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[narrator] The earth is
over 4.5 billion years old.
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00:00:05,878 --> 00:00:09,246
Its history is shaped
by disaster...
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...after disaster.
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00:00:14,086 --> 00:00:16,253
[Paul M. Sutter] Asteroid
and comet collisions,
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flares from the Sun.
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[Jani Radebaugh]
Mass extinctions,
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supernova explosions,
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cosmic ray bombardment.
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You name it,
we've experienced it.
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It's kind of a miracle
we're here at all.
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[narrator]
These violent events
could be why Earth has life
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[Nina Lanza] We tend to thin
of disaster as a bad thing,
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but out of chaos
can come possibility.
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When we destroy something,
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we can also create
something new.
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[narrator] Earth has walked
the line between survival..
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...and destruction.
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It's tipping that fine
balance of luck
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between a good disaster
and a bad disaster.
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[narrator]
Could catastrophe and chaos
be the essential ingredient
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for life?
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2021.
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Scientists investigate
something mysterious
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buried deep inside the earth
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It's a long hidden clue
to our violent past.
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[Michelle Thaller] Deep down
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1,800 miles
below the surface
of the earth,
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our core is surrounded
by fluid rock,
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but inside that,
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600 miles high
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and thousands of miles across
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are two denser regions,
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and they kind of cup
the core of our planet
like two hands.
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One of them is, you know,
half the size of Australia,
for crying out loud.
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So, I mean, they're
big lumps down there.
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There's no reason
they should be there.
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It's a mystery to us.
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[narrator] To solve
this mystery,
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scientists need
to examine the rocks
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buried over 1,000 miles
beneath the surface.
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We don't really know
what these two big rocks
are made of,
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sitting there on the core.
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However, we've been
able to sample them.
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How in the world
is that possible?
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Well, these blobs are actual
feeding mantle plumes
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that are rising
up through the mantle.
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[Dan Durda] So, volcanoes
in Iceland and Samoa,
for instance,
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will dredge up some
of these lumps of rock
from the mantle.
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It's a precious chance
for us to sample some
of that deep rock
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that we'd normally not
get a chance to see.
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[narrator] These rocks
are old.
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Very old.
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[Radebaugh] It turns out
that the samples in the lav
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that we think came
from these blobs of rock
in the mantle
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are 4.5 billion years old.
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That is as old
as the age of the earth.
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[Durda] So, they tell us
something about, you know,
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how the internal
structure of our planet
was, uh, arranged
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in the earliest days
of the formation
of our planet,
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so getting samples
from that time is
very, very important.
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[narrator] The age
of the rocks may be
a clue to their origin.
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They date back to a time
of monstrous cosmic mayhem.
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[Kevin Walsh]
4.5 billion years ago,
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the solar system was
still a pretty wild place.
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We're approaching the end
of the formation of planets.
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Earth would still be growing.
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[James Bullock] Back then,
you wouldn't necessarily
recognize the earth.
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In fact, you wouldn't
recognize the earth at all.
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For example, no moon.
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The earth did not have a moon
when it first formed.
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[narrator]
The young earth orbits the S
with other infant planets.
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One of them is an object
scientists call Theia...
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...and it's
on a collision course
with our home.
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[Bullock]
The Theia collision would ha
been a spectacular event.
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It would've been one
of the coolest things
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you could possibly witness
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in the origin
of the solar system,
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certainly the biggest event
in the history of the earth.
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[Konstantin Batygin]
The Theia event is
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something that completely
reshaped the earth.
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The planet that the earth
was before the Theia event
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is gone forever.
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[narrator] The impact
melts rock
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and throws out over a billio
billion tons of debris.
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[Thaller] During
this incredible collision,
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these two planets were
literally broken apart
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and combined
into one big planet.
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Huge chunks of Theia
stayed together
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as the now molten earth
began to form anew.
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[Radebaugh] Now, we can
kind of paint a picture
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of where these big lumps
of rock might have come from.
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They're very old.
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They're, in fact, the same age
as that large impact event.
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They could be pieces of Thei
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[narrator] The giant slabs
of Theia sink down
into our planet...
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...and lie undiscovered
for billions of years.
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Earth reforms from the ruin
of both planets.
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Now, you might think
that a collision like this
is just devastating,
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there's no upside at all,
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but there's some
things that came out
of this collision
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that may have led
to the possibility of life.
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[narrator] When these two
planets combined,
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parts of Theia's iron core
merged with Earth's.
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So, that means that Earth
collected a much bigger core
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than it might have
possessed on its own.
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This is good news for us
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because the core is the source
of the magnetic field
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that protects us.
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[narrator] Liquid metal
flowing around
in the outer core
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generates Earth's
magnetic field...
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...a protective shield
from the Sun.
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[Thaller] The Sun can actual
output billions of tons
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of high-energy
protons and electrons
in a single burp.
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That, eventually, would hav
stripped away our atmosphere
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If it weren't
for that active core
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and that magnetic field,
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we would look like Mars,
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just sort of a bare
and barren desert.
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[narrator] Thanks
to Theia's extra iron,
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Earth's molten
outer core is large...
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...so it cools slowly,
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staying molten,
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and keeps on generating
a strong magnetic shield.
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[Thaller]
Because of that collision,
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the extra iron,
the extra heat,
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we've stayed active.
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We have a magnetic field.
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We are protected,
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and, in fact, that's why we're
here talking about it.
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[narrator]
The catastrophic impact
helped life in other ways.
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[Walsh] The Theia event
was absolutely huge,
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and not an impact like
a 100-mile asteroid making
a big crater in the desert,
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but a planet hitting a planet,
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causing a huge disk of debris
spread out from the earth,
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out of which formed the Moon
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[narrator]
After the collision,
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the earth tilts on its side
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and spins incredibly fast.
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A day only lasts a few hours
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The earth itself rotates
slightly on its side,
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and, if left to its
own devices,
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would, in fact,
experience unpredictable,
chaotic wobbling.
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The fact that the Moon
is there
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stabilizes the earth,
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stabilizes our climate.
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[narrator] The Moon's
gravitational pull
on our oceans
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creates tides and slows
down the earth's spin...
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...creating a world
primed for life.
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We actually owe quite a bit
to the Moon and Theia,
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its progenitor,
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for making Earth
a hospitable planet
for life.
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[Sutter] A giant collision
4.5 billion years ago
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sounds like a catastrophe,
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but it was probably the best
thing to happen to the earth.
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Theia, I would shake your ha
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because we have
a lot to owe you.
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[narrator] We also owe
the science of chance
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because we lucked out
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with a one
in a million impact.
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If the impact from Theia
had been a little bit harder,
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the earth may not have
recovered as well as it did,
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and we may not be here
to talk about it right now.
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If it had been a little bit
less forceful,
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then the impact of it may no
have made the changes
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that we think were needed
for us to be here now.
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We got lucky.
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Most planets
don't get to survive
a collision like that
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and get a bonus moon
out of the deal.
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[narrator] Earth's
huge collision with Theia
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was not our planet's
first brush with danger.
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An earlier explosive event
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could have stopped
the solar system
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from sparking into life...
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...and the earth from formin
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[narrator] Supernovas
are one of the universe's
most destructive events...
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...releasing, in one second.
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...as much energy
as our sun will
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in its entire lifetime.
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But rather than wipe us out
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supernovas may have
kick-started the solar syste
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4.6 billion years ago,
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the solar system's not even
really the solar system.
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It's the precursor
of the solar system.
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[Phil Plait] So, what we ha
was a cloud of gas and dust
collapsing in on itself,
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forming the Sun in the cente
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a big, flat disk around it
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out of which all the planets
were forming.
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[Thaller] There are all kind
of vast clouds of dust and g
floating around the Galaxy.
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What actually causes them
to start collapsing
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and forming new stars?
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Well, you have to give
that cloud a push.
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[narrator] Scientists
think this push could
be a stellar blast...
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...a supernova.
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[Sarafina Nance] Supernova
are some of the most powerfu
events in the universe.
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One explosion can light up
brighter than a galaxy.
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So, not only do they eject
elements and material,
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they also eject a lot
of light and energy.
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[narrator]
A supernova explosion
sends a shock wave
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racing out into space
at 18,000 miles per second.
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00:11:04,903 --> 00:11:07,137
The shock wave
from a nearby supernova
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compresses material together
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until it begins to collapse
under its own gravity.
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[narrator] Was this how
our solar system started?
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[Bullock] So far,
it's been really difficult
to find, uh, evidence
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that there was some supernova,
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or point to something
that happened
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that really kick-started
the solar system.
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[narrator] The ancient
supernova blast faded
away a long time ago.
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[Plait] Imagine a crime scen
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Now, imagine waiting
4.6 billion years
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after the crime is committed,
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and looking at it and going,
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00:11:43,975 --> 00:11:44,574
"There's... There's
nothing here.
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What are we doing?"
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00:11:45,710 --> 00:11:48,278
Uh, that's kinda what
we're trying to do here.
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[narrator] Researchers from
the University of Minnesota
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tried to solve
this ancient crime...
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...by studying asteroids
that fell to Earth
as meteorites.
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Asteroids are critical
for understanding
the early solar system,
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and this is because they
have frozen in place
all the conditions
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that existed
in that very early
solar nebula,
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right at 4.5 billion
years ago.
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[narrator] The asteroids
contain information
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about the time leading
up to the birth of the Sun
and the solar system.
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When a massive star ends
its life as a supernova,
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it undergoes what we
call nucleogenesis.
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In fact, we call it
explosive nucleogenesis.
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Literally, the explosion
is generating new types
of nuclei,
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new elements,
heavier elements.
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Well, it turns out the types
of elements it makes
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depends on the star
that blew up.
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[narrator] The Minnesota tea
ran computer simulations
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00:12:49,674 --> 00:12:53,042
to investigate
which elements form
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00:12:53,044 --> 00:12:58,014
when a star up to 12 times
the mass of the Sun explodes
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Then, they compared
the results
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00:13:02,521 --> 00:13:06,122
with analysis of elements
found in asteroids
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00:13:06,124 --> 00:13:09,159
dating back to the birth
of the solar system.
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They match.
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[Nance] So, the remains
of this supernova was actual
under our noses all along
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00:13:18,603 --> 00:13:22,472
in the elements that have been
in our solar system for ages.
241
00:13:23,241 --> 00:13:26,009
[narrator] And perhaps
in the earth as well.
242
00:13:27,712 --> 00:13:30,613
[Thaller] The earth has
lots of rocks that's made
of, uh, silicon.
243
00:13:30,682 --> 00:13:33,817
That's only produced
in supernova explosions,
244
00:13:33,819 --> 00:13:35,151
and the very core
of our earth,
245
00:13:35,153 --> 00:13:36,553
the thing that keeps us alive,
246
00:13:36,555 --> 00:13:38,021
that's iron, nickel.
247
00:13:38,023 --> 00:13:41,324
Again, you only get that
in supernova explosions.
248
00:13:42,761 --> 00:13:44,727
[narrator] In February 2021
249
00:13:44,729 --> 00:13:47,730
scientists shed light
on the supernova explosions
250
00:13:47,732 --> 00:13:49,966
that helped seed
our solar system
251
00:13:49,968 --> 00:13:53,203
and provided the materials
to build our planet.
252
00:13:55,774 --> 00:13:58,041
The research
examined fragments
253
00:13:58,043 --> 00:14:01,244
blasted off the giant
space rock, Vesta...
254
00:14:02,781 --> 00:14:04,781
...4.5 billion years ago,
255
00:14:04,783 --> 00:14:07,050
and later landed on Earth.
256
00:14:11,122 --> 00:14:13,590
These asteroid fragments
contain the fingerprints
257
00:14:13,592 --> 00:14:14,891
of not one,
258
00:14:14,959 --> 00:14:19,696
but at least two
supernova explosions.
259
00:14:19,764 --> 00:14:26,102
Our solar system was seeded,
was enriched, by at least two
separate supernova explosions.
260
00:14:26,371 --> 00:14:27,837
That's incredibly lucky
261
00:14:27,872 --> 00:14:32,141
because that is what
delivers the ingredients
necessary for life.
262
00:14:33,979 --> 00:14:37,647
[narrator] Scientists believ
that these two supernovas
263
00:14:37,649 --> 00:14:40,116
may have enriched
different parts
264
00:14:40,118 --> 00:14:41,684
of the infant solar system.
265
00:14:41,686 --> 00:14:43,920
One provided the materials
266
00:14:43,922 --> 00:14:46,322
that helped form
the outer gas planets.
267
00:14:48,793 --> 00:14:52,795
The other supernova seeded
the inner solar system
268
00:14:52,797 --> 00:14:56,032
with elements that built
the rocky planets,
269
00:14:56,368 --> 00:14:58,001
including the earth.
270
00:15:00,605 --> 00:15:03,940
Once again, our fate
came down to pure chance.
271
00:15:04,776 --> 00:15:08,845
A series of extraordinarily
violent supernova blasts
272
00:15:08,847 --> 00:15:11,714
gave the solar system
the kick-start it needed
273
00:15:11,716 --> 00:15:14,417
and the elements
to build the planets
274
00:15:14,485 --> 00:15:17,754
without destroying
our future home.
275
00:15:17,822 --> 00:15:21,090
It's a fine line between being
too close to a supernova,
276
00:15:21,092 --> 00:15:23,893
which will just shred
your pre-stellar cloud...
277
00:15:23,962 --> 00:15:27,163
...and not too far away
that you don't get any
of the good stuff.
278
00:15:29,267 --> 00:15:33,069
Supernova play both
creation stories
279
00:15:33,071 --> 00:15:34,037
and destruction stories.
280
00:15:34,039 --> 00:15:35,405
They play both roles.
281
00:15:37,342 --> 00:15:38,541
[narrator] We lucked out.
282
00:15:38,543 --> 00:15:41,945
This chapter
of the story ends well.
283
00:15:41,947 --> 00:15:46,316
The solar system gets
the ingredients it needs
to build planets.
284
00:15:47,152 --> 00:15:49,752
Earth forms
in a good location,
285
00:15:49,787 --> 00:15:51,087
close to its star.
286
00:15:52,857 --> 00:15:54,357
The future looks bright,
287
00:15:54,793 --> 00:15:55,959
but then,
288
00:15:56,027 --> 00:15:58,328
the biggest bombardment
in history
289
00:15:58,630 --> 00:16:01,097
smashes into the earth.
290
00:16:12,777 --> 00:16:15,111
[narrator] From the moment
our planet formed...
291
00:16:16,815 --> 00:16:18,147
...we've been under fire.
292
00:16:22,454 --> 00:16:23,819
2021.
293
00:16:23,821 --> 00:16:27,056
A fireball streaks
across the night sky
in Europe.
294
00:16:28,860 --> 00:16:30,159
2018.
295
00:16:30,161 --> 00:16:35,131
A 1,500-ton meteor explodes
over the Bering Sea
296
00:16:35,133 --> 00:16:38,468
with 10 times the energy
of an atomic bomb.
297
00:16:41,840 --> 00:16:43,072
2013.
298
00:16:43,141 --> 00:16:45,508
An asteroid explodes
over Russia,
299
00:16:45,510 --> 00:16:48,044
injuring over 1,000 people.
300
00:16:50,615 --> 00:16:53,149
The earth is hit
by quite a few asteroids
every day.
301
00:16:53,151 --> 00:16:53,850
You see them
as shooting stars,
302
00:16:53,852 --> 00:16:55,418
meteors in the sky.
303
00:16:56,321 --> 00:17:00,123
[narrator] These events
are violent and destructive
304
00:17:00,125 --> 00:17:05,962
but these space invaders
also brought something
every living planet needs:
305
00:17:05,997 --> 00:17:07,764
volatiles.
306
00:17:07,766 --> 00:17:08,998
[Radebaugh] When we
say volatiles,
307
00:17:09,000 --> 00:17:11,200
what we mean are elements
that are really light
308
00:17:11,202 --> 00:17:12,702
and easily moved around.
309
00:17:12,704 --> 00:17:13,736
Often, they're gases,
310
00:17:13,805 --> 00:17:16,873
so that's oxygen, and water,
and carbon dioxide,
311
00:17:16,875 --> 00:17:18,608
and just all
those light elements
312
00:17:18,610 --> 00:17:21,544
that are really important
building blocks for life.
313
00:17:21,546 --> 00:17:24,981
[narrator] These elements ar
abundant on our planet today
314
00:17:24,983 --> 00:17:28,918
but were not
when it first formed.
315
00:17:28,953 --> 00:17:31,854
[Thaller] From observing
other solar systems forming
all around us in space,
316
00:17:31,890 --> 00:17:35,391
we know that planets
as close to their stars
as we are to the Sun,
317
00:17:35,460 --> 00:17:37,660
when they form,
they're very hot and dry.
318
00:17:37,728 --> 00:17:39,695
There's probably some littl
bit of water around there,
319
00:17:39,764 --> 00:17:41,264
but really not very much.
320
00:17:42,667 --> 00:17:44,000
[Hakeem Oluseyi] So,
what this means
321
00:17:44,002 --> 00:17:47,503
is any volatiles will
basically be boiled away.
322
00:17:47,572 --> 00:17:49,705
If you have a molten surface,
323
00:17:49,707 --> 00:17:53,009
anything like water is
gonna get boiled away.
324
00:17:54,779 --> 00:17:57,747
[narrator] Young Earth
was a dry planet,
325
00:17:57,782 --> 00:18:01,150
devoid of all the precious
volatiles needed for life.
326
00:18:02,320 --> 00:18:07,356
These materials must have
been delivered to Earth
after its formation.
327
00:18:11,496 --> 00:18:15,965
We think volatiles
arrived in the early days
of the solar system...
328
00:18:16,835 --> 00:18:19,435
...when the giant planets,
including Jupiter,
329
00:18:19,437 --> 00:18:21,003
moved around...
330
00:18:21,840 --> 00:18:24,373
...and stirred up the conten
of the solar system.
331
00:18:26,411 --> 00:18:27,676
[Plait] As Jupiter moves,
332
00:18:27,678 --> 00:18:29,946
its gravity is pulling
on all the objects in there
333
00:18:29,948 --> 00:18:31,614
basically speeding them up,
334
00:18:31,616 --> 00:18:33,683
and there's a little
bit of chaos there
in the first place,
335
00:18:33,685 --> 00:18:36,085
but now, Jupiter is basically
supercharging it.
336
00:18:36,921 --> 00:18:40,823
[narrator] Jupiter's
path sends countless
asteroids and comets
337
00:18:40,825 --> 00:18:43,326
on a collision course
with the earth.
338
00:18:44,896 --> 00:18:47,029
[Radebaugh] It would have
been utterly chaotic.
339
00:18:47,098 --> 00:18:49,298
This is a rain
of large objects
340
00:18:49,300 --> 00:18:50,900
onto all of the inner planets,
341
00:18:51,035 --> 00:18:56,005
but these objects that came
screaming into Earth
were gigantic.
342
00:18:57,709 --> 00:18:59,876
[narrator] Four billion
years ago,
343
00:18:59,878 --> 00:19:03,012
a storm of giant
asteroids and comets
344
00:19:03,047 --> 00:19:04,147
hits the earth.
345
00:19:05,016 --> 00:19:08,050
Some are tens of miles wide
346
00:19:08,453 --> 00:19:09,919
They bring the volatiles
347
00:19:09,987 --> 00:19:11,687
that help fill
the earth's oceans
348
00:19:11,689 --> 00:19:13,956
and build its atmosphere...
349
00:19:15,160 --> 00:19:17,927
...but cosmic deliveries
can both give
350
00:19:17,995 --> 00:19:19,362
and take.
351
00:19:20,832 --> 00:19:22,865
The importance of impacts
for atmosphere
352
00:19:22,934 --> 00:19:23,966
could go either way.
353
00:19:23,968 --> 00:19:25,835
You could have a...
A really big,
354
00:19:25,870 --> 00:19:27,303
really powerful impact...
355
00:19:28,106 --> 00:19:29,438
...that blows away
the atmosphere
356
00:19:29,474 --> 00:19:31,941
of a small, fledgling planet
357
00:19:31,943 --> 00:19:36,045
or you could have
a bunch of small impacts
of water-rich asteroids
358
00:19:36,047 --> 00:19:38,848
that are simply
contributing water,
and volatiles,
359
00:19:38,850 --> 00:19:40,550
and new chemicals
to the surface
360
00:19:40,552 --> 00:19:43,986
that might help the atmosphe
that's already there.
361
00:19:43,988 --> 00:19:45,922
[Oluseyi] When you
think about an object
coming to Earth,
362
00:19:45,924 --> 00:19:47,990
is it gonna land on Earth,
363
00:19:47,992 --> 00:19:49,759
and if it does land,
364
00:19:49,761 --> 00:19:53,462
is it gonna be a...
An erosive event,
365
00:19:53,464 --> 00:19:55,698
where material is lost
from the earth,
366
00:19:55,766 --> 00:19:57,700
or is it gonna be
an accretion event,
367
00:19:57,768 --> 00:20:00,636
where the earth
gains material?
368
00:20:00,638 --> 00:20:02,305
Well, the devil's
in the details.
369
00:20:03,841 --> 00:20:06,809
[narrator] Details like
the size of the impactor.
370
00:20:06,844 --> 00:20:08,811
One study suggests
371
00:20:08,813 --> 00:20:13,683
that asteroids between 60 fe
and 3,300 feet wide
372
00:20:13,685 --> 00:20:17,353
add more to the atmosphere
than they take away.
373
00:20:24,896 --> 00:20:28,297
And speed at the point
of impact also matters.
374
00:20:29,367 --> 00:20:31,667
Asteroids are orbiting
the sun.
375
00:20:31,669 --> 00:20:34,537
And when they fall
towards the sun,
they are gaining speed,
376
00:20:34,605 --> 00:20:36,572
they're gaining velocity.
377
00:20:36,574 --> 00:20:40,042
Imagine dropping
a coin into one of those
spiral wells.
378
00:20:40,979 --> 00:20:42,578
As the coin gets
closer and closer
to the middle,
379
00:20:42,580 --> 00:20:45,047
it spins up faster and faste
380
00:20:47,752 --> 00:20:50,620
[narrator] The closer
an asteroid gets to the sun
381
00:20:50,622 --> 00:20:53,456
the stronger
the sun's
gravitational pull...
382
00:20:54,525 --> 00:20:57,126
...and the faster
the asteroid travels.
383
00:20:59,731 --> 00:21:01,964
[Jessie Christiansen]
So proximity to your star
384
00:21:01,966 --> 00:21:04,433
is a vital factor
in how intense
any impacts will be.
385
00:21:14,178 --> 00:21:15,678
[James Bullock] It's possibl
that the Earth
386
00:21:15,713 --> 00:21:18,114
is the right distance
from its host star
387
00:21:18,116 --> 00:21:19,282
so that when
an impact happens,
388
00:21:19,317 --> 00:21:22,218
the energy
isn't insanely high.
389
00:21:22,220 --> 00:21:26,055
It's just the right amount
that it's the right speed
to make everything work.
390
00:21:27,725 --> 00:21:30,726
[narrator] Supernovas seed
the solar system
391
00:21:30,728 --> 00:21:33,829
with the elements
to build the planets.
392
00:21:33,865 --> 00:21:39,669
Asteroids and comets delive
volatile chemicals
to the surface of the Earth
393
00:21:39,671 --> 00:21:44,507
Together they create
a habitable environment.
394
00:21:44,509 --> 00:21:49,478
So we need
those impacts to happen
to have life on Earth.
395
00:21:49,480 --> 00:21:54,750
[narrator] Disasters create
a planet primed for life.
396
00:21:54,752 --> 00:21:57,620
But it appears that even mor
mayhem and chaos
397
00:21:57,688 --> 00:22:01,957
are needed
to trigger life itself.
398
00:22:10,868 --> 00:22:14,070
[narrator] An asteroid tear
through the solar system,
399
00:22:14,138 --> 00:22:18,174
hurdling through space
at 40,000 miles an hour.
400
00:22:19,911 --> 00:22:21,043
It's destination,
401
00:22:21,045 --> 00:22:22,344
Earth.
402
00:22:23,748 --> 00:22:27,216
Will this space rock inflic
unimaginable damage...
403
00:22:27,952 --> 00:22:31,020
...or will it bring
the spark of life?
404
00:22:34,792 --> 00:22:36,559
This idea of a spark of life,
405
00:22:36,561 --> 00:22:37,626
we've all kinda seen it
406
00:22:37,695 --> 00:22:39,995
in the Frankenstein movies,
right? "It's alive!"
407
00:22:40,565 --> 00:22:43,599
This comes from legend,
from myth, from history
408
00:22:43,634 --> 00:22:46,602
that there's some sort of
a spark that differentiates
409
00:22:46,604 --> 00:22:49,705
cold inanimate matter
from living stuff.
410
00:22:49,707 --> 00:22:52,375
And in some sense
it's kind of true.
411
00:22:56,114 --> 00:22:59,515
[narrator] On Earth, we thin
this spark may have arrived
412
00:22:59,517 --> 00:23:01,951
over 4 billion years ago.
413
00:23:04,689 --> 00:23:07,823
The Hadean Eon
was the time
from the Earth's formation
414
00:23:07,892 --> 00:23:10,192
about 4.6 billion years ago
415
00:23:10,227 --> 00:23:11,761
to about 4 billion years ago.
416
00:23:11,763 --> 00:23:14,430
It's named
after literally Hades.
417
00:23:14,465 --> 00:23:18,234
So the conditions on Earth
were literally hellish.
418
00:23:20,571 --> 00:23:23,706
[Dan Durda]
It was hot and soupy,
a lot of water vapor around
419
00:23:23,774 --> 00:23:26,375
high pressure atmosphere,
very intense heat.
420
00:23:26,811 --> 00:23:28,511
You wouldn't survive.
421
00:23:28,579 --> 00:23:30,379
The planet would
literally kill you back then.
422
00:23:34,452 --> 00:23:37,887
It's shocking.
And I mean, really shocking
423
00:23:37,889 --> 00:23:40,890
that the evidence
of first life that we have
on Earth
424
00:23:40,958 --> 00:23:42,958
dates to the Hadean Eon.
425
00:23:42,993 --> 00:23:45,628
This was a terrible place,
426
00:23:45,630 --> 00:23:48,898
molten and poisonous
and awful.
427
00:23:48,900 --> 00:23:52,201
And yet life somehow arose
in all of that mess.
428
00:23:54,972 --> 00:23:56,939
[narrator] June 2020,
429
00:23:57,007 --> 00:23:59,775
Japanese scientists simulat
the conditions
430
00:23:59,844 --> 00:24:02,044
of this hellish planet...
431
00:24:02,847 --> 00:24:06,949
...and then try to recreate
the spark of life.
432
00:24:06,951 --> 00:24:09,718
So what the scientists
were trying to do was mimic
those conditions
433
00:24:09,720 --> 00:24:11,086
and see what would happen.
434
00:24:11,155 --> 00:24:13,956
If you smash a meteorite
into the ocean back then,
435
00:24:13,958 --> 00:24:15,724
could it produce sort of
the same chemicals
436
00:24:15,759 --> 00:24:18,961
that we see life using today?
437
00:24:18,963 --> 00:24:23,933
[narrator] They use a mix
of carbon dioxide, nitrogen
water, and iron
438
00:24:23,935 --> 00:24:27,036
to replicate
the Hadean environment.
439
00:24:29,574 --> 00:24:35,044
Firing a mini meteor
at 2,000 miles an hour
into this chemical soup
440
00:24:35,046 --> 00:24:39,215
triggers a reaction between
the basic organic elements..
441
00:24:40,485 --> 00:24:43,052
...creating amino acids.
442
00:24:44,522 --> 00:24:47,957
We call amino acids
the building blocks of life.
443
00:24:47,959 --> 00:24:49,925
Really they're
the building blocks
of proteins.
444
00:24:49,927 --> 00:24:52,428
And life needs
proteins to exist.
445
00:24:52,496 --> 00:24:53,896
But that's why
they're so important.
446
00:24:53,898 --> 00:24:56,065
Without amino acids,
there's no proteins,
447
00:24:56,133 --> 00:24:58,467
without proteins,
no life as we know it.
448
00:25:00,805 --> 00:25:02,371
[narrator]
The experiment proves
449
00:25:02,373 --> 00:25:06,308
that meteorite impacts
can help build
the components for life.
450
00:25:09,780 --> 00:25:12,114
But for these building block
to come together
451
00:25:12,182 --> 00:25:14,049
and create life,
452
00:25:14,051 --> 00:25:15,417
we need more.
453
00:25:17,188 --> 00:25:18,787
It's like making a cake.
454
00:25:18,789 --> 00:25:21,924
You can put together
the oil, and the flour,
and the butter, and the sugar,
455
00:25:21,926 --> 00:25:22,958
but if you don't put it
in an oven,
456
00:25:22,960 --> 00:25:24,660
you're not gonna end up
with a cake.
457
00:25:24,662 --> 00:25:26,195
You're gonna end up
with something else.
458
00:25:26,998 --> 00:25:29,832
[narrator] We thought
that the violence
of asteroid impacts
459
00:25:29,834 --> 00:25:32,368
prevented life from forming
460
00:25:35,273 --> 00:25:40,009
Now, we think they could be
an essential ingredient.
461
00:25:40,978 --> 00:25:43,746
[Phil Plait]
If the asteroid impact
is big enough and fast enoug
462
00:25:43,748 --> 00:25:46,081
it can punch
right through the crust.
463
00:25:47,985 --> 00:25:49,952
Then you're getting
geothermal heat,
464
00:25:49,987 --> 00:25:52,354
heat the bubbles up
from the mantle.
465
00:25:52,423 --> 00:25:56,759
And it is certainly possibl
to get an asteroid impact
that big.
466
00:25:56,761 --> 00:26:01,897
[narrator]
Large meteorite impacts
can create hydrothermal vent
467
00:26:01,899 --> 00:26:05,334
which some scientists believ
were the cradles of life.
468
00:26:06,370 --> 00:26:09,638
They provide
warm, wet environments
469
00:26:09,640 --> 00:26:13,242
and bring up chemicals
from deep inside
the Earth's crust...
470
00:26:14,979 --> 00:26:18,280
...the perfect place
for life to begin.
471
00:26:20,184 --> 00:26:22,718
As bad as those conditions
seem to us,
472
00:26:22,720 --> 00:26:27,923
to the molecules
that are beginning to combin
and do their thing,
473
00:26:27,925 --> 00:26:30,059
that was
a wonderful place to be.
474
00:26:30,127 --> 00:26:31,794
That could actually be
that the conditions
475
00:26:31,796 --> 00:26:33,729
that are best for early life
476
00:26:33,731 --> 00:26:36,432
might actually be those
just after an impact.
477
00:26:37,568 --> 00:26:40,769
So you have sort of
this petri dish environment
478
00:26:40,771 --> 00:26:43,272
in which life
could really thrive.
479
00:26:47,278 --> 00:26:48,410
[narrator] These vents
might be similar
480
00:26:48,479 --> 00:26:52,047
to those we see
in the oceans today.
481
00:26:53,217 --> 00:26:57,052
[Lewis Dartnell]
These hydrothermal vents
provide little window
482
00:26:57,054 --> 00:27:00,522
into what the conditions
on the primordial Earth
would've been like.
483
00:27:00,558 --> 00:27:02,591
And the sort of chemistry
484
00:27:02,593 --> 00:27:05,594
that goes on
in those hydrothermal fluids
485
00:27:05,630 --> 00:27:10,165
seems to be the right
kind of chemistry
for creating life.
486
00:27:12,803 --> 00:27:16,005
[narrator] Once again,
Earth got lucky.
487
00:27:17,942 --> 00:27:22,011
Impacts that could've
destroyed everything...
488
00:27:22,647 --> 00:27:26,949
...may have helped
spark life into existence.
489
00:27:28,386 --> 00:27:31,153
[Hakeem Oluseyi] I once hear
this quote from Confucious..
490
00:27:31,155 --> 00:27:35,324
...that creation is quiet
but destruction is loud.
491
00:27:36,694 --> 00:27:38,727
Well, these impacts
492
00:27:38,729 --> 00:27:43,098
were both destructive,
but they also
may have been creators.
493
00:27:43,768 --> 00:27:47,069
[narrator] Earth leaves behi
the Hadean age.
494
00:27:47,772 --> 00:27:51,340
The planet calms,
and life takes hold.
495
00:27:51,342 --> 00:27:55,511
But disaster
is our constant companion
496
00:27:55,546 --> 00:28:00,449
as we prepare to face a stor
of deadly cosmic bullets.
497
00:28:12,763 --> 00:28:16,098
[narrator] The universe
is a dangerous place for lif
498
00:28:16,100 --> 00:28:18,434
There are asteroid impacts..
499
00:28:22,073 --> 00:28:24,006
...black holes...
500
00:28:25,743 --> 00:28:27,209
...and exploding stars.
501
00:28:29,180 --> 00:28:31,513
But public enemy No. 1
502
00:28:31,515 --> 00:28:32,847
cosmic rays...
503
00:28:35,052 --> 00:28:39,655
...lethal energic particles
born in violent events.
504
00:28:39,657 --> 00:28:42,891
Cosmic rays
are incredibly small
505
00:28:42,893 --> 00:28:46,061
but travel so fast,
near the speed of light,
506
00:28:46,063 --> 00:28:49,298
but they can tear
through our DNA and damage i
507
00:28:49,900 --> 00:28:51,600
Your full of DNA.
508
00:28:51,602 --> 00:28:53,769
If that DNA gets broken apart,
guess what happens?
509
00:28:53,771 --> 00:28:57,072
That could lead
to cancer and death.
510
00:28:57,074 --> 00:29:01,610
At first glance,
these cosmic rays
are the worst things for life.
511
00:29:01,612 --> 00:29:03,112
They're terrible.
512
00:29:03,748 --> 00:29:05,981
[narrator] Despite
their frighting rap sheet,
513
00:29:06,049 --> 00:29:10,219
cosmic rays may have played
a crucial roll
in the evolution of life.
514
00:29:14,458 --> 00:29:16,024
2020,
515
00:29:16,059 --> 00:29:18,594
scientists at New York
and Stanford universities
516
00:29:18,596 --> 00:29:23,098
investigate
biological molecules
that have a twin...
517
00:29:24,201 --> 00:29:28,370
...mirror image versions
called chiral molecules.
518
00:29:29,473 --> 00:29:31,640
The concept of chirality
in chemistry
519
00:29:31,642 --> 00:29:33,575
is when you have
two molecules, two chemicals,
520
00:29:33,577 --> 00:29:34,943
that are physically the same
521
00:29:34,945 --> 00:29:37,546
They're made
of exactly the same things,
522
00:29:37,581 --> 00:29:38,881
but their structure
is different.
523
00:29:38,916 --> 00:29:40,749
And they're
not just different,
524
00:29:40,751 --> 00:29:42,618
they're reflections
of each other.
525
00:29:42,620 --> 00:29:44,153
It's literally
called handedness
526
00:29:44,221 --> 00:29:45,587
because look
here's my right hand
527
00:29:45,589 --> 00:29:47,790
with my thumb over here
and my fingers over here,
528
00:29:47,792 --> 00:29:50,726
here's my left hand
with my thumb over here
and my fingers over here.
529
00:29:50,794 --> 00:29:53,495
I can't wear a left glove
on my right hand.
530
00:29:53,497 --> 00:29:56,965
There's nothing I can do
to make these guys the same.
531
00:29:56,967 --> 00:29:59,835
And it turns out this
is true not just for hands,
532
00:29:59,837 --> 00:30:05,174
but also for large number
of simple organic compounds,
533
00:30:05,209 --> 00:30:08,443
things like amino acids
or sugars,
534
00:30:08,445 --> 00:30:12,347
which are the building blocks
of all life on Earth.
535
00:30:13,851 --> 00:30:16,985
[narrator]
Billions of years ago,
early life may have had
536
00:30:16,987 --> 00:30:21,323
both left- and right-handed
DNA and RNA.
537
00:30:22,560 --> 00:30:26,562
But life chose to use
mostly right-handed molecule
538
00:30:26,564 --> 00:30:29,364
The reason may have been
cosmic rays.
539
00:30:33,838 --> 00:30:37,272
When cosmic rays hit
Earth's atmosphere...
540
00:30:38,442 --> 00:30:42,611
...they degrade
into even smaller
subatomic particles
541
00:30:42,613 --> 00:30:44,046
called muons.
542
00:30:44,582 --> 00:30:48,784
Most muons spin
in one direction.
543
00:30:48,786 --> 00:30:51,520
So we have these little muons,
which are very energetic,
544
00:30:51,522 --> 00:30:53,455
and they're spinning
a certain way.
545
00:30:53,457 --> 00:30:56,391
And when they hit a molecule
they interact with it.
546
00:30:56,460 --> 00:30:59,494
They can disrupt it.
They can change it.
547
00:30:59,496 --> 00:31:02,898
[narrator]
Some scientists believe
these spinning muons
548
00:31:02,966 --> 00:31:07,269
interact more readily
with right-handed DNA
and RNA...
549
00:31:09,607 --> 00:31:12,541
...triggering mutations.
550
00:31:12,609 --> 00:31:15,911
[Plait]
Some mutations are beneficia
but they have to get a chanc
551
00:31:15,913 --> 00:31:19,348
So if you have
right-handed molecules
and left-handed molecules,
552
00:31:19,350 --> 00:31:21,316
and they're both being hit
by muons,
553
00:31:21,318 --> 00:31:26,154
the one that's hit more gets
more chances to have
a beneficial mutation.
554
00:31:27,091 --> 00:31:30,859
[narrator] Cosmic rays
may have given
right-handed life
555
00:31:30,861 --> 00:31:32,995
an evolutionary advantage.
556
00:31:34,064 --> 00:31:37,266
Left-handed life
could not compete.
557
00:31:38,869 --> 00:31:39,801
It's like throwing dice.
558
00:31:39,803 --> 00:31:41,603
If you're trying
to get double sixes,
559
00:31:41,672 --> 00:31:43,872
and the left hand only gets
to throw ten times,
560
00:31:43,941 --> 00:31:46,608
and the right hand gets
to throw 100 times,
561
00:31:46,610 --> 00:31:47,743
more likely to get
double sixes
562
00:31:47,745 --> 00:31:50,312
with the right hand
than the left hand.
563
00:31:51,882 --> 00:31:55,751
[narrator] But the dice
don't always land
in our favor.
564
00:31:55,786 --> 00:32:00,188
359 million years ago,
Earth's luck ran out.
565
00:32:00,958 --> 00:32:04,693
And cosmic rays
may have lived up
to their reputation
566
00:32:04,761 --> 00:32:07,262
as the baddest particle
on the block.
567
00:32:09,867 --> 00:32:13,268
[Dartnell] Earth's oceans
were teeming with marine lif
568
00:32:15,873 --> 00:32:17,572
And by this period as well,
569
00:32:17,574 --> 00:32:22,644
plants had started
to colonize onto the contents
and landmasses,
570
00:32:22,646 --> 00:32:26,148
attracting animal life,
insects, millipedes.
571
00:32:26,650 --> 00:32:29,451
And it's in this environmen
572
00:32:29,453 --> 00:32:33,422
the Earth experienced
one of the greatest
mass extensions
573
00:32:33,424 --> 00:32:35,157
in the history of life.
574
00:32:38,762 --> 00:32:44,900
[narrator] Something
killed off 97%
of all vertebrae species.
575
00:32:44,935 --> 00:32:49,204
We call this wipeout
the end Devonian extinction
576
00:32:53,510 --> 00:32:57,245
One possible explanation,
a supernova.
577
00:32:58,248 --> 00:33:03,318
When some dying stars explod
they fire out cosmic rays.
578
00:33:04,755 --> 00:33:09,491
[Dartnell] This radiation
bombards the upper atmospher
of the Earth
579
00:33:09,526 --> 00:33:14,997
and drives the chemistry
of nitrogen, turning
into nitrogen dioxide,
580
00:33:14,999 --> 00:33:17,833
a gas which itself
then reacts
with the ozone layer
581
00:33:17,901 --> 00:33:20,102
and destroys it.
582
00:33:20,804 --> 00:33:22,838
[narrator]
Without the protective
ozone layer,
583
00:33:22,840 --> 00:33:27,476
ultra violet radiation
from the sun bombards Earth
584
00:33:28,579 --> 00:33:32,414
Radiation rains down
for thousands of years...
585
00:33:33,951 --> 00:33:37,085
...damaging the DNA
of plants and animals.
586
00:33:40,324 --> 00:33:42,090
Many species die out.
587
00:33:45,696 --> 00:33:50,465
[Dartnell] The end Devonian
mass extinction
mostly effected marine life
588
00:33:50,467 --> 00:33:55,570
This is where we see
the greatest percentage
of deaths.
589
00:33:55,639 --> 00:34:00,308
[narrator] The oceans
once populated by fish
the size of school buses...
590
00:34:01,578 --> 00:34:05,047
...now host fish
no bigger than a sardine.
591
00:34:06,850 --> 00:34:10,919
These smaller fish
reproduce quickly.
592
00:34:10,921 --> 00:34:12,187
In the challenging
environment,
593
00:34:12,189 --> 00:34:17,292
they adapt and diversify
faster than larger species.
594
00:34:17,327 --> 00:34:20,362
Mass extinction
is not only
wipe the slate clean
595
00:34:20,364 --> 00:34:24,699
and provide other animals
and other life forms
an opportunity,
596
00:34:24,768 --> 00:34:28,370
it creates a sort of chaoti
and complex environment
597
00:34:28,372 --> 00:34:32,374
that drives natural selectio
and evolution.
598
00:34:35,079 --> 00:34:38,580
[narrator] If a supernova
was to blame
for this extinction event,
599
00:34:38,582 --> 00:34:44,086
scientists believe
that the culprit
was 65 light years away.
600
00:34:45,756 --> 00:34:50,258
Any closer and Earth's luck
would've run out completely
601
00:34:50,994 --> 00:34:52,427
It seems the existence of life
602
00:34:52,429 --> 00:34:54,095
is always balanced
on a knife edge.
603
00:34:55,999 --> 00:34:59,201
When an exploding star
goes off a little bit
too close to us...
604
00:35:01,038 --> 00:35:03,171
...and we are all destroyed
605
00:35:05,809 --> 00:35:08,276
So there's
this wonderful balance
606
00:35:08,311 --> 00:35:10,645
between just violent enough
and too violent.
607
00:35:10,714 --> 00:35:15,350
And we have been lucky enough
to dance on that edge
for 4.5 billion years.
608
00:35:16,620 --> 00:35:20,422
[narrator]
This mass extinction
reset life on Earth
609
00:35:20,457 --> 00:35:22,858
and paved the way
for four-legged creatures,
610
00:35:22,926 --> 00:35:25,260
our distant ancestors.
611
00:35:28,832 --> 00:35:31,733
Cataclysmic events
go hand in hand
612
00:35:31,735 --> 00:35:33,368
with human evolution.
613
00:35:33,804 --> 00:35:36,138
Some knocked us back
614
00:35:36,140 --> 00:35:40,976
and others like the event
66 million years ago
615
00:35:40,978 --> 00:35:42,377
gave us a push forward.
616
00:35:49,520 --> 00:35:50,919
[narrator]
66 million years ago
617
00:35:50,921 --> 00:35:54,456
a massive asteroid crashes
into the Earth.
618
00:35:57,761 --> 00:36:01,429
It triggers
a huge extinction event.
619
00:36:01,431 --> 00:36:05,100
Without it humans
may have never evolved.
620
00:36:05,636 --> 00:36:07,302
[Nina Lanza] At this time
in Earth's history,
621
00:36:07,370 --> 00:36:10,872
we had
these enormous plants
and gigantic insects
622
00:36:10,874 --> 00:36:14,409
that actually would be
incredibly terrifying
if we saw them today.
623
00:36:17,147 --> 00:36:19,614
[Christiansen] Pterosaurs sa
through the air.
624
00:36:19,616 --> 00:36:22,150
Huge marine reptiles dominat
the oceans.
625
00:36:22,653 --> 00:36:25,053
And the T. rex is the king
of the world.
626
00:36:29,693 --> 00:36:33,428
[narrator]
Then a glowing object appear
in the sky.
627
00:36:38,602 --> 00:36:39,834
[Durda] I'm sitting
on the beach
628
00:36:39,836 --> 00:36:43,805
what was then gonna be
the Yucatan of Mexico
629
00:36:43,807 --> 00:36:46,441
enjoying a drink
with a, you know,
a little umbrella,
630
00:36:46,443 --> 00:36:49,911
but up there in the sky
all of sudden
631
00:36:49,946 --> 00:36:52,914
approaching me
at 40,000 miles an hour
632
00:36:52,950 --> 00:36:59,621
is Mount Everest glowing
thousands of times
more intensity than the sun...
633
00:36:59,623 --> 00:37:02,991
...and it's just seconds away
from dropping on my head.
634
00:37:03,794 --> 00:37:06,361
[narrator]
A 6 mile wide asteroid...
635
00:37:07,464 --> 00:37:10,031
...slams into the Earth.
636
00:37:15,539 --> 00:37:21,176
The impact throws
trillions of tons
of rock and dust into the ai
637
00:37:23,080 --> 00:37:26,214
The rocks heat up
as they fall back to Earth..
638
00:37:27,351 --> 00:37:29,417
...setting the planet on fir
639
00:37:33,490 --> 00:37:37,392
That beach holiday
suddenly turns into
absolute nightmare.
640
00:37:39,062 --> 00:37:41,630
[narrator] The impact
also throws up soot,
641
00:37:41,632 --> 00:37:43,465
chocking the atmosphere.
642
00:37:44,635 --> 00:37:47,802
Now, the skies are blotted out
by all these materials,
643
00:37:47,804 --> 00:37:52,073
so the sun
is no longer shining brightly
on the surface.
644
00:37:52,976 --> 00:37:56,311
[narrator] Plants need
sunlight to photosynthesize
645
00:37:57,781 --> 00:37:59,948
Without this
vital energy source,
646
00:37:59,950 --> 00:38:02,117
many species die out.
647
00:38:04,788 --> 00:38:06,755
With their food source gone
648
00:38:06,823 --> 00:38:09,824
plant eating dinosaurs starv
to death,
649
00:38:09,826 --> 00:38:12,394
followed by their predators
650
00:38:13,330 --> 00:38:16,631
It was a huge disruption
to all of life on Earth.
651
00:38:16,633 --> 00:38:20,535
The dinosaurs have been
around for 160 million years
at this point.
652
00:38:20,537 --> 00:38:21,703
That's astronomical
amount of time.
653
00:38:21,705 --> 00:38:24,039
And in one event,
[snaps fingers] they're gone.
654
00:38:24,841 --> 00:38:28,777
[narrator] Again the dice ro
is in our favor.
655
00:38:28,779 --> 00:38:31,012
Most dinosaurs become extinc
656
00:38:31,014 --> 00:38:34,482
paving the way
for the evolution
of mammals...
657
00:38:35,752 --> 00:38:39,087
...leading eventually
to humans.
658
00:38:40,090 --> 00:38:44,893
Without the asteroid impact
we wouldn't be here.
659
00:38:44,895 --> 00:38:47,996
As a furry primate
on this planet, I kinda like
the K-Pg impact, right?
660
00:38:48,064 --> 00:38:48,697
I'm here because of it.
661
00:38:48,699 --> 00:38:50,365
We all are.
662
00:38:52,803 --> 00:38:55,203
[narrator]
Some plants benefited
from the asteroid strike.
663
00:38:56,873 --> 00:38:59,708
To learn out plants changed
after the impact,
664
00:38:59,710 --> 00:39:05,080
Smithsonian scientist
examined thousands
of tropical plant fossils
665
00:39:05,082 --> 00:39:06,547
from the time of the die off
666
00:39:09,586 --> 00:39:13,121
This disaster opened the way
for new types of plants
to develop.
667
00:39:14,624 --> 00:39:17,892
[Christiansen] It transforme
the plant kingdom...
668
00:39:17,894 --> 00:39:21,262
...producing a richer
and more diverse
global ecosystem.
669
00:39:21,631 --> 00:39:23,732
[narrator]
Before the asteroid strike,
670
00:39:23,734 --> 00:39:29,137
conifers and ferns dominate
the tropical forests
of South America.
671
00:39:29,973 --> 00:39:33,041
But afterwards,
falling ash from the impact
672
00:39:33,043 --> 00:39:34,609
enriched the soil.
673
00:39:34,611 --> 00:39:39,047
And fast growing
flowering plants took over.
674
00:39:40,584 --> 00:39:42,984
[Lanza] The impact
was very hard to recover fro
675
00:39:43,052 --> 00:39:46,020
but it actually opened
the opportunity
676
00:39:46,055 --> 00:39:47,522
for a greater diversity
of plant life,
677
00:39:47,524 --> 00:39:50,125
which ultimately has benefited
us as humans
678
00:39:50,160 --> 00:39:52,327
because it has allowed us
to have more food sources.
679
00:39:54,564 --> 00:39:57,832
[narrator]
This new world order
eventually gave rise
680
00:39:57,834 --> 00:39:59,634
to the modern
Amazon Rainforest,
681
00:39:59,636 --> 00:40:05,006
home to 10%
of all species on Earth.
682
00:40:06,777 --> 00:40:10,445
[Christiansen]
It really destroyed and rema
our entire environment.
683
00:40:11,715 --> 00:40:13,882
The world grew back,
of course it did, here we are,
684
00:40:13,884 --> 00:40:15,316
but it changed everything.
685
00:40:16,820 --> 00:40:21,656
[narrator] And another age
may be just around the corne
686
00:40:21,658 --> 00:40:23,591
[Dartnell] We should
absolutely expect
687
00:40:23,593 --> 00:40:25,927
that at some point
in the future,
688
00:40:25,929 --> 00:40:28,596
and I'm not saying
you should lose sleep over it,
689
00:40:28,598 --> 00:40:34,002
but at some point
there will be
another mass extinction.
690
00:40:36,940 --> 00:40:39,307
Maybe that will be
the end our days.
691
00:40:40,510 --> 00:40:41,709
It's intriguing question is
692
00:40:41,778 --> 00:40:46,181
what might come after humans
on planet Earth?
693
00:40:47,784 --> 00:40:51,586
[narrator] Catastrophe may b
the universe's recipe for li
694
00:40:51,621 --> 00:40:53,354
throughout the cosmos...
695
00:40:54,558 --> 00:40:57,892
...one that every planet
must follow.
696
00:40:57,961 --> 00:40:59,761
[Plait] Looking
at our own history,
697
00:40:59,763 --> 00:41:01,796
life thrives on catastrophes
698
00:41:01,798 --> 00:41:05,433
We need these disasters
for evolution to work.
699
00:41:05,435 --> 00:41:09,537
So, hopefully,
and I hate saying this,
I know how it sounds,
700
00:41:09,539 --> 00:41:13,208
hopefully, these other plane
have had terrible disasters
as well.
701
00:41:14,811 --> 00:41:16,144
[Michelle Thaller] Think abo
the word disaster.
702
00:41:16,146 --> 00:41:17,846
It means bad star.
703
00:41:17,848 --> 00:41:19,414
It means that something
has gone wrong,
704
00:41:19,482 --> 00:41:20,782
something that's dangerous.
705
00:41:20,784 --> 00:41:24,152
We are children of disasters
706
00:41:25,489 --> 00:41:28,990
There's no way you get us
without planets colliding...
707
00:41:30,393 --> 00:41:33,995
...without asteroids
and comets streaming
through the atmosphere...
708
00:41:37,701 --> 00:41:40,301
...without even
stars exploding
and supernovas.
709
00:41:44,808 --> 00:41:46,174
You are a child
of that violence.
710
00:41:46,242 --> 00:41:49,978
That's part of the environment
that we grew up in
in a cosmic way.
711
00:41:49,980 --> 00:41:52,146
And I think that
is tremendously beautiful.