NARRATOR (VOICEOVER): In the
beginning, there was darkness. And then, bang-- [explosion] --giving birth to an
endless expanding existence of time, space, and matter. Every day, new discoveries
are unlocking the mysterious, the mind-blowing, the deadly
secrets of a place we call the universe. [dramatic orchestral music] Thousands of witnesses
have claimed to see UFOs. [camera shutter sound effect] And their accounts are
often strikingly similar. You have a crashed saucer,
but also some crashed bodies. You have government cover-up. NARRATOR (VOICEOVER):
Mainstream science says the evidence
just isn't there. MAN 1: Oh my god. It's a big jump between a
UFO and an extraterrestrial spacecraft. NARRATOR (VOICEOVER):
But if UFOs were really extraterrestrial
craft, what kind of mind-bending technologies
would we find under the hood? You'd have to have some
sort of technology that was capable of canceling
the effects of inertia. NARRATOR (VOICEOVER): When it
comes to unidentified flying objects, what is the real deal? [whoosh] [whoosh] [explosion] [zooming sound] [zooming sound] [ambient music] For millions of believers, it
all began on June 24, 1947. A businessman and pilot named
Kenneth Arnold is flying solo near Mount Rainier, Washington. Suddenly he sees a group
of nine aircraft moving at incredible speeds. WILLIAM R. ALSCHULER: They
were highly reflective. And they were flying
at supersonic speeds, in formation, changing
course abruptly. The speeds were
unattainable at the time. This was before the age of jets
and certainly supersonic jets. KEVIN GRAZIER: Being
a trained pilot, he did several things to
corroborate their existence to make sure he wasn't
seeing some kind of atmospheric effect. He changed his-- his head angle,
he changed the aircraft angle. He even positioned
the aircraft such that there was a light
snow in the background behind the objects. And they appeared dark
against a light surface. NARRATOR (VOICEOVER): Before
Arnold can maneuver closer, the objects are gone. It was basically
unprecedented in modern times. No one had seen
anything like this. NARRATOR (VOICEOVER):
In the days that follow, newspaper reporters
misquote Arnold as he tries to make
sense of the incident. SETH SHOSTAK: In fact, he said
it moved like saucers skipping on water. Now, of course the
reporter kind of messed that up in
reporting it, and said that they looked like saucers. NARRATOR (VOICEOVER): The
term, flying saucer, is born. And Arnold's encounter launches
the modern UFO phenomenon. [digital ringing] Weeks later, in
the summer of 1947, perhaps the most famous
incident involving an unidentified flying
object is reported near Roswell, New Mexico. SETH SHOSTAK: Roswell has become
the poster child of the UFO phenomenon because it has all
the necessary ingredients. You have a crashed saucer,
but also some crashed bodies. You have government cover-up. There was some sort of cover-up. There was misinformation
given out by the authorities. WILLIAM R. ALSCHULER: The
original account put out by the Air Force at the time was
that this was a flying saucer of alien origin. And then, later, very
quickly was denied. And the story then was that
this was a weather balloon which had crashed, and that there
were no occupants on board, and that there was nothing
extraterrestrial about it. [eerie music] NARRATOR (VOICEOVER):
Other witnesses claim to have seen actual
pieces of a crashed spacecraft, materials that are reportedly
unknown to science. Both Arnold sightings
and the Roswell incident remain officially unconfirmed
and highly controversial. Just about every year, there
are thousands of reported sightings, mostly in the sky,
of objects that they assume are extraterrestrial
craft, so-called UFOs. The U is important, of course. They're unidentified. KEVIN GRAZIER: I personally
have seen a bright light start at the horizon and
shoot off into the clouds. Now, strictly speaking,
that was a UFO. It's a big jump between a
UFO and an extraterrestrial spacecraft. NARRATOR (VOICEOVER): Scientists
argue that most UFO sightings either have earthly origins-- like satellites,
balloons, and aircraft-- or cosmic origins, such
as meteors, comets, or even an especially
bright planet Venus. But when a UFO sighting
has no known explanation, could it be an
extraterrestrial craft? And if so, what
kind of technologies could possibly
explain the behaviors that witnesses actually report? [whoosh] How would such craft be built? And what problems would
they have to overcome? A lot of the behavior
of refers that people have reported are things that
are beyond our current level of physics-- extreme rates of speed
or extreme acceleration, extreme turn rates,
things that just we're not capable of doing without
extreme harm to a pilot or destroying a spacecraft. [techno music] NARRATOR (VOICEOVER):
Eyewitness accounts of super-fast accelerations,
lightning turns, and sudden stops seem to
violate known laws of physics. But could aliens find a
way around these laws? So what we have
to keep in mind here is the principle of inertia. That principle, stated
first by Isaac Newton, says that an object
at rest or in motion tends to stay at
rest or in motion unless acted on by
an outside force. [billiard balls clacking] So to generate these kinds
of crazy changes in inertia, you'd really have to act on that
object with an immense amount of force. [techno music] NARRATOR (VOICEOVER): Following
the same logic, a fighter pilot traveling near the speed
of sound attempting to make a 90-degree turn
at the same speed would experience something
close to 300 Gs of force. The most that a human pilot
wearing a pressure suit can manage without blacking
out is around 10 Gs. If his physiology were
remotely similar to humans, an extraterrestrial pilot
undergoing a 300-G maneuver would instantly perish. His internal organs would
continue moving forward and crush against the skeleton. If they were
similar to us, they'd probably have to have a
way of injecting fluid-- internal fluid, inside their
bodies, so that they dealt with this problem of their
organs floating around inside, and if they were
strapped in properly and cushioned properly, end up
not having internal damage when they accelerated
and decelerated. NARRATOR (VOICEOVER):
To effectively cancel the inertial effects
on the craft itself, the pilots might switch
on a technology that is beyond the reach
of modern humans. LUCIANNE WALKOWICZ: So
in order to cancel out the effects of a
300-G turn and not be squished by that
amount of force, you'd have to have
some sort of technology or a device that was
capable of canceling the effects of inertia. NARRATOR (VOICEOVER): The
device would have to manipulate the force of gravity using
a type of force field to counteract the
gravitational forces that rule the entire universe. This device, you could
turn on if you wanted to, then turn it off
if you wanted to, or maybe it would come
on and off automatically. This is high technology
that's out of sight. [ambient music] NARRATOR (VOICEOVER):
But if science can't yet explain how these craft could
overcome the deadly problem of inertia, can it help explain
their shapes, particularly the most famous shape of
all, the flying saucer. In the late 1950s, the US Air
Force tested the Avro Car. But the design
had poor stability and few aerodynamic advantages,
proving that high speeds are unattainable for saucer
craft in Earth's atmosphere. The delta wing, or wedge shape,
is a far stronger candidate, a fact that is well known
by modern military aircraft designers. In fact, the percentage
of UFO sightings reporting a wedge-shaped craft have
increased in recent decades, a trend that mirrors the
emergence of swept-wing jets and even flying wing designs,
like the B2 stealth bomber. The shapes that people have
reported over the years have changed, with the most recent
ones being more wedge-shaped. So really people's accounts tend
to reflect the most advanced aircraft of the time. NARRATOR (VOICEOVER): Beyond
movement and shape, any attempt to explain the science of UFOs
has to deal with the noise factor, or rather
the lack of noise. UFO reports consistently
claim that the objects move without making any sound. Almost all of these sightings,
it's a real rule there's no noise, which you would expect to
hear from any fast-moving craft in the Earth's atmosphere. You would hear it. CLIFFORD JOHNSON:
What actually happens is that you get what's
called a sonic boom. And that's a special
pressure wave that sweeps through
the atmosphere along with the craft. So you're on the ground. And that huge sonic boom is
a result of that pressure difference between the
front of the aircraft and the back of
the aircraft as it pushes through the atmosphere. [boom] NARRATOR (VOICEOVER): Could
an alien craft somehow cancel out the enormous pressure
wave that supersonic flight generates? The answer could lie in the
technology used in the latest generation of digital
noise-canceling headphones. [ambient music] So there is such a thing as
a sound canceling technology, where you take a particular
sound that you're interested in canceling and
kind of broadcast the negative of that sound to cancel it out. Now, I'm not aware of
any technology that's capable of doing that
with shock waves. NARRATOR (VOICEOVER):
Canceling out the ear-splitting, body-shaking
effect of a sonic boom would certainly require some
advanced engineering skills. And if there is silence,
what about invisibility? Some reports claim that UFOs
simply disappear into thin air. One promising human technology
currently being researched might explain such phenomenon. There is a technology
on the horizon which might change things visually. And that is a kind of
light-bending technology. As a class, they're
called metamaterials. If you want to think
about popular movies, think the invisibility cloak
in the Harry Potter movies. NARRATOR (VOICEOVER):
Metamaterials use combinations of polymer substrates,
gold, and copper, to forcibly bend electromagnetic
waves around an object. The light is guided
around the object rather than being
reflected or refracted. But advanced materials,
stealth capability, and mind-bending maneuverability
would all come to nothing if our visitors
were unable to get to Earth in the first place. I'd say that the chances of
another civilization making it here to visit us are
pretty minuscule. But if they did make it, it
would mean that they had solved a whole bunch of
problems, including material-science problems,
that we don't have answers to. So they'd have technology
far beyond ours, perhaps even beyond what we've
dreamt of at this point. NARRATOR (VOICEOVER):
But scientists can imagine several ingenious
technologies that could bridge the seemingly unbridgeable
distance between the stars, including one explosive
propulsion source that's so apocalyptic we might see
them coming light years away. [orchestral music] [whooshing] For decades,
countless UFO reports have surfaced from cities and
countries around the globe. But not all UFO sightings have
been reported from the surface of planet Earth. On July 19, 2009, viewers of a
NASA video feed from the space shuttle Endeavor reported seeing
a disk-shaped object hovering above the shuttle's
mechanical arm. [radio chatter] Space-based UFO
sightings like this have purportedly happened
throughout the history of manned space flight. Unspecified cosmic phenomenon? Or could it suggest
the possibility that huge extraterrestrial
starships are cruising the Milky Way galaxy? SETH SHOSTAK: Space
travel between the stars, it's a staple of
science fiction, right? You see it every
night on television. You see it in the
movies all the time. But could we really do it? Or could any species
really do it? Well, the distances
between the stars are enormous, really enormous. [new age music] Interstellar travel
doesn't violate physics. It isn't that you can rule it
out and say there's absolutely no way they can come here. It's just that it's
very, very hard. NARRATOR (VOICEOVER):
Just traveling from the Earth to Alpha
Centauri, our closest neighboring star, at nearly
4 and 1/2 light years, is beyond the reach of
our most powerful rockets. KEVIN GRAZIER: If an advanced
civilization were to visit us from a distant star system,
we can pretty much rule out that they would use chemical
rockets to get here. Despite the impressive
pillar of fire and smoke that we see during Apollo
Saturn V or shuttle launches, chemical rockets don't get you
very far in the solar system. [combustive rumble] To give you some
context for that distance, our furthest known space probe
is Voyager I, launched in 1977. It's been flying for 34 years
at 38,000 miles per hour. And it's only now starting
to leave our solar system. If its destination
were Alpha Centauri, it would take over 56,000 years
to reach even the closest star system. To engage in
interstellar missions on time frames of
a human lifetime, around about 50
years, we can see that we need to increase
the speed that we can travel by at least a factor of 1,000. NARRATOR (VOICEOVER):
Scientists have determined that the speed of light
is a mindblowing 186,000 miles per second. A spacecraft traveling
the star systems would have to reach a
significant percentage of that speed even to
reach the nearest star. [ethereal fusion music] The biggest obstacle is weight. A chemical rocket exacts
a huge weight penalty because its entire fuel supply
must be carried on board. [rocket roaring] We can calculate that even to
reach 6% of the speed of light using chemical rocket fuel
you would need more rocket fuel than excess
mass in the universe. So we really know
that it's actually impossible to reach another star
system using chemical rocket fuel. NARRATOR (VOICEOVER): If
extraterrestrial visitations are even possible,
their spacecraft must solve this problem. In 2011, NASA's NanoSail-D
became the first solar sail to orbit the Earth. The ultra-thin,
100-square-foot sail uses sunlight, or
photon pressure, as a source of propulsion. One of the immutable
limitations of rocket propulsion is the
fact that any rocket has to carry its fuel with it. A solar sail can take advantage
of the naturally-occurring resources, namely photons
emanating from the sun, which can be used to propel
that solar sail. Similarly, a hang glider can fly
without any fuel or an engine, just by taking advantage of
the natural resources we're surrounded by, namely the
atmosphere and the laws of aerodynamics. [ambient music] NARRATOR (VOICEOVER): To
achieve sufficient speeds to tow a spacecraft supporting
life forms, the sail would have to be huge, up to hundreds
of miles in diameter. And because the photon
pressure from a star would decrease the
further the sail traveled. Some have envisioned a
concentrated laser beam directing energy at the sail. [whooshing] [thud] Eventually-- and sadly-- this hang glider and all
hang gliders, at some point, have to land. But a solar sail riding
a beam of laser energy could conceivably
travel to the stars. [telemetric beeping] NARRATOR (VOICEOVER): The
max speed of a solar sail? About 10% the speed of light. Travel from Earth
to Alpha Centauri using laser-generated photons? About 45 years. Currently NASA and
other space agencies have plans for launching
more solar sails. But there are other
more powerful sources of propulsion-- [explosion] --in the universe. KEVIN GRAZIER: In the 1960s,
a method of propulsion was proposed where a
spacecraft would literally drop a series of explosive
charges out the back, and the force of the explosions
would push the spacecraft forward. [robotic noise] The prototype was
called the Orion Drive. And there were actually
a series of experiments done with conventional charges
to show that it would work. The Orion Drive
however, was proposed to use nuclear charges. [combustive roar] In order to simulate an
Orion-style propulsion system, Paul and Jim here are rigging
up a demonstration where they're going to put a small chemical
charge inside this barrel. And we're going to lift this
off the ground 50, 60 feet in the air. We're going to actually
calculate the energy release in this explosion and compare
it to a nuclear charge you might find an actual Orion
spacecraft system. [combustive roar] Our Orion spacecraft simulator
is rigged and ready to go. We're going to light off the
charges inside, blow the can up into the air, and compare
that with the energy release from a typical nuclear
explosion that would be used on an Orion-style drive. [sharp blast] [crash] NARRATOR (VOICEOVER):
The Orion spacecraft, studied at Los Alamos
in the late 1950s, proposed nuclear fission
as its propulsion source. [five punctuated blasts] Fission energy is produced
when the nucleus of an atom splits into smaller parts,
producing free neutrons and protons that release
tremendous gamma-ray energy. [thunderous rumble] [sharp blast] [tense music] [hollow thud] [man chuckles] The explosive charge in this
35-pound barrel lofted about 60 feet in the air. A small nuclear charge
in the Hiroshima range would liberate about 27
million times more energy. Clearly that's a
practical propulsion drive for interplanetary or
even interstellar travel. Because of the huge explosions
that an Orion Drive would require, on the back
of the spacecraft, you would have a huge, thick
metal plate that would absorb the thrust of the explosion,
and a series of shock absorbers to keep the crew from
getting jolted each time the-- the chargers went up. NARRATOR (VOICEOVER):
The max speed of a nuclear-powered
fission spacecraft? About 5% the speed of light. Travel time from Earth
to Alpha Centauri? About 90 years. [ambient music] Despite its powerful
fuel source, the fission craft is actually
slower than a solar sail. [whooshing] Boosting speed would
mean turning to another, more intense nuclear reaction. Fission technology is
well known and understood, and we've been using it
to generate power here on Earth for decades. But there's another kind
of nuclear technology, and that's nuclear fusion. [low, steady roar] KEVIN GRAZIER: Fusion is
the power source of the sun. In the core of our
sun, the temperatures are so high, atoms
are moving so fast, that they slam into each
other, creating new elements and liberating energy. NARRATOR (VOICEOVER): The
opposite of fission, fusion energy, is produced when two
atomic nuclei fuse together to form a single,
heavier nucleus. The result is a huge
liberation of energy. A fusion-powered spacecraft
was proposed in a 1970 study called Project Daedalus. Its mission called for a
trip to Barnard's Star, some 5.9 light years distant. Instead of nuclear bombs,
the fusion-powered craft creates the propulsion on
board in a reaction chamber. The fuel pellets for the
Daedalus-class starship consisted of pellets composed
of a deuterium-helium-3 mix. These would have been
ignited by what we call relativistic electron beams. These are extremely-high-energy
electrons that would have hit the deuterium-helium-3
pellets, cause them to fuse, and a huge amount of
energy would be released. The Daedalus design
for 250 of these pellets to be released every
second for over two years. The spacecraft would have
weighed 55,000 tons, most of which would have been fuel. NARRATOR (VOICEOVER): The weight
penalty for such a spacecraft would be high. But an advanced civilization
could eliminate the problem by mining the hydrogen fuel
during its interstellar journey. Deuterium, or heavy hydrogen,
exists in abundance on Earth, notably in seawater. But helium-3 is a
much rarer isotope. In our solar system, it
can be found on the moon, and in vast quantities
on Jupiter and Saturn. Scientists have proposed using
huge hydrogen scoops to mine the helium-3 needed to
cross the void of space. So it's conceivable that
if you had a craft that was powered by nuclear fusion,
you could go to another star system, and then use the
hydrogen available from that star to refuel NARRATOR (VOICEOVER): The
self-contained, fusion-powered spacecraft could avoid
a huge weight penalty and reach speeds that could
allow near-star exploration in a reasonable time frame. The max speed of a
nuclear-powered fusion spacecraft? Up to 15% the speed of light. Travel time from Earth
to Alpha Centauri? About 35 years. The immense costs,
the logistics, and even the politics of
nuclear-powered space flight long ago caused humanity
to scrap any and all plans. [stirring orchestral music] But a sufficiently
advanced society could trade nuclear
propulsion for what seems like an impossible paradox-- traveling at light speed
without moving at all. [poignant orchestral music] Can UFOs actually achieve
the immense speeds required for interstellar travel? One potential
answer may be buried 30 feet beneath the ground
in America's heartland, the Fermilab Tevatron collider,
outside Chicago, Illinois. Racing just below
the speed of light, particles of protons
and antiprotons are launched in
opposing directions. They meet in a
high-energy collision. [explosion] The impact produces gamma rays,
the highest-energy source known in the universe, and potentially
the key to interstellar travel. The best way of making
antimatter here on Earth is to employ probably the most
famous equation that Einstein taught us, which is E equals
mc squared, which tells us that, for a certain amount
of matter, we can get energy. It's a great idea, because
it's incredibly efficient. You essentially take all of
the mass in those particles, and convert it into energy. NARRATOR (VOICEOVER):
But how can antimatter exist in the universe if it must
be artificially manufactured? That's the question that
Stefan H. from Philadelphia texted "The Universe." Stefan, antimatter
definitely exists. And when it meets up
with normal matter, it explodes in a burst of
electromagnetic radiation. Now, we can make small bits
of antimatter in laboratories, but we can also collect
antimatter from space. Some cosmic rays
which are charged, very energetic particles
coming from space actually consist of antimatter. [whooshing] NARRATOR (VOICEOVER):
Currently, the supercollider is the only practical way
to produce antimatter. [explosion] And right now it's created
in very small quantities. WILLIAM R. ALSCHULER: If
we could figure out a way to both create and
store enough antimatter, we would have a
storable fuel which, when mixed with ordinary matter,
would liberate a huge amount of energy at a rate way
beyond what either fission or fusion can do. RICHARD OBOUSY: Because we know
antimatter exists and we know antimatter can be
created and stored, it is conceivable that an
advanced civilization could create and harness the
power of antimatter in sufficient quantities to
create an antimatter rocket. NARRATOR (VOICEOVER):
An antimatter ship could achieve unbelievable
velocities, cruising just below light speed,
nearly matching the speed of a starbeam
streaking across the galaxy. [techno music] Travel time from Earth to Alpha
Centauri, 4 and 1/2 light years distant? About five years. In human terms, the cost of
creating enough antimatter particles to power such a
starship would be astronomical. [explosion] It might be affordable
in alien currency, but an antimatter
spacecraft like this comes at a high price. The gamma rays from
antimatter propulsion are so dangerous they could
destroy the cell structure of any living
beings aboard ship. This starship would
have to include an advanced shielding mechanism
to keep the crew alive. And at such high
rates of speed, there are equally destructive
threats in the universe. LUCIANNE WALKOWICZ:
Space is pretty empty. But if you are moving close
to the speed of light, you'd need an extremely
effective shielding system that would allow you to be protected
from interstellar dust particles that would all
but annihilate a spacecraft traveling that fast. [moody orchestral theme] NARRATOR (VOICEOVER): But if
space debris is so dangerous, why not avoid it completely? The solution might be one
familiar to "Star Trek" fans, namely a starship that
could achieve light speed without even moving. In effect, one
would create what is called a warp bubble,
the name taken straight out of science fiction. And that would
involve compressing a region of spacetime
in front of a spacecraft and expanding a region of
spacetime behind a spacecraft while the spacecraft
itself sat stationary inside this flat bubble. So one would effectively be
riding a wave of spacetime. [techno music] NARRATOR (VOICEOVER):
A warp drive may seem like pure sci-fi
fantasy, but in 1994, a well-respected young physicist
named Miguel Alcubierre published a serious proposal
outlining how to travel in a controllable space warp. [whooshing] There are huge obstacles
to Alcubierre's warp-drive solution. The biggest is
called dark energy, a cosmic phenomenon
recognized in 2011, when three scientists were
awarded the Nobel Prize for proving its existence. The simplest
explanation that's been proposed for the
phenomenon of dark energy is that there's an intrinsic
property of space itself that makes it want to expand. But you can actually see it
by looking at receding parts of the universe and seeing that
there's this extra acceleration component. But it isn't a stored energy
source like solar energy or other kinds of energy. RICHARD OBOUSY: And so
it's not inconceivable. It's not beyond the
realm of possibility that some advanced
civilization existing somewhere in the universe has learned
how to harness dark energy to create an exotic
form of propulsion. NARRATOR (VOICEOVER): But
there's another obstacle to a workable warp drive. The only known way to
pull a spacecraft forward within a warp requires
harnessing the intense energy of a black hole. WILLIAM R. ALSCHULER:
This sort of simple notion is somehow to make a very
concentrated bit of matter extremely concentrated,
on the level which would cause a black hole. If you could generate a
black hole on a small scale, so to speak, you could dangle
it in front of the ship and use its space distortion
to just sort of drag the ship along. NARRATOR (VOICEOVER): And
exactly how fast could a warp drive tow an
extraterrestrial spacecraft? The clear implication
of Alcubierre's work was that it should be
possible, if you can make his design of a warp drive,
to achieve speeds almost any multiple of
the speed of light. NARRATOR (VOICEOVER):
Travel time from Earth to Alpha Centauri
aboard a light speed craft powered by a space warp? About 4 and 1/2 years-- or less, as long as everyone
on board doesn't incinerate. One problem with
the Alcubierre drive is, within that warp
bubble, temperatures would rise to far hotter
than the core of our sun. That's hot. NARRATOR (VOICEOVER): Just
one more small problem to solve for the chance
to reach planet Earth. But what if such
an alien spacecraft were to arrive in Earth's
atmosphere riding in a warp bubble, towed by a black hole? It might not be the first
mass-witness UFO sighting, but it would
certainly be the last. [ominous musical drone] March 13, 1997,
thousands of people witness an optical phenomenon
drifting across the Arizona skies. Reports of a series of bright
lights and geometric patterns are widespread, including
multiple sightings over Phoenix of a craft up to a mile wide
with lights winking on and off in sequence. Reconstructing the
events of that evening, the lights of the Phoenix Lights
were almost certainly flares dropped by an Air Force A-10
aircraft in conjunction with the human tendency to envision
a solid shape connecting them. [crackling] That's the best explanation
for the Phoenix Lights. NARRATOR (VOICEOVER): For many,
the Phoenix Lights incident was direct proof that a huge
extraterrestrial craft had arrived. Some even called
it a mothership. The purpose of an
extraterrestrial mothership is fundamental to the
theories of alien visitation. It's the only way to bridge the
vast distances of interstellar space. The term, mothership,
I think came into being around the same time
that flying saucers, as a term, came into being. And I think the
universal notion was you couldn't make
an interstellar trip in a person-sized craft. You have to have
something really large. An apt earthly
analogy of a mothership is that of an aircraft carrier. An aircraft carrier
travels the vast distances across the oceans,
but its purpose is to transport smaller aircraft
which can then go on and engage in whatever their
missions may be. NARRATOR (VOICEOVER):
If the journey to Earth is long, on the order of
centuries or even millennia, the mothership would be much
more than just an aircraft carrier. KEVIN GRAZIER: There's a
generational or ark ship, which is a very large spacecraft
that is essentially an enclosed ecosystem, in which
generations of inhabitants expect to be born, grow old,
and die over the long period it takes the spacecraft to reach
its ultimate destination. NARRATOR (VOICEOVER):
Perhaps with technology such as suspended animation,
biological alien passengers could be put to sleep and
revived after the vast journey. [ambient music] Surviving such a
journey would also mean surviving the destructive
energy powering the spacecraft itself. One logical design solution,
a cigar-shaped mothership, is precisely what many UFO
witnesses claim to have seen. [low, steady roar] RICHARD OBOUSY: For any
advanced propulsion system you would want to situate the
crew as far away as possible from the engine source. So one possible design would
be a very long, thin design, with the engine located at
one end of the spacecraft, and then some kind of truss
connecting the crew section as far away as possible
so as to avoid damage from high-energy neutrons,
X-rays, or gamma rays from the advanced
propulsion system. [new age rock music] NARRATOR (VOICEOVER): If such
ark ships have in fact visited planet Earth, the evidence would
be overwhelming and undeniable. Something all these exotic
and advanced propulsion technologies have in common
is that they all radiate prodigious amounts of energy. And so we'd be able to see them,
like beacons on a lighthouse, from sometimes light years away. A concentrated emission
of X-rays, gamma rays, or subatomic particles
would be suspicious. Because we don't see
that in our environment locally under any
normal circumstances. Beyond the obvious
visual evidence, the physical effect of a
mothership approaching so close to the Earth's surface
could be a terrifying form of apocalypse. [roaring wind] If, for whatever reason, this
extraterrestrial technology or civilization chose not
to turn off their engines, it could be catastrophic
for life on Earth, as we would be bathed in
high-energy neutrons, X-rays, and gamma rays. WILLIAM R. ALSCHULER:
If it's something which is a version of a warp
drive, then you're talking about space distortion. And you wouldn't want to be
too close to any major mass, including a planet. NARRATOR (VOICEOVER): Such
catastrophic visitations assume that aliens are willing
to risk their own lives in interstellar space. But there might be a better way. They could stay at home and
explore the cosmos using a race of thinking machines. For many ardent believers
in the UFO phenomenon, the Roswell, New Mexico
event in the summer of 1947 is the defining alien
encounter in human history. [telemetric beeping] In popular culture,
the most lasting detail from the purported crash
came from the descriptions of extraterrestrial
bodies found at the scene. In the ensuing
decades, this vision of alien beings
known as "the greys" became the accepted standard in
science fiction and recurring alien encounter reports. The oversized heads may
explain an expected feature in alien biology-- greater intelligence. The larger skulls would contain
larger, more advanced brains compared to ours. Mastering the profound
challenges of interstellar travel would certainly
require great intelligence. But might it require something
that is beyond organic biology? One area of science fiction
where we might be making kind of a big mistake is to assume
that the aliens are biological, that they're living things. [telemetric beeping] I think that the possibilities
for the kinds of organisms which might travel between the
stars are really wide open. And one possibility that has
appeared on occasion in science fiction is machine intelligence. [ambient music] NARRATOR (VOICEOVER): According
to a recent earthly equation known as Moore's law,
the number of transistors on a single computer chip
doubles every 18 months, meaning computer
processing speed doubles. This trend has continued for
more than half a century, and is expected to continue
through 2020 or later. The exponential explosion
of processing speed is opening the door on a staple
of science fiction called artificial intelligence. So if you invent
a thinking machine, 100 years later that machine is
not only smarter than you are, it's smarter than all
humans that have ever lived. And that's the difference
between artificial intelligence and real intelligence. Artificial intelligence can
evolve enormously faster. But I think the
form of AI that we find most both menacing and
promising is the kind of that could, in fact, do
what our brains can do, can think the way we can think. NARRATOR (VOICEOVER):
At Stanford University's Artificial Intelligence
Laboratory, the future of truly
intelligent machines is rapidly approaching. ANDREW NG: There are a few
things that make AI difficult. One is we don't really know
yet how to make computers learn as effectively as humans can. It seems that our computers
today just aren't as fast as we would like them to
yet, to simulate the learning processes that take
place in the human brain. [techno music] NARRATOR (VOICEOVER):
To demonstrate early-stage artificial
intelligence, Stanford students designed a fighting
robot, one that attempts to learn as it fights. OK, so what it's doing now,
it's trying to defend itself. So it's reacting to your motion. So depending on how
you move your sword, the robot will adapt to your
motion and to your behavior. SETH SHOSTAK: How
important a step on the road to true
artificial intelligence are robots like this, Thorson? So here we are using
artificial intelligence methods, like learning methods,
to adapt to the environment of the robot. But we are still not at a
stage where the robot is really thinking. So these computers are
still far less intelligent than almost any human. But in the future, I think
computers could eventually reach and maybe even
surpass human intelligence. And if that's the case,
imagine that each of us has a computer in our wallet or
the cell phone in wallet that was as smart as Einstein
or even smarter. How would civilization change? And what are the amazing
things we could do then? NARRATOR (VOICEOVER):
Advanced as it is on Earth, the fencing robot is but a crude
analogy for the type of machine intelligence that could pilot
an interstellar spacecraft. [whirring] The immense obstacles
of space travel, including the sheer time
scale and cosmic hazards, build a strong case that a
race of intelligent machines will make first contact. But honestly, if interstellar
travel really takes place, it seems sort of reasonable to
not send the biological beings. I mean, they're fragile. They have finite lifetimes. KEVIN GRAZIER: Just as NASA
sends robotic probes to explore the solar system in
advance of human explorers, our first contact with an
alien civilization maybe with its robotic probes. NARRATOR (VOICEOVER): Biologic
being or AI superbeing? Our vision of an
extraterrestrial will remain mere speculation
until first contact is made. But how long will we wait? And despite a lack of hard
evidence, just how likely is the existence of another
intelligent civilization? Some believe it is highly
likely that the universe teems with life. The galaxy has been
around for a long time. The solar system has been
around for quite a long time, but the galaxy much longer. And the stars in
it, many of them are much older and
our solar system. So the chances are, if
civilizations are out there, they've been around for
longer than we have. If they exist, say,
for 100,000 years, then the chances
are pretty good, I think, they will have
learned to either communicate across interstellar
space or possibly travel. [eerie orchestral music] NARRATOR (VOICEOVER):
Until first contact occurs, humanity will continue to
scan the skies for UFOs. None have been proven to be
extraterrestrial craft so far, but that does not rule out the
possibility that humanity may one day discover evidence of
an intelligent civilization, either in the far-flung
heavens or much closer to home.
