also

becomes progressively enriched

in heavy elements,

out of which form new

generations of stars and

planets, life and intelligence.

The events in one star can

influence a world halfway

across the galaxy and a

billion years in the future.

Surrounding the Milky Way is

a halo of matter, which

includes the globular clusters, each

containing up to a million

elderly stars.

At the centers of globular

clusters and at the core of

the galaxy, there may be massive

black holes ticking and

purring, the subject of

future exploration.

We on Earth marvel, and

rightly so, at the daily

return of our single sun.

But from a planet orbiting a

star in a distant globular

cluster, a still more glorious

dawn awaits.

Not a sunrise, but a galaxy rise.

A morning filled with 400

billion suns, the rising of

the Milky Way.

An enormous spiral form with

collapsing gas clouds,

condensing planetary systems, luminous

supergiants, stable middle-aged

stars, red giants, white

dwarfs, planetary nebulas, supernovas,

neutron stars, pulsars, black

holes, and, there is every

reason to think, other exotic

objects that we have not

yet discovered.

From such a world high above

the disk of the Milky Way,

it would be clear, as it is beginning

to be clear on our world,

that we are made by the

atoms and the stars, that our matter

and our form are determined

by the cosmos of which we are a part.

Here we are in the

constellation Andromeda.

This star is Beta Andromedae.

The light by which we see

this star has spent 75 years

traversing interstellar space on

its journey to the Earth.

In the unlikely event that

Beta Andromedae blew itself up

a week ago Tuesday, we will

not know of it for another

75 years as this interesting

information traveling at the speed

of light crosses the enormous

interstellar distances.

When the light we see from

the star set out on its long

interstellar voyage, the young

Albert Einstein, working as a

Swiss patent clerk, had just

published his epical special

theory of relativity here on Earth.

We see that space and time

are intertwined.

we cannot look out into space

without looking back into time.

The speed of

light is very fast but space

is very empty and the stars

are very far apart.

In fact the distances that

we've been talking about up

to now are very small

by the usual astronomical standards.

In fact the distance from the

Earth to the

center of the Milky Way

galaxy is 30,000 light-years.

From our galaxy to the

nearest spiral galaxy like our

own, called M31, is two

million light-years.

When the light we see today

from M31 left on its journey

for Earth, there were

no human beings on the Earth,

although our ancestors were

nicely evolving and

very rapidly to our present form.

There are much greater

distances in astronomy. The distance

from the Earth to the most

distant quasars is 8 or 10

billion light
years. We see them

as they were before the Earth

itself accumulated, before the

Milky Way galaxy was formed. The

fastest space vehicles ever

launched by the human species

are the Voyager spacecraft.

They are traveling so fast

that it's only 10,000 times

slower than the speed of light.

The Voyager spacecraft will

take 40,000 years to go the

distance to the nearest stars, and

they're not even headed

towards the nearest stars.

But is there a method by

which we could travel in a

conveniently short time to the stars?

Can we travel close to the

speed of light?

And what's magic about the

speed of light?

Can't we travel faster than that?

It turns out that there is

something very strange about

the speed of light.

Something that provides the

key to our understanding of

time and space.

If the world is to be

understood, if we are to

avoid logical paradoxes when travelling

at high speeds, then there

are certain rules which must be obeyed.

Einstein called these rules

the special theory of relativity.

Light from a moving object

travels at the same speed

no matter whether the object

is at rest or in motion.

Thou shalt not add my speed

to the speed of light.

Also, no material object can

travel at or beyond the speed of light.

There's nothing in physics

that prevents you from traveling

as close to the speed of

light as you like.

99.9% the speed of light is just fine.

But no matter how hard you try,

you can never gain that last

decimal point.

For the world to be logically

consistent,

there must be a cosmic speed limit.

The most bizarre aspect of

traveling near the speed of light

is that time slows down.

All clocks, mechanical and biological,

tick more slowly near the

speed of light.

But stationary clocks tick at

their usual rate.

If we travel close to light

speed, we age more slowly

than those we left behind.

Today, we have preliminary

designs of ships which will

take people to the stars.

They are constructed in Earth

orbit, and from there, they

venture on their great

interstellar journeys.

One of them is called Project Orion.

It utilizes nuclear weapons,

hydrogen bombs, against an

inertial plate,

each explosion providing a

kind of putt-putt of vast

nuclear motorboat in space.

Orion seems entirely practical

and was under serious

development in the United States

until the signing of the

international treaty forbidding

nuclear weapons explosions in space.

Orion might go 10% the speed of light.

So a trip to Alpha Centauri,

four and a half light years

away, would take 45 years,

less than a human lifetime.

Such ships could not travel

close enough to the speed of light

for the time-slowing effects

of special relativity to

become important.

It does not seem likely that

such ships would be built

before the middle of the 21st century,

although we could build an

Orion starship now.

For voyages beyond the nearest

stars, something must be added.

Perhaps they could be used as

multi-generation ships,

so those arriving would be

the remote descendants of

those who had originally set

out centuries before.

Or perhaps some safe means of

human hibernation might be found,

so that the space travelers

might be frozen and then

bought out when they arrive

at the destination centuries later.

But fast interstellar space

flight, approaching the speed

of light, is much more difficult.

That's an objective not for a

hundred years, but for a

thousand, or for ten thousand.

But it also is possible.

A kind of interstellar ramjet

has been proposed,

which scoops up the hydrogen

atoms which float between the stars,

accelerates them into an

engine, and spits them out the back.

For most of the trip, the

velocity would be very close

to the speed of light,

and time would slow down enormously.

By how much?

Barnard's star could be

reached by such a ship

in eight years' ship time.

The center of the Milky Way

galaxy in 21 years.

The Andromeda galaxy in 28 years.

Of course, the people left

behind on the Earth

would see things somewhat differently.

Instead of 21 years to the

center of the galaxy,

they would measure it as 30,000 years.

When we got back, very few

of our friends would

be around to greet us.

In principle, such a journey,

mounting the decimal points closer

and closer to the speed of

light, would even permit us

to circumnavigate the known universe

in 56 years ship time.

We would return tens of

billions
of years in the far

future with the Earth a

charred cinder and the Sun dead.

Relativistic space

flight makes the universe

accessible to advanced

civilizations but only to those

who go on the journey, not

to those who stay home.

These designs are probably further

from the actual interstellar

spacecraft of the future

than Leonardo's models are

from the supersonic transports

of the present.

But if we do not destroy ourselves,

I believe that we will one

day venture to the stars.

When our solar system is all explored,

the planets of other stars will beckon.

Even when our descendants are

established on near-Earth

asteroids and Mars

and the Moons of the outer

solar system and the Kuiper comet belt,

it still won't be entirely safe.

In the long run, the Sun may

generate stupendous X-ray and

ultraviolet outbursts.

The solar system will enter

one of the vast interstellar clouds

lurking nearby, and the

planets will darken and cool.

A shower of deadly

comets will come roaring out

of the Oort cloud, threatening

civilizations on many adjacent worlds.

We will recognize that a

nearby star is about to

become a supernova.

And in the really long run,

the Sun, on its way to

becoming a red giant

star will get bigger and brighter.

The Earth will begin to lose

its air and water to space.

The soil will char.

The oceans will evaporate and boil.

The rocks will vaporize. And our

planet may even be swallowed

up into the interior of the Sun.

Far from being made for us, eventually

the solar system will become

too dangerous for us.

In the long run, putting

all our eggs in a single

stellar basket, no matter how

reliable the solar system

has been lately, may be too risky.

In the long run, as

Tsiolkovsky and Goddard

long ago recognized, we need

to leave the solar system.

Such a future would, I think,

naturally evolve by slow

increments, even without any

grand goal of interstellar travel.

Here's how it might work.

For safety, some communities may

wish to sever their ties with

the rest of humanity,

uninfluenced by other

societies, other ethical codes,

other technological imperatives.

In a time when comets and

asteroids are being routinely

repositioned, we will

be able to populate a small

world and then cut it loose.

In successive generations, as

this world sped outward, the

Earth would fade from bright

star to pale dot to invisibility.

The Sun would appear dimmer

until it was no more than a

vaguely yellow point of light lost

among thousands of others.

The travelers would approach

interstellar night.

Some
such communities may be

content with occasional radio

and laser traffic with

the old home worlds.

Others, confident of the

superiority of their own survival

chances and wary of

contamination, may try to disappear.

Perhaps all contact

with them will ultimately be

lost, their very existence forgotten.

Even the resources of a

sizeable asteroid or comet are

finite, and eventually more resources

must be sought elsewhere,

especially water needed for

drink, for a breathable oxygen

atmosphere and for hydrogen to

power fusion reactors.

So, in the long run, these

communities must migrate from

world to world with no lasting

loyalty to any.

We might call it pioneering

or homesteading.

A less sympathetic observer

might describe it as sucking

dry the resources of little

world after little world.

But there are a trillion

little worlds in the Oort Comet Cloud.

Living in small numbers on a

modest stepmother world, far

from the Sun, we will know that

every scrap of food and every

drop of water is dependent on

the smooth operation of a

farsighted technology.

But these conditions are not

radically unlike those to

which we are already accustomed.

Digging resources out of the

ground and stalking passing

resources seems oddly familiar,

like a forgotten memory of childhood.

It is, with a few significant

changes, the strategy of our

hunter-gatherer ancestors.

For 99.9% of the tenure of

humans on Earth we lived such a life.

Judging from some of the last

surviving hunter-gatherers, just

before they were engulfed by

the present global civilization,

we may have been relatively happy.

It's the kind of life that forged us.

So, after a brief, only

partially successful, sedentary

experiment, we may become

wanderers again.

More technological than last

time, but even then, our

technology, stone tools and

fire was our only hedge

against extinction.

I don't know where my train

of argument ends.

As more time passes,

attractive new denizens of the

cosmic zoo will draw us

further outward,

hard, and increasingly

improbable and deadly

catastrophes must come to pass.

The probabilities are

cumulative, but as time goes

on, technological species will

also accrue

greater and greater powers,

far surpassing any we can

imagine today.

Perhaps if we're very

skillful—lucky, I think, won't

be enough—we will ultimately

spread far from home, sailing

through the starry archipelagos

of the vast Milky Way galaxy.

Even a modest extrapolation of

our recent advances in

transportation suggests that in

only a few centuries we will

be able to travel close to

the speed of light.

Perhaps this is hopelessly optimistic.

Perhaps it will really take

millennia or more.

But unless we destroy ourselves first,

we will be inventing new

technologies as strange to us,

as Voyager might be to our

hunter-gatherer ancestors.

Even today we can think of ways,

clumsy, ruinously expensive,

inefficient to be sure,

of constructing a starship

that approaches light speed.

In time, the designs will

become more elegant, more

affordable, more efficient.

The day will come when we

overcome the necessity of

jumping from comet to comet,

we will begin

to soar through the light

years and, as St.

Augustine said of the gods of the

ancient
Greeks and Romans, colonize the sky.

Such descendants may be tens

or hundreds of generations

removed from anyone who ever lived

on the surface of a planet.

Their cultures will be

different, their technologies

far advanced, their languages

changed, their

association with machine

intelligence much more

intimate, perhaps their very

appearances

markedly altered from that of

their nearly mythical ancestors

who first tentatively set forth in the

late 20th century into the

sea of space.

But they will be human, at

least in large part. They will

be practitioners of high technology.

They will have historical records.

Despite Augustine's

judgment on Lot's wife that

no one who is being saved

should long for what he is leaving.

They will not wholly forget the Earth.

In modern western society,

writes the scholar Charles

Lindholm, the erosion of tradition

and the collapse of accepted

religious belief leaves us

without a telos, an end to which

we strive, a sanctified notion

of humanity's potential.

Bereft of a sacred project,

we have only a demystified

image of a frail and fallible

humanity no longer capable of

becoming godlike."

I believe it's healthy, indeed

essential, to keep our frailty

and fallibility firmly

in mind, and I worry about

people who aspire to be god-like.

But as for a long-term goal,

and a sacred project, there

is one before us.

On it, the very survival of

our species depends.

If we've been locked and

bolted into a prison of the

self, here is an escape hatch.

something worthy, something

vastly larger than ourselves,

a crucial act on behalf of humanity.

Peopling other worlds unifies

nations and ethnic groups,

binds the generations,

and requires us to be both

smart and wise.

It liberates our nature and, in part,

returns us to our beginnings.

Even now, this new telos is

within our grasp.

In 1633, the Roman Catholic

Church condemned Galileo for

teaching that the Earth goes

around the Sun.

Let's take a closer look at

this famous controversy.

In the preface to his

book comparing the two

hypotheses, an Earth-centered

and a Sun-centered universe,

Galileo had written

In these words, the celestial

phenomena will be examined,

strengthening the Copernican

hypothesis until it might seem

that this must triumph absolutely.

And later in the book he

confessed, Nor can I ever

sufficiently admire Copernicus

and his followers.

They have, through sheer force

of intellect, done such

violence to their own senses as

to prefer what reason told

them over what sensible

experience plainly showed them.

The Church declared, in its

indictment of Galileo, the

doctrine that the Earth is neither

the center of the universe

nor immovable, but moves even

with a daily rotation, is absurd,

and both psychologically and

theologically false, and at

the least an error of faith.

Galileo replied, The doctrine

of the movements of the Earth

and the fixity of the Sun is

condemned on the ground that

the scriptures
speak in many

places of the Sun moving and

the Earth standing still.

It is piously spoken that the

scriptures cannot lie, but

none will deny that they are frequently

abstruse and their true

meaning difficult to discover

and more than the bare words signify.

I think that in the

discussion of natural problems

we ought to begin not with

the Scriptures,

but with experiments

and demonstrations.

But in his recantation on

June 22, 1633, Galileo was

made to say these words,

having been admonished

by the Holy Office entirely

to abandon the false opinion

that the Sun was the center

of the universe and immovable,

and that the Earth was not

the center of the same, and

that it moved, I have been

suspected of heresy, that is,

of having held and believed that

the Sun is the center of the

universe and immovable, and

that the Earth is not the center

of the same, and that it does move.

I abjure with a sincere heart

and unfeigned faith.

I curse and detest the same

errors and heresies, and

generally all and every error and sect

contrary to the Holy Catholic Church.

It took the Church until 1832

to remove Galileo's work from

its list of books which Catholics

were forbidden to read at the

risk of dire punishment of

their immortal souls.

To its credit, although

belatedly and reluctantly, the

Church in 1992 repudiated its

denunciation of Galileo.

It still cannot quite bring

itself, though, to see the

significance of its opposition.

In a 1992 speech, Pope John

Paul II argued as follows.

From the beginning of the Age

of Enlightenment, he said,

down to our own day, the Galileo

case has been a sort of

myth, in which the image

fabricated out of the events is quite

far removed from reality.

In this perspective, the

Galileo case was a symbol of

the Catholic Church's supposed

rejection of scientific

progress, or of dogmatic

obscurantism opposed to the

free search for

truth."

But surely the Holy

Inquisition, ushering the

elderly and infirm Galileo in

to inspect

the instruments of torture in

the dungeons of the Church

not only admits, but requires

just such an interpretation.

This was not mere scientific

caution and restraint, a

reluctance to shift the

paradigm until compelling

evidence such as the annual

parallax was available.

This was fear of discussion

and debate, censoring

alternative views and

threatening to torture

their proponents, betray a

lack of faith in the very

doctrine and parishioners that are

ostensibly being protected?

Why were threats and Galileo's

house arrest needed?

Can a truth defend itself in

its confrontation with error?

The Pope does, though, go on

to add, The error of the

theologians of the time, when they

maintained the centrality of

the Earth, was to think that

our understanding of the physical

world structure was in some

way imposed by the literal

sense of sacred scriptures."

But if the Bible is not

everywhere literally true,

which parts are divinely inspired and

which are merely fallible and human?

As soon as we admit that

there are scriptural mistakes

or concessions to the ignorance of

the times, then how can the

Bible be an inerrant guide to

ethics and morals?

Might sects and individuals

now accept as authentic the

parts of the Bible they like,

and reject those that are

inconvenient or burdensome?

We lack consensus about our

place in the universe.

There is no generally

agreed-upon, long-term vision

of the goal of our species, other than

perhaps simple survival.

Especially when times are

hard, we become desperate for

encouragement, unreceptive to

the litany of great demotions

and dashed hopes, and much

more willing to hear that

we're special,

never mind if the evidence is

paper thin.

If it takes a little myth

and ritual to get us through

a night that seems endless, who

among us cannot sympathize

and understand?

But if our objective is deep

knowledge rather than shallow

reassurance, the gains from this

new perspective far outweigh

the losses.

circumstances.

The scientific revolution

permitted us to glimpse an

underlying, ordered universe in

which there was a literal

harmony of the worlds.

If we understand nature, there

is a prospect of controlling

it, or at least mitigating

the harm it may bring.

In this sense, science brought hope.

Most of the great

deprovincializing debates were

entered into with no thought

for their practical implications.

Passionate and curious humans

wish to understand their

actual circumstances,

how unique or pedestrian they

in their world are,

their ultimate origins and

destinies, how the universe works.

Surprisingly, some of these

debates have yielded the most

profound practical benefits.

The very method of

mathematical reasoning that

Isaac Newton introduced

to explain the motion of the

planets around the Sun

has led to most of the

technology of our modern world.

The Industrial Revolution, for

all its shortcomings,

is still the global model of

how an agricultural nation can

emerge from poverty.

These debates have

bread-and-butter consequences.

It might have been otherwise.

It might have been that the

balance lay elsewhere,

that humans by and large did

not want to know about a

disquieting universe,

universe, that we were

unwilling to permit challenges

to the prevailing wisdom.

Despite determined resistance

in every age, it is very

much to our credit that we have

allowed ourselves to follow

the evidence, to draw

conclusions that at first

seemed daunting.

A universe so much larger and

older, that our personal and

historical experience is

dwarfed and humbled.

A universe in which every day

suns are born and worlds

obliterated, a universe in which

humanity, newly arrived, clings

to an obscure clod of matter.

In everyday life we often

sense, in the bedrooms of

teenagers or in national politics, that

chaos is natural and order

imposed from above.

While there are deeper

irregularities in the universe

than the simple circumstances we

generally described as orderly,

all that order, simple and

complex, seems to derive from laws

of nature established at the

Big Bang, or maybe earlier,

rather than as a consequence

of belated intervention by an

imperfect deity.

God is to be found in the

details, is the famous dictum

of the German scholar Aby Warburg.

But, amid much elegance and

precision, the details of life

in the universe also exhibit

haphazard, jury-rigged

arrangements and much poor planning.

What shall we make of this?

An edifice abandoned early in

construction by the architect?

The evidence, so far at

least, and laws of nature

aside, does not require a designer.

Maybe there's one hiding,

maddeningly unwilling to be revealed.

Sometimes it seems a very slender hope.

The cosmic calendar compresses

the local history of the

universe into a single year.

If the universe began on

January 1st, it was not until

May that the Milky Way formed.

Other planetary systems may

have appeared in June, July and August,

but our Sun and Earth not

until mid-September.

Life arose soon after.

Everything humans have ever

done occurred in that bright

speck at the

lower right of the cosmic calendar.

The Big Bang is at upper

left in the first

second of January 1st.

Fifteen billion years later is

our present time, the last

second of December 31st.

Every month is one and a

quarter billion years long.

Each day represents 40 million years.

Each second stands for some

500 years of our history, the

blinking of an eye in the drama

of cosmic time.

At this scale, the cosmic

calendar is the size of a

football field, but all of human

history would occupy an area

the size of my hand.

We're just beginning to trace the

long and tortuous path which

began with the primeval

fireball and led to the

condensation of matter, gas,

dust, stars, galaxies, and at

least in our little

nook of the universe, planets

and life, intelligence and

inquisitive men and women.

We've emerged so

recently that the familiar

events of our recorded history

occupy only the last seconds

of the last minute of December 31st.

Some critical events for the

human species, however, began

much earlier, minutes earlier.

The secrets of evolution are

time and death, time for the

slow accumulation of favorable

mutations and death to make

room for new species.

Life on Earth arose in

September of the cosmic calendar...

...when our world, still

heavily battered and cratered

from its violent origin...

...may have looked a little

like the Moon.

The Earth is about four and

a half billion years old.

In the cosmic calendar, it

condensed out of interstellar

gas and dust...

...around September 14th.

We know from the fossil

record that the origin of

life happened soon afterwards...

...maybe around September 25th,

something like that...

...probably in the ponds and

oceans of the primitive Earth.

Now, the first living things

were not anything so complex

as a one-celled organism...

...which already is a highly

sophisticated form of life.

No, the first stirrings of

life were much more humble...

...and happened on the molecular level.

In those early days, lightning

and ultraviolet light from the Sun...

...were breaking apart simple

hydrogen-rich molecules in the

primitive atmosphere...

...and the fragments of the

molecules were

spontaneously recombining...

...into more and more

complex molecules.

The products of this early

chemistry dissolved in the oceans...

...forming a kind of organic

soup of gradually

increasing complexity...

...until one day, quite by accident...

...a molecule arose which was

able to make crude copies of

itself, using as building

blocks the other molecules in the soup.

This was the ancestor of DNA,

the master molecule of life on Earth.

It's made of four different

molecular parts called

nucleotides, which constitute the four

letters of the genetic code,

the language of heredity.

Each of the four nucleotides,

the rungs on the DNA ladder,

are a different color in this model.

The instructions that are

spelled out are different for

different organisms.

That's why organisms are different.

Now, a mutation is a change

of a nucleotide,

a misspelling of the

genetic instructions.

Most mutations spell genetic

nonsense, as you'd expect,

because they're random.

They're harmful for the

next generation.

...but a very few, by

accident, make better sense

than the original instructions...

...and aid the evolution of life.

DNA is about a billion times

smaller than we see it here.

In fact, each of these things

that looks like a piece of

fruit is an atom.

Without the tools of science,

the machinery of life would

be invisible.

Four billion years ago, the

ancestors of DNA were

competing for molecular building blocks

and leaving crude copies of themselves.

There were no predators, the

stuff of life was everywhere,

so the oceans and the murky

pools that filled the craters

were for these molecules a

Garden of Eden.

With reproduction, mutation and

natural selection, the

evolution of living molecules

was well underway.

Varieties with specialized functions

then joined together, making a

collective,

the first cell.

The organic soup eventually

ate itself up.

But by this time, plants had evolved,

able to use sunlight to make

their own building blocks.

They turned the waters green.

A number of one-celled plants

joined together,

the first multicellular organisms.

Equally important was the

invention, not made until

early November, of sex.

It was stumbled upon by the microbes.

By December 1st, green plants

had released copious amounts

of oxygen and nitrogen into

the atmosphere.

The sky is made by life.

Then, suddenly, on December 15th,

there was an enormous

proliferation of new life forms,

an event called the Cambrian Explosion.

By December 18th, there were

vast herds of trilobites

foraging on the ocean bottom,

and squid-like creatures with

their multicolored shells

were everywhere.

We know enough to sketch in

a few of the subsequent details,

The first fish and the first

vertebrates appeared on December 19th.

Plants began to colonize the

land on December 20th.

The first winged insects

fluttered by on December 22nd.

And on this date also, there

were the first amphibians,

creatures something like the lungfish,

able to survive both on land

and in water.

Our direct ancestors were now

leaving the oceans behind.

The first trees and the first

reptiles evolved on December

23rd, two amazing

evolutionary developments.

We're descended from some of

those reptiles.

The dinosaurs appeared on

Christmas Eve.

There were many different

kinds of dinosaurs.

The Earth was once their planet.

Many stood upright and had

some fair intelligence.

Great lizards crashed and

thundered through the steaming jungles.

Unnoticed by the dinosaurs, a

new creature,

whose young were born live

and helpless,

was making its timid debut.

The first mammals emerged on

December 26th,

the first birds on the following day.

But the dinosaurs still

dominated the planet.

Then, suddenly, without

warning, all over the planet at once,

the dinosaurs died.

The cause is unknown, but the

lesson is clear.

Even 160 million years on a

planet is no guarantee of survival.

The dinosaurs perished around

the time of the first flower.

On December 30th, the first

creatures who looked even a

little bit human evolved,

accompanied by a spectacular

increase in the size of their brains.

...and then, on the evening

of the last day of the last

month, only a few million years

ago, the first true humans

took their place on the

cosmic calendar.

We humans appear on the

cosmic calendar so recently

that our recorded history occupies

only the last few seconds of

the last minute of December 31st.

in the vast ocean of time

which this calendar represents.

All our memories are confined

to this small square.

Every person we've ever heard

of lived somewhere in there.

All those kings and battles,

migrations and inventions,

wars and loves, everything in

the history books

This happens here, in the

last 10 seconds of the cosmic calendar.

We on Earth have just

awakened to the great oceans

of space and time from which

we have emerged.

We are the legacy of 15

billion years of cosmic evolution.

We have a choice.

We can enhance life and come

to know the universe that

made us, or we can squander

our 15 billion

billion year heritage in

meaningless self-destruction.

What happens in the first

second of the next cosmic

year depends on what we do here and

now with our intelligence and

our knowledge of the cosmos.

There are an enormous number of stars.

Only some of them will have

planets suitable for life.

On only some of those worlds

will intelligence arise, and

perhaps a few of those civilizations

will avoid the trap jointly

set by their technology and

their passions.

If there are many

civilizations, one of them

should be rather close by.

If there are few

civilizations, then even the

nearest may be very far away.

So, if civilizations do not

always destroy themselves

shortly after discovering radio

astronomy, then the sky may

be softly humming with

messages from the stars, with signals

from civilizations enormously

older and wiser than we.

If there are millions of

technical civilizations in the

Milky Way, each capable of

radio astronomy,

how far away is the nearest one?

If they're distributed more or

less randomly through space,

then the nearest one will be

some 200 light years away.

But within 200 light years,

there are hundreds of

thousands of stars.

To find the needle in this

haystack requires a dedicated

and systematic search.

There are many cosmic radio

sources having nothing to do

with intelligent life.

So, how would we know that

we were receiving a message?

The transmitting civilization

could make it very easy for

us, if they wished.

Imagine we're in the course

of a systematic search, or in

the midst of some more conventional

radio observations, and suppose

one day we find a strong

signal slowly emerging, not

just some background hiss, but

a methodical series of pulses.

The numbers 1, 2, 3, 5, 7,

11, 13, a signal made of

prime numbers, numbers divisible only

by one and themselves.

There is no natural

astrophysical process that

generates prime numbers.

we would have to conclude

that someone fond of

elementary mathematics was

saying hello.

This would be no more than a

beacon to attract our attention.

The main message will be subtler,

more hidden, far richer.

We may have to work hard to find it.

Think of the glories of an

An exotic civilization far

more advanced than we,

collected by the great radio

telescopes of Earth.

The receipt of an interstellar

message would be one of the

major events in human history,

and the beginning of the

deprovincialization of our planet.

A serious and systematic radio

search for extraterrestrial

civilizations may come soon.

It's comparatively inexpensive.

A search taking decades would

cost less than the budget overruns

on a single modest weapons

system in a single year.

But whether there are only a

few advanced galactic

civilizations or millions, shouldn't

some of them have voyaged to Earth?

There are many possible

answers, including the

contention that they have come here.

Although
Well the evidence for that is

pitifully slim.

Or there may be no one else

out there, because they

destroy themselves with almost

no exceptions

before they achieve

interstellar flight.

Or maybe, because in a galaxy

of
400 billion suns, ours is

the first technical civilization.

A more likely explanation, I

think, arises from the simple

fact that space is vast and

the stars are far apart.

Even if there were

civilizations much older and

much more advanced than we, expanding

out from their home worlds,

reworking new worlds, and then

continuing onward to other

stars, they would be unlikely

to be here yet.

And because the speed of light is

finite, the TV and radar news

that a technical civilization

has arisen on

some planet of the Sun has

not reached them yet.

Should optimistic estimates

prevail, and one in every

million stars shelters a

nearby technological civilization.

And if, as well, they're

randomly strewn through the Milky Way,

then the nearest one, we

recall, would be a few

hundred light-years distant. At the

closest, maybe a hundred light-years.

More likely, a thousand light-years.

And, of

course, perhaps nowhere, no

matter how far. Suppose, just just for

discussion, suppose

the nearest civilization on a

planet of another star is,

say, 200 light years away.

Then, some 150 years from

now, they'll begin to receive

our feeble post-World War II television

and radar emission.

What will they make of it?

With each passing year, the

signal will get louder, more

interesting, perhaps more alarming.

Eventually, they may respond

by returning a radio message

or by visiting.

In either case, the response

will likely be limited by the

finite value of the speed of light.

With these admittedly wildly

uncertain numbers, the answer

to our unintentional mid-century

recall into the depths of

space, will not arrive until

around the year 2350. If

they're farther away, of

course, it'll take longer.

And if much farther away, much longer.

But the beacon signal alone

would be profoundly significant.

It would mean

that someone has learned to

survive technological adolescence.

That
self-destruction is not

inevitable, that we also may

have a future.

Such knowledge, it seems to

me, might be worth a great price.

There are places in and

around our great cities where

the natural world has all

but disappeared.

You can make out streets and

sidewalks, autos, parking

garages, advertising billboards,

monuments

of glass and steel, but not

a tree or a blade of grass

or any animal, besides, of

course, the humans.

There are lots of humans.

Only when you look straight

up through the skyscraper

canyons can you make out a star

or a patch of blue—reminders

of what was there long before

humans came to be.

But the bright lights of the

big cities bleach out the

stars, and even that patch of blue

is sometimes gone, tinted

brown by industrial technology.

It's not hard, going to work

every day in such a place,

to be impressed with ourselves,

how we've transformed the

Earth for our benefit and convenience.

But a few hundred miles up

or down, there are no humans.

Apart from a thin film of

life at the very surface of

the Earth, an occasional intrepid

spacecraft and some radio

static, our impact on the

universe is nil.

It knows nothing of us.

What?

I sometimes ask myself in amazement.

Our ancestors walked from East

Africa to Novaya Zemlya and

Ayers Rock and Patagonia.

They hunted elephants with

stone spear points.

They traversed the polar seas

in open boats seven thousand years ago.

They circumnavigated the Earth

propelled by nothing but wind.

They walked the Moon a decade

after entering space, and were

daunted by a voyage to Mars.

But then I remind myself of

the avoidable human suffering on Earth.

How a few dollars can save

the life of a child dying

of dehydration.

How many children we could

save for the cost of a trip

to Mars, and for the moment

I changed my mind.

Is it unworthy to stay home,

or unworthy to go?

Or have I posed a false dichotomy?

Isn't it possible to make a

better life for everyone on

Earth, and to reach for the planets

and the stars?

We had an expansive run in

the 60s and 70s.

You might have thought, as I

did then, that

our species would be on Mars

before the century was over.

But instead, we've pulled inward.

Robots aside, we've backed off

from the planets and the stars.

I keep asking myself, is it

failure of nerve or a sign of maturity.

Maybe it's the most we could

reasonably have expected.

In a way, it's amazing that

it was possible at all.

We sent a dozen humans on

week-long excursions to the

moon, and we were given the resources

to make a preliminary

reconnaissance of the whole

solar system—out to Neptune, anyway.

life, missions that returned a

wealth of data, but nothing

of short-term, every-day,

bread-on-the-table

practical value, or at least not much.

They lifted the human spirit, though.

They enlightened us about our

place in the universe.

It is easy to imagine schemes

of historical causality, in

which there were no race to

the Moon, and no planetary program.

But it is also possible to

imagine a much more serious

devotion to exploration, because

of which we would today have

robot vehicles probing the

atmospheres of all the Jovian

planets and dozens of moons,

comets and asteroids.

There were many possible

historical paths.

us, our particular causality

scheme has brought us to a

modest and rudimentary, although in

many respects heroic, series

of explorations.

But it is far inferior to

what might have been, and

what may one day be.

In more than one respect,

exploring the solar system and

homesteading other worlds constitutes

constitutes the beginning, much

more than the end, of history.

And so, after a voyage of

100 million kilometers, on

July 20th, 1976, Viking 1 landed right

on target in the Cricey Plain.

It was less than 80 years

since Robert Goddard had his

epiphanal vision in a cherry

tree in Massachusetts.

The Viking Lander is a

superbly instrumented and

designed machine.

It extends human capabilities

to other and alien landscapes.

By some standards, it's about

as smart as a grasshopper.

By others, only as intelligent

as a bacterium.

There's nothing demeaning in

these comparisons.

It took nature hundreds of

millions of years to evolve a

bacterium,

and billions of years to make

a grasshopper.

With only a little experience

in this sort of business,

we're getting pretty good at it.

One of the things that a

grasshopper can do, but Viking

can't, is move.

We landed in the dull places on Mars.

For all the solid scientific

findings and tantalizing hints

which Viking provided,

we know that there are an

enormous number of places on

the planet far more interesting.

What we need is a roving

vehicle with advanced

experiments in biology and

organic chemistry,

able to land in the safe but

dull places and wander to the

interesting places.

A Mars rover hasn't got time

to ask whether it should

attempt the steep slope.

Radio waves traveling at the

speed of light take about 20

minutes for the round trip to Earth.

By the time it got an

answer, it might be a heap

of twisted metal at the

bottom of a canyon.

A rover has to think for itself.

Imagine a rover with laser

eyes like this one,

but packed with sophisticated

biological and chemical instruments,

sampler arms, microscopes and

television cameras,

wandering over the Martian landscape.

It could drive to its own

horizon every day,

a distant feature that barely

resolves at sunrise.

It can be sniffing and

tasting by nightfall.

Billions of people could watch

the unfolding adventure on

their television sets

as the rover explores the

ancient river bottoms

or cautiously approaches the

enigmatic pyramids of Elysium.

Most of the human species

would witness the exploration

of another world.

A new age of discovery would

have begun.

Science is a collaborative

enterprise spanning the generations.

When it permits us to see

the far side of some new

horizon, we remember those who prepared

the way, seeing for them also.