The physics of the universe itself stands as a challenge for the discovery of extraterrestrial life, but with advanced technology, experts and scientists are hoping for a major breakthrough, the proof of which might already be in existence.
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LearningTranscript
00:00Aliens.
00:07Little green men.
00:08A thousand eyes or one eye.
00:10Sci-fi movie monsters.
00:13Free floating with tentacles.
00:15Some unknown hyper advanced civilization.
00:18Could science fiction ever become fact?
00:23I think it's really simple why Hollywood is fascinated with the concept of first contact with aliens.
00:28Because that would be probably the greatest scientific discovery in all of human history.
00:35Problem is, our universe creates massive barriers to meeting extraterrestrials.
00:41It's almost as if the universe is deliberately stopping us from making first contact.
00:48We're searching the cosmos.
00:50Will we ever find intelligent alien life?
00:54Or are we alone?
00:58Arecibo Observatory, Puerto Rico.
01:0545 years ago, it sent a powerful radio message deep into space.
01:11Kickstarting our efforts to make first contact.
01:18The Arecibo message was the first communication or attempt to communicate with a possible civilization out there in the galaxy or outside of our galaxy.
01:31Today, that message is speeding towards the M13 galaxy cluster, 25,000 light years away.
01:46It contains information about our world, where we are, even the makeup of our DNA.
02:01The purpose of this message was, of course, trying to say hi, and also to light up this question about are we alone in the universe.
02:14But what chances are there that an intelligent alien race is out there waiting to receive our message?
02:23Do I think there's other intelligent life out there in the universe?
02:26The answer is a resounding yes.
02:27Yes, I do.
02:28We know that life began on Earth pretty much as soon as our planet solidified.
02:32So why wouldn't that have happened somewhere else?
02:35If life has evolved on other worlds, just how many alien civilizations are out there that we could potentially contact?
02:45Astronomer Frank Drake developed an equation to help answer this crucial question.
02:51The Drake equation is a really admirable attempt to apply some quantitative reasoning to the probability or the possibility that there is life beyond the Earth.
03:04You multiply the star formation rate for stars in our galaxy times the number of planets that each star has, times the probability that you would have life forming on that planet,
03:17times the probability that that life form becomes intelligent.
03:22And they estimated that there were about 10,000 intelligent civilizations within our galaxy.
03:34Since the Drake equation was first proposed, our understanding of the galaxy has radically transformed.
03:41We have now discovered worlds outside our solar system.
03:46Exoplanets.
03:49Exoplanets are being discovered all over the place.
03:52There are about 4,000 of them now known.
03:55And techniques are finding more every day.
04:00Scientists believe what we've found is the tip of the iceberg.
04:07So, if the cosmos is so good at making planets, perhaps it can produce the conditions to make life throughout the universe.
04:16When the Drake equation was devised all those decades ago, we didn't know that exoplanets existed.
04:22And now we think that there are quite literally more planets than there are stars in the universe.
04:28So, even if life is really rare, there are an enormous number of chances for it to take hold in the universe.
04:34And for this reason, it is very likely that there is life relatively abundant in the universe, including an uncountable number of advanced alien civilizations.
04:43This isn't science fiction. It's just basic probability.
04:49Probability suggests a multitude of alien civilizations are out there.
04:53So, isn't it a little strange we haven't made first contact?
05:00I think there's every reason to believe that there are civilizations out there, but we have no evidence of them yet.
05:06Why haven't we found other civilizations out there?
05:08One answer could be the sheer vastness of the cosmos.
05:14Look at all these lights out here over this cityscape.
05:18You can think of these lights as like stars in the galaxy.
05:20Now, if there's 10,000 communicating civilizations out there in the galaxy, you might think,
05:26oh, man, look, there's one right there, right down the street.
05:30The problem is there are hundreds of billions of stars in the galaxy,
05:34which means that maybe our nearest neighbor that we can communicate with is not right there, but way across the city.
05:39We live in the suburbs of the Milky Way, 75,000 late years from the furthest edge.
05:52Radio signals travel at the speed of light.
05:58This speed limit means that any signal sent to the opposite side of the galaxy would take 75,000 years to reach its destination.
06:07The thing you have to remember is the galaxy is gigantic.
06:12Even if there are 10,000 civilizations in the galaxy, it's possible that the distances between stars are just so huge
06:19that we're never going to be able to communicate with each other.
06:22So, the 45-year-old Arecibo radio message could still be tens of thousands of years away from any potential alien civilization.
06:31The target was 25,000 light years from here. The message is now 45 light years from here, because it's traveling speed of light, so it's really far from the target.
06:43The vast size of the universe is a huge roadblock to making first contact.
06:49And the laws of physics prevent radio signals from overcoming it.
06:56You just cannot go faster than the speed of light. So, our galaxy may be filled with life, filled with civilizations, but they're so far away.
07:03I don't want to be the bearer of bad news, but the universe is just really, really far too large.
07:10The universe may be large, but we're putting the most advanced technology on Earth into action to try and speed up the search.
07:20There really is a serious, scientifically valid way to go looking for other civilizations.
07:27And the Breakthrough Listen project is really the best thing we have right now.
07:31State-of-the-art facilities around the world, radio telescopes, optical telescopes as well, are all looking up to the sky together.
07:38Breakthrough Listen is targeting the one million stars and 100 galaxies closest to Earth.
07:44It is the most comprehensive search for alien communications ever undertaken.
07:53If there was an aircraft giving off a radar signal, and that aircraft was around any of the 1,000 nearest stars, the Breakthrough Listen project could hear that.
08:03So, if there's something out there that's actually giving off a signal, Breakthrough Listen has a chance to find it.
08:07Breakthrough has started by listening in on the nearest 1,700 stars to Earth.
08:15So far, silence.
08:18This is the wonderfully, beautifully frustrating position that we find ourselves in.
08:22We haven't heard anything yet.
08:24So, we're in this position where a negative result doesn't mean there aren't civilizations, but we have no proof that there are.
08:30Breakthrough Listen is just beginning its hunt.
08:33There's much more real estate in the cosmos for it to search.
08:38It's a big job, demanding a lot of patience.
08:42If you go through Drake's equation and find this number of 10,000 intelligent civilizations out there, there are something like 250 billion stars in the galaxy.
08:54So, that's only one civilization per 25 million stars.
08:59That's a lot of cold calling.
09:00The size of our universe means we could be waiting a very long time to pick up any alien communication.
09:13But, even if we pick up a signal, it may have arrived too late.
09:18If we do receive a message, given that it probably took years to get here, that civilization could be long gone.
09:25So, are we simply too late? Have any aliens out there already died out?
09:31Earth has orbited the sun for over 4.5 billion years.
09:38Time enough for humankind to evolve into an intelligent and technologically advanced species.
09:45But, compared to the age of the universe, planet Earth is just a kid.
09:46The Earth is over 4.5 billion years old.
09:47And we think it's taken this long to create the first technological civilization.
09:48Us.
09:49There are star systems out there, much more than just a kid.
09:50Earth has orbited the sun for over 4.5 billion years.
09:51Time enough for humankind to evolve into an intelligent and technologically advanced species.
10:00But, compared to the age of the universe, planet Earth is just a kid.
10:07The Earth is over 4.5 billion years old.
10:10And we think it's taken this long to create the first technological civilization.
10:15Us.
10:16There are star systems out there much older than we are.
10:19The universe is 13.8 billion years old.
10:22We tend to think we're hot stuff, right?
10:25We're technologically capable.
10:27We can build rockets and we can listen to radio waves.
10:29But, a typical other intelligent advanced civilization would be literally millions of years ahead of us in technology.
10:37So, if an alien society has been around longer than us, how much more technologically advanced could they be?
10:50One method of measuring just how much is provided by the Kardashev scale.
10:55The Kardashev scale classifies potential alien civilizations into three types based on the amount of energy that they're able to harness from their local environment.
11:03A Type I civilization can harness the energy of only its home planet.
11:07A Type II could hypothetically harness the energy of its own solar system.
11:10And a Type III could harness the energy, potentially, of an entire galaxy.
11:14If you're wondering where we fit on that scale, prepare for some bad news.
11:20We're somewhere between a zero and a one.
11:25We can't use all of Earth's resources.
11:27So, we're at about a point seven.
11:30An advanced species reaching Kardashev level two, or even three, could create highly advanced structures that can harness the power of a star.
11:41If you get to be an advanced enough civilization, eventually, if your energy demands are so huge, you might build solar panels that you have enveloped your star.
11:52This was first thought of by Freeman Dyson, and so we call these Dyson spheres.
11:59If such epic engineering occurs in other star systems, or even other galaxies, could we pick up some evidence and then make first contact?
12:11The thing about a Dyson sphere is that you've completely blocked all the light coming out from a star, except for the infrared.
12:20Because these panels are absorbing that sunlight and warming up.
12:24When you warm up an object, it gives off what's called thermal infrared light.
12:28You can scan the skies looking for that signature to see if there are any Dyson spheres out there.
12:34In 2015, NASA's Wide Field Infrared Survey Explorer scanned 100,000 nearby galaxies to locate advanced Kardashev civilizations by observing infrared light leaking away from Dyson spheres.
12:54They detected nothing.
12:57No such galaxy was found, so they didn't find any infrared smoking gun.
13:03Given our universe is so old, surely other civilizations should have had time to evolve.
13:09If so, maybe we've simply missed them.
13:13It's entirely possible that civilizations arose, tried to communicate with the galaxy around them, and the problem was they were asking too early for us.
13:22They're trying to knock on our door, but our house wasn't built yet.
13:26Earth has been around for under one third of the universe's 13.8 billion year lifespan.
13:34The human race, just 300,000 years.
13:38A relatively tiny window of opportunity to make first contact.
13:43We've been looking at the sky for tens of years, something like that.
13:47What is the likelihood that at that exact moment someone is going to be beaming a signal toward us?
13:53Perhaps the universe prevents intelligent civilizations from surviving for very long, making our chances for first contact even more unlikely.
14:05Maybe there is something out there that is filtering us from seeing them.
14:10We actually call this the great filter.
14:12Maybe there is something that says, yeah, you're not getting past here.
14:15Rocky planets like ours are ideal for hosting life, but they're fragile.
14:21And this fragility means the universe could filter out intelligent life quickly.
14:34We've discovered very violent star explosions like gamma-ray bursts.
14:38These are powerful enough they may sterilize planets, even across an entire galaxy.
14:44And even if intelligent species survive natural phenomenon, they may still be filtered out by hitting the self-destruct button.
14:58As we can tell from our own experience, the moment that we started developing technology,
15:04we also developed the means for our own destruction by changing the climate on our planet,
15:09by developing weapons of mass destruction.
15:12And so it's quite possible that civilizations that are advanced enough are short-lived.
15:17And if they are short-lived, that would explain why at this point in time there are very few of them that might be around to communicate with us.
15:27Finding the relics of an extinct alien civilization could be the ultimate cosmic warning for the human race.
15:36If we were to find a civilization out there that may have destroyed themselves by pollution or conflict,
15:42it would be almost like staring into a mirror.
15:45And it would be a very grim foreshadowing and maybe a lessons learned for us humans here on Earth.
15:51We can only hope that some advanced alien species escaped the universe's deadly filter.
15:58But even if E.T. still exists out there, the odds are still stacked against first contact.
16:13One other way that we've got this alien contact story a bit wrong is just down to the laws of physics.
16:22Every day, the physics of the cosmos makes our chances of contact worse
16:28because our universe is expanding, and it's expanding fast.
16:49February 2018.
16:52Astrophysicists at the University of Oklahoma find a potential series of rogue planets 3.8 billion light-years away.
17:04Ranging between the size of our Moon and Jupiter,
17:08these would be the first alien worlds ever discovered outside our galaxy.
17:16And maybe the first of many.
17:19Our galaxy alone has trillions of planets.
17:22The observable universe has trillions of galaxies.
17:25It's estimated about two trillion.
17:27So trillions of trillions?
17:29Come on.
17:31But finding exoplanets is no guarantee of finding alien life.
17:36And when it comes to contacting extraterrestrials, our efforts have met with silence.
17:43Our search for life has come up empty.
17:46Do we need to change our tactics?
17:48Are we doing something wrong?
17:50I think it's going to be very, very hard to find extraterrestrial intelligence the way that we're looking for it.
17:57We would have to get really, really lucky.
18:00But I don't think we're going to get lucky.
18:02I think that if we want to know whether there's life out there in the cosmos, we have to go visit it.
18:06We've sent the New Horizons probe billions of miles across the solar system to Pluto.
18:15Perhaps one day we'll be able to send spacecraft across the universe to search for alien life on distant rogue planets.
18:25But if a craft left our galaxy to visit these new worlds, its mission would be tough, thanks to the physics of the cosmos.
18:40From our perspective here in the Milky Way, every galaxy is on average receding away from us.
18:49It looks like nobody likes us and is trying to get as far away from us as possible.
18:55This is because our giant universe is expanding.
19:02When we talk about the expanding universe, we don't mean that galaxies are doing something active to run away from one another.
19:09Actually, it's the underlying space that's expanding, and the galaxies are embedded in that, and that's what causes everything to move apart from everything else.
19:18The regions of the universe within three million light years of us are expanding at around 45 miles a second.
19:27That's over 160,000 miles an hour.
19:30So with our current technology, do we have any chance of actually seeing what these other planets are like?
19:37Well, think about the fastest and farthest things we have right now, like the Voyager spacecraft.
19:41They've been in space for more than 30 years, going incredibly fast, 38,000 miles an hour.
19:4738,000 miles an hour is fast.
19:52But the closest galaxies to us are moving away at over four times that speed.
19:59And the further away a probe is sent to travel, the tougher its task.
20:04The thing about the expansion of the universe is that the farther away something is, the faster it's moving away from you.
20:11The more distant two objects are away from each other, the more space there is between them.
20:17And the more space there is between them, the more space there is to expand.
20:23The rate at which they're moving away is proportional to their distance.
20:26If it's twice as far away, it moves away twice as fast.
20:30If it's three times farther away, it moves away three times as fast.
20:33Scale it up to the planets we've discovered 3.8 billion light years away.
20:39And thanks to the expansion of the universe, those extra galactic worlds are moving away from us at over 49,000 miles per second.
20:50Imagine that you're a runner and you see the finish line.
20:54You're getting a bit closer to it.
20:56But now actually the track itself is expanding.
20:59And as the track expands faster and faster, it's expanding faster than you can possibly run.
21:04All of a sudden that finish line starts receding and you're never, ever going to reach it.
21:09Say one day we're able to build probes that travel at the fastest speed physics allows, the speed of light.
21:24Even that might not be enough because sometimes the universe itself doesn't play by the rules.
21:31It's not possible for things to travel through space faster than the speed of light.
21:36But it is possible for space to expand faster than the speed of light.
21:41Everywhere we look, we see very distant galaxies that are apparently receding or moving away from Earth at greater than the speed of light.
21:48There are distant galaxies we can see in the sky that even if we were to build the most advanced spaceship possible,
21:53that could even move at the speed of light, we could never get there.
21:5797% of the galaxies that we can see in the distant sky are actually unreachable to us.
22:05So, for all the galaxies out there, and all the planets that could harbor life, most of them are out of our reach.
22:15The physics of the universe has dealt an immense blow to first contact.
22:20The true reality of the universe will always be hidden from us because of this, because of this expansion.
22:26The further we look out into the universe, the more unlikely first contact becomes.
22:35We might need an advanced alien race to come and visit us instead.
22:41Suppose we get that lucky. Even then, would first contact actually be feasible?
22:48We think aliens are like us. They're not. We're assuming that the life is like us and that their planetary environment is like ours.
22:56I don't think that's going to be the case for most of the life in the universe.
23:00So, could extraterrestrials even survive first contact with us and our planet?
23:10hovering in the universe and our planet is once again.
23:22July, 2019.
23:26The TESS satellite discovered a new alien world 31 light-years from us, named GJ-357D.
23:35At over six times the mass of our home planet, it's thought to be a super-Earth.
23:41And from our observations, super-Earths appear to be prime real estate.
23:47What we see is that the most common type of terrestrial planet is what we call a super-Earth.
23:52So that means it's a terrestrial planet, but much more massive.
23:57More massive can mean more gravity, creating a planetary environment completely unlike our own.
24:05And life, completely unlike ours.
24:08If they're on the surface of a super-Earth, it could be that gravity is going to be way stronger.
24:14So these aliens aren't going to be very tall, but they are going to be very strong.
24:20Super-Earths are just one of the many avenues the universe creates.
24:26There are other exoplanets orbiting red stars ten times smaller than our sun.
24:31And others making binary systems comprising two stars instead of one.
24:38We see planets of all shapes and sizes around stars of all shapes and sizes of all sorts of configurations.
24:47The potential for life is much more rich and varied than we ever thought before.
24:54Retro-rockets, five and six, fire.
24:57Images of science fiction have fueled numerous fantasies of first contact.
25:03But our knowledge of the universe suggests reality could be far, far stranger.
25:09If anything, Hollywood has kind of constrained our imagination in terms of presenting so many aliens that basically look like, you know, humans wearing a rubber suit or something.
25:19Lower landing legs.
25:20We have to, have to let go of this obsession that they're going to be anything like us.
25:29So if we're looking for two-legged dudes, forget it.
25:32Say an intelligent alien species lives in our stellar neighborhood and wants to make first contact with us.
25:46If that alien evolved on a super-Earth or orbited a red star instead of a yellow one,
25:53its wildly different biology may prevent it from ever setting foot or tentacle on planet Earth.
26:00When you look at life here on Earth, it's almost as if it was custom made for this temperature, for these elements, for this environment.
26:12An exoplanet with conditions to support life could still be completely different than life here on Earth.
26:17What are things going to be like on an alien world which has a little bit more potassium or is warmer than average on Earth or has a thicker atmosphere?
26:27Each one of these small variations can mean a completely different ecosystem.
26:34So could an alien organism really adapt to our ecosystem when it lands on Earth?
26:40Maybe we haven't made first contact because they can't actually visit us.
26:48They could step through the airlock of their spaceship and onto the Earth and just find something toxic with our environment.
26:55For some reason they're not compatible with the surface of the Earth.
26:59It's almost as if the universe is out there deliberately trying to stop us meeting any aliens.
27:06Biology creates another obstacle for making first contact.
27:11But as planetary scientist Janie Radabaugh finds, even life on Earth can get pretty weird,
27:17taking extreme measures to adapt to a potentially hostile environment.
27:21This is the Great Salt Lake.
27:23It is the remains of what used to be a much larger lake in the past.
27:27And when it evaporated away, it left behind all of the salt.
27:30The Great Salt Lake is nearly ten times saltier than Earth's oceans.
27:38The extreme salt content should make it an inhospitable place for life.
27:44Despite this, there are organisms thriving in the water.
27:48As we look at life in this vast lake and find that there are billions of microbes living here in this unexpected environment,
27:57then we start to realize, well, life forms in ways that we just don't expect, in places we don't expect.
28:04Microbial life, known as extremophiles, have developed an ingenious way to survive in the lake.
28:10Well, they actually use these solar-powered pumps to pull the salt out of their cells so that they can operate more normally.
28:18But in order to do that, they have to live very close to the surface, which means they get a huge amount of UV radiation.
28:23So all this pink color that you see behind me is actually the pink of the organisms.
28:29And it's sort of like a built-in sunscreen that helps protect them against the UV radiation.
28:33Extremophiles are rewriting our expectations of where life can survive on Earth.
28:41Could alien biology be much more resilient than we think?
28:46These extremophiles should be a little reminder that we haven't been thinking big enough.
28:52Maybe E.T. could readily adapt to our environment.
28:55Or perhaps they've got other ideas, using technology to overcome any biological barriers.
29:04Maybe the first aliens we meet will be robots.
29:08They can build much more powerful life if they don't limit themselves to meat bags.
29:14Advanced aliens could have left their biological brains and bodies behind,
29:19traveling instead as mobile, artificial intelligence.
29:23We tend to think of intelligence and consciousness as something mysterious
29:28that can only exist inside of biological organisms like us
29:31and somehow therefore can't be copied.
29:36But what's given us the whole AI revolution, right?
29:39The idea that no, intelligence and probably consciousness too is just information processing.
29:44It's just the information processing that really matters.
29:47Perhaps an alien would be able to download its consciousness into some sort of computer
29:52and travel as a disembodied consciousness.
29:58And in this state, you'd be essentially immortal.
30:05So it's possible an advanced species could find ways to face the challenges of first contact.
30:11Maybe the reason that intelligent aliens haven't ever come to the Earth to visit us is maybe we're just not that interesting.
30:31So maybe the biggest barrier for first contact is the fact that aliens don't actually want to meet us.
30:38In the movies, first contact usually leads to an alien invasion.
31:00Cities get zapped, humanity faces annihilation.
31:12Maybe a visit from E.T. isn't such a good thing after all.
31:17Imagine if we got an intergalactic email from, you know, superioraliencivilization.org
31:25saying, hey, we're going to show up in 30 years.
31:29Would we just be like, oh, well, let's get back to watching our reality TV shows and worry about that when they get here.
31:35No, we would seriously freak out.
31:37People might freak out.
31:41But the truth is, we've been signposting our location into the cosmos for decades.
31:47The Earth has been a detectably technological world for about 100 years.
31:52We've been broadcasting signals.
31:55And yet that apparently hasn't attracted anyone's attention.
31:59It's pretty noteworthy that none of them has shown any interest when they could have turned Earth into a parking lot if they wanted, right?
32:09Perhaps no one has redeveloped planet Earth because an advanced civilization simply doesn't want to make first contact.
32:18Frankly, if they're that intelligent, they're not going to be very interested in us.
32:23So maybe that's why they haven't bothered to make contact.
32:25And if the alien is that advanced, we're probably not very interesting to it.
32:31It's a little bit like, you know, wandering around outside and seeing ants on the sidewalk.
32:40Alien invasion makes for great science fiction.
32:43But what do we actually have on Earth that's worth all that alien effort?
32:49How realistic really are these depictions from Hollywood?
32:53One common trope is the aliens coming to devour the human race.
32:59But the science doesn't really support this being possible.
33:03Would an alien even be able to digest the human body?
33:08When eating, enzymes in our digestive system break down molecules in our food.
33:14The food we can eat and these enzymes are very specific to the molecules they can attack and break down.
33:23The same rules would apply to a hungry alien.
33:27To be able to digest us and for us to be nutritious for them,
33:31we'd have to have a very, very similar biochemistry to what exists on the aliens' home world,
33:36what their bodies have adapted to.
33:38So it seems highly unlikely that aliens would come looking for food.
33:44But how about a drink?
33:47In order for life as we know it to exist, one needs liquid water.
33:52If aliens live on a barren desert planet,
33:56a water world like ours could be highly attractive.
33:59While we call ourselves the blue planet,
34:03our oceans are not unique.
34:06The universe offers far greater water resources.
34:10In our solar system, we're finding that most of the liquid water exists in moons around the gas giants.
34:17We believe Jupiter's moon, Europa, has a layer of water ice around 15 miles thick,
34:25floating on an ocean up to 100 miles deep.
34:29This single moon may have twice as much water as all Earth's oceans combined.
34:36Europa is the water world of our solar system and not the Earth.
34:40So if you were an alien looking for water,
34:44you wouldn't bother going to a big planet like the Earth
34:47to suck it up through some kind of giant straw.
34:50You'd go to the outer solar system.
34:53You might harvest icy moons.
34:56Instead of working against the powerful gravitational pull of Earth,
35:02an alien race could draw water from Europa,
35:05where gravity is almost 10 times weaker.
35:07So, what other resources have we got to offer?
35:13Maybe aliens come to strip mine the Earth's crust
35:17for metals, iron or titanium or platinum.
35:22Aliens might use these metals for exactly the same things that we do,
35:26for building spaceships, for building their technology.
35:32Such materials could be useful for any alien civilization,
35:36short on mineral resources.
35:39Problem is, a lot of our planet's metals are buried deep in the Earth's interior.
35:44When the Earth formed,
35:47the great deal of its iron sunk down into the core of our planet
35:50and took a lot of metals with it.
35:52So they're actually quite hard to mine on the Earth.
35:56An alien race would be better off prospecting
35:59for more accessible minerals situated in the asteroid belt.
36:05In the asteroid belt, there's an asteroid called Psyche,
36:07which is made up of pure iron nickel,
36:10just like the core of the Earth.
36:13Psyche provides a near 150-mile exposed strip of iron nickel.
36:19Yet another reason E.T. wouldn't need to bother with us.
36:23For my money, none of those reasons would draw aliens to our Earth.
36:29All these things could be found far more easily elsewhere.
36:33The possibility of first contact is beginning to sound increasingly remote.
36:38The universe throws up massive barriers,
36:40stopping us from communicating with an intelligent alien race,
36:44a race that might very well have absolutely no interest in contacting us.
36:49Unless, of course, they already have.
36:53Is it possible that there have been alien signals that we've already detected,
36:56but we didn't realize what they are?
36:59Scientists have discovered a powerful cosmic signal
37:02that they cannot explain.
37:05Could this finally be first contact?
37:08July, 2018.
37:26The Chime Telescope in British Columbia
37:29detected a short flash of radio energy,
37:32quicker than a blinking eye.
37:34It's called a fast radio burst.
37:38These are intensely powerful,
37:40very, very short-lived radio bursts
37:42that can be a thousand times brighter than the sun at radio wavelengths
37:45that arrive and disappear in an instant.
37:52Most fast radio bursts are one-offs,
37:55blinking into existence, then disappearing forever.
37:58But not this one.
38:01A few days later, scientists caught the flash again.
38:04The amount of energy that it takes to produce a burst like this,
38:09for us to detect it here on Earth from billions of light years,
38:12is immense.
38:14And we've run across things like this before.
38:17Exploding stars, gamma-ray bursts.
38:19These are all very strange objects.
38:21But that does not explain these,
38:24because some of these fast radio bursts repeat.
38:26So whatever it is that can generate this kind of energy,
38:29it can do it more than once.
38:36Light comes in many different wavelengths.
38:39Radio waves are the longest,
38:41making them good for long-distance communication.
38:43We've used radio waves for over a hundred years,
38:49from wireless radio to TV,
38:52from cell phone calls to communications with space probes.
38:57Could alien civilizations be using radio waves,
39:01but on a much larger scale?
39:04What if we already intercepted alien communications,
39:07but we just don't know it?
39:08Our radio and television signals only use
39:13a very narrow band of the radio spectrum.
39:17Fast radio bursts are different,
39:19and that's a problem.
39:22Here's the thing about fast radio bursts.
39:24They are emitting a broad range of wavelengths,
39:26so it's not the best way to communicate.
39:28If these are aliens,
39:30they're not very smart aliens.
39:33It turns out that broad-range wavelengths
39:36are easy to distort.
39:37There is a very thin gas out there between the stars,
39:42and when you emit radio waves,
39:44the radio waves interact with this gas,
39:46and the way they interact
39:48depends on the wavelength you're talking about.
39:51If you use a broad range of wavelengths
39:54to send a signal across interstellar space,
39:56by the time somebody receives it,
39:57it can be a little distorted and weird.
39:59If aliens are sending out radio bursts,
40:05the signal would get so degraded
40:07that by the time it reaches us,
40:10we wouldn't be able to decipher it.
40:13As a calling card,
40:15not incredibly useful.
40:17Whether these mysterious bursts
40:19really are aliens trying to say hello,
40:22or just a natural phenomenon,
40:24this is not first contact.
40:27At least, not yet.
40:29I want to be careful here, right?
40:31I'm not a naysayer.
40:32I'm not going to poo-poo aliens.
40:34But, you know,
40:34let's go through the other things first,
40:35because the universe is filled with weird stuff,
40:38and let's see what that is.
40:40And if we eliminate all those,
40:41and all that's left is aliens,
40:43yeah, let's talk.
40:44If extraterrestrial species are out there,
40:49our universe makes it extremely difficult
40:51to contact them.
40:54But, in spite of all the obstacles,
40:57maybe there's still hope.
41:01We once thought that there could be
41:0310,000 intelligent civilizations
41:05in the Milky Way alone.
41:07Now, we know that our cosmos
41:09is filled with planets
41:11just waiting to be found.
41:14Our technology is evolving.
41:16Searches are expanding.
41:18The truth about our mission
41:19to make first contact is this.
41:22We are only just getting started.
41:27I'd love for tomorrow morning
41:29some sort of interstellar tweet
41:32to be beamed at the Earth,
41:34and we would then realize
41:35that we are not alone in this cosmos.
41:38I'm ready to celebrate.
41:40Here we have already a champagne on ice
41:42and she'll pop when they find it.
41:46Scientists really do hope
41:48we find evidence of extraterrestrial life someday.
41:51We have observatories and satellites
41:53that look at the sky
41:54all day, all night, every day.
41:56The discovery of alien life
42:00would simultaneously be
42:02in a way unsurprising
42:03and yet the greatest discovery
42:05in all of human history.
42:07Even if life is really, really rare,
42:09the universe is really, really big,
42:11and so there could be
42:12countless alien civilizations out there.
42:14But the actual discovery
42:15or confirmation of that,
42:17I can think of no greater
42:19scientific discovery.
42:20It would quite literally
42:21change our entire civilization.
42:22to the universe.
42:28We'll see you next time.
42:29Bye.
42:30Bye.
42:33Bye.
42:35Bye.
42:36Bye.
42:37Bye.
42:38Bye.
42:39Bye.
42:39Bye.
42:45Bye.
42:49Bye.
42:50Bye.
42:51Bye.
42:51Bye.