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In the beginning,
there was darkness...
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and then, bang...
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giving birth to an endless
expanding existence...
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of time, space, and matter.
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Now, see further
than we've ever imagined...
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beyond the limits of our existence...
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in a place we call "The Universe. "
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It's perhaps the holy grail
of planetary science.
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Are we alone in the universe?
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It's one of the grandest questions
we could answer.
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We don't really have
a definition of life...
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but I think I'll know it
when I discover it.
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Life can take
many twists and turns...
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and I think
the really cool thing about it...
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is the variety that we're
going to be able to find elsewhere.
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Are we a lonely planet,
or does life exist beyond Earth?
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Members of the groundbreaking
field of astrobiology...
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have joined forces
to solve this enduring mystery.
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Life, is it rare in our universe...
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or is space a galactic zoo,
teeming with all sorts of creatures?
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Everybody has this sort of
iconic view of the aliens.
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They're going to be little gray guys
with big eyeballs and small noses.
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Well, maybe, but I don't think so.
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On far-off planets, life may be
as far out as buggy-eyed microbes...
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or sci-fi sea monsters
like galactic manta rays.
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Others may be home
to cybernetic organisms...
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hybrids of biology and machines.
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One way to get a handle on thinking
about super advanced aliens...
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is to try to imagine
the possibilities of our own future.
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Maybe it'll be
machine-enabled humans.
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I feel like I've already become
a machine-human hybrid.
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I mean, I have this laptop computer
that I take with me everywhere...
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which is really kind of
the third hemisphere of my brain.
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My body is even changing...
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and becoming sort of shaped like
a person using a laptop computer...
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and so I'm becoming
a Homo laptopicus.
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It's likely
that the universe is full of life.
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We don't have evidence yet
that we're not alone.
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So we're out there, and we're looking.
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When it comes
to hunting for alien life...
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planetary scientist
and musician David Grinspoon...
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walks to a different beat.
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I do wonder,
in terms of extraterrestrial life...
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whether they'll have music
or something like music.
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Music is fundamentally
waves and rhythms...
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and that's sort of the nature
of our universe.
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There is a certain musicality
ofjust the fact...
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that it's all vibrations and waves
and rhythms and modulated tones.
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So I can imagine,
and this is just my wild fantasy...
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some analogy to world music
far in the future...
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where we're mixing our musical cultures
with alien musical cultures.
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I think you'll get many different shades
of astrobiology...
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if you talk to different scientists...
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but I think you'll get a lot
of agreement on the broad goals.
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We want to find life elsewhere,
but in the meantime...
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we're learning a lot about
the history of life on Earth.
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In the field of astrobiology...
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one of the fundamental goals
in searching for life elsewhere...
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is first figuring out
how life evolved here on Earth.
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One of the big unsolved mysteries
in astrobiology, of course...
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is how life got started
on Earth...
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because if we can understand that,
then we would have some insight...
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into whether it could have
gotten started elsewhere.
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Earth orbits in what's called
the "habitable zone. "
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It's a region of space where conditions
are favorable for life forms...
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that we know can be found
on our planet.
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We are at just the right distance
from the Sun...
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so our oceans don't evaporate...
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our temperatures
are not too hot or too cold...
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and we have oxygen
in our atmosphere so we can breathe.
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Earth's been a cosmic paradise
for all types of life...
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from small single-celled organisms,
such as bacteria...
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to large multicellular mammals,
including man.
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It's believed
that all life on our planet...
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descended from a single
common microbial ancestry...
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approximately
3.4 to 3.8 billion years ago.
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But how that microbe came
into being remains puzzling.
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One way to search for answers
is to look for ancient rocks...
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where microbes leave
trace evidence of their existence.
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Geology is a crucial tool...
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for understanding the origins
and evolution of life on Earth...
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because the historical record
of life on Earth...
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is almost entirely recorded
in the rocks that we walk on.
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Geologist Abigail Allwood's journey
to discover the origins of life...
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took her no farther
than her own backyard.
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The Pilbara region
of West Australia...
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contains some of the oldest rocks
on our planet.
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They're almost 31/2 billion years old.
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The Pilbara contains rocks
from the early Archean era...
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that have survived on the Earth today.
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They contain several rock units
that contain possible evidence for life.
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Planet Earth has been around
for over 4.6 billion years.
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But most of its original surface
has been obliterated...
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by plate tectonics and erosion.
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The extremely thick crust
in the Pilbara...
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has helped it resist
destructive geologic processes.
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The Pilbara hasn't been strongly
affected by plate tectonics...
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and the original features
in the sedimentary rocks...
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are more or less ready
for us to interpret.
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There are also sedimentary rocks
of similar age...
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almost 31/2 billion years old,
in South Africa.
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So far the Pilbara seems
to have yielded a richer fossil record.
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Allwood spent
more than three years...
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surveying some of the rock formations
in the Pilbara...
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examining unusual structures
called stromatolites...
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fossils formed by living organisms
31/2 billion years ago.
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We realized that
what we were looking at...
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was the remnants of an ancient reef,
a microbial reef.
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It's not a reef made of coral
like we're familiar with today...
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but a reef made of stromatolites,
structures formed by microorganisms.
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Stromatolites are rocky structures
that form on the sea floor...
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where fine layers of sediment
are built up into cones, domes...
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and other shapes over a long time
with the help of tiny organisms.
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A stromatolite is not alive...
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but is a structure
made by living things.
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When we find one
in the fossil record...
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it is like finding the footprint
of long-dead microorganisms.
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But the microbes themselves are
almost never preserved as fossils...
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inside the stromatolites.
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And without that,
it is extremely difficult to be sure...
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an ancient stromatolite is proof of life.
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But in this case, Allwood found
that the Pilbara stromatolites...
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are, in fact, biological.
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She just may have discovered
the oldest evidence of life on our planet.
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These stromatolites are the oldest
convincing evidence of life on Earth.
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In these amazing pronounced
conical structures...
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that are not like any kind
of wave ripple
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or a structure that you'd expect to see
on the sea floor...
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where there's no biology.
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These are interpreted
as stromatolites...
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sedimentary structures
formed by microorganisms...
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that lived at the interface
between the sediment and the ocean.
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Allwood used geological techniques
to interpret the environment...
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these fossilized microorganisms
may have lived in...
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almost 31/2 billion years ago.
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What we saw was that...
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immediately before
the stromatolites formed...
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was a setting pretty much
just like this, a rocky coastline.
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We see that the stromatolites only
exist in the shallow-water environment...
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and don't exist in the deep-water areas
that were existing at the same time.
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This fossilized ecosystem
provides a glimpse into the past...
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and what might be the remains
of man's earliest ancestors.
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With the rise of astrobiology...
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00:10:03,436 --> 00:10:06,438
and new techniques and approaches
to interpret evidence for life...
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we can be fairly confident
about saying that life was on Earth...
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at least 3,430 million years ago.
147
00:10:16,949 --> 00:10:20,327
But could life have existed
even earlier on our planet?
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00:10:22,913 --> 00:10:25,999
The oldest evidence of life
is not evidence of the oldest life.
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We do not have
any geologic record...
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for the first half billion years
of Earth's history...
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so there's a whole bunch
of stuff missing.
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What's not preserved
in the fossil record...
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is how life formed
in the first place.
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We humans are the descendants
of stardust.
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4.6 billion years ago, stellar debris
created vast clouds of gas...
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within our solar system.
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These gaseous clouds formed
dust particles, which stuck together.
158
00:11:09,251 --> 00:11:11,461
They eventually
formed large boulders...
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made of rock and ice
called asteroids and comets.
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00:11:17,551 --> 00:11:19,135
For millions of years...
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these bodies collided and coalesced
to form planets, including Earth.
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During this heavy bombardment,
Earth was a hot, toxic water world.
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But in the midst
of this volatile period...
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life may have taken hold
below the ocean surface...
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in hydrothermal vents,
which are formed near volcanoes.
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There, atmospheric chemicals
and energy...
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may have formed
a cocktail of amino acids...
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the essential elements of life.
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One of the popular hypotheses...
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is that life arose
around a hydrothermal vent...
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because of the particular
conditions there...
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that it would've been
a deeper-water environment...
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which offers protection from impact.
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Shallow-water environments
would have been very hostile...
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during the period
of heavy bombardment.
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But the key question
for astrobiology is...
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where did the spark occur
that took nonliving matter...
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and turns it into living matter?
179
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Chris McKay is a giant
in the field of astrobiology.
180
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The NASA scientist has spent
over twenty-five years...
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00:12:34,587 --> 00:12:39,549
trying to decode the origin
of life on Earth and find it elsewhere.
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There's a whole set of theories...
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that suggests that everything
needed for life...
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started and was
created here on Earth.
185
00:12:47,850 --> 00:12:50,894
So the organic material
that led to the first life...
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00:12:50,936 --> 00:12:54,773
could have been produced
in lightning discharges on Earth.
187
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An alternative theory is that
the organics that led to life...
188
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weren't created on Earth,
but came into Earth.
189
00:13:01,280 --> 00:13:04,199
Comets, for example,
could be a source of organics.
190
00:13:04,241 --> 00:13:07,660
Meteorites from Mars
or asteroid infall...
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00:13:07,703 --> 00:13:09,329
could have been a source
for organics.
192
00:13:09,371 --> 00:13:14,667
So now the raw materials are imported,
but life is still homegrown.
193
00:13:14,710 --> 00:13:15,919
Yet another theory suggests...
194
00:13:15,961 --> 00:13:18,922
that not only did the organics
for life come in...
195
00:13:18,964 --> 00:13:22,091
but life itself might have
come in from outer space.
196
00:13:22,134 --> 00:13:25,428
We don't really know how to choose
between those three alternatives.
197
00:13:28,140 --> 00:13:32,101
All life on Earth is made up
of essential building blocks...
198
00:13:32,144 --> 00:13:36,523
including carbon, hydrogen,
oxygen, and nitrogen...
199
00:13:36,565 --> 00:13:39,609
as well as two dozen
other ingredients.
200
00:13:39,652 --> 00:13:44,614
But the fundamental properties
appear to be water and carbon.
201
00:13:46,784 --> 00:13:51,287
The carbon-and-water model of biology
is the one that we're familiar with...
202
00:13:51,330 --> 00:13:54,082
and it seems to be the best way
for biology to operate.
203
00:13:55,709 --> 00:13:59,921
Scientists think the best chance
for finding extraterrestrial life...
204
00:13:59,964 --> 00:14:03,174
is to search for traces
of carbon and water...
205
00:14:03,217 --> 00:14:05,593
on planets
in our own solar system.
206
00:14:08,013 --> 00:14:11,099
Mercury and Venus are
too close to our sun...
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00:14:11,141 --> 00:14:16,354
to sustain liquid water
or an Earthlike atmosphere.
208
00:14:16,397 --> 00:14:19,858
But what about Mars,
the fourth planet from the Sun?
209
00:14:23,028 --> 00:14:25,989
Studying the oldest evidence
for life on Earth...
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00:14:26,031 --> 00:14:28,408
is relevant to the search
for life on Mars.
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00:14:28,450 --> 00:14:30,994
We have strong evidence
that some time in the past...
212
00:14:31,036 --> 00:14:32,912
Mars may have been
more hospitable...
213
00:14:32,955 --> 00:14:35,206
wetter and warmer,
had an atmosphere.
214
00:14:37,376 --> 00:14:41,462
Today, Mars looks like
a dusty red desert.
215
00:14:42,923 --> 00:14:46,175
Its atmosphere is so thin
that liquid water...
216
00:14:46,218 --> 00:14:50,346
would freeze and evaporate
at the same time on its surface.
217
00:14:50,389 --> 00:14:56,978
But Mars' topography reveals polar
ice caps, gullies, and volcanoes...
218
00:14:57,021 --> 00:15:01,482
including Olympus Mons,
the largest in the solar system.
219
00:15:02,526 --> 00:15:06,613
So could liquid water still exist
beneath the surface...
220
00:15:06,655 --> 00:15:08,573
where temperatures are warmer?
221
00:15:17,416 --> 00:15:22,045
Scientists believe the best chance
for finding life beyond planet Earth...
222
00:15:22,087 --> 00:15:24,923
might be next door
in our solar system.
223
00:15:27,676 --> 00:15:30,720
Mars, the fourth rock from the Sun...
224
00:15:30,763 --> 00:15:33,932
may have liquid water
beneath its surface...
225
00:15:35,225 --> 00:15:37,310
a good signature for life.
226
00:15:39,855 --> 00:15:42,941
Hydrothermal systems
can definitely exist on Mars...
227
00:15:42,983 --> 00:15:46,277
because we can see
massive volcanoes.
228
00:15:46,320 --> 00:15:49,364
We know there's plenty of water
still on the surface of Mars.
229
00:15:49,406 --> 00:15:51,532
That heat source,
the water source...
230
00:15:51,575 --> 00:15:54,869
provides all
the ingredients necessary...
231
00:15:54,912 --> 00:15:56,829
to make microbial life very happy.
232
00:15:58,832 --> 00:16:01,709
To better understand
the geology on Mars...
233
00:16:01,752 --> 00:16:07,423
astrobiologist Dr. Adrian Brown
investigates the hot spots on Earth...
234
00:16:07,466 --> 00:16:12,053
particularly Lassen Volcanic National
Park in northern California.
235
00:16:14,932 --> 00:16:17,266
The reason I'm interested
in Lassen Volcanic Park...
236
00:16:17,309 --> 00:16:20,687
is because of these
hydrothermal hot spot areas...
237
00:16:20,729 --> 00:16:23,147
where we can find minerals
that are forming...
238
00:16:23,190 --> 00:16:25,942
that don't form anywhere else
but these areas.
239
00:16:25,985 --> 00:16:30,571
These sulfate-rich minerals that
you see in the sides of the hills here...
240
00:16:30,614 --> 00:16:34,283
are areas that we think
that are analogous to Mars.
241
00:16:34,326 --> 00:16:35,994
And the fact that they're
still active today...
242
00:16:36,036 --> 00:16:39,539
means that we can get an idea
of how friendly they are for life.
243
00:16:42,459 --> 00:16:46,045
Hydrothermal hot springs
are formed near volcanoes.
244
00:16:48,549 --> 00:16:52,760
Deep underground, the searing heat
of volcanic magma chambers...
245
00:16:52,803 --> 00:16:55,471
propels hot water
and dissolved minerals...
246
00:16:55,514 --> 00:16:58,266
into cracks and fissures
in the subsurface...
247
00:16:59,685 --> 00:17:02,478
which then erupts
onto the surface of the Earth.
248
00:17:02,521 --> 00:17:05,815
The spring surrounds itself
with a treasure trove...
249
00:17:05,858 --> 00:17:10,111
of energy-laden minerals
suitable for a microbial feast.
250
00:17:13,198 --> 00:17:16,367
A hydrothermal spring,
just like the one behind me here...
251
00:17:16,410 --> 00:17:19,037
would be exactly the place
that we'd want to land on Mars.
252
00:17:19,079 --> 00:17:24,417
This sort of area would be
just perfect for life to exist...
253
00:17:24,460 --> 00:17:29,005
perhaps even for life to form,
the origins of life.
254
00:17:29,048 --> 00:17:33,301
This area where water has been
forced up through conduits...
255
00:17:33,343 --> 00:17:37,180
and carried along minerals,
energy sources, to the surface...
256
00:17:37,222 --> 00:17:39,390
and then spread them out
around the deposit...
257
00:17:39,433 --> 00:17:42,643
for microbes to feed on
as an energy source.
258
00:17:44,563 --> 00:17:49,192
Brown thinks if Mars
is still volcanically active...
259
00:17:49,234 --> 00:17:51,903
similar hydrothermal areas will exist.
260
00:17:53,155 --> 00:17:56,324
They might be places where life
may have originated...
261
00:17:56,366 --> 00:17:59,744
or still exists just below the surface.
262
00:18:02,748 --> 00:18:05,124
Mars is a red planet
that we see from orbit.
263
00:18:06,376 --> 00:18:09,504
But just underneath
a thin layer of dust...
264
00:18:09,546 --> 00:18:13,174
we see a whole rich array
of sulfate-rich minerals...
265
00:18:13,217 --> 00:18:16,886
that many scientists believe
may have been formed hydrothermally.
266
00:18:16,929 --> 00:18:19,430
And we see those
very similar minerals...
267
00:18:19,473 --> 00:18:22,642
in the rocks and the hills
surrounding us here at Lassen.
268
00:18:26,605 --> 00:18:33,736
In 2006, NASA's Mars Reconnaissance
Orbiter probe arrived at the red planet.
269
00:18:33,779 --> 00:18:34,862
It's equipped...
270
00:18:34,905 --> 00:18:38,699
with the Compact Reconnaissance
Imaging Spectrometer for Mars...
271
00:18:38,742 --> 00:18:44,956
better known as CRISM, which plans
to revolutionize our view of the planet.
272
00:18:47,960 --> 00:18:50,837
Using visible and infrared light...
273
00:18:50,879 --> 00:18:54,507
the instrument has been scanning
for evidence of ancient liquid water...
274
00:18:54,550 --> 00:18:58,761
in Valles Marineris,
a massive canyon system...
275
00:18:58,804 --> 00:19:02,431
ripped into the surface
by the volcano Olympus Mons.
276
00:19:03,559 --> 00:19:06,769
The area may hold
hydrothermal deposits.
277
00:19:09,648 --> 00:19:11,983
Mars is unlikely to be
active at the moment.
278
00:19:12,025 --> 00:19:16,821
But in its active phase, it may have
been that hydrothermal waters...
279
00:19:16,864 --> 00:19:20,867
were driven by the massive volcanoes
that we see on Mars today.
280
00:19:20,909 --> 00:19:24,287
And Mars
may have been able to form...
281
00:19:24,329 --> 00:19:27,331
active hydrothermal systems,
such as this...
282
00:19:27,374 --> 00:19:32,295
and build up a rich layer of sulfate
minerals on the surface of Mars.
283
00:19:36,466 --> 00:19:39,969
Early Mars was much more habitable
than the current-day Mars.
284
00:19:40,012 --> 00:19:41,137
The planet cooled off.
285
00:19:41,180 --> 00:19:44,223
It's now too cold and too dry
to support life.
286
00:19:44,266 --> 00:19:46,934
So if there was early life on Mars...
287
00:19:46,977 --> 00:19:48,853
it's probably not
on the surface anymore...
288
00:19:48,896 --> 00:19:51,564
and it could potentially
have migrated into the subsurface...
289
00:19:51,607 --> 00:19:54,609
into inhabitable environments
below the ground.
290
00:19:57,029 --> 00:19:59,071
Research scientist
Jennifer Heldmann...
291
00:19:59,114 --> 00:20:02,658
is also on a quest
to find life on Mars...
292
00:20:02,701 --> 00:20:05,161
by understanding
how microscopic organisms...
293
00:20:05,204 --> 00:20:08,623
survive in extreme
environments on Earth.
294
00:20:08,665 --> 00:20:12,335
But instead of investigating
the hot spots on our planet...
295
00:20:14,004 --> 00:20:17,048
she scours for life in cold places.
296
00:20:18,884 --> 00:20:21,260
Right now, specifically
at Lassen Volcanic Park...
297
00:20:21,303 --> 00:20:23,179
we are looking
at snowpack deposits...
298
00:20:23,222 --> 00:20:25,681
and we're especially interested
in these snowpacks...
299
00:20:25,724 --> 00:20:28,351
because they have snow algae
living in them.
300
00:20:28,393 --> 00:20:30,561
So in the late spring,
summer months...
301
00:20:30,604 --> 00:20:32,772
you'll see the snowpacks
colored bright red...
302
00:20:32,814 --> 00:20:35,024
streaks and ribbons of red
running through the snowpack.
303
00:20:35,067 --> 00:20:36,067
And that's the algae.
304
00:20:36,109 --> 00:20:38,611
So there's actually life
living in these snowpacks.
305
00:20:38,654 --> 00:20:40,363
And so we're studying
the physical conditions...
306
00:20:40,405 --> 00:20:42,198
that the snow algae like to live in...
307
00:20:42,241 --> 00:20:44,325
and applying that
to snowpacks on Mars...
308
00:20:44,368 --> 00:20:47,828
to see if the same conditions
within snowpacks on Mars might exist.
309
00:20:50,415 --> 00:20:54,877
NASA's Mars Global Surveyor has
recently discovered Martian gullies...
310
00:20:54,920 --> 00:20:58,256
that could be the ancient
remains of snowpacks.
311
00:21:00,759 --> 00:21:03,552
We're looking at these
to study this phenomenon.
312
00:21:03,595 --> 00:21:07,139
Can those snowpacks actually melt,
generate liquid water...
313
00:21:07,182 --> 00:21:10,309
and also potentially provide
habitable environments for life?
314
00:21:13,105 --> 00:21:16,607
To better understand
snowpacks on Mars...
315
00:21:16,650 --> 00:21:20,278
Heldmann conducts experiments
in Lassen Volcanic Park.
316
00:21:22,447 --> 00:21:24,907
So this is our setup for measuring...
317
00:21:24,950 --> 00:21:27,743
temperature and light profiles
through the snowpack.
318
00:21:27,786 --> 00:21:30,955
And what we're doing is using
this instrumentation to understand...
319
00:21:30,998 --> 00:21:33,291
the physical conditions
within a snowpack...
320
00:21:33,333 --> 00:21:35,293
that are able to support
snow algae.
321
00:21:37,629 --> 00:21:41,007
This winter, this will get completely
covered in snow and buried.
322
00:21:41,049 --> 00:21:43,426
And so we have sensors
mounted on a pole here.
323
00:21:43,468 --> 00:21:46,804
So we have some moisture sensors
here and here.
324
00:21:46,847 --> 00:21:49,849
And then these little ones
are just temperature sensors.
325
00:21:49,891 --> 00:21:52,476
And then at the very top of a pole,
we have a light sensor...
326
00:21:52,519 --> 00:21:54,562
which measures
incoming solar radiation.
327
00:21:54,604 --> 00:21:57,231
And then down here
covered in the bucket...
328
00:21:57,274 --> 00:21:58,774
we have a tipping rain gauge...
329
00:21:58,817 --> 00:22:00,943
and this will measure
the amount of liquid water...
330
00:22:00,986 --> 00:22:02,570
that flows down
through this bucket.
331
00:22:04,614 --> 00:22:06,282
The snow algae
that we're seeing here...
332
00:22:06,325 --> 00:22:09,076
thrives in these
very low condition environments.
333
00:22:09,119 --> 00:22:11,662
It's very happy being
at zero degrees C.
334
00:22:11,705 --> 00:22:13,706
It's very happy
in low-light conditions...
335
00:22:13,749 --> 00:22:16,625
It's very happy in the nutrient-poor
conditions of a snowpack.
336
00:22:18,545 --> 00:22:19,795
Once we understand
the conditions...
337
00:22:19,838 --> 00:22:22,631
that support life here
in the snowpack at Lassen...
338
00:22:22,674 --> 00:22:25,051
then we're also doing studies
of snowpacks on Mars.
339
00:22:25,093 --> 00:22:27,762
And if we find
the same conditions on Mars...
340
00:22:27,804 --> 00:22:29,430
you have to ask yourself
the question...
341
00:22:29,473 --> 00:22:31,349
well, if these snowpacks
on Earth are habitable...
342
00:22:31,391 --> 00:22:33,893
could those snowpacks on Mars
also be habitable?
343
00:22:38,231 --> 00:22:42,943
In addition to Martian gullies,
two massive polar regions...
344
00:22:42,986 --> 00:22:46,864
may also be places
where life still exists on Mars.
345
00:22:48,158 --> 00:22:54,747
On August 4, 2007, NASA launched
the Phoenix Mars Lander spacecraft.
346
00:22:55,916 --> 00:22:59,293
When it finally arrives
on the red planet in early June...
347
00:23:00,337 --> 00:23:02,671
it will probe its icy poles.
348
00:23:03,924 --> 00:23:07,343
Aboard the craft,
robotic arms that dig trenches...
349
00:23:07,386 --> 00:23:09,428
will plow through the layers
of water ice...
350
00:23:10,722 --> 00:23:15,184
to see if there are organic compounds,
the building blocks of life.
351
00:23:16,645 --> 00:23:19,021
We might go
to the polar regions on Mars...
352
00:23:19,064 --> 00:23:24,068
drill down into the ancient ice,
bring up organisms that are dead.
353
00:23:24,111 --> 00:23:26,195
They've been shelled by radiation.
354
00:23:26,238 --> 00:23:29,365
But we might be able to,
by studying their biochemistry...
355
00:23:29,408 --> 00:23:32,660
patch them back up
and resurrect them.
356
00:23:34,121 --> 00:23:36,455
But even if Mars holds liquid water...
357
00:23:37,416 --> 00:23:40,501
could it have ever sustained
larger animal life?
358
00:23:45,590 --> 00:23:48,801
When searching for Earthlike life
in our solar system...
359
00:23:50,095 --> 00:23:53,973
scientists look for the presence
of liquid water and carbon.
360
00:23:54,933 --> 00:23:58,018
They're crucial ingredients
for life on Earth.
361
00:23:59,062 --> 00:24:00,729
But are there other indicators?
362
00:24:02,524 --> 00:24:08,863
Some scientists believe plate tectonics
is necessary to promote biodiversity...
363
00:24:08,905 --> 00:24:12,032
and act as a defense
against mass extinctions.
364
00:24:14,119 --> 00:24:17,913
On Earth, plate-shifting
created continents.
365
00:24:17,956 --> 00:24:21,792
Without land masses, Earth
would have remained a water world...
366
00:24:21,835 --> 00:24:24,962
and, therefore, many species,
including humans,
367
00:24:25,005 --> 00:24:26,422
may not have evolved.
368
00:24:29,384 --> 00:24:32,803
So why does plate tectonics
exist on Earth...
369
00:24:33,889 --> 00:24:37,975
and not on other terrestrial
planets such as Mars?
370
00:24:39,603 --> 00:24:44,148
Because Mars is smaller than Earth,
likely its interior cooled off faster.
371
00:24:44,191 --> 00:24:48,277
And it cooled off before, really,
plate tectonics were able to start on Mars.
372
00:24:48,320 --> 00:24:50,321
Fortunately, on Earth,
we still have plate tectonics.
373
00:24:50,363 --> 00:24:54,116
And plate tectonics is the grand
recycling system of our planet...
374
00:24:54,159 --> 00:24:55,701
recycling materials
from the atmosphere...
375
00:24:55,744 --> 00:24:57,411
and the surface
and the subsurface...
376
00:24:57,454 --> 00:24:59,121
and Mars never had that.
377
00:25:00,540 --> 00:25:04,126
Plate tectonics also keeps
Earth's temperatures moderate...
378
00:25:05,337 --> 00:25:08,964
by recycling chemicals to keep
the volume of carbon dioxide...
379
00:25:09,007 --> 00:25:11,342
in our atmosphere uniform.
380
00:25:12,511 --> 00:25:16,639
Lacking plate tectonics,
it didn't have the persistence of Earth.
381
00:25:16,681 --> 00:25:19,058
It developed
maybe habitable conditions...
382
00:25:19,100 --> 00:25:22,770
and maybe complex multicellular
life very quickly...
383
00:25:22,812 --> 00:25:26,357
and then it dies off because it
doesn't have the long-term potential...
384
00:25:26,399 --> 00:25:28,651
that plate tectonics gives the Earth.
385
00:25:30,362 --> 00:25:34,406
Plate tectonics may be
one indicator for Earthlike life.
386
00:25:36,159 --> 00:25:40,746
But evidence suggests
there may exist another type of life...
387
00:25:40,789 --> 00:25:44,708
on a moon that belongs
to the Lord of the Rings.
388
00:25:47,587 --> 00:25:51,131
In 2004, NASA's Cassini mission...
389
00:25:51,174 --> 00:25:55,177
conducted fly-bys around
the gas giant planet of Saturn.
390
00:25:57,514 --> 00:26:02,101
A year later, the spacecraft
released its Huygens probe...
391
00:26:02,143 --> 00:26:06,397
into the atmosphere of Saturn's
largest moon, Titan.
392
00:26:07,732 --> 00:26:11,735
The images revealed that Titan
has similar features to Earth...
393
00:26:11,778 --> 00:26:15,072
such as weather cycles
and volcanism.
394
00:26:16,074 --> 00:26:18,951
Saturn's moon, Titan,
is a very complex place...
395
00:26:18,994 --> 00:26:21,870
with rainfall, rivers, and seasons...
396
00:26:21,913 --> 00:26:24,373
and meteorology
and a complex atmosphere...
397
00:26:24,416 --> 00:26:25,916
and interesting chemistry.
398
00:26:25,959 --> 00:26:27,585
Again, it's not going to be
our kind of life...
399
00:26:27,627 --> 00:26:30,754
but there are flows of energy
and organic compounds...
400
00:26:30,797 --> 00:26:33,799
and some other kind of life
could flourish.
401
00:26:35,969 --> 00:26:40,556
Radar imaging data has revealed
the presence of liquid lakes on Titan.
402
00:26:42,517 --> 00:26:45,561
Although they're comprised
of ethane and methane...
403
00:26:45,604 --> 00:26:50,608
they may be reminiscent of what water
on Earth was like four billion years ago.
404
00:26:53,111 --> 00:26:55,571
Titan, the moon of Saturn,
is a really cool place...
405
00:26:55,614 --> 00:26:56,864
literally and figuratively.
406
00:26:56,906 --> 00:26:59,908
It's so cold that
there is no liquid water.
407
00:26:59,951 --> 00:27:02,953
The ice there would be
as hard as rocks, water ice...
408
00:27:02,996 --> 00:27:06,248
but there is a liquid-
liquid methane, liquid ethane.
409
00:27:06,291 --> 00:27:07,291
So maybe there's life.
410
00:27:07,334 --> 00:27:10,169
Maybe life doesn't need liquid water.
411
00:27:10,211 --> 00:27:13,464
Maybe life can survive
on another liquid, liquid methane.
412
00:27:17,802 --> 00:27:23,265
Titan's temperature is a chilly
minus 289 degrees Fahrenheit...
413
00:27:23,308 --> 00:27:27,811
but it has a nitrogen-rich atmosphere
which produces hydrocarbons...
414
00:27:27,854 --> 00:27:30,481
that can stay liquid
at cooler temperatures.
415
00:27:33,151 --> 00:27:36,111
So it's possible that Titan
may be hospitable...
416
00:27:36,154 --> 00:27:39,323
to a new type
of so-called extremophile...
417
00:27:40,533 --> 00:27:43,911
an organism that thrives
in extreme environments.
418
00:27:46,206 --> 00:27:50,167
In the case of Titan,
they may be psychrophiles...
419
00:27:50,210 --> 00:27:53,462
bacteria that thrives
in frigid temperatures...
420
00:27:53,505 --> 00:27:56,340
and uses methane
to produce energy.
421
00:28:00,679 --> 00:28:03,472
Chris McKay
has observed psychrophiles...
422
00:28:03,515 --> 00:28:06,350
under ice-covered lakes
in Antarctica.
423
00:28:07,686 --> 00:28:11,063
Some organisms live
at the bottom of these waters...
424
00:28:12,232 --> 00:28:16,360
where their biological activities
have created a zone...
425
00:28:16,403 --> 00:28:23,033
devoid of oxygen and rich
in organic molecules like methane.
426
00:28:25,203 --> 00:28:27,788
One of the interesting
ecosystems in the Antarctic...
427
00:28:27,831 --> 00:28:29,415
are the ice-covered lakes...
428
00:28:29,457 --> 00:28:33,335
which have a persistent ice cover
of about fifteen feet of ice.
429
00:28:33,378 --> 00:28:35,713
Below that ice, there's liquid water.
430
00:28:35,755 --> 00:28:37,840
Given that there's water,
it's not too surprising...
431
00:28:37,882 --> 00:28:41,176
that there's algae and bacteria
living in that water.
432
00:28:43,888 --> 00:28:48,016
Like Antarctica,
Titan's lakes may also contain...
433
00:28:48,059 --> 00:28:51,979
similar extreme organisms
that survive on methane.
434
00:28:54,232 --> 00:28:57,568
And Titan may not be
the only moon harboring life.
435
00:29:01,906 --> 00:29:06,326
In 2003,
NASA's Galileo space probe...
436
00:29:06,369 --> 00:29:09,705
snapped pictures
of Jupiter's moon, Europa.
437
00:29:11,207 --> 00:29:16,920
Evidence suggests liquid water
may exist underneath its frozen crust.
438
00:29:19,591 --> 00:29:24,470
Scientists think Europa has an ocean
that's over fifty miles deep.
439
00:29:25,930 --> 00:29:28,515
There are also signs
of volcanic activity.
440
00:29:30,268 --> 00:29:34,521
So Europa's icy water
could be warmed to a liquid state...
441
00:29:34,564 --> 00:29:37,441
by volcanic vents
on the ocean floor.
442
00:29:37,484 --> 00:29:39,401
And this volcanic activity...
443
00:29:39,444 --> 00:29:43,447
would aid in cooking up
chemicals necessary for life.
444
00:29:46,576 --> 00:29:49,953
We have very convincing evidence
that below the icy surface...
445
00:29:49,996 --> 00:29:51,163
there's an ocean.
446
00:29:51,206 --> 00:29:53,916
Ocean water, water, maybe life.
447
00:29:53,958 --> 00:29:55,167
And we also have evidence...
448
00:29:55,210 --> 00:29:57,294
that there are possible
energy sources in Europa.
449
00:29:57,337 --> 00:30:01,465
So all the necessary ingredients
for life seem to be there.
450
00:30:04,636 --> 00:30:08,555
The ice on the surface
of Europa is extremely thick...
451
00:30:08,598 --> 00:30:11,266
maybe as much as six miles deep.
452
00:30:11,309 --> 00:30:14,228
So it is unlikely
that a human spacecraft...
453
00:30:14,270 --> 00:30:18,273
will be able to drill down
into its ocean anytime soon.
454
00:30:20,193 --> 00:30:23,195
I think a realistic mission
to Europa...
455
00:30:23,238 --> 00:30:26,448
would be to search the surface
for evidence of organisms...
456
00:30:26,491 --> 00:30:28,200
that have been carried up
through the cracks...
457
00:30:28,243 --> 00:30:30,452
and deposited on the surface.
458
00:30:30,495 --> 00:30:32,996
They would be dead,
but they would be biological...
459
00:30:33,039 --> 00:30:34,414
and we could study them.
460
00:30:36,125 --> 00:30:39,795
Our solar system is full of diverse,
interesting places...
461
00:30:39,838 --> 00:30:42,631
and we shouldn't rule
any of them out for life...
462
00:30:43,508 --> 00:30:45,133
until we explore broadly...
463
00:30:45,176 --> 00:30:47,219
'cause we don't really know
what we're looking for.
464
00:30:48,972 --> 00:30:50,973
Armed with new technologies...
465
00:30:51,015 --> 00:30:55,686
astrobiologists have widened
their search for extraterrestrial life.
466
00:30:56,229 --> 00:31:02,484
The next frontier includes
our entire Milky Way galaxy and beyond.
467
00:31:09,033 --> 00:31:13,537
Astrobiology is pushing back
the boundaries of modern science.
468
00:31:14,747 --> 00:31:18,333
Researchers now have
the technological instruments...
469
00:31:18,376 --> 00:31:20,294
to locate exoplanets.
470
00:31:21,629 --> 00:31:25,757
These are planets that exist
outside our solar system.
471
00:31:28,219 --> 00:31:31,638
Exoplanets need
to pass several tests...
472
00:31:31,681 --> 00:31:35,434
in order to be considered
suitable for Earthlike life.
473
00:31:37,312 --> 00:31:41,106
Most importantly, they need
to be within a habitable zone...
474
00:31:41,149 --> 00:31:46,570
of a central star, like our Sun,
in order to support liquid water.
475
00:31:48,197 --> 00:31:49,323
Our star is just right.
476
00:31:49,365 --> 00:31:51,283
It's not too hot,
and it's not too cold.
477
00:31:51,326 --> 00:31:56,288
And so we're just right in this perfect
area where life was able to evolve.
478
00:31:59,334 --> 00:32:05,255
In 2008, NASA plans to launch
a space telescope called Kepler...
479
00:32:05,298 --> 00:32:08,800
to search for terrestrial
Earth-sized planets.
480
00:32:10,428 --> 00:32:14,765
The spacecraft's instruments
will be able to detect exoplanets...
481
00:32:14,807 --> 00:32:18,769
by measuring changes
in a star's light curve...
482
00:32:18,811 --> 00:32:23,023
as a planet passes
between the star and the spacecraft.
483
00:32:24,943 --> 00:32:28,403
Geoff Marcy is one
of the world's leading planet hunters.
484
00:32:31,115 --> 00:32:33,825
We would estimate
that there are some fifty billion...
485
00:32:33,868 --> 00:32:37,162
maybe sixty billion
Earthlike planets...
486
00:32:37,205 --> 00:32:40,374
within just
our Milky Way galaxy alone...
487
00:32:40,416 --> 00:32:42,668
and remember,
our Milky Way galaxy...
488
00:32:42,710 --> 00:32:47,005
is just one of hundreds
of billions of galaxies out there...
489
00:32:47,048 --> 00:32:48,966
more or less like our Milky Way.
490
00:32:49,008 --> 00:32:51,677
So the number of Earthlike
planets in our universe...
491
00:32:51,719 --> 00:32:54,054
is a nearly uncountable number.
492
00:32:56,516 --> 00:33:01,395
But locating exoplanets is only
half the battle for an astrobiologist.
493
00:33:01,437 --> 00:33:03,355
In the next twenty years...
494
00:33:03,398 --> 00:33:06,650
NASA will launch
the Terrestrial Planet Finder.
495
00:33:10,113 --> 00:33:13,323
This collection of highly
sensitive space telescopes...
496
00:33:13,366 --> 00:33:17,911
will actually recognize if a planet
has the right atmospheric gases...
497
00:33:18,830 --> 00:33:23,959
such as water vapor, carbon dioxide,
methane, and ozone...
498
00:33:24,002 --> 00:33:27,671
all necessary to sustain
Earthlike life.
499
00:33:29,590 --> 00:33:32,884
With that picture, we can
then take the light from that planet...
500
00:33:32,927 --> 00:33:35,762
spread it out into all of its colors
or wavelengths:
501
00:33:35,805 --> 00:33:38,390
blue, green, yellow, red,
even to the infrared...
502
00:33:38,433 --> 00:33:41,685
and analyze that light
for the chemical composition...
503
00:33:41,728 --> 00:33:45,272
maybe even the biological
composition of that planet.
504
00:33:45,314 --> 00:33:50,485
What we might find are signs
of life in a variety of forms.
505
00:33:50,528 --> 00:33:52,237
For example, oxygen.
506
00:33:55,533 --> 00:33:59,786
When it comes to producing
larger Earthlike life...
507
00:33:59,829 --> 00:34:02,372
a planet or moon
needs oxygen.
508
00:34:04,459 --> 00:34:09,421
3.4 billion years ago,
the only life on our planet...
509
00:34:09,464 --> 00:34:12,299
were single-celled
microbial organisms.
510
00:34:13,885 --> 00:34:17,846
But as this primitive life
absorbed energy from the sun...
511
00:34:19,057 --> 00:34:22,768
it formed a green pigment
called chlorophyll.
512
00:34:25,146 --> 00:34:28,940
This produced photosynthesis,
a chemical process...
513
00:34:28,983 --> 00:34:32,360
which converts carbon dioxide
and water into energy...
514
00:34:32,403 --> 00:34:35,530
with oxygen as a waste product.
515
00:34:35,573 --> 00:34:39,242
Single-celled organisms
evolved into cyanobacteria...
516
00:34:39,285 --> 00:34:41,661
one of the Earth's
earliest structures.
517
00:34:43,831 --> 00:34:48,919
Cyanobacteria injected vast amounts
of oxygen into the oceans and air.
518
00:34:50,171 --> 00:34:55,717
New life emerged, which
diversified and developed...
519
00:34:55,760 --> 00:35:00,972
into large, multicellular species
and, eventually, man.
520
00:35:02,308 --> 00:35:05,227
Our Earth would not have
oxygen in the atmosphere...
521
00:35:05,269 --> 00:35:09,564
if it were not for plant life,
by photosynthesis...
522
00:35:09,607 --> 00:35:14,820
generating the oxygen that otherwise
would oxidize rocks and vanish.
523
00:35:14,862 --> 00:35:20,200
So oxygen is a biomarker
for the Earth.
524
00:35:20,243 --> 00:35:22,828
If we could examine
another Earthlike planet...
525
00:35:22,870 --> 00:35:25,580
and detect oxygen
in its atmosphere...
526
00:35:25,623 --> 00:35:29,334
it would be one key sign-
not yet definitive-
527
00:35:29,377 --> 00:35:31,336
but one element of the argument...
528
00:35:31,379 --> 00:35:35,173
that that planet, too,
has photosynthetic life.
529
00:35:38,845 --> 00:35:41,555
At NASA's Ames Research Center...
530
00:35:41,597 --> 00:35:45,433
astrochemist Lee Bebout
and her colleagues...
531
00:35:45,476 --> 00:35:49,312
are cultivating oxygen-bearing
ecosystems in a greenhouse.
532
00:35:50,648 --> 00:35:54,484
They're microbial mats,
complex microbe communities...
533
00:35:54,527 --> 00:35:58,071
often found on muddy
and sandy sediment surfaces...
534
00:35:58,114 --> 00:36:01,116
in hyper-salty waters
and carbonate beaches.
535
00:36:03,703 --> 00:36:08,748
These microbial mats are the oldest
known living ecosystems on Earth.
536
00:36:10,042 --> 00:36:15,297
Bebout wants to know if these microbes
could exist on other planets...
537
00:36:15,339 --> 00:36:20,177
producing oxygen, thereby
enabling life to evolve.
538
00:36:22,305 --> 00:36:26,224
We know that, with the advent
of oxygen production...
539
00:36:26,267 --> 00:36:29,769
through photosynthesis,
these microbial ecosystems...
540
00:36:29,812 --> 00:36:33,481
in particular the cyanobacteria,
began to change our atmosphere.
541
00:36:33,524 --> 00:36:36,985
We're very curious how that happened,
how that transitioned...
542
00:36:37,028 --> 00:36:39,321
how these microbes
adapted and spread...
543
00:36:39,363 --> 00:36:42,157
to diversify and fill
so many niches on our planet.
544
00:36:42,200 --> 00:36:46,995
This is important in helping us decide
what to look for on other places...
545
00:36:47,038 --> 00:36:49,998
say, Mars or other
extraterrestrial places.
546
00:36:53,711 --> 00:36:59,841
If life exists far off in our galaxy
or in distant galaxies...
547
00:36:59,884 --> 00:37:02,636
will it truly be Earthlike?
548
00:37:03,888 --> 00:37:07,766
On our planet,
all life contains DNA...
549
00:37:09,101 --> 00:37:14,314
a long chain of molecules that holds
the blueprint for every living thing.
550
00:37:16,108 --> 00:37:19,277
It allows life to duplicate
and branch out...
551
00:37:19,320 --> 00:37:22,989
essentially creating
the tree of life.
552
00:37:23,032 --> 00:37:24,824
But are there alternatives?
553
00:37:27,328 --> 00:37:30,538
Maybe life on another world
is still carbon and water-based...
554
00:37:30,581 --> 00:37:32,832
but doesn't use DNA at all.
555
00:37:32,875 --> 00:37:36,962
Maybe it uses a completely different type
of molecule to store information.
556
00:37:37,004 --> 00:37:38,672
That would be very exciting.
557
00:37:39,382 --> 00:37:44,594
And could there be life that doesn't
require DNA, carbon, or water?
558
00:37:46,847 --> 00:37:49,140
It may be that ours
is kind of a crappy planet...
559
00:37:49,183 --> 00:37:50,392
compared to what's out there...
560
00:37:50,434 --> 00:37:51,434
that there
may be other planets...
561
00:37:51,477 --> 00:37:54,437
that are much more optimized
for advanced life.
562
00:37:56,440 --> 00:37:59,484
Many of my colleagues, which are
doing astrobiological research...
563
00:37:59,527 --> 00:38:04,114
they're looking for life that, unkindly,
I might typify as stupid life.
564
00:38:04,156 --> 00:38:05,740
They're looking for microbes mostly.
565
00:38:05,783 --> 00:38:07,534
There may be something
a little bit bigger.
566
00:38:09,412 --> 00:38:12,080
Some astrobiologists
want a close encounter...
567
00:38:12,123 --> 00:38:14,916
with something more
than just a microbe.
568
00:38:18,129 --> 00:38:24,050
They're looking for intelligent life
that's perhaps even smarter than us.
569
00:38:30,224 --> 00:38:35,687
The search for life extends
beyond looking for slimy bacteria.
570
00:38:38,190 --> 00:38:41,943
In astrobiology,
a crack team of scientists...
571
00:38:41,986 --> 00:38:45,655
wants to make contact
with something much grander.
572
00:38:46,824 --> 00:38:50,160
SETl, of course, is looking
for intelligent life in space...
573
00:38:50,202 --> 00:38:51,619
but it doesn't just stop there.
574
00:38:51,662 --> 00:38:53,663
They have to be not only intelligent...
575
00:38:53,706 --> 00:38:55,665
but they have to be
technologically competent.
576
00:39:00,004 --> 00:39:03,548
The Search for Extraterrestrial
Intelligence Institute...
577
00:39:03,591 --> 00:39:07,719
better known as SETl,
uses radio technology...
578
00:39:07,762 --> 00:39:11,931
to listen for radio leaks
from alien civilizations.
579
00:39:13,017 --> 00:39:16,311
It's based on the premise
that humans need to communicate.
580
00:39:16,354 --> 00:39:20,440
So perhaps alien nations also
want to get their message out.
581
00:39:22,693 --> 00:39:25,904
What we try and do is simply
try and eavesdrop on signals...
582
00:39:25,946 --> 00:39:29,324
either radio waves that
we could pick up with our antennas...
583
00:39:29,367 --> 00:39:31,368
or flashing laser lights.
584
00:39:31,410 --> 00:39:35,246
They might be using big lasers
to aim pulses of light in our direction.
585
00:39:38,042 --> 00:39:39,417
I am not man.
586
00:39:39,460 --> 00:39:40,919
I am microbe.
587
00:39:40,961 --> 00:39:43,671
I'm also Seth Shostak
for the SETl Institute...
588
00:39:43,714 --> 00:39:45,382
whose mission is to understand...
589
00:39:45,424 --> 00:39:47,175
the nature and origin
of life in the universe.
590
00:39:47,218 --> 00:39:49,677
And I'm Molly Bentley.
Welcome to "Are We Alone?"
591
00:39:49,720 --> 00:39:52,013
We'll remind you
that there's more to life...
592
00:39:52,056 --> 00:39:54,391
than just what you find
at your local zoo.
593
00:39:57,186 --> 00:40:00,939
At SETl, senior astronomer
Seth Shostak...
594
00:40:00,981 --> 00:40:04,859
hosts a regular radio show
that's podcasted.
595
00:40:04,902 --> 00:40:06,820
We're buggin' out with microbes.
596
00:40:06,862 --> 00:40:08,988
There are so many
cohabitating with you.
597
00:40:09,031 --> 00:40:11,658
You're listening to
"Hand Me A Microbe. "
598
00:40:11,700 --> 00:40:13,535
Shostak broadcasts lively...
599
00:40:13,577 --> 00:40:17,205
yet informative
science-related news to Earthlings...
600
00:40:17,248 --> 00:40:22,877
as well as other advanced civilizations
that have the means to listen in.
601
00:40:22,920 --> 00:40:25,213
Cynthia Phillips,
thanks forjoining me today.
602
00:40:25,256 --> 00:40:28,007
We are so fond of radio
for listening...
603
00:40:28,050 --> 00:40:32,345
that we started a weekly radio show
in which we, in a sense, broadcast.
604
00:40:32,388 --> 00:40:34,973
There are a lot of people
who are interested in SETl...
605
00:40:35,015 --> 00:40:37,559
because everybody's interested
in aliens in the same way...
606
00:40:37,601 --> 00:40:39,853
that just about everybody's
interested in dinosaurs.
607
00:40:39,895 --> 00:40:41,521
People are just interested in that.
608
00:40:41,564 --> 00:40:43,565
So we're trying to take
advantage of the fact...
609
00:40:43,607 --> 00:40:45,358
that they're interested
in what we do...
610
00:40:45,401 --> 00:40:48,069
to get them interested
in some broader subjects...
611
00:40:48,112 --> 00:40:50,155
in science and also technology.
612
00:40:53,659 --> 00:40:57,495
SETl has been listening
for signals since the 1960s...
613
00:40:58,456 --> 00:41:00,915
but E.T. hasn't phoned in.
614
00:41:03,127 --> 00:41:06,087
This silence has fueled skepticism.
615
00:41:08,090 --> 00:41:10,967
And we're going to find
lots of planets with life.
616
00:41:11,010 --> 00:41:14,137
I'm guessing that intelligence
will be rare...
617
00:41:14,180 --> 00:41:17,015
but they won't be smart in the way
that humans are smart.
618
00:41:17,057 --> 00:41:18,391
That's going to be rare.
619
00:41:19,059 --> 00:41:21,352
But, again, that's just my intuition.
620
00:41:21,395 --> 00:41:24,272
Aliens can't get here faster
than the speed of light.
621
00:41:24,315 --> 00:41:26,149
Physics doesn't allow that.
622
00:41:26,192 --> 00:41:27,942
And that means,
since we've only been broadcasting...
623
00:41:27,985 --> 00:41:29,444
for, say, sixty years...
624
00:41:29,487 --> 00:41:34,073
they can't be coming from a planet
more than thirty light-years away.
625
00:41:34,116 --> 00:41:37,702
Well, the number of stars
within thirty light-years is pretty small.
626
00:41:42,166 --> 00:41:47,086
Our universe is
over twelve billion years old.
627
00:41:47,129 --> 00:41:51,841
Planet Earth has only been around
for over 4.6 billion years.
628
00:41:53,552 --> 00:41:59,390
Therefore, there are planets millions
and billions of years older than us.
629
00:42:00,684 --> 00:42:03,811
So, if there's life
beyond the Milky Way galaxy...
630
00:42:04,605 --> 00:42:06,773
it potentially could be millions...
631
00:42:06,815 --> 00:42:09,943
to billions of years
more advanced than us.
632
00:42:12,279 --> 00:42:14,864
I think that the truly
intelligent species out there...
633
00:42:14,907 --> 00:42:17,200
if they ever happened upon us...
634
00:42:17,243 --> 00:42:21,496
would maybe regard us
as we regard ants or bacteria...
635
00:42:21,539 --> 00:42:23,790
as some primitive example of life.
636
00:42:24,542 --> 00:42:29,337
Anybody we meet is going to be
much more advanced than us...
637
00:42:29,380 --> 00:42:31,589
at least certainly
much more aged than us...
638
00:42:31,632 --> 00:42:34,551
in terms of how long
they have been a civilization.
639
00:42:37,596 --> 00:42:41,307
If intelligent civilizations
do exist beyond Earth...
640
00:42:41,350 --> 00:42:43,017
what would they look like?
641
00:42:44,687 --> 00:42:46,938
If we find intelligence in space...
642
00:42:46,981 --> 00:42:49,732
it's moved on
beyond biological intelligence...
643
00:42:49,775 --> 00:42:52,110
and moved on
to machine intelligence.
644
00:42:53,237 --> 00:42:56,656
A thinking machine that represents
a million years' evolution...
645
00:42:56,699 --> 00:42:58,408
beyond where we are.
646
00:42:58,450 --> 00:42:59,784
Who knows how it's built?
647
00:42:59,827 --> 00:43:02,912
All you know is that it might
be really, really smart.
648
00:43:03,747 --> 00:43:07,875
There's no logical reason
why there shouldn't be machines...
649
00:43:07,918 --> 00:43:10,378
from other worlds
exploring our planet...
650
00:43:10,421 --> 00:43:13,214
coming into our airspace...
651
00:43:13,257 --> 00:43:16,259
maybe even attempting
to interact with us in some way.
652
00:43:19,847 --> 00:43:25,351
Whether we find a trace of bacteria
or a high-tech civilization...
653
00:43:25,394 --> 00:43:28,646
any discovery of life
will revolutionize...
654
00:43:28,689 --> 00:43:33,192
the way we think
about the universe and ourselves.
655
00:43:35,237 --> 00:43:37,697
Until then, it remains...
656
00:43:37,740 --> 00:43:41,951
one of the greatest
unsolved mysteries of all time.
657
00:43:43,954 --> 00:43:46,372
And we're going to see
a real zoo out there...
658
00:43:46,415 --> 00:43:48,416
when we finally do
discover alien life.
659
00:43:48,459 --> 00:43:51,628
All sorts of different ways
of coding information...
660
00:43:51,670 --> 00:43:55,465
and making molecules,
causing the phenomenon of life.
661
00:43:58,093 --> 00:43:59,802
The people that work
on this field are geeks...
662
00:43:59,845 --> 00:44:02,555
so we imagine making contact
with alien geeks, right?
663
00:44:02,598 --> 00:44:05,433
And that we're going to have fun
talking about equations together...
664
00:44:05,476 --> 00:44:07,727
but maybe we'll end up
making contact...
665
00:44:07,770 --> 00:44:09,228
with alien hipsters or bohemians...
666
00:44:09,271 --> 00:44:10,813
and we'll need
some other forum.
667
00:44:13,942 --> 00:44:16,653
So, life as we don't know it.
668
00:44:16,695 --> 00:44:18,279
Thanks very much
for talking with me.
669
00:44:18,322 --> 00:44:20,448
I'm Seth Shostak
for the SETl institute...
670
00:44:20,491 --> 00:44:21,949
where we always listen...
671
00:44:21,992 --> 00:44:23,993
but, occasionally,
we broadcast.
59967
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