BBC Horizon_We are the Aliens
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00:00If scientists had to come up with a completely crazy theory about where humans came from,
00:08what could it be?
00:09How about, we're all descended from aliens?
00:15If you go back far enough, then the ancestor of living things on earth would be extraterrestrials.
00:22And that would include humans.
00:24And that would include humans.
00:27It's an astonishing claim.
00:30Have all these scientists, beavering away in their ivory towers, been reading too much
00:33science fiction?
00:36Ten years ago, I think there were very, very few people who would have taken the idea of
00:41life coming to the earth from outside seriously.
00:47If you can't go to Mars, being descended from Martians is probably the next best thing.
00:57It's a hot and humid July in 2001, and something very strange has happened on planet earth.
01:20Here in southern India, many villages are the focus of a possible alien invasion.
01:26It starts with rain, red rain.
01:33The local people were horrified.
01:42In some places it was very intense, it was as red as blood.
01:47The people were so scared, they threw it away.
02:00According to Hindu religion, it is an era of destruction, Kali Yugam, and these are
02:05the signs.
02:06There will be chaos and it will rain fire.
02:15I thought it was the end of the world.
02:18Ever since I was a child, I was told that the world would end in the year 2000.
02:21And when the rain came, I thought it was a warning sent from God and I was very scared.
02:41The world didn't end, in fact.
02:44But the red rain continued for two long months.
02:48Working in the area was a physicist.
02:50He didn't know it at the time, but his life was about to change forever.
02:56His name is Dr. Godfrey Lewis.
02:58I heard about the news reports, and as the days went by, it became more and more mysterious.
03:08What it is, nobody seems to give a clear answer.
03:11So from that moment, I was interested in that.
03:16The first official explanation for the red rain was pretty dull.
03:21Government officials claimed that it was red-coloured dust that had blown in from Arabia.
03:27Godfrey didn't buy this.
03:29He was convinced that there was something extra special about the red rain.
03:33He trailed around villages collecting samples, and under an electron microscope, he saw that
03:39the particles weren't dust at all.
03:44They were alive.
03:45It's quite exciting to see this.
03:52They look like red blood cells, but they're not, because this is having a very thick cell
03:56wall, and that cell wall is not there in the blood cells.
04:05But what was this mysterious life form?
04:08There was only one way to find out.
04:11Take a look at the DNA.
04:17The results came back.
04:19There was no DNA.
04:22It was life, but not as we know it.
04:29All life on Earth depends in one way or another on DNA, the carrier of all genetic information.
04:36If the red rain cells didn't have DNA, then it meant only one thing to Godfrey.
04:42They had come from outer space.
04:44The staggering claim is that this is possibly extraterrestrial.
04:50That's a big claim, I know.
04:52But all the experiments are supporting this claim.
04:56A big claim is putting it mildly.
04:59These tiny cells, just eight thousandths of a millimetre across, might actually be
05:05aliens.
05:07A close encounter is big news, and around the world the wires were buzzing, people desperate
05:14to find out more.
05:24Godfrey contacted the one scientist in the UK who might take his claim seriously.
05:29Chandra Wickramasinghe, a brilliant astrophysicist full of maverick ideas.
05:35He's been based at Cardiff University for the last thirty years.
05:46In the late 1960s, Chandra was working with world famous astronomer Sir Fred Hoyle.
05:53Together they came up with a startling claim, that the universe was teeming with organic
05:58compounds, the building blocks of life.
06:01Sir Fred and Chandra then went even further.
06:04They were convinced that comets actually contain life itself, and they had used clever astronomical
06:10techniques to prove it.
06:12I think it's true to say, isn't it, that if your theory is correct, life not only may
06:16be spread throughout the universe, it must be.
06:20Surely there must be many places where this has happened.
06:26Do you have an idea of the numbers?
06:27The numbers must be very favourable, Fred, isn't it?
06:29There are billions of stars in the galaxy which are probably very similar to the sun,
06:33and very similar to the extent of being able to support planetary systems.
06:37So it would really be very surprising if life is not, if the galaxy is not just teeming
06:42with life.
06:48They weren't talking about large scale life like fish, rather tiny bacteria and viruses
06:54hitching a lift through the cosmos.
06:57In the same way that plant seeds can travel around earth to find suitable conditions to
07:01flourish, so microorganisms could journey through space on the back of a comet, seeding
07:07other planets.
07:08And this might be how life on earth began.
07:11The name of their theory was panspermia.
07:19But it was all too much for the establishment.
07:22Their theory was ridiculed.
07:25I think the implication was that we were just a pair of crazy lunatics who had jumped
07:31onto the wrong bandwagon or something, and there was no arguments presented to say that
07:38you are wrong for such and such a reason.
07:43Chandra's been living on the outskirts of the scientific mainstream ever since, waiting
07:47for that one piece of killer evidence.
07:56Flying saucers have invaded our planet.
07:58Washington, London, Moscow are key targets.
08:01The whole world is under attack.
08:03Can it survive?
08:06Hello, Godfrey.
08:10So nice to meet you after all the weeks of correspondence.
08:19Thank you.
08:20Thank you very much.
08:23Could the red rain really be the smoking gun he's been waiting for?
08:30Chandra has come to India to find out.
08:34Godfrey, I think what I would like to see is the experiments that you did replicating
08:40these red rain microorganisms.
08:45Because that definitely is good evidence to show that this is biology.
08:51If it is true that these are alien bugs from space, then it is an absolute clear-cut proof
08:57of panspermia, ongoing panspermia.
09:00And that would be absolutely fascinating, and that would be over the moon.
09:17For the theory of panspermia to have any credibility requires a massive leap in our understanding
09:23of the universe.
09:25That leap of faith is, there is life beyond Earth.
09:30Until recently, it's been assumed outer space was just too cruel an environment for life
09:34to exist.
09:35But closer to home, scientists have been discovering bugs that are surprisingly tough little blighters,
09:42living in some of the harshest places imaginable, such as here, in Mono Lake, California.
09:47Yes, that's mud for me.
09:50Yes.
09:51One of NASA's top astrobiologists, Richard B. Hoover, has the job of tracking them down.
09:58He's an extremophile hunter, and mud is a good place to start.
10:03It's a nice grayish mud, with a slightly sulfur smell.
10:08I love it.
10:09I love it.
10:10That's fantastic.
10:12That's fantastic.
10:17Mono Lake is one of the most spectacular and wonderful places on Earth, as far as astrobiologists
10:23are concerned.
10:24It has no fish.
10:26It's about three times the salinity of seawater, and it has a very high pH, like strong soap.
10:34And under these conditions, only a few forms of life are able to live.
10:43The water temperature here has gone to 85.
10:49Look at the brine shrimp in the water.
10:52They're there by the billions.
10:55I'll take a sample of that, yes.
10:59We call them extremophiles because they live in what we consider to be extreme conditions.
11:04The microorganisms that live here would actually think where we're living would be extreme conditions
11:09because of all this terribly poisonous oxygen around.
11:14Extremophiles are far tougher than anyone had thought possible.
11:18Life can live just about anywhere, and Richard has had to resort to ever more drastic measures
11:23to track it down.
11:29We have a new microorganism that was collected in the guano of the penguin during the expedition
11:36to Antarctica, and this microorganism is actually able to grow at temperatures of minus five C.
11:43That's fantastic.
11:44But basically you found it in penguin shit.
11:47Penguin doo is perhaps the more polite way.
11:51But yes, guano is a very interesting source for these kind of strange, exotic microorganisms,
11:58particularly from places like Antarctica and Patagonia.
12:02And we thought you were weird getting mud samples.
12:10Life has even been found living in a place more extreme than frozen penguin doo,
12:15happily making home in the heart of a nuclear reactor.
12:20They discovered that there was a microorganism that was living in this highly alkaline water
12:26in the presence of spent nuclear fuel rods and growing in the water and on the fuel rods
12:32and eating holes in the stainless steel cylinders.
12:35So these microorganisms were able to live in incredibly high radiation environments,
12:41high alkalinity environments, and their primary food source was the iron itself of the stainless steel.
12:50While Richard continues work on these earth organisms,
12:54what he would really like to find is an alien version.
12:59And here I have a hormogonium of this cyanobacteria.
13:03It's a collection of individual cells. It's a reproductive state.
13:08Ah, this is gorgeous.
13:11The main reason that astrobiologists are interested in extremophiles
13:17is because most of the other bodies of the solar system
13:21are either very cold or very dry or very barren atmosphere.
13:29So from the Earth's perspective, those conditions are extreme conditions.
13:34So the kinds of things that we find in these extreme environments on Earth
13:39are very good models for the kinds of things that we should look for
13:43on other places in the solar system.
13:47We have...
13:52If life is ever found beyond Earth,
13:55it will be a vital pillar to the theory of panspermia.
13:59And the guys most likely to succeed are NASA.
14:09One of the most ambitious NASA projects is based in this nondescript shed in Texas.
14:15It's part of a plan to look for life on a tiny moon of Jupiter called Europa.
14:24Leading the team is alien hunter Bill Stone.
14:28I'm just an engineer and an explorer.
14:31To me, there's a frontier out there for us to explore.
14:34Some of those things we can do by ourselves, manned exploration.
14:38Personally, I would prefer to do that if I could,
14:41but there are some places that right now we can't go,
14:44but there's robots we can learn from,
14:46and Europa is one of those places right now.
14:52Bill's goal is to make an autonomous robot submarine
14:56that will hopefully find alien life on Europa.
15:03Europa is a very popular destination for NASA.
15:07The reason that it is of such great interest is the fact that, for sure, it has water.
15:12Those high-resolution photographs showed that the surface indicated tidal cracking of ice
15:19in such a fashion that it produced pressure ridges similar to what we see in the Arctic Ocean on Earth.
15:24You can only have that with an ocean of water underneath.
15:28When you have water, you have high possibility for the presence of life.
15:33So that's why Europa is such a direct hit in terms of the astrobiology interest.
15:42This bold mission is planned for 12 years' time.
15:46Unfortunately, their machine is still in bits.
15:52Do we know whether this is a 2005 or a 2006 cable?
15:55No idea.
15:57Because one of those is a no-connect.
15:59This is John Kerr. John's our lab manager and also jack-of-all-trades.
16:03This is Bart Hogan from the University of Maryland.
16:06He's working on the power subsystems for the entire vehicle.
16:11The Europa mission is probably the greatest technological challenge that mankind has ever undertaken.
16:18To break it down in pieces, a master lander comes down from the mothership.
16:22It lands on the surface of Europa in a flat area that's safe, not in an area where you have cracks or anything.
16:28You have a second stage of the lander that melts its way through three kilometers' worth of ice.
16:34There will be something that will be not unlike the autonomous underwater vehicles that are being developed today.
16:40They look fish-like. They look torpedo-like.
16:42They move fast, so we call that portion the fast mover.
16:46On the nose of this will be the successor to that device right there.
16:51And whether it's called DepthX or something else at that point, who knows?
16:54But it's going to inherit what we've learned from this device.
16:58It sounds pretty happy. It sounds like it's coming along.
17:05Here's a good question for these guys here, okay?
17:07How many lines of code do you guys think are going to be in the whole bot when we're done?
17:11For each sensor system, there's about 1,500 lines of code.
17:14And there's 96 sensors in the system and six actuators.
17:18Any thoughts?
17:19That's the most important thing.
17:21That's why we want it to be as short as possible.
17:23They don't know.
17:30When we say we're searching for life, okay, we're not talking about aliens, okay?
17:33Anthropomorphic creatures that come down and do nasty things to humans.
17:37No, we're talking about microbiological life.
17:40Things that are so small you can't see them except with a microscope, okay?
17:44Those things form the bulk of life in the universe as far as we can tell.
17:48And so it's that is what we expect to find.
17:51Non-intelligent, very, very tiny life.
17:55Non-intelligent, very, very tiny life.
17:59Sounds familiar.
18:02Chandra is hoping that this is just the sort of organism
18:05that the red rain of southern India might be.
18:09Bacteria are perhaps not as exciting as little green men,
18:12but they are much, much tougher,
18:15making it easier for them to survive a trek through the solar system.
18:19They've got to endure the extreme cold of space,
18:22the vacuum of space, ultraviolet radiation, cosmic rays, X-rays.
18:27That sounds like a tall order, but bacteria do that.
18:30From what we know, survival out in space is more or less ensured.
18:34Bacteria, I think, seem to me to be born space travelers.
18:43One simple, noisy fact has convinced Godfrey Lewis he is right.
18:47Just before the red rain came down, there was an enormous explosion.
18:51According to Godfrey, this could be a comet or a meteorite
18:54hitting the Earth's atmosphere and disintegrating,
18:57just the sort of object that could be transporting aliens.
19:03He spoke to one of the witnesses.
19:08It happened around 5.30 in the morning.
19:12I was sleeping in this room.
19:18The noise was very intense.
19:22It was like a very strong booming sound,
19:24like an object cracking into pieces.
19:28I saw it from here.
19:32Come in, Professor Chandra.
19:35This is some of the samples we have collected.
19:38Right, right.
19:39Pretty good sample we have.
19:41You can see the...
19:42So this is the real stuff?
19:44Yeah, this is the real stuff.
19:45It's red for sure.
19:46Godfrey's research on the red rain is now in the scientific literature.
19:51But many in the establishment remain highly sceptical.
19:55They have come up with their own bizarre earthbound explanations.
20:03One theory is that a meteorite struck a flock of bats.
20:09And it was their blood that came down as red rain.
20:12This would explain the lack of DNA,
20:14because red blood cells don't have any.
20:18But where are all the other bat bits?
20:21Where are the bats' remnants?
20:23And how can, for two months, the bats continuously get killed?
20:28This is a very funny theory.
20:31It's a flock of bats.
20:36Another idea is that millions of lichen spores
20:39were swept up from trees and into the atmosphere,
20:43and then returned as the red rain.
20:46But where's the DNA that lichen cells should have?
20:49Godfrey's unimpressed.
20:51If you look at the magnitude of the rain,
20:53the amount of quantity of material that has fallen down,
20:57and the geographical distribution of this throughout the entire state,
21:02this theory cannot explain the phenomenon.
21:07But if it's alien, it's pretty dangerous, isn't it?
21:09No, that is a popular concept.
21:11Every alien should be dangerous.
21:13But that may not be the case.
21:15You can have friendly aliens also.
21:19An invasion of friendly aliens in southern India might seem far-fetched.
21:25But there is one man who's supposed to take it all very seriously.
21:34Close to the corridors of power in Washington, D.C.,
21:37he has perhaps the most important job this side of Pluto.
21:42He is the planetary protection officer for NASA.
21:46So, John, do you ever get tired of your Man in Black image?
21:49I'm not sure I've developed one yet.
21:52But you like the film?
21:54Oh, I enjoy the film very much. Yeah, it's a good film.
21:57When the out of this world gets out of control,
22:00don't bother calling the CIA.
22:03Forget the FBI,
22:05because there's only one government agency we can turn to.
22:10This is my office,
22:12and this is from where I hold forth when I'm in Washington, D.C.
22:19Well, my guess is that if there's life out there,
22:22it would be interesting,
22:24it might even be compelling in its lessons,
22:27but it wouldn't be dangerous.
22:29But that's just my guess.
22:31And one of the things that I have to acknowledge
22:33is that ignorance is not bliss.
22:35I'm not going to be able to guarantee to anybody
22:38that life out there isn't dangerous.
22:40Oh, that looks beautiful from here, too.
22:42It has a stark beauty all its own.
22:45It's like much of the high desert of the United States.
22:49It's different, but it's very pretty out here.
22:54John's job has been around for some time.
22:57Ever since they put a man on the moon in 1969,
23:00NASA has been nervous about what they might bring back to Earth.
23:05In fact, the Apollo astronauts,
23:07the concern was whether or not there would be a disease
23:10that the astronauts would pick up from a lunar microbe.
23:15NASA took no chances.
23:17The Apollo astronauts were put into sealed quarantine
23:20and kept there for 21 days.
23:23They didn't think alien life could survive on the moon.
23:27But they had to make sure.
23:30Even President Nixon wanted to check they were alien-free.
23:34The lunar quarantine was accomplished both in Texas
23:38as well as at NASA Ames in Moffett Field, California.
23:42And they really did test the lunar material
23:45against everything that they could think of.
23:47So they were injecting it into animals and things?
23:50Injecting it into animals, testing it against plants,
23:53feeding it to chickens, you know, what have you.
23:56Anything that they thought was, you know,
23:58potentially going to show you an effect.
24:01And did they find anything?
24:03No, other than chickens don't like lunar dust.
24:13But during a mission, they had found something rather special.
24:18This is Surveyor 3.
24:20It was an unmanned probe sent to scope out potential landing sites.
24:25It arrived two and a half years before the first moon landing.
24:29On board was a camera,
24:31which the astronauts were instructed to bring home.
24:35We're ready to start getting a TV camera.
24:38Okay.
24:40And a big smile.
24:41Okay.
24:43And when this camera was studied in great detail,
24:46there was found to be evidence of a living microorganism
24:51on the inside of a piece of foam on the interior of the camera.
24:55The scientists concluded that this microorganism
24:58had remained alive on the surface of the moon for approximately 30 months.
25:02But it was not thought to be an extraterrestrial life form,
25:06but rather a contaminant that got into the camera
25:09during the testing on Earth
25:11before the Surveyor spacecraft was sent to the moon.
25:14It was a common microorganism, Streptococcus mitis.
25:17Somebody probably sneezed when they were assembling the camera
25:21before it went to the moon.
25:23That means that microbial life could conceivably survive in space
25:27and could conceivably be transferred from one place to another,
25:31which is the fundamental concept of panspermia.
25:37While protecting the planet takes up much of John Rummel's time,
25:41the rest of his working day is spent making sure
25:44we don't contaminate other planets.
25:47Any probe sent to Mars or Europa has to be spotless.
25:51There's a test before they can launch,
25:54and the planetary protection officer is responsible for providing that test.
25:58And we go down and we assay the spacecraft
26:01for the presence of microbes,
26:03and they get a passing grade or a failing grade.
26:06But you'd be able to cancel the mission?
26:09Yeah. I would have the authority to say stop.
26:12More likely, I would say, clean it first.
26:15Then you can launch it.
26:17We have main engine start, zero,
26:20and liftoff of the Stardust spacecraft,
26:23returning a time capsule with the elements of the formation of our solar system.
26:28If the panspermia theory is to be proven one way or the other,
26:32it's vital not to contaminate other planets.
26:36We have solid motor jettison. All four solids came off.
26:42If we go to other moons,
26:44other worlds, et cetera, and take Earth contamination there,
26:47and then later go back and discover life,
26:50and go, golly, life on Mars looks just like life in Florida.
26:53How about that?
26:55We're actually ruining the principal element
26:58that NASA focuses on is preserving the science.
27:02Things look very good at this point.
27:05Going just under 5,000 miles an hour.
27:09You guys ready?
27:11The greater the likelihood of finding life,
27:14the stricter the cleanliness required.
27:17Devtex will have to be spotless for her voyage to Europa.
27:21But sneezing into the machine
27:24is the least of Bill Stone's problems at the moment.
27:28You ever hear that dirty, hairy line?
27:31Do you feel lucky?
27:34In this case, we ask everybody,
27:37did you check all the O-rings?
27:40Instead of sending Devtex all the way to Europa
27:43on her maiden voyage,
27:46they're going to lower her into a tank of water
27:49on the other side of the workshop.
27:52And even here, there's still much to go wrong,
27:55not least to find out whether this $5 million submarine is waterproof.
27:58Okay, and I've got two connectors over here,
28:01two make tens that are open.
28:04Let's just vent it all the way.
28:07Yeah, let's just vent it all the way.
28:10Right, just to the surface.
28:13Okay, lower.
28:16All right.
28:19Southwest Research and MCU's wet.
28:22No leaks.
28:25No leaks so far.
28:28We're going wet.
28:31While Bill and his team continue their hunt
28:34for alien life in the solar system,
28:37panspermians are waiting for the party to come here,
28:40hidden amongst some of the 500 tons of meteorite
28:43that fall to Earth every year.
28:46One particularly rare type of meteorite
28:49is the carbonaceous chondrite,
28:52a sort of burnt-out comet.
28:55It's the most comfortable form of transport for an alien visitor,
28:58and Richard B. Hoover is convinced
29:01he's found the evidence of just such an intergalactic joyride.
29:04It's called the Murchison meteorite,
29:07and it fell into the Australian outback.
29:10One lady was hanging up her laundry,
29:13and she saw the sun in the sky,
29:16and she thought it was strange because it was in the wrong part of the sky,
29:19and then she looked and saw that the sun was in the right part of the sky,
29:22and she was actually seeing the fireball
29:25associated with the Murchison meteorite when it came in,
29:28and large chunks of Murchison black rock landed all around her.
29:31One piece actually came smashing through the roof of a shed.
29:37In fact, this is one of the pieces of Murchison that fell,
29:42and in fact when you open the vial,
29:45you can actually get a bit of the aroma,
29:48the odor of the Murchison meteorite.
29:52And it has a tarry, sulfurous smell.
29:55It's really quite spectacular.
29:58These are the organic gases that are still continuing
30:01to come off of the meteorite.
30:04We take the meteorite, and we break it in
30:07in a fresh fracture, and then put it under the electron microscope
30:10so that we look at a freshly broken piece of the meteorite,
30:13and we found a lot of very, very complex
30:16structures that look like
30:19microfossils of blue-green algae,
30:22not just in terms of shape,
30:25but also in terms of precise detail
30:28in structures like reproductive structures
30:31and the presence of external structures as well.
30:34You found evidence of life.
30:37Well, I think it's tremendously interesting
30:40that the meteorites appear to contain the remains of living organisms.
30:43I think that these living organisms
30:46are moving on a body like a comet.
30:49If, in fact, this is correct,
30:52this means that comets may be carriers of life
30:55from one place of the solar system to another.
31:01He's found fossils, entire colonies of fossil microorganisms
31:04just stuck in the middle of these space rocks.
31:07It's amazing.
31:10I think it is amazing.
31:13If comets were the carriers of life,
31:16are still the carriers of life,
31:19and when a comet becomes exhausted,
31:22when all the gases flow out of them,
31:25then these fossils remain, and that's what he's finding.
31:28Richard's claim that this is fossilized life
31:31is highly contentious,
31:34and it still leaves open the question
31:37as to whether life forms on a meteorite
31:40I'd say it's not the falling that kills you,
31:43but the sudden stop at the end.
31:58What Mike is doing today
32:01is he's taking small grains of rock which have bugs in,
32:04and then putting them into a missile, a carrier,
32:07and then he's going to go on and hit the target.
32:10The bug is sitting in a rock.
32:13It lives in the rock and is quite happy there as bugs go.
32:16But in our case, that bug is suddenly going to be accelerated.
32:19At the University of Kent,
32:22they're trying to replicate what happens to the bugs
32:25when they crash into Earth on the back of a meteorite.
32:28For this, they need a very big gun and some very small bugs.
32:31Oh, and a belief in panspermia.
32:35So what will happen next is we fire the gun,
32:38and we want to reach a speed of 5 kilometers a second.
32:41That's about 10,000 to 15,000 miles per hour.
32:44So it's going to be fast.
32:47The target is water with a rock behind it.
32:50So it's like hitting an ocean,
32:53where first you have the water and then there's an ocean floor beneath it.
32:56They will hit the water as if they've come from space
32:59at these 10,000, 20,000 miles per hour,
33:02and the bugs will be very heavily shocked,
33:05and this would normally kill most things.
33:15The only question is, will it survive?
33:18And if it does, it will just be happy again, growing in its new home.
33:22The Bugs
33:31The firing of the gun happens in a vacuum to maximize the speed.
33:36The bugs are now on a 15,000-mile-per-hour roller coaster.
33:42And remember, in space, no one can hear you scream.
33:51Have any of the bugs survived?
34:00And I'm afraid nothing's hit the target.
34:03The rock has come off slightly off axis,
34:06and instead of going through the hole here, has hit the container up here,
34:09so our target's still intact, and our bugs have hit solid metal,
34:13and that's a lot harder than water when you hit it at high speed,
34:17and so they've probably been crushed
34:20and almost certainly all are dead.
34:22So, hey-ho, it's a bug's life.
34:25But other experiments by Mark have confirmed that bugs can survive.
34:30These are some of the lucky ones.
34:33The casualty rate is very high, but this is not a problem.
34:37What would happen is, if you went into the garden
34:40and dug up one gram of soil,
34:42one little small cubic centimetre, perhaps, of soil,
34:45you'd find 10 or 100 million bugs in there.
34:49If we could fire a rock that size in our gun,
34:52with that number of bugs in,
34:54we would find about 10 or 100 of them survive our experiments.
34:57So the survival rate is very, very low.
35:00But you only need 10 or 100, and they just multiply.
35:03About five or six years ago, when I went to the first meeting
35:06and announced this work, we were still doing tests and didn't have success,
35:09but someone in the audience just stood up and said,
35:11this is crazy, why are you doing this?
35:13Everyone knows the answer. Nothing survives.
35:16Well, we then did some more experiments.
35:18We started to show that in high-speed impacts, bugs can survive
35:21and potentially could have come from space if they were out there
35:25and invaded the Earth, as it were.
35:27At which stage, when we started announcing the results in conference,
35:30a different person stood up in the audience and said,
35:32well, why are you doing these experiments?
35:34Everyone knows the answer. Of course they survive.
35:36So in the space of just a few years, it went from being a denouncement
35:39to, why are you wasting our time? Of course it's trivial.
35:42It's not trivial by any means,
35:45because Mark's experiments have helped to support panspermia.
35:49And it's not just been experiments in the lab that have verified the concept.
35:54Columbia, Houston, UHF comm check.
36:04A tragic real-life event has added support to the idea.
36:08In 2003, the Columbia Space Shuttle blew up during re-entry
36:13and seven astronauts lost their lives.
36:16What is not well known is that some of the microorganisms
36:20on board the space shuttle survived.
36:23Columbia was a mission that effectively broke up over a multi-state area.
36:28And inside of some of those pieces were experiments
36:33that had been flown for biological purposes.
36:36And in at least one of those experiments, the organism survived the trip.
36:42The Columbia accident was a tragedy that involved not only the melting of a wing,
36:48but the physical dismantling of a shuttle.
36:52It's a very interesting fact that things falling from high up on the earth can survive.
37:04All scientists now agree that microorganisms can survive extraordinary conditions,
37:10be it radiation, extreme cold, extreme heat, extreme impacts.
37:17Most space scientists also believe that the solar system
37:20almost certainly contains other life forms and are very, very keen to find them.
37:26And a few scientists are convinced that certain meteorites contain the remains of life.
37:32Putting all the evidence together, Chandra believes
37:35that this is how life on earth began in the first place.
37:38It arrived on the back of a comet 3.8 billion years ago.
37:51Life did not start here on the earth.
37:54We came in ready, packaged, genetic bits and pieces from space.
38:03Other scientists disagree.
38:05They think life started here on earth.
38:13One scientist who argues that it all began here, in a small bubbly puddle, is David Diemer.
38:22If you never thought about it, if this was the first time you ever saw a soap bubble,
38:26you'd be astonished that this kind of a structure could just appear out of nowhere.
38:32David is not blowing bubbles just for fun.
38:37He's interested in how soap bubbles, by assembling themselves,
38:41will help explain the origin of life.
38:45So this is what we mean by a self-assembly process.
38:48It's one of the very simplest self-assembly processes.
38:54He's using his expertise in bubble blowing to try to create new life in the lab.
39:01It's alive! It's alive! It's alive! It's alive!
39:10It's alive! In the name of God! Now I know what it feels like to be God!
39:26David uses soapy material to form microscopic bubbles.
39:32This froth is what David believes was the first step in the origin of life on earth.
39:37No comet required.
39:41The bubbles, or vesicles as he calls them, are crucial to his theory
39:45because they provide the perfect place for making new life from scratch.
39:50So we think that vesicles were very much part of the first forms of cellular life.
39:55All life today is cellular.
39:57It means there's a membrane surrounding a compartment
40:00and what we're doing here is stepping through the evolutionary process
40:04that must have occurred on the earth about three and a half billion years ago
40:08when the first forms of cellular life appeared.
40:14David then inserts small chunks of DNA inside his artificial cells.
40:24Is it alive? Not yet.
40:27But it's a shared goal of a number of laboratories now
40:32to actually make an artificial form of life.
40:36And some might say a dangerous goal.
40:38I don't think so.
40:40The fact is that there are all sorts of dangerous life out there right now,
40:45the latest being the avian flu virus, for example.
40:49And what we might do in a laboratory would not stand a chance of surviving, I think,
40:55in today's biological world.
41:01We think, however, that we're trying to do something
41:05that simulates what happened on the early earth
41:09and not trying to put together a living being in the sense that Frankenstein was.
41:16I think they're playing it good.
41:18I think the object of all these experiments
41:21is to show that life is not that special a system.
41:27I would be exceedingly surprised if anybody succeeded
41:31because the improbabilities are so immense
41:35and to think that they could be overcome in a small laboratory flask
41:41is asking not for the moon, it's asking for the cosmos.
41:46David Diemer is the first to admit
41:49that his cells are not fully fledged living organisms.
41:52But if he does succeed in creating life relatively easily,
41:56then it makes it much more credible that life could have started on earth.
42:02I'm always attracted to what we call Occam's razor.
42:06Look for the simplest explanation.
42:08And the simplest explanation is that there was a set of organisms
42:14a set of organic molecules
42:16which could self-assemble into microscopic structures
42:20that increasingly took on the properties of life as we know it.
42:25So, to sum up, life began on the earth
42:29and was not delivered to the earth.
42:35We still don't know how life began on earth.
42:38We don't know how life would have begun on other places in the cosmos.
42:43Even though it's generally accepted
42:45that life began on earth through these primordial reactions
42:51in the ancient oceans,
42:53it's quite possible that life began on earth
42:55as a result of transfer of biological materials
42:59from other portions of the solar system.
43:05It's these arguments that make Chandra so determined
43:08to get to the bottom of the red rain.
43:11If the red cells really are alien life,
43:14then it must be proof of panspermia.
43:22Chandra has been doing independent tests on samples of the red rain.
43:29In science, things are rarely clear-cut
43:32and he has very different results from Godfrey.
43:36And these are positive amplification products.
43:39So this is DNA from the red rain.
43:42Wow, there's no doubt about it.
43:44It's absolutely conclusive as far as I can see.
43:48The discovery of DNA in the red rain cells
43:50has been corroborated by another lab.
43:54Yet this recent finding has done nothing
43:56to dent Chandra's unshakable belief
43:58that the red rain is extraterrestrial.
44:01He believes that all life in the cosmos
44:03will probably share various types of DNA.
44:06Before I came, I had grave doubts
44:08as to whether the red rain was really an indication
44:11of life coming from space, new life coming from space.
44:14But on reflection and after talking to Godfrey,
44:18I think I would now fairly firmly believe
44:23that it did represent an invasion of microbes from space.
44:30Over in Washington, D.C.,
44:32the planetary protection officer remains skeptical.
44:36He thinks the red rain has a more mundane origin.
44:41The material when examined by astrophysicists
44:45and people who are looking for evidence to support a view
44:50doesn't appear to be anything that they've ever seen before.
44:54But people who actually have seen things before
44:56say, looks like red algae to me.
44:59I would tend to go with the people
45:01who have seen more things in the biological kingdom
45:04rather than those who are looking to support
45:06their own ideas about how the world should work
45:09without the data to back it up.
45:14For the moment, the jury's out.
45:16But Chandra remains convinced
45:18that this sort of interplanetary transfer of microbes
45:21is how life first originated on Earth.
45:25And Chandra is not alone.
45:27There are an increasing number of scientists
45:29who are happy to put their family ancestry down to aliens.
45:33Earth life is essentially alien life.
45:36It is not a life that was indigenous to the Earth by any means.
45:40And if we evolve from that life,
45:43then I think we are the products of evolution from alien life.
45:50If the hypothesis is correct,
45:53then all of the life that we see today
45:56originated from material that was brought into our planet.
45:59And if it's coming from beyond the atmosphere,
46:03then it is extraterrestrial.
46:05That's not an unusual concept.
46:07That's the way in which life propagates on Earth.
46:10You have seeds, and these seeds are carried by the winds,
46:14and they start growing at other places
46:16when they find conditions are suitable.
46:21In that sense, we are all extraterrestrials.
46:24The ancestors are probably outside Earth.
46:29So we have actually emerged
46:33from some extraterrestrial organism, actually.
46:39Hans Sperma, the idea that life comes from space,
46:42only actually tells you how life started on Earth.
46:44It still doesn't address the big question,
46:46how did life itself start?
46:48But at least it starts giving us an answer to
46:50what's it like here on Earth, why is there life here on Earth,
46:53and it would suggest there's life elsewhere,
46:55which is something else a lot of people want to know,
46:57one way or the other.
46:58Maybe we are Martians.
47:00Maybe life here on Earth came from Mars.
47:05Much of Chandra's work on Hans Sperma has now been vindicated.
47:10So are we really descended from aliens?
47:14It could have come straight from a comic book.
47:18I think science fiction is always a very appealing thing
47:22for many of us to read,
47:23but sometimes science fiction turns into science fact.
47:27But the journey towards the truth
47:29is always a rewarding one, I think,
47:31and I saw this as a journey towards discovering a truth
47:34that was quite plain to me
47:37and is becoming plainer and plainer to other people now
47:40after 30-odd years.
47:45If you want an experience of being humbled,
47:49go look at the NASA Hubble deep space image
47:53that looked into the darkest, darkest little tiny segment of the sky,
47:59and what they saw back in that picture, to me,
48:01was the most devastating news of all
48:03for people who think we're important.
48:05What you saw were clusters of light that were not stars.
48:09They were galaxies,
48:11and there were thousands and thousands of galaxies
48:13in that little picture of the darkest part of the universe.
48:17If you think that there's not other life out there,
48:21think again.
48:29So what other strange ideas in science might just turn out to be true?
48:33Visit our website at bbc.co.uk slash horizon
48:37to let us know which phenomena we should put to the test.
48:40From telepathy to time travel,
48:42we'll find out if there's any fact behind the theory.
48:45And Horizon returns in the new year here on BBC Two.