NARRATOR: They roam
the planetary surface, fly underwater, and soar
through the heavens. But this is no wildlife
safari on planet Earth. This is an expedition of
astronomical proportions. MAN (ON RADIO): Everything
looks good from here. MAN (ON RADIO):
OK, we copy that. NARRATOR: When the human race
discovers it is not alone, what will our cosmic brothers
and sisters look like? To answer this question, leading
astronomers and astrobiologists have applied the principles
of evolution and physics to five types of alien
worlds likely to be found in the cosmos. These are the creatures
that could be out there. [music playing] Prepare to take an
intergalactic safari and peer directly into
the eyes of Alien Faces. [music playing] The universe, an
intergalactic sanctuary of billions of galaxies
and trillions of stars. Could it only be a
lifeless, barren wasteland of gamma ray bursts, burning
stars, and black holes? Or does life exist beyond
Earth in this cosmic paradise? Do alien faces gaze towards us,
pondering the age old question, are we alone? Scientists are still searching
for the first signs of life beyond our planet, but many
are convinced it's out there, waiting for us to find it. But what on Earth, if
anything, would it look like? With a potent mix of earth
science, logic, and the theory of evolution, computer
graphic artists are able to bring some of
these alien faces to life. [music playing] And to come face-to-face
with these extraterrestrial creations, we will embark
on a fantasy safari through the unexplored
reaches of the universe, like a tourist in an
intergalactic zoo. Our first stop, the
theoretical planet Aranel. [music playing] DAVID AGUILAR: The planet
Aranel Nell is an odd planet. First of all, it doesn't circle
around a star like our sun. It circles around
a little red dwarf. These are tiny stars. They're sometimes a fifth,
a sixth the size of our sun. So the habitable zone is going
to be much closer to that star. NARRATOR: This habitable zone
is a crucial piece of the puzzle when understanding the evolution
of life on any alien planet. A habitable zone
in a solar system is the distance from the
star where water can exist as a liquid on the surface. Gets enough heat energy from
the star to have liquid water and stay liquid water. NARRATOR: Liquid water is one
of the basic elements for life to begin. But on Aranel,
the habitable zone is so close to this glowing
ball of burning gas, the star's gravity causes
Aranel to be tidally locked, much like Earth's moon, as we
only see one side of the lunar surface at all times. This would mean
that half of Aranel is constantly in daylight, and
the other half is constantly in darkness. In the middle, there would
be a 200-mile wide area that stretches from the North
Pole to the South Pole which is in a constant
state of Twilight. So it makes you wonder,
where would we find life on this planet? Well, truthfully, you're
going to find it everywhere. But if it's on the
dark side, It's life that's been adapted
for living in the dark, and if it's on the
bright side, it's life that's been adapted for
living only in the bright side. And in this twilight
zone area, you're going to find creatures
that are attempted for both. They can wander and stray
into both sides on this world. They really control
their own destinies and where they want to go
and where they want to hunt. [music playing] CRAIG FREUDENRICH:
On Aranel, you're gonna have a photosynthetic
organism, probably-- likely, in the marine environment,
a red alga, or a bacteria that will be adapted to
taking an infrared light and taking what energy it can
out of that and making food. On land, it would probably
be a lichen-like thing, because it's cold, mosses that
would be adapted that way. You'd have organisms that
are going to feed off those. NARRATOR: This algae on
Aranel represents the bottom of a very long food chain. Everything plays a
vital role for survival, from the plant life, to the
larger, more complex creatures. One example on Aranel that uses
this algae as a food source is the insect known as an achom. DAVID AGUILAR: The achoms are
a bizarre little creature. On Earth, we know what
we call metamorphosis. It's the odd ability of a
creature to change from one shape to another. We see it in butterflies. Caterpillar eating
in your garden will climb up on the fence,
spin a cocoon, months later, hatch out into a butterfly. These do that too, but they
do it in a very odd way. They look almost eel-like with
two sets of fins that stick out on either side. At some peculiar moment, they
move over to some of the plant life, lock themselves
in, and attach themselves and form a shell around them. When that shell splits,
out come something that we've never seen before. Taking the hydrogen
from the water, splitting the hydrogen
from the oxygen, it inflates a little bubble,
and they lift right out of the water. The breeze is picking
them up, carrying them to high altitudes,
spreading them out over the planet towards
the twilight zones as the breezes move. And they're almost like
parachutists coming back down. NARRATOR: Once the
achoms reach the ground, they immediately create a burrow
where they primarily live. But as the achoms scavenge
through the dirt for food, they're hunted from above by one
of the next links in the food chain, the pinapod. DAVID AGUILAR: Now,
one of the creatures that we find most interesting
on this world is the pinapod. It's an odd little
creature, because its eyes wrap all the way around so it
can see any movement behind it. NARRATOR: In the
twilight zone of Aranel, it is going to be
very dark and cold due to the low light of its star
and the hunters, or even the hunted, will have
developed large eyes like owls or other nocturnal
creatures here on Earth. But there is an interesting
adaptation that developed in most creatures on Aranel. DAVID AGUILAR: Aranel
orbits an M star. M stars emit most of
their light in infrared. Infrared is the light that-- it's actually heat that you
feel when you open up the oven. That's what these
creatures would see. They would see the heat
expended by their bodies in the world around them. It would look very different
than it does to you or me. NARRATOR: To see heat signatures
on the dark side of the planet gives one of the biggest links
on the food chain of Aranel, the kurja, a cunning advantage. DAVID AGUILAR: They're-- in
their sense, in their moves, in the way they act together,
they resemble jackals in the plains of Africa. They move in herds. They're hunters. They're predators. Ugly little nasty creatures
that will surround a pinapod or a colony of
them, ferret them out, and that's their meal. They have the odd
ability, however, to see not only in the
twilight regions with eyes like we might normally have,
but they have a second set of smaller eyes right
above, that once they move into the darker regions,
the nighttime side, they can now pick up the
heat signatures of creatures in that area. NARRATOR: These are only a few
of the creatures that could live on a planet like Aranel,
but at least for now, they are simply a product
of our imagination. LYNN ROTHSCHILD: In
science, we can sit there and we can imagine
life elsewhere. But if we have examples-- we have one data point, in
fact, and that's planet Earth. And so if we can look
at life on Earth, it provides us with an
amazing wealth of information that we can then take forward
to look for life elsewhere. CRAIG FREUDENRICH: We have
a variety of ecosystems that we can study, and we
can look at challenges. What are in ecosystems? What challenges do the
living things face? And we can apply these
principles to alien life. NARRATOR: To understand
how these principles can be applied, we must continue our
intergalactic fantasy safari. We leave the surface of Aranel
and zip across the cosmos 322 light years away
to a new solar system at the theoretical
planet AG 143. DAVID AGUILAR: AG 143 is
bigger than the Earth, much bigger than the Earth. It has a beautiful ring
system that circles around it. But more importantly, it is
a big, gigantic, dry desert with three times the
gravitational field that we feel here on the Earth. NARRATOR: A human weighing
in at 175 pounds on Earth would step off onto
the surface of AG 143 to weigh about 525 pounds. Certainly, life
would need to adapt. But how? David Aguilar of Harvard
University's Center for Astrophysics
believes the best way to envision the adaptations
of complex alien lifeforms is by looking at the variety
of creatures that have evolved to inhabit the diverse
ecosystems of our own world. We're here at the
North Carolina Zoo because, of all the zoos
in the country right now, this is very special. It is large. It's big. And the environments
here to duplicate the different environments
we find on our planet. This here today is a marvelous
example of the variety of life on our planet. NARRATOR: And within this
variety of life on Earth, Aguilar believes that creatures
supporting an extremely heavy structure become the perfect
model for understanding evolution on AG 143. When we talk about an animal
adapted for a heavy world environment, a world with
more gravity, this is it. Look at what we have
out here, the prototype legs that can
suspend a huge body. Of course, we would
have to move him down, move him closer to the
ground, but this is perfect, what we would see. Shorter, squattier, but heavy
like this, adapted to a planet with much stronger gravity. [music playing] NARRATOR: Although
life forms on AG 143 have certain comparable
characteristics to creatures on Earth, their alien
faces are beyond anything found on our planet. [music playing] MAN (ON RADIO): Everything
looks good from here. MAN (ON RADIO):
OK, we copy that. Sounds good. MAN (ON RADIO): I
wish we were with you. NARRATOR: What if, one day,
a deep space probe detects life outside our solar system? What would an alien look like? To better understand these
other worldly creatures and how they might have
evolved, scientists believe you must
first understand a few simple concepts about
the physical environments where life might begin. When looking at planets
around distant stars, there are two factors that
we scientists zero in on. First is distance
to the mother star. That determines how
much energy you have, and whether or not
you have liquid water. Second, the mass, the
size of the planet. That determines gravity and what
kind of organisms you may have. LYNN ROTHSCHILD:
When people think about evolutionary
biology, we tend to think of the whole nature,
red in tooth and claw, the whole Darwinian
competition among organisms and among species, and so
on, that we forget that it's the physical environment
that really shapes life. What gravity you have, what
temperature, what pressure, what composition the atmosphere
is, if there is any atmosphere, and so on. NARRATOR: The laws of physics
don't change as you travel through the universe, so
understanding how creatures evolved in our
Earthly environment has allowed scientists to
imagine what life forms might arise on other types of worlds,
like the theoretical planet AG 143. AG 143 orbits a
bright, F class star. Only 10% of this world is
covered with surface water, and pockets of this liquid
H2O collect under the sands from sparse rainfall. The environment on
AG 143 is hot, arid, and the sunshine
extremely bright. Now, because the star
is an F class star, OK, which is brighter
than the sun, you're gonna have UV output,
ultraviolet light output. So the organisms there are gonna
have to somehow be shielded, either in the atmosphere,
or in their own coverings. NARRATOR: These coverings may
be in the form of thick shells or other exteriors that would
absorb the harsh UV radiation. But the creatures
on AG 143 would also develop other physical
characteristics that are unique to this world. It's really
interesting to imagine what life might be like on a
planet with higher gravity. Well, from a microbe's
point of view, there might not be a
whole lot of difference. Where the differences
would start to come is when you go out
on land, for example, and there, you have to
worry about standing up. Darned gravity,
you know, I just-- I just can't pull myself up. NARRATOR: But another
byproduct of strong gravity may also give rise to an
unlikely cast of characters on the surface of AG
143, or rather, slightly above the surface. On Earth, our atmosphere is
79% nitrogen, 20% oxygen, and 1% other gases
that is held in place due to the gravitational
pull of the Earth. But on a planet like AG
143, the stronger gravity would hold a much
thicker atmosphere, perfect for achieving flight. It may also hold a much
higher level of oxygen. We went through a period a
couple of hundred million years ago where we think the Earth
had a higher concentration of oxygen for a while. And what we see in
the fossil record is giant insects, huge wings,
giant flying organisms, because if you
think about it, you have more oxygen for metabolism,
so you can do things with more energy. It's like taking in a higher
oxygen with an oxygen tank or something, you
feel all pumped up. And that's how these
organisms must've felt. NARRATOR: With a thicker
atmosphere and higher concentration of oxygen,
the skies of AG 143 would be full of
large, flying creatures that could stay airborne
for as long as they need. One example could be the sargon. This creature would live
most of its life soaring through the atmosphere, looking
for pockets of water that scarcely pepper the planet. Once the sargon finds
a watering hole, they swoop down in
hopes to not only drink, but hunt any creatures
that may have found their way to the oasis. A creature like the moblent. DAVID AGUILAR: At first sight,
you might almost mistake a moblent for a starfish. It has stubby little arms that
it moves across the desert. But the odd thing
about these arms is they have long tentacles
that probe the sand for pockets of precious water
that may be hidden. And the odd thing
about this creature is if it finds a large,
large pocket of water, it begins pulling the water up
like it's pulling it up a well, and it grows in size,
and it grows in size, and stores the water
up like a camel does. NARRATOR: Adaptations to
locate and store water are crucial for survival. To be stuck out in the middle
of a desert hundreds of miles from anything
resembling a liquid would be a death sentence for
almost any Earth creature. The same would be true for life
on our theoretical planet AG 143. This is why the folus lives
primarily near the water deposits, so that
it will remain close to this precious commodity. One of the most bizarre
creatures on AG 143 is the folus. Short, squatty, it's
a mouth supported by three legs on a
pedestal platform that has scales underneath. It glides across the sand almost
like a sidewinder as it moves. It has the uncanny ability to
sense chemically whether or not its prey is nearby. It hunts around the edges of
streams and small little lakes, and if it finds its
prey, it suddenly stops, it freezes and
camouflages itself so that it almost becomes
invisible, waiting, until a hapless creature moves,
and then suddenly, out it snaps. It's found its dinner. NARRATOR: And the folus's
method of movement, gliding across the surface
like a snake on grass, is another evolutionary
characteristic caused by the stronger
gravity of the planet. To slide with scales
rather than lifting a leg would be a lot easier
for any creature. That, and it offers a quiet
advantage over its prey. They may never hear
the folus coming. But as the food chain goes
on AG 143, nothing is safe. For lurking in
these pools of water lies a silent, but deadly
creature known as the hethor. As we end our examination
of the food chain on AG 143, we've seen the
extreme challenges that creatures on a world with
little surface water and higher gravity must overcome. But what if the planetary
conditions were reversed? What if a planet had a
suitable amount of water for life, but also a much
weaker gravitational force? The answer might lie
right above our heads in the skies above the Earth. On our intergalactic
safari, we've seen how leading astrobiologists
used present day Earth science to hypothesize about the
size, shape, and behavior of creatures on
an imaginary world with much stronger
gravity than Earth. [music playing] But what would happen if
the gravity was much weaker? To find out we lift off from
the strong gravity of AG 143 to another planet 89
light years away, GPC 925. DAVID AGUILAR: GPC 925 is
smaller than the Earth. It's about half the
size of the Earth. It's borderline for
an Earth-like planet. And because it's smaller,
it has less gravity. The star that in circles
around is cooler than our sun, and because of that, it's
a cross between frozen ice patches, green photosynthetic
plants peeking through, and some bodies of water. It would look very much like
the northern part of our planet. You get up towards the northern
parts of Canada and Greenland, we call it the taiga areas. GPC 925 would be a very
specific type of environment. You wouldn't find
deserts on this world. You'd find very few mountains,
actually, on this world. It would be a world
that was cooler, more preserved than what we
see on our own planet. But beautiful just the same. CHRIS MCKAY: This
world with much lower gravity could generate much
larger, more elegant lifeforms. I'm 6' 6". Imagine how tall I could
be if I had evolved in a world with a half
or a third the gravity. Imagine what a redwood would
look like in a world with lower gravity. [music playing] NARRATOR: These types
of gravitational effects on the surface life
would shape and model different characteristics. It would also appear that
on a world like GPC 925, much of that surface
life would not be found on the surface at all. [music playing] Here we are in the aviary. Up in these trees are the
remnants of the dinosaurs. This is what was left behind
when the dinosaurs passed on. These birds are meant to fly. Their bones are hollow, their
feathers locked together. These birds were meant
to rule the skies. But on a low gravity planet,
this is what you would see. It would rule the planet. CRAIG FREUDENRICH: Because
gravity is going to be light, flight is going to be very easy. And flight is something that's
been done on Earth by a number of organisms in different ways. Bats stretch membranes
between their fingers and create wings to fly. Flying squirrels put
flaps out of their fur and glide that way. NARRATOR: But not
everything on GPC 925 is comparable to
creatures on Earth. DAVID AGUILAR: The strangest
of the airborne creatures one could imagine
are the lollygars. Imagine floating sacks
that almost looked like inflated lungs, with long,
long, long tentacles hanging down that drape
along the countryside as they slowly move and
float over the scenery. Heated by internal heat
inside, the warm air inflates their sacks. They almost look like jellyfish
floating through the air. And like jellyfish,
they sting and grab anything that scurries over
the ground in front of them. To see them moving,
bobbing up and down in the wind like a herd of-- of psychedelic jellyfish
is something beyond what we can imagine. And yet, here,
it's quite common. [music playing] NARRATOR: Even
life on the ground would push the limits of
science as we know it. DAVID AGUILAR: When we
take a look at this world, think of the swaystacks. They look like they're long
stalks that extend 15, 20, 30 feet into the air,
numerous ones coming up with a bulb on the end. They sway in the wind. But what's amazing is
these aren't plants. These are animals with roots
that pick up and slowly move across the planet's surface and
anchor themselves back down, swaying in the wind where they
wait for any creature that happens by. As the creature moves
by, the top of them, like little Frisbees, shoot
off and wedge into the side of the creature, into their
leg, into their carapace, into their hair,
stuck, for the moment. As they move on, they reach
a new area, they drop off, and they begin growing
all over again. They're simply spreading their
seeds, these tiny little disks flying through the air once
they set something moving by. On this planet, we
see similar things with the plants in the
weeds that grow here, but nothing to this
size and extent. And the idea that we
begin crossing plants that look like animals and animals
that look like plants, this is a bizarre world indeed. NARRATOR: Creatures like the
swaystacks and the lollygars would enjoy an adequate
amount of water on GPC 925. But what would happen
on a world where there was even more water? A lot more. Specifically, a planet with no
land whatsoever, a water world. Since we embarked on our
intergalactic safari, we have seen the amazing
lifecycle of the achom on Aranel, the bizarre-looking
folus on AG 143, and the floating
lollygars of GPC 925. All of these
theoretical lifeforms on these imaginary worlds have
been created by scientists based on knowledge about the
development of life on Earth. But how would these creatures
have gotten their start on these strange,
far-flung planets? ROCCO MANCINELLI:
The requirements that we know have to be there
for life is based on the life that we know. And the chemistry
that we think leads to the origin and
evolution of life is carbon chemistry and
aqueous or water solution. So we need liquid water, we need
carbon, and we need nitrogen. SETH SHOSTAK: And you
need some sort of energy, because life, even
microbes, needs food. They've got to have
some sort of metabolism. So you need some
source of energy. Sunlight works pretty well,
but it isn't the only source of energy, even on Earth. [music playing] NARRATOR: For hundreds
of years, scientists believed that sunlight was the
only energy source for life. But within the past few
decades, new findings showed they were wrong. Boiling water temperatures
found around hydrothermal vents on the seafloor
were once believed to be incompatible with life. But recently, scientists
have discovered the areas around
these black smokers are perfectly suitable for
a flourishing underwater community. Instead of the sun, these
creatures take their energy from the heat,
gases, and minerals spewing from the vents. These highly tenacious lifeforms
are known as extremophiles. ROCCO MANCINELLI: The
existence of extremophiles broadens our aspects of what
we think organisms can do and what we know
organisms can do. In other words, if you look
at all of the different kinds of environments that
we find here on Earth, it ranges from extremely cold,
to extremely hot, to acid, to alkaline. Just about anything
you can think of, and just about
everywhere, you find life. NARRATOR: The fact that life
has found it all on Earth is due in large part to our
position in the solar system. MICHIO KAKU: We scientists
used to believe that in order to get life off the
ground on a planet, it has to be in the
Goldilocks zone of the sun. Not too close, because water
will boil, not too far, because water will freeze,
but just right to have a liquid ocean out of
which DNA can form. Well, that picture,
we now know, is wrong. We now believe that even on icy
moons of planets like Jupiter, it is possible to get
life off the ground. Europa is a moon of Jupiter. It's covered in ice. But beneath the ice, there is
apparently a gigantic ocean, perhaps stable for billions of
years, containing liquid water. [music playing] And so that sent the
physicists on scrambling. How could you end up with liquid
water so far away from the sun? Now, what it turns
out the idea is is that there's something
called tidal flexing. NARRATOR: For
Europa, tidal flexing is caused by the immense
size and gravitational pull of Jupiter, which causes
the ice on the moon to pull and stretch, generating heat. Once the insulated lower
layers get warm enough, the ice will melt,
creating oceans. Now, add the types
of organic compounds that are believed
to exist on Europa, and you've got a slightly
altered, but very realistic recipe for life. This brings us to our next stop
in our intergalactic safari. [music playing] As we leave the busy
skies of GPC 925 behind, we can travel 72 light years to
a theoretical gas giant known as Anear G, a planet
circled by right moons. DAVID AGUILAR: Normally, we
wouldn't bother with Anear G. It's a gas giant, and we
don't think life could exist on these worlds. The world were interested
in is the moon Arnabus. It's about twice
the size of mercury. It's a world very similar
to the moon Europa that circles around Jupiter. Imagine a planet
covered with oceans, and on the surface, ice, a lot
of ice that locks everything inside. There's no ground to
walk on this planet, but inside these oceans, they
could be teeming with life. [music playing] NARRATOR: And with the
constant pull by Anear G, Arnabus would most likely
have a large amount of geothermal activity that
could be a prime source of energy for life to begin. Near the surface on Arnabus,
small amounts of light may bleed through the
thinner areas of ice to the water below. Here, some creatures
may have evolved eyes. This may provide
them with advantages, but would also make them
vulnerable to certain defense techniques. One example of a cunning
underwater escape artist is amabos. To us, light is just light. But think of the amabos,
a small little almost gelatinous-looking creature
that swims through the water, innocent. As anything comes close
to it that threatens it, it throws out a brilliant
flash of sparkling lights all around it, blinding whatever
creature came up to it. And in that moment, it's gone. Much like a squid might
shoot out a big ink cloud or an octopus underwater. It is suddenly masked by
brilliant lights that-- almost like the 4th of July. And it's gone. Light, in that sense, is
a protective mechanism. NARRATOR: But creatures that
live much deeper in the oceans would adapt other
methods for survival. One example is the zaolena. DAVID AGUILAR:
The zaolena looked like a cross between a weird,
weird spider and a very strange crab. But they have an
odd, odd ability. They don't sense their
world through eyes. They don't sense their
world through ears. They sense their world
through an electric field that they generate
around their bodies. This field can be stretched out
so that its senses everything that's moving around it. It sees its world
by what impinges on this electronic field. And the interesting
thing about it is once they've
locked on to something that they think
is prey, they wait till it draws nearer, and
nearer, and all of a sudden, zap. [ELECTRICITY CRACKLING, MUSIC
PLAYING] A huge bolt of electricity
jets out, stuns their prey, and a tentacle whips out and
grabs it and pulls it right in. It hunts by using electricity. NARRATOR: As we see the immense
challenges that creatures like this would have to
overcome in a water world, there is one last
factor yet to explore. When the time comes
that the people of Earth discover life in the cosmos,
or that life finally decides to reveal itself
to the human race, it may not be a
biological entity at all. Rather than flesh,
blood, and carbon, we might be met with steel
and silicon, a machine. [music playing] As we approach the theoretical
planet Gialayo, our final stop, we notice three extremely
large craters on the surface. An asteroid collision with
a life-supporting planet would be catastrophic. But on Gialayo,
something's different. We approach the surface and
see tiny mechanical creatures roaming around. Although our journey thus far
has explored an imaginary edge of the universe filled
with biological creatures of all shapes and
sizes, some scientists believe an alien
world could instead be a land of synthetic
machines, much like Gialayo. [music playing] Dr. Seth Shostak of the
Search for Extraterrestrial Intelligence, or SETI
Institute, believes that when life beyond
Earth is discovered, our cosmic relative may be made
of steel and silicon rather than flesh and blood. SETH SHOSTAK: Any aliens that
have gotten clever enough to build a radio transmitter
and get on the air so that we could hear them have
probably gone the next step, and the next step might be
the development of thinking machines. NARRATOR: To better understand
the origin of an alien planet teeming with these
types of machines, scientists say we
only have to look as far as our own evolution
of intelligence here on Earth, specifically,
artificial intelligence. Artificial intelligence,
you might say, is the science of making
babies from scratch. Instead of the
old-fashioned way. It's the science
and engineering that tries to put together
a mind by understanding how the mind works. Now, we haven't done that. We haven't built
thinking machines. But people who work
in that area seem to think that that's likely
to happen within 20 years, 50 years, 100 years. It's conceivable that
hundreds, perhaps thousands of years into the
future, we may want to merge with our machines. Realize that in the
coming centuries, machines could actually
become smarter than us. And it's always the danger
that our creations will put us in zoos behind bars
and throw peanuts at us and make us dance, just like
we make bears dance at zoos. NARRATOR: But instead of merging
with the machines, one day, humans may, in fact,
become the machines. And once the CPU
surpasses the human brain, sophisticated software
could give these beings an unparalleled
advantage over us. If you've got artificial
intelligences running on brains a million times
faster than human, and thinking a million
times fast as human, they can theoretically do
10,000 years worth of thinking in 3 and 1/2 days. NARRATOR: Vast amounts of
energy would be their lifeline to achieving such a feat. Once they harvested Gialayo
for all usable resources, these small, robotic
creatures known as sevels could build a planetary
highway to space. Then the next level of
machines, the fishers, would have access to virtually
an unlimited amount of energy for their survival. MICHIO KAKU: Just realize
that the Earth only uses a tiny fraction of
the energy from the sun. If the sun were
this big, the Earth would be nothing but a
head of a pin compared to the size of the sun. So we absorb only the
tiniest fraction of energy from the sun. NARRATOR: To harvest
the energy from the sun, a theoretical structure
known as a Dyson sphere could be built around
it or any other star. MICHIO KAKU: A Dyson sphere
is a gigantic sphere that is built to surround
a star to absorb all the energy from that star. In this way, you can absorb
the entire output of a star without getting
burned in the process. NARRATOR: Once a star
is dissected for parts, and its energy is
depleted, the fishers could dismantle the sphere
and propel themselves towards the next
galactic battery. [music playing] If scientists are correct,
this rise of the machines may even happen on a
planet closer to home. [music playing] As each year passes,
new scientific findings are being made that push the
envelope in understanding not only ourselves, but
life in the universe. There is a whole new
world, or rather, worlds, ready for us to
discover out there. And if life elsewhere in the
universe is finally discovered, the sheer number
of stars assures us that there is a diverse,
colorful, and vast array of life to be found, and
more alien faces than anyone could ever imagine. [music playing]
