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The sun -
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brilliant, powerful, giver of life.
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But this is the story of how the sun
will one day become our enemy.
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If we are to survive,
we will have to leave the Earth.
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We'll need to seek out new homes
in amazing new places.
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And change other worlds
to re-create the Earth we left behind.
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In the far future, our sun
will become a monster.
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It will burn all life from our planet,
destroy entire worlds.
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And finally, our sun
will even destroy itself.
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It's going to happen.
Our sun will die and we'll go with it.
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It's time to think about the future.
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For five billion years,
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the sun has nourished the Earth.
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It is the sun that provides
energy for plants to grow.
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It is the sun that makes
life on Earth possible.
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But that will change.
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Slowly, unstoppably, our sun
is getting hotter and hotter.
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Once it gave life to us all.
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But what it gave...
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..it can also take away.
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If human beings
are to have a long-term future,
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we must leave our planet behind
and search for new places to live.
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One day, our homes
will be out there...
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..somewhere in space.
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In the distant future,
this could be our home.
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Out here in space,
we'll have to seek refuge
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on new worlds
where we could settle and live.
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And the reason is,
we have to escape from our sun.
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Some new worlds
may be difficult to adapt to.
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Others may be very like our own.
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But what is it
that makes our planet so special?
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And why is it
so dependent on the sun?
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Here is the sun as it is today,
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in the centre of our solar system.
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The Earth goes round it about there.
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And there are the other planets.
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The reason our planet
is the one with life on it
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is that it's the right distance
from the sun.
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Closer in and we'd boil,
further out and we'd freeze.
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We live in a kind of safe zone
that's perfect for life.
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Trouble is, that zone is moving.
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The sun is getting hotter
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and the region where life can exist
is shifting further out.
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Ultimately, the safe zone
will leave Earth behind.
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When it does,
we'll be in serious trouble.
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Our planet will die.
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This is how it will happen.
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As the sun burns up its nuclear energy,
it'll become ever hotter.
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By the time it's 5% hotter,
plant life everywhere will be dying.
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10% hotter and animals, too,
will begin to die.
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15% hotter, rivers and oceans
will evaporate,
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creating huge cloud banks,
trapping more and more heat.
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In the far future,
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life on Earth
will become impossible.
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And there's nothing
we can do about it.
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What will happen to us then?
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Astronautical engineer
Robert Zubrin
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believes he has the answer.
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He wants to find us
a new place to live.
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The only real choice that we have
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is to grow, expand,
become a space-faring civilisation,
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or become extinct.
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Not only would WE become extinct,
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but unless we bring Earth life
out with us into the universe,
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all life on Earth
will become extinct.
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Robert Zubrin's goal
is to make us a home...on Mars.
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Today, Mars is cold and lifeless.
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Temperatures regularly drop
to 100 below freezing.
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Its atmosphere is 200 times
thinner than ours.
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A person standing unprotected
on the surface would die in seconds.
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Yet some scientists believe
we could learn to call this home.
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Mars is the only other planet
in our solar system
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that has all the resources
needed to support life.
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It has water, albeit frozen
as ice and permafrost.
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It's got carbon dioxide
and nitrogen in the atmosphere.
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If humans go to Mars and develop
the craft of using these resources,
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then we can make Mars a place
where we can sustain ourselves.
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A world for our posterity.
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No species can expect to last long
if it stays in one place.
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In a sense,
humans aren't native to the Earth.
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We're not native to America or Europe.
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We're native to Kenya -
long arms, no fur.
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But humans were able to leave there
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and colonise the Earth
by becoming creative.
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That's how we coped
with Ice Age Europe
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and it's how we'll cope with Mars.
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In a remote part of Canada,
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researchers have already
been preparing for life on Mars.
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Living in a space pod
did prove difficult, but they coped.
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Zubrin is optimistic.
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We're ready to take this on.
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Frankly, if we shrink from this
challenge, what it will mean
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is that we've become much less
than the kind of people we once were.
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We are much better prepared
today to send humans to Mars
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than we were to send people to the moon
in 1961 at the start of Apollo.
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I believe this nation
should commit itself
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to achieving the goal
of landing a man on the moon
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and returning him safely to Earth.
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(ZUBRIN) We were there
eight years later.
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Nothing in this
is beyond our technology.
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It's a question of showing moxie.
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For Zubrin, it's not the technology
that's lacking. It's the will.
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But technology and willpower alone
may not be enough.
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Just look at what we'd leave behind.
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This is our life support system -
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the plants that create oxygen,
countless species of animal.
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How will we fare without them?
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Our survival depends on the living
things we share our planet with.
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The air we breathe,
the food we eat -
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all this is created
by other forms of life.
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If Mars is to be our home,
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it must be home to all this, too.
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15 years ago, we thought
we knew the answer.
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This is Biosphere Two -
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a huge glass dome covering
three acres of Arizona Desert
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completely sealed off from the planet.
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The theory was
that people could survive in it
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because it was self-sustaining.
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Trees would provide oxygen.
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Artificial clouds and oceans
would regulate the climate.
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But the experiment failed.
Food rapidly ran short.
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Extra air had to be pumped in.
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On Mars, that failure
would have killed them all.
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If we're ever going to call
the red planet our home,
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clearly something's
going to have to change.
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And the easiest thing to change
may be Mars itself.
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It's an idea called terra forming.
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The aim is to transform a planet
from somewhere we couldn't survive,
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to one where we could.
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NASA scientist Chris McKay
believes we can turn Mars
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into something
surprisingly like Earth.
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When we think about going
into space, we focus on humans.
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In fact, it's easier for plants
and micro organisms to go to Mars first.
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They'll be the first Martians.
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In Death Valley, California,
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McKay is seeking the Earth's
hardiest creatures.
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Creatures that might survive
on Mars.
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That's our guy!
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These green smears are algae,
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microscopic organisms that can thrive
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even in the harsh variable climate
of Death Valley.
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And they could thrive on Mars,
too,
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sucking in its thin atmosphere
of carbon dioxide,
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and pumping out oxygen
in its place.
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Except, at the moment,
even the algae would find Mars deadly.
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The first step
to making Mars habitable
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is to warm it up a bit.
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Right now, it's too cold and dry
for any type of life from Earth.
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Warming up a planet is something
we know. We're doing it on Earth.
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The pollution on Earth
would be the medicine on Mars.
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It's a strange twist.
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The best way to make Mars a place
we could live may be to pollute it.
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Here's how it would work.
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First, a spacecraft has to drop off
the pollution-creating machines.
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The machines' job is to suck up
a mixture of dust and atmosphere
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and process it into new chemicals.
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It belches out these greenhouse
gases to warm the planet
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and dark soot to soak up heat
from the sun.
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If we send enough machines,
over time,
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Mars will warm enough to allow
these algae to survive.
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The algae will begin to give Mars
an oxygen atmosphere.
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But for speed, we'd need
more efficient oxygen makers.
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And the best that we know
are plants and trees.
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The real goal
is to get trees growing there.
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Those trees will be the ones
that make a habitable world.
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Then things will really start happening.
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As the oxygen level rose, insects
then larger animals could survive.
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We could change Mars.
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If I laid out a timescale, I'd say,
50 years humans go to Mars,
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and soon thereafter the algae
and bacteria go to Mars.
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Maybe 30 years later,
the trees go to Mars
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and then the humans come back,
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but this time to a setting
biologically suitable for them.
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And then we've learned
to become a lifeform
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that lives on two planets.
Not just humans, all life.
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It's a bold and astonishing plan.
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If it works, we could turn Mars
into a planet very like Earth.
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But even Mars
will not last forever.
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Even there, we could never escape
the power of the sun.
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As the sun keeps getting hotter,
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the safe zone for life
moves further out.
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This is Mars.
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Now Earth's dead, this is our home.
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Thanks to our terra forming,
it looks a lot like Earth,
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and thanks to a hotter sun,
it's now in a safe zone.
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The only trouble is,
the sun is still getting hotter.
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Eventually, the safe zone
will leave Mars behind, too.
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With Mars dead, where next?
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Once again, human beings will be
looking for a new home.
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And, once again, we'll have to move
further from our brightening sun.
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But the planets further out
are impossibly hostile worlds.
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Gas giants like Jupiter and Saturn
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are not places
we could ever hope to transform.
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If we're going to survive
on these alien worlds,
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it won't be the planets
we'll have to change...
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..we may have to change ourselves.
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00:18:10,687 --> 00:18:14,236
David Brin
is a science fiction writer.
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He imagines future worlds
for a living.
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It's a big universe and the Earth
is a very specialised environment.
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We won't find many Earths out there.
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If we want to spread out,
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then we're going to have
to adapt to the universe.
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It's not easy for humans
to get accustomed to that idea
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because we're used to making
the universe adapt to us.
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(CHILDREN)
Five, four, three, two, one!
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As the sun becomes hotter,
new worlds will form into life.
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This is Europa,
one of Jupiter's huge moons.
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We know it today
as a frozen planet -
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airless,
with a crust of iron-hard ice.
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But in the future, it will be
something else entirely.
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00:19:17,327 --> 00:19:21,957
The ice will have melted.
Europa will become an ocean world.
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00:19:22,127 --> 00:19:27,326
After Mars, perhaps we'll come here
and make this our new home.
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00:19:51,567 --> 00:19:56,038
We could live in cities
at the bottom of an alien sea.
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00:19:57,927 --> 00:20:02,159
But David Brin thinks that,
in the end, a life behind glass
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00:20:02,327 --> 00:20:04,158
may not be the solution.
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00:20:07,807 --> 00:20:10,799
Now we're thinking
of going to other planets.
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00:20:10,967 --> 00:20:14,482
At first, we'll arrive
in spacesuits, live in domes,
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00:20:14,647 --> 00:20:16,444
bring environments with us.
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00:20:16,607 --> 00:20:19,804
But we'll want to get out
of those domes,
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00:20:19,967 --> 00:20:25,200
so we'll have to change ourselves
to fit into new environments.
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00:20:25,367 --> 00:20:28,882
Our ancestors evolved
for life on Earth.
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00:20:29,047 --> 00:20:32,926
But Brin thinks our descendants may
redesign themselves
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for a future on other worlds.
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Human beings have been
wonderfully inventive
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in the last 20 million years.
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00:20:41,007 --> 00:20:44,158
And yet, other species
have not been idle.
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Birds developed lungs
in which the air flows
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00:20:47,287 --> 00:20:50,836
from one side to the other
so that all the lungs are used.
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00:20:51,007 --> 00:20:53,521
We only use half our lung capacity.
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If we genetically engineered ourselves
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so our lungs flowed through,
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think of the thin atmospheres
we could live in.
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00:21:03,047 --> 00:21:07,438
Wouldn't it be great
to hibernate like a bear?
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We'd be able to travel to far planets,
possibly even far stars.
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00:21:15,247 --> 00:21:18,159
And if they live and work
in zero gravity,
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00:21:18,327 --> 00:21:22,445
they'll get tired of pulling around
these useless legs,
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00:21:22,607 --> 00:21:26,998
which are only good occasionally
for pushing us against walls.
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00:21:27,167 --> 00:21:30,523
Why have legs
if you're in zero gravity,
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00:21:30,687 --> 00:21:33,997
when you could have additional arms?
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00:21:34,167 --> 00:21:36,158
Wouldn't it be more functional
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00:21:36,327 --> 00:21:39,046
jumping all over the place
like gibbons?
242
00:21:40,327 --> 00:21:45,845
Can genetic engineering achieve
any of these things? Who knows?
243
00:21:46,007 --> 00:21:49,363
We're just at the beginning
of this grand adventure.
244
00:21:49,527 --> 00:21:52,758
But it's an extravagant
version of tomorrow
245
00:21:52,927 --> 00:21:55,395
that we should be thinking about.
246
00:21:55,567 --> 00:21:58,445
Wouldn't it be a desirable thing
247
00:21:58,607 --> 00:22:01,724
if we're happy, creative, productive,
248
00:22:01,887 --> 00:22:04,196
part of a great civilisation?
249
00:22:04,367 --> 00:22:06,164
Vive la différence!
250
00:22:11,127 --> 00:22:14,085
We can only guess at the future.
251
00:22:14,247 --> 00:22:19,037
What will our descendants be like?
We'll have to wait and see.
252
00:22:22,927 --> 00:22:25,077
And where will they live?
253
00:22:25,247 --> 00:22:29,684
The only certainty is,
it cannot possibly be here.
254
00:22:33,767 --> 00:22:38,841
It's not just that the sun will
have seared all life from Earth.
255
00:22:39,007 --> 00:22:43,046
It's that the planet itself
will no longer exist.
256
00:22:43,207 --> 00:22:46,119
Everything we know
will have disappeared.
257
00:22:46,287 --> 00:22:49,165
In the far future, our sun
will turn into a monster.
258
00:22:58,287 --> 00:23:02,121
It's going to consume
the solar system.
259
00:23:03,287 --> 00:23:07,246
Its first victim
is the closest planet - Mercury.
260
00:23:13,127 --> 00:23:16,722
Next, Venus is transformed
into a molten fireball...
261
00:23:22,327 --> 00:23:24,761
and, ultimately, boiled away.
262
00:23:35,327 --> 00:23:37,522
And still the sun grows.
263
00:23:37,687 --> 00:23:42,920
It's 160 times its original size,
2,000 times hotter!
264
00:23:44,927 --> 00:23:47,600
And its next victim is the Earth.
265
00:24:06,287 --> 00:24:09,518
Long since seared barren
by the sun,
266
00:24:09,687 --> 00:24:14,681
the place we once called home
now melts and is engulfed.
267
00:24:16,287 --> 00:24:20,883
Seven billion years from now,
the Earth will be gone.
268
00:24:36,247 --> 00:24:39,319
For us today, one question remains.
269
00:24:39,487 --> 00:24:44,242
Is the future of our planet
also OUR future?
270
00:24:44,407 --> 00:24:48,559
Can we really survive
the death of Planet Earth?
271
00:24:49,727 --> 00:24:52,241
Look at how far we have come.
272
00:24:52,407 --> 00:24:55,080
Compared to the world
of 100 years ago,
273
00:24:55,247 --> 00:24:58,205
we're living
in a science fiction universe
274
00:24:58,367 --> 00:25:00,835
with skyscrapers 100 storeys tall!
275
00:25:01,007 --> 00:25:03,043
Who can believe, seeing that,
276
00:25:03,207 --> 00:25:05,960
that looking forward 100 years,
277
00:25:06,127 --> 00:25:09,563
there will not be a new
civilisation on Mars?
278
00:25:09,727 --> 00:25:14,517
And look back 1,000 years -
the world lit only by fire.
279
00:25:14,687 --> 00:25:17,724
Who can say that 1,000 years
from now,
280
00:25:17,887 --> 00:25:22,244
there will not be hundreds of new
branches of human civilisation
281
00:25:22,407 --> 00:25:26,161
filling worlds,
orbiting hundreds of stars
282
00:25:26,327 --> 00:25:29,239
and listening to the galaxy?
283
00:25:32,247 --> 00:25:36,604
Some people think that we are
living at the end of history,
284
00:25:36,767 --> 00:25:40,203
but I think we're living
at the beginning of time.
285
00:25:40,367 --> 00:25:44,679
We're present at the creation.
It's a glorious time to live.
286
00:25:47,967 --> 00:25:49,958
(JOHN MCKAY) For all we know,
287
00:25:50,127 --> 00:25:53,199
we might be the only lifeform
in the universe.
288
00:25:53,367 --> 00:25:56,882
If that's true, that really deepens
the importance
289
00:25:57,047 --> 00:25:59,561
of spreading life beyond the Earth.
290
00:26:03,047 --> 00:26:05,322
If we're the only spark of life,
291
00:26:05,487 --> 00:26:08,365
we certainly don't want that spark
to go out.
292
00:26:11,767 --> 00:26:15,043
Our scientists today
are already imagining
293
00:26:15,207 --> 00:26:18,165
strange, far-off tomorrows
for our kind.
294
00:26:18,327 --> 00:26:22,240
And, if we do survive,
perhaps we will be there
295
00:26:22,407 --> 00:26:27,197
to witness the moment when our
sun's transformations finally end.
296
00:26:27,367 --> 00:26:32,964
It was first the giver of life,
then the destroyer of worlds...
297
00:26:35,287 --> 00:26:38,006
..and now, it, too, is doomed.
298
00:26:40,007 --> 00:26:43,397
This is the sun
at the end of its life.
299
00:26:53,607 --> 00:26:57,361
Layer after layer,
it is blowing itself apart.
300
00:26:57,527 --> 00:27:00,963
Huge clouds of star stuff
drift into space.
301
00:27:01,127 --> 00:27:04,597
It's a slow process
that takes millions of years.
302
00:27:04,767 --> 00:27:09,887
What follows is inevitable -
the death of our sun.
303
00:27:16,447 --> 00:27:19,325
It casts off one final layer,
304
00:27:19,487 --> 00:27:22,877
and its spark
is extinguished forever.
305
00:27:31,207 --> 00:27:33,562
So, the sun will one day go out.
306
00:27:33,727 --> 00:27:38,482
Will it be significant to our
descendants in billions of years?
307
00:27:38,647 --> 00:27:42,640
I don't think so. They will have
observed similar phenomena
308
00:27:42,807 --> 00:27:45,367
on innumerable other stars
before then.
309
00:27:45,527 --> 00:27:49,520
But, if they did think about it,
they'd note with gratitude
310
00:27:49,687 --> 00:27:54,124
that their ancestors did not stay
on that one little world
311
00:27:54,287 --> 00:27:56,084
and await their doom,
312
00:27:56,247 --> 00:28:00,035
but spread into the universe
and made their life possible.
313
00:28:05,647 --> 00:28:08,320
No one can know our future,
314
00:28:08,487 --> 00:28:11,559
but our sun's future is certain.
315
00:28:11,727 --> 00:28:16,357
There will come a time when we
must leave our Earth behind.
316
00:28:16,527 --> 00:28:19,041
Our planet will be gone.
317
00:28:20,047 --> 00:28:23,039
Our home will be in space.