Aliens almost certainly do exist. So why haven't we yet met E.T.? It turns out we're only just developing instruments powerful enough to scan for them, and science sophisticated enough to know where to look. As a result, race is on to find the first intelligent aliens. But what would they look like, and how would they interact with us if we met? The answers may come to us sooner than we imagine, for one leading astronomer believes she may already have heard a hint of their first efforts to communicate.
Featuring astrobiologist Lynn Rothschild of NASA Ames Research Center, astronomer Jill Tarter, physicist and SETI projects affiliate Paul Davies, astronomer Geoff Marcy and his student Paul Butler, and space scientist William Borucki. This episode talks about the Murchison meteorite, the Allen Telescope Array, 51 Pegasi b, and the Kepler Space Telescope mission.
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Featuring astrobiologist Lynn Rothschild of NASA Ames Research Center, astronomer Jill Tarter, physicist and SETI projects affiliate Paul Davies, astronomer Geoff Marcy and his student Paul Butler, and space scientist William Borucki. This episode talks about the Murchison meteorite, the Allen Telescope Array, 51 Pegasi b, and the Kepler Space Telescope mission.
Thanks for watching. Follow for more videos.
#cosmosspacescience
#throughthewormhole
#season1
#episode6
#cosmology
#astronomy
#spacetime
#spacescience
#space
#nasa
#morganfreeman
#spacedocumentary
#aliens
#arewealone
#alienlife
Category
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LearningTranscript
00:01It's one of the great mysteries of science.
00:05A mystery that, if solved, will force us to rethink our place in the universe.
00:13Is life on Earth unique?
00:16Or is it spread throughout the cosmos?
00:20If we share the stars with aliens, why haven't we heard from them?
00:25Or are we truly alone?
00:30Space. Time. Life itself.
00:40The secrets of the cosmos lie through the wormhole.
00:53We've all done it.
00:55Stared into the night sky.
00:57I gazed at the vast canopy of stars and wondered what or who is out there.
01:05Is there other life in the universe?
01:08Maybe on a planet like ours with water and air?
01:13Or on some other kind of planet or moon, supporting an alien form of life?
01:18As a young boy growing up in the Mississippi Delta, I'd sit on the porch in the evening with my family.
01:30And we'd talk about things.
01:34When it was cloudy, it was very dark.
01:37Pitch black.
01:39We would think we were all alone.
01:40And then sometimes people would just appear out of the darkness.
01:46Who do you see coming, Morris?
01:47It's David and Travis.
01:49Hi, boys. How are you?
01:51Could our universe be just as deceiving?
01:54Might other sentient life forms just appear out of the seeming darkness of space?
01:59There are more stars in the universe than all the grains of sand on every beach on Earth.
02:09And countless planets orbit those stars.
02:13So it would be arrogant to think that we are the only creatures in the cosmos.
02:18I think it's easy to imagine life on other worlds.
02:21And I'm not alone.
02:27A whole category of scientists investigate alien life.
02:31They are called astrobiologists.
02:34Lynn Rothschild of the NASA Ames Research Center is one of them.
02:42I am so lucky that I have a job that is so incredibly fascinating.
02:47Because, to me, it's impossible not to be fascinated with the potential for life.
02:54To me, looking for the bizarre, the extreme, the exceptions, and some of it's here on Earth,
03:02but there may even be some of it elsewhere.
03:05And, I mean, that's the sort of thing that just absolutely blows your mind.
03:12We form theories about alien life by first looking at life on Earth.
03:18Our planet is filled with an incredible diversity of creatures uniquely tailored to their environment
03:25by billions of years of evolution.
03:30A normal condition for life, what we see is all lovely,
03:35and it's just sort of these medium temperatures and so on,
03:38but it only describes a very tiny slice of where life can actually survive.
03:44We need to have liquid water, but there are organisms that can beat the odds
03:49and live above the boiling temperature of water and below the freezing temperature.
03:53We have to be in a certain environment that's not too acidic and not too basic,
03:58and yet there are organisms that can live down incredibly acidic conditions.
04:02Life on Earth can survive in extreme environments, but can life survive on other worlds?
04:13It's a mystery set in space, and that makes it tough to investigate because the human race has barely left Earth.
04:23Searching for clues is incredibly difficult.
04:28Fortunately, sometimes, the clues come to us.
04:33In 1969, a 220-pound meteorite crashed into Murchison, Australia.
04:40The Murchison meteorite was more than just a piece of rock floating through space.
04:53It was a doorway to alien life.
04:57A piece of the meteorite is kept here, at the California Academy of Sciences.
05:02The reason this is so exciting to scientists is that it's as old as the solar system, and yet we found that it contains the building blocks of light,
05:13things like amino acids and other sorts of chemicals that we use to make our own bodies in all life on Earth.
05:20So what it shows is that these building blocks were around in our solar system before life arose on the Earth.
05:26Life may have come to Earth in a meteorite like this, and life similar to ours may be spread through the universe in the same way,
05:38as meteorites act like seeds, raining down the ingredients for life on fertile planets.
05:46So what does this mean for our hunt for E.T.?
05:52For one thing, if the common elements of life as we know it are spread throughout the universe, then life on other planets might be similar to life on Earth.
06:06If we look at enough sci-fi movies, there are all sorts of weird and wonderful aliens out there.
06:11But what we're really interested in is what these organisms are built from.
06:15And if you look at life on Earth, we're all built on a form of carbon chemistry called organic chemistry.
06:22And this seems to be the language of life. If you look out into the interstellar medium, the same compounds are there as on Earth.
06:30If you look at what we're made of secondarily, it's water. There's water all over the universe.
06:35So in terms of our biochemistry, life everywhere, I think, would be very similar to Earth in terms of its biochemistry.
06:42But alien life would not necessarily look like human life. Life evolves to suit its environment.
06:51One of the big things that would affect what life looks like on another planet, particularly if you're starting to look at large life, macroscopic life like us, is what the gravity's like.
07:01Now on Earth, we've all evolved under one G, one gravity.
07:06But if we evolved on a planet with 2G or 5G, for example, we would have to have correspondingly thicker legs, would have to have much stronger limbs to hold up our weight.
07:18And maybe at some point we'd be pushed so we were basically flat in the ground because we couldn't hold up any weight at all.
07:23But conversely, if we had evolved on a planet that, say, had half G, maybe we'd be tall and thin and avatar-like creatures and not the way we are today.
07:40So gravity is something we don't tend to think about, but that really is one of the things that shapes life.
07:45If there are aliens out there, finding them will be incredibly difficult.
07:54Astrobiologists are like detectives that can't get near the crime scene.
07:59They are limited by our technology, which so far can barely send probes to nearby planets.
08:05These probes tell us that Earth harbors the only currently known sentient life in our solar system.
08:11Which doesn't mean there isn't any life out there.
08:16NASA is optimistic about someday finding simple forms of life on one or more of our neighbors.
08:24Microbes may live in the Martian soil or float in the clouds of Venus.
08:31Strange creatures could swim in the icy waters of Saturn's moons.
08:36If we find alien microbes outside the Earth, or even Earth microbes thriving on other worlds, it greatly raises the odds that life is scattered across the universe.
08:55E.T. probably isn't in our neighborhood.
09:01But the universe is unimaginably large.
09:04He, she, or it may be out there somewhere.
09:09So around the world, science detectives have sent out an all-points bulletin for extraterrestrial life.
09:16They're listening to the stars, staking out possible layers, putting together composite sketches, and looking for clues it may have left behind.
09:32The hunt is on.
09:37And now we're discovering the incredible truth.
09:40We don't have proof that we share the universe with other intelligent species.
09:56But many scientists believe that they are out there, proof or not.
10:00Perhaps extraterrestrials are watching us right now.
10:06Maybe they just sent us a message.
10:09Or maybe they have no idea that we're here, and they're talking among themselves.
10:15We'll never know the truth.
10:18Unless we listen.
10:19For half a century, the SETI project, the search for extraterrestrial intelligence, has done just that.
10:33SETI homes the sky with radio telescopes, hoping to hear alien transmissions.
10:40They're trying to wiretap E.T., but they don't have his phone number.
10:44So, much as the CIA hunts for terrorist chatter, SETI tries to listen to everything out there.
10:55It's a daunting task.
10:58For starters, how can we tell the difference between a natural signal from the stars
11:05and an intelligent signal sent by strange alien beings?
11:09Dr. Jill Tartar is SETI's chief alien hunter.
11:17If you'd like to listen to the cosmos, take an old-fashioned radio like this, an analog radio,
11:23and tune the radio between stations.
11:28Can you hear that hiss?
11:30About 10% of that noise is actually coming from the cosmos.
11:35That's synchrotron radiation from the Milky Way galaxy.
11:37SETI has combed the cosmic radio dial for 50 years.
11:45Most days it's quiet out there, but once in a great while, something exciting happens.
11:54In 1977, a SETI astronomer picked up a signal from the constellation Sagittarius.
12:00It lasted 72 seconds.
12:03The full duration the radio telescope was pointed at it.
12:07Going through the data, the scientists circled the signal and wrote,
12:13WOW!
12:14The signal looked like the kind of engineered pulse that we expect will come from an alien civilization.
12:21The WOW signal was a one-time event.
12:25Astronomers have returned to that part of space looking for the signal, hoping for a repeat,
12:31but always coming away disappointed.
12:33To this day, there is still no explanation for what happened.
12:40In 1997, 20 years after the WOW signal, SETI detected another signal from space,
12:48and Jill Tartar was there to witness it.
12:50At 6 o'clock in the morning at an observatory in West Virginia,
12:58Tartar and her team heard a mysterious sound coming from the SETI constellation.
13:05The signal showed up early one morning at the Greenbank National Radio Astronomy Observatory
13:12when we were using the 140-foot telescope there.
13:16I was actually at the telescope.
13:18We detected a signal, and it was clearly a manufactured signal.
13:22It wasn't just one tone on the radio dial.
13:25It was like a cone.
13:27Many different signals, all narrow, all separated by the same amount of frequency.
13:34Mother Nature wasn't doing that.
13:37After years and years of listening,
13:39years and years of silence, Tartar wondered,
13:45is this it?
13:47I was incredibly excited,
13:48and I was scheduled to finish up my observing shift in West Virginia at 8 o'clock,
13:54and get on a plane and come home.
13:56When this started at 6 o'clock in the morning,
13:59I certainly wasn't going to get on any plane and leave the signal behind.
14:04Tartar initiated a series of tests to verify the signal
14:08and find out if it was natural, man-made, or alien-made.
14:15We moved the telescope off the star we were pointing on.
14:19The signal went away.
14:21We moved it back on the star.
14:23The signal was there.
14:26I thought, oh, I wonder if any of our other observations have seen that same kind of signal.
14:32But I was so excited that when I looked at the output, I didn't see that exactly what I was looking for was there.
14:42We had, at previous occasions, detected this signal with this frequency spacing.
14:49It turned out that it was a signal that was coming not from the direction that we were looking in,
14:56but a signal that was coming in our side lobes.
15:02Tartar and her colleagues had made a mistake.
15:05The signal they detected was not alien.
15:07It came from a man-made space probe orbiting the sun called SOHO.
15:15SETI learned that to communicate in the cosmos, it needed better technology.
15:20And now, they're getting it.
15:23In Northern California, SETI is building hundreds of new devices to wiretap ET.
15:29We're here in Northern California at the Hat Creek Radio Observatory.
15:38Right now, what we have is the Allen Telescope Array, an innovative new way to build a radio telescope,
15:47a large telescope out of small pieces.
15:52By linking together a large number of small telescopes,
15:55the ATA gives astronomers a wide field of view,
16:00a radial picture ten times the size of the full moon.
16:04Today, we've got 42 of these dishes that are 20 feet across,
16:09and we're looking forward to expanding it until there are 350 of these small dishes.
16:15It may be just the right tool, finally.
16:18The ATA gives SETI the ability to observe many more channels on the cosmic radio dial.
16:25Now, because of technology, we simultaneously observe hundreds of millions of channels.
16:32And I look forward to the future when I can do billions of channels all at once.
16:37So technology has enabled the search on a scale that might finally be big enough to be able to detect something.
16:45SETI scientists have wiretapped the stars for 50 years, but there's still no sign of extraterrestrial life.
16:56The great silence remains.
16:59And maybe that's not surprising.
17:02SETI really is a needle in the haystack search without any guarantee that there's a needle out there.
17:14Professor Paul Davies is a physicist and a SETI affiliate.
17:19But he's something of a heretic within the group.
17:24The traditional approach to SETI is to scan the skies with a radio telescope
17:29in the hope of picking up a message from some alien civilization that's being deliberately beamed towards Earth.
17:35I don't think that's credible, and here's why.
17:38One of the big problems in this whole SETI business is the vast scale of things.
17:46The universe is really, really big.
17:49By human standards, it's just stupendously big.
17:52Imagine we get the smallest speck of dirt from the desert floor,
17:57and that represents the size of our solar system right up to the orbit of Pluto.
18:01And then ask, how big is our galaxy?
18:05How far would you have to go to get to the far side of the Milky Way?
18:08And the answer is, all the way to those hills, right in the distance over there.
18:13And if you ask, how far do you have to go to get to the edge of the observable universe?
18:18Well, you'd need to go right up to the orbit of Mars.
18:20It's often said that because our radio and television signals have beamed into space for 80 years now,
18:32aliens should have figured out that we're here and have sent us a message.
18:37But this argument overlooks a basic law of physics.
18:42Another way of thinking about this is in terms of the speed of light,
18:45which travels at 186,000 miles every second.
18:48It takes light about 100,000 years to cross our galaxy,
18:53and it takes 13.7 billion years for it to cross the universe.
18:59Our first radio signals, which leaked out into space about 100 years ago,
19:04have gone about that far by comparison.
19:09Suppose there's a civilization 1,000 light years away,
19:12and that's actually pretty close by even SETI optimist standards.
19:15Well, they don't see Earth as it is today.
19:19They see it as it was 1,000 years ago.
19:21There were no radio telescopes here then,
19:23so it would make no sense for them to start sending messages to us
19:27until they knew that we were on the air.
19:29And they're not going to know we're on the air until our first radio messages reach them,
19:33and that's going to be in another 900 years.
19:35Listening for signals from the stars is a long shot.
19:43So how can we do a better job of tracking down extraterrestrial life?
19:49As SETI monitors its cosmic wiretaps,
19:53another set of science detectives follow radical new leads,
19:56leads that may take us right to E.T.'s doorstep.
20:09Listening for signals from the stars is one way to search for other intelligent life in the universe.
20:15But there are other ways we can find out where E.T. lives.
20:19Astronomer Jeff Marcy hunts the sky for planets that could sustain alien life.
20:29For many years, people thought he might be crazy.
20:33When I would tell other scientists that I was hunting for planets around other stars,
20:39they would look down at their shoes embarrassed for me.
20:42You might as well be looking for fairies or for alien civilizations in the pyramids.
20:52It's hard to believe.
20:54But until recently, there was no proof that other planets exist outside our solar system.
20:59No telescope on Earth, nor satellite in space was powerful enough
21:04to spot anything smaller than stars.
21:07The reason is simple.
21:09Planets don't shine.
21:12They don't reflect very much light from their host star.
21:15They're dark specks of dust, if you will, floating around the universe.
21:20And people understood you probably could never detect them.
21:26Marcy refused to accept that.
21:29Risking professional ridicule, he was determined to find a way to spot far-off worlds.
21:35Eventually, he found one.
21:37It turns out that while planets may hide from our eyes,
21:43they can't hide from the stars they orbit,
21:46what astronomers call their host stars.
21:50Finding planets is actually very simple.
21:54We watch the host star, represented by my head,
21:58as the planet, represented by the tennis ball,
22:00orbits that star and pulls gravitationally on the star.
22:06As it does so, the star, my head,
22:10wobbles around, being pulled by the planet,
22:13and back on Earth, our telescopes can watch to see the wobble of the host star
22:18as the planet goes around it.
22:20Even if you don't see the planet, you can see the star wobble around.
22:23It's difficult to see it directly, but we use the Doppler shift of the star's light.
22:30As the star comes at you, the light waves emitted toward the Earth get compressed.
22:34And as the star goes away from you, the light waves get stretched out in their travels to the Earth.
22:39And so you can see the light waves compressing and stretching and compressing and stretching,
22:45which to our human eyes means the color changes.
22:49We see the colors change from bluer to redder to bluer to redder,
22:54and we can measure that at the back end of a telescope.
22:57This effect is well known, the Doppler effect, with sound.
23:01You can hear the pitch of a train whistle change as the train goes by you.
23:06Even with your eyes closed, you can tell whether the train is a-coming or a-going,
23:12and so it is with light waves from a star.
23:14You can tell whether the star is a-coming or a-going from the changing pitch of the light waves.
23:23For nearly a decade, the Doppler shift method of planet hunting was an experiment with no positive results.
23:29Marsy still couldn't prove that planets exist outside our solar system,
23:36but he slowly won a few astronomers over to his way of thinking.
23:41He was no longer the sole detective on the investigation.
23:46In 1995, his patience was rewarded.
23:50A group of Swiss astronomers had their eyes on a bright object in the Pegasus constellation called 51 Pegasi b.
24:02The Swiss suspected they had found what everyone was looking for.
24:07A very large planet.
24:10The first one seen outside of our solar system.
24:13But they needed confirmation.
24:14Luckily, my student Paul Butler and I had telescope time assigned to us just a week later on the Lick Observatory 3-meter telescope.
24:25Four consecutive nights, and as luck would have it, the supposed orbital period of this planet, around 51 Peg, was four days.
24:35Perfect match. We went to the telescope. All four nights were clear.
24:38We measured the Doppler shift of 51 Peg, and we drove off the mountain 100% convinced that the Swiss had been correct.
24:48It was a marvelous moment, and the world was introduced at that time, in mid-October of 95, to the notion that our solar system was not alone.
25:01The discovery of 51 Pegasi b changed the entire game.
25:04The Doppler shift method of planet detection was proven successful.
25:09And soon, Marcy and his colleagues found more and more alien worlds.
25:14They have slowly confirmed nearly 450.
25:18There are likely billions more.
25:21But Marcy's goal hasn't changed.
25:24He wants to find worlds like Earth that orbit in the habitable zones around their host stars.
25:29The comfortable place where it's not too hot and not too cold.
25:35Worlds that could possibly support some form of life.
25:42Planets in this habitable zone may have a key ingredient for life as we know it.
25:48If you took any organism on Earth and you took out the water,
25:52you'd end up with some powdered amino acids, proteins, nucleic acids, a few fats, you know, these sorts of things.
26:02But they don't work in a powdered form.
26:04You don't get the chemistry that would make life.
26:07So you need some kind of liquid, some kind of solvent to dissolve all these chemicals in.
26:12What all life on Earth uses as its solvent is water, liquid water.
26:18And so that is what we look for as a first step to looking for life elsewhere.
26:23The presence of liquid water.
26:27But finding habitable planets isn't easy.
26:30Planets like Earth are small and their host stars shine billions of times brighter.
26:36So they're hard to see.
26:38Looking for solar wobbles isn't easy either.
26:43Now imagine a smaller planet.
26:46My head still represents the host star.
26:49And as this small planet orbits the star, it has so little mass,
26:54it hardly yanks gravitationally on my head, the host star, at all.
27:00Making the detection of small Earth-sized planets very difficult.
27:04Marcy has gone from crazy outsider to the peak of his profession without changing his position.
27:12He doesn't back down in the face of a challenge.
27:16He plans to keep combing the cosmos a section at a time,
27:23looking for stars similar to our sun,
27:26and enjoying the fruits of our ever-evolving technology.
27:30Here we are, about to answer a question that the ancient Greeks asked,
27:39and humans undoubtedly asked even before then.
27:42It's a treasure of a moment in human history that we suddenly have at our fingertips.
27:48The telescopes, the computers, the light detectors, and the knowledge to answer a philosophical question that humans have been asking since antiquity.
28:00As a youngster, I read a lot of science fiction, which opened my mind to the possibility of life on other worlds.
28:14Until recently, we humans could only guess about this.
28:18But today, we live in a scientific renaissance.
28:25A golden age of technology, where fictional possibilities give way to extraordinary discoveries.
28:34Thanks to our high-tech tools, we may be on the verge of solving the mystery of alien life.
28:41For instance, until recently, the investigators tracking down E.T. had to search from down here on Earth.
28:51But now, we finally have a detective in outer space.
28:56On March 6, 2009, NASA launched the Kepler Space Telescope.
29:12Kepler is the first-ever satellite solely devoted to the hunt for planets outside our solar system.
29:18The hope is that Kepler will not just find more planets, but will discover planets roughly similar in size and atmosphere to Earth.
29:29Such planets could support life.
29:33William Barucki is the principal investigator for the Kepler mission.
29:38He's been planning this for 25 years.
29:43Ever since I was a little boy, I was interested in space exploration.
29:48We used to lie on a garage roof during meteor showers and use cameras to take pictures of meteors.
29:54So it's a dream come true to work with NASA and actually be able to come up with a mission that will help us understand what might be out in space.
30:03The beauty of Kepler is its simplicity.
30:07It looks for planets by measuring how much light a planet blocks when it passes in front of its sun.
30:13This is called a transit.
30:17A familiar example occurs during a lunar or solar eclipse, when sunlight is blocked by the moon or Earth's shadow.
30:26This is easy for us to see with the naked eye.
30:29But finding an Earth-like planet transiting a distant star is much more difficult.
30:35An Earth-sized transit is really, really tiny.
30:39So it's like watching a Klee crossing a car headlight at a really long distance.
30:45And you find that, and you measure it, and you measure it accurately.
30:49Kepler measures these minute changes in light.
30:53Tiny differences between light and dark tells it where the planets are.
30:57So what you see is some curve showing light being constant, a dip, and the planet goes across and it comes back up again.
31:05So you're looking for that dip in light for each star when a planet goes across.
31:10And the bigger the planet, the more light it blocks, the bigger the dip.
31:14So we can tell the size of the planet from the size of the dip.
31:16But it isn't practical to observe one star at a time.
31:22Barucki had to find a way to look at many stars together.
31:27An unprecedented, some said impossible, goal.
31:31We had to show that we can measure the brightness of these stars.
31:37A hundred thousand of them simultaneously.
31:40It was met with a great deal of skepticism.
31:42And the science community actually published an article saying that can't be done.
31:48And so it took us quite a while to show that, yes, you can do that.
31:52You can build a wide field of your telescope with a huge number of pixels that measure all these stars simultaneously.
31:59And then you can watch each and every individual star to see if a planet is crossing it.
32:05Kepler does this with amazing accuracy.
32:08Basically, it's a huge camera that orbits in space.
32:13It does not orbit the Earth.
32:15It orbits the sun.
32:16And so it can look at one group of stars between the Cygnus constellation and the constellation of Lyra.
32:22A hundred and fifty thousand stars simultaneously.
32:26And make a measurement of each of those every six seconds.
32:28Once Kepler detects a planet, the planet's orbital size can be calculated, along with its mass and surface temperature.
32:38As a member of the Kepler Science Working Group, Jeff Marcy believes that Kepler is the next great step toward finding life on other planets.
32:46I think in the next few years we will find the first planets of Earth size, Earth mass, maybe even Earth-like temperatures, rendering them habitable.
33:00And I think it's fair to say that one of the great goals of the next decade or two is to build a terrestrial planet finder that can actually take pictures of other Earths and ascertain whether there's any habitability possible on that planet and indeed life there as well.
33:20The payoff is just the pure knowledge of are there Earths, lots of Earths out there.
33:30If there are, there's probably a lot of life out there.
33:33If the opposite occurs, we don't find any, there never will be a Star Trek.
33:38There's no place to go to.
33:42Better technology is getting us closer to finding those other Earths.
33:46For instance, by fine-tuning our sensors, we can now read the light reflected off a planet's surface.
33:55This lets us determine the chemical composition of that planet's atmosphere.
34:00Now that we can analyze atmospheres, we can start looking for the unique environmental signatures of alien civilizations.
34:09Every form of technology leaves a footprint on its environment.
34:15For example, if you're looking at Earth from a long way away, you see global warming.
34:20That's our footprint.
34:22Well, we can imagine a civilization that might have been around for an immense period of time would leave a much bigger footprint.
34:28Maybe not just on its planet, but on its entire astronomical environment.
34:31So we should look for anything out there in space.
34:35Any anomaly, anything that looks like it could not have a natural explanation.
34:45We're finding new planets every day.
34:48But, so far, our investigation hasn't turned up any aliens.
34:51What if we're looking in the wrong places for the wrong things?
34:56What if a real-life alien isn't anything like the creatures of our imagination?
35:12We're hunting for Earth-like planets and Earth-like life.
35:15And maybe, we hope, alien civilizations.
35:21But what if they aren't Earth-like at all?
35:25What if the aliens don't need things like bodies?
35:30Looking for life as we know it could be a mistake.
35:34Because, some say, life as we know it will soon be an artifact of the past.
35:40I think it's entirely possible that we will discover microbial life on some extrasolar planet.
35:49But, I think what people really want is they want aliens.
35:53They want somebody we can talk to.
35:56Somebody that we can relate to as thinking individuals.
36:01Will Wright is the creator of two revolutionary video games.
36:06Wright designs software that creates alien life.
36:12Creatures uniquely adapted to the myriad conditions that might be encountered out in the universe.
36:20Of course, it's all simulated inside his computer.
36:25Wright believes that life on Earth is radically changing.
36:29A new form of life is being created.
36:32Part human, part machine.
36:34You can almost look at any technology that we use today as an extension of the human body.
36:41The buildings are an extension of our skin.
36:45Cars are an extension of our legs.
36:48Telephone is an extension of our mouth.
36:51Humans have been so intertwined with technology for thousands of years already,
36:55that it's really hard to almost pull the two apart.
36:58And that seems to just be increasing and accelerating over time.
37:01Some believe that we might eventually get rid of our bodies completely,
37:06and become creatures of pure consciousness, living in a giant computer.
37:11If this is slowly happening to the human race right now,
37:17has it already happened out in the stars?
37:20It's probably likely that if we ever do meet intelligent alien life out there,
37:27I would imagine that they probably are going to be trans-biological in some sense.
37:33They might be entirely a mechanical civilization.
37:35Physicist Paul Davies agrees.
37:37In my view, biological intelligence is just a transitory phase in the evolution of intelligence in the universe.
37:45So after millions of years, you'd be dealing with something that might be distributed across the whole surface of a planet,
37:51wouldn't be a living organism, it would be a sort of gigantic, throbbing megabrain.
37:54It's possible these alien super-beings, whatever they may be, are sending us messages right now, but we aren't advanced enough to detect them.
38:08And again, maybe that's for the best.
38:13It could be that these alien intelligences have entirely different intentions,
38:18and therefore, maybe they aren't broadcasting where they are.
38:21Maybe it's a hostile universe.
38:23There are a lot of science fiction scenarios that go down the path of the ones that basically start calling out into the deep forest
38:29are the ones that get eaten by the wolves.
38:33The intelligences that are out there trying to talk to everybody else are the ones that get eaten first.
38:37And that's why everybody else is being really quiet.
38:40Maybe the aliens aren't friendly.
38:45On the other hand, they may not even think we're worth contacting,
38:50particularly if they're ancient, throbbing megabrains.
38:54I think it's very unlikely that some super-intellect that has been the product of millions of years of design
39:02is going to have very much interest in traveling around the universe.
39:06It would long ago have sent probes out and gathered all the information it needed.
39:12I think it's much more likely that something that has been around for such a long period of time
39:17and has such enormous intellectual power is going to retreat into a sort of inner cyberspace.
39:23Probably lose interest with its immediate surroundings, so long as someone's paying the electricity bill
39:28and defending this throbbing megabrain from asteroid impacts and other dangers,
39:34I imagine that it's not going to be very mobile.
39:37And there's another even bleaker possibility.
39:42What if there was other intelligent life in the universe?
39:47But now, it's gone.
39:49SETI's been going for about 50 years now, and all the astronomers have got to show for it is a silence,
39:55I would say an eerie silence, because many people feel that there should be intelligent life out there,
40:01there should be other civilizations, and if so, they're ominously quiet.
40:05Maybe the reason they're ominously quiet is because they've all died out.
40:09They've wiped themselves out, or some horrible fate has befallen them.
40:15If it is all silence, then that bodes ill for the future of humanity.
40:22All of this leads back to where we started, with a simple question.
40:27Is there other life in the universe?
40:32Absolutely. There must be other life forms in the universe,
40:35and I'm even willing to go the next step and say,
40:39there must be intelligent technological life elsewhere in the universe.
40:44When you count up all the stars that are out there,
40:47those billions, trillions, even more Earth-like planets,
40:51offer an enormous number of throws of the dice,
40:55even if life is one in a million or one in a billion,
40:58there are just too many throws of the biological dice out there in the cosmos
41:03for us to be alone.
41:06We have no evidence, one way or the other,
41:09for any life beyond Earth, let alone intelligent life.
41:12Therefore, my feeling about it is, we wait and see.
41:17I've got to be skeptical until I get some evidence otherwise.
41:21What's that cry?
41:23What's all the wreckage?
41:26I would find it incomprehensible that the answer would be no.
41:28If it was no, that would be an amazing bit of information to have.
41:35I mean, even understanding how rare we are, you know,
41:39that maybe intelligent life, like we might understand it,
41:42is very, very far away from us, puts an incredible responsibility on us.
41:46All of a sudden, Earth, humans, directed intelligence, becomes incredibly precious.
41:57Our search for E.T. has been going on for half a century.
42:02But the universe is a very big place.
42:06And we've only just started to unravel its mysteries.
42:10If you dip a glass in the ocean, and you look at it, and your glass has no fish,
42:16what's your conclusion?
42:18Is your conclusion that the ocean doesn't have any fish in it?
42:21Or is your conclusion, it's an awfully big ocean, and I didn't sample very much of it with my glass?
42:27Fifty years of exploration of the cosmic oceans is minuscule.
42:35We haven't looked yet. We've hardly begun to search.
42:39We ought to do a much better job of searching before we draw any extraordinary conclusions.
42:45The building blocks of life are spread all around the universe.
42:57It's hard to imagine they haven't taken root in one of the countless other planets out there.
43:02Is any of that life what we would consider intelligent?
43:06And if alien civilizations are out there, why are they so quiet?
43:12Maybe their signals are still on the way.
43:17Or maybe they use technology we don't understand.
43:20Or they may not be there at all.
43:25We just don't know.
43:27But one thing is certain.
43:30If we find life outside of Earth,
43:35it will profoundly change the way we look at life and ourselves.
43:40In the meantime, we have our hopes and dreams and the silence of the cosmos.