Our Search for Extraterrestrials

27 December 2016
Presented by Graihagh Jackson.

Is there anybody out there, or are we alone in the Universe? Graihagh Jackson ponders one of the fundamental questions of humanity, from flying saucers and UFOs to why we haven’t found any evidence and what it would mean to find ET...

In this episode

Alien Abduction

00:49 - UFOs, flying saucers and alien abductions

Why do we enjoy conspiracy theories and where did they come from?

UFOs, flying saucers and alien abductions
with Dallas Campbell, science writer and broadcaster

Dallas Campbell paints Graihagh Jackson a picture of an alien abduction...

Dallas - You’re out walking the dog.  It’s late afternoon and getting dark. In the sky, you see a bright light. Is it moving - you think so? You try and think what it might be starting with the most likely: aircraft landing lights, Venus, foil balloon reflecting the light, iridium satellite flare, could it simply be floaters in your eye. You’re close to the nearby military base, perhaps it’s an exotic aircraft or one of those drones we hear so much about these days.

Suddenly it dawns on you. Of course, it must be an alien scout craft from the Zeta Reticuli star system piloted by three telepathic greys with the tacit approval by the clandestine majestic twelve U.S. government group. It can only be a matter of moments before you’re abducted, after which you’ll experience a feeling of paralysis, suffocation, missing time, and pain around the genitals. You will retain no memory of the event except during regression hypnosis, after which you’ll discover a small metal implant on the nape of your neck.
It’s bound to be one of them. Your dog barks excitedly at you in agreement.

Graihagh - Dallas Campbell…

Dallas - Science broadcaster, television presenter, reluctant writer.

Graihagh - Perhaps not so much a reluctant writer when it comes to conspiracy theories, though! The segment Dallas read is from his chapter in a new book called Aliens in which he charters where it all began…

Dallas - As long as human beings have been roaming the Earth there’s been conspiracy theories. The point is, I think we are all conspiracy theorists just at various different degrees. We all have, probably, irrational beliefs that we justify in the secret ways that we justify beliefs. But the modern story of flying saucers began in the 1940s.

Graihagh - What happened in the '40s - what was this initial spike in interest?

Dallas - The beginning of the modern UFO phenomena. Kenneth Arnold was a civilian pilot who was out flying above the mountains in Northwest America. He thought he saw something and reported seeing bright flashing lights which he described a being like a saucer if you skipped it across the water, and the press picked up on this. And, of course, this is during the cold war; general paranoia about the Soviets, and suddenly this term “flying saucer” was cottoned onto.

Graihagh - What was it? Well, nobody quite knows - it was investigated by the air force at the time and their report is a bit of an oxymoron - they concluded than Kenneth Arnold was both a credible witness, but that what he has seen was a mirage.

The pandemonium wasn’t limited to the States, though - 3 years later, the UK Ministry of Defence’s UFO Project set up one of the best-named scientific studies around - the flying saucer working party! The MOD’s chief scientific advisor, Sir Henry Tizard, insisted that UFO sightings should not be dismissed without scientific study.

Their report, published in 1951, argued that all phenomena could be explained by balloons, birds and blimps; Illusions, delusions and hoaxes; Oh, and weather!

They concluded:

“We accordingly recommend very strongly that no further investigation of reported mysterious aerial phenomena be undertaken, unless and until some material evidence becomes available.”

...from then on it went crazy. People starting seeing flying saucers everywhere. And, of course, from 1947 we have Roswell, which was the modern culture today is still post child of flying saucer conspiracy theories, that and Area 51.

Graihagh - I know Independence Day, that film was based at Area 51, or based around that area and I remember seeing this - I think I was aged about 12 or 13 at a sleepover. And I was so frightened by the scene where, I think, an alien gets pressed up against the glass, or they press up a dead person against the glass, and I vomited straight into my lap and was sent home.

Dallas - No you didn’t - seriously? I watched The Exorcist aged about 12 or 13 and I remember having a similar reaction at the moment where she vomited in The Exorcist. And I had a similar reaction but not at Independence Day! Quite tame Independence Day.

Graihagh - I think it’s only a 12 as well!

Dallas - I think so. Maybe you had a stomach bug as well. Maybe it was the combination.

Graihagh - Or too many sweets maybe at a sleepover.

Dallas - Or maybe you've been abducted and the memory has been repressed and somehow that triggered a feeling.

Graihagh - Maybe.

Dallas - Could it have been that?

Graihagh - Possibly. I do have this lump at the back of my neck come to think of it. Could it be a metal chip?

Dallas - It could be a metal implant. I’ve been to Area 51 a few times, and there’s a wonderful sign as you approach. It’s called Groom Lake Road - you go off from the main 375 highway and you drive down about 30 miles on this dead straight dust track. You get to a turn in the road and there’s some hills, and beyond those hills is the actual base. You can’t actually see the base but you come to a sign and, of course, the exciting bit about the sign is it just says “Use of Deadly Force Authorised.” And if you go past that line in the road you are quite within their rights to shoot you if they want to and nobody will have to answer any questions or justify it. And then, of course, you want to go past the line.

The exciting this is, just on the hills at that junction in the road you can see these white Jeep Cherokees and they’re just sitting there watching you with binoculars waiting for you to go past. The reality is though, if you do go past, what tends to happen is they come out and stop you and give you a hefty fine and send you on your way. I don’t think anyone has actually been shot but it’s all the technology that goes with it. It’s the motion sensors, it’s the drones, it’s the Jeep Cherokees, the exotic signage. All that adds to this wonderful conspiracy theory story that behind that line lurks the aliens.

Graihagh - Did you dare cross the line?

Dallas - Yeah, no. Well, I’ve always been really interested in UFOs just from a sort of cultural point of view. I like the UFO folklore and the subcultures that surround these stories. Of course, people see things in the sky all the time. Are they aliens for out of space? No. I think, with a high degree of certainty, we can say that they’re not that. 

Graihagh - Having said that, some do believe it’s true. In fact, had she won, Hillary Clinton had pledged to open up any government UFO files. What does Dallas think we would have seen?

Dallas - I think that the reality, we like to think… well there’s a lot of files that have been released. There’s been big chunks of files that have been released and, of course, there’s nothing in the them. The exciting thing about unopened files is the fact that they’re unopened. As soon as you open the box and you realise that they’re actually really, really boring and there’s actually no evidence of aliens whatsoever, and the fact that Area 51 is just a secret military base where they test exotic aircrafts, everyone will be very, very disappointed. That’s the reality, unfortunately.

Graihagh - Would you want to know, that being said? I mean it’s mystery that we enjoy in itself and all the stories that go round. I’m thinking of knock-on effects in culture. You mentioned Roswell and I’m thinking of the 90s I used to watch a TV series called Roswell High. There’s all that enjoyment that surrounds it.

Dallas - You’re absolutely right. It’s the not knowing, it’s the fact that you will never know because it’s untestable, unprovable, it’s unfalsifiable. You can never prove the ET hypothesis and that’s exactly right, it’s what makes it so tantalizing the fact that you can never disprove that aliens landed at Rendlesham Forest, or Roswell, or Area 51. It’s untestable and, of course, that’s what people like. They love that sense of mystery, that excitement that there is agency beyond what we know. It’s that feeling that - yeah, I’m right -  that sense that we have of something else being out there is all wrapped up in those stories and it’s great for popular culture. Exactly, the Roswell has spawned a zillion TV shows, and episodes of The Simpsons, and throughout popular culture.

Dandelion

09:21 - What is life?

Will all life in the Universe be like ours? Or something completely different?

What is life?
with Dr. Nick Lane, UCL

Will all life in the Universe be like ours? Or something completely different? Nick Lane and Graihagh Jackson ponder the possibilities...

Graihagh - Perhaps then, it’s best left a mystery when it comes to alien visitations… But what about the possibility of life beyond Earth? Well, to that, we probably need to know what life is…

Nick - It is notoriously difficult to do and actually, I think it’s almost pointless to try to define life.

Graihagh - Ok then, maybe not. This is Nick Lane - he’s a biochemist at UCL and is a bit of an authority on the origins of life here on Earth. Perhaps it’s best to think about what life does, rather than is.

Nick - I mean, there’s hundreds of definitions of life out there and they’re all wrong in one way or another. And the problem is that life is really a continuum from a non-living state to a living state and there’s all kinds of intermediate stages. So, is a virus alive or not is a question which is often discussed. It’s really what life does rather than what it is, and in all these cases, life is making copies of itself and it’s using the environment to do so. So, one of the problems with most attempts to define life is that it excludes the environment. All life parasitizes the environment in one way or another. Plants do, they require sunlight, they require carbon dioxide, they require water, and so on, that’s all they require. We parasitize the environment a lot more. We go around eating plants and so on. But essentially, all life is parasitizing an environment which is providing it with its energy needs to make copies of itself, so I think you’d say there are about six different things a cell requires. It requires a carbon source to make more copies of itself, it requires energy to bind things together, to make polymers and to produce more cells, it requires excretion, you’ve got to get rid of the waste products and the end products to drive reactions in a forward direction. There has to be some form of compartmentalization, a cell-like structure that makes the insides different from the outside. There have to be catalysts, the beginnings of biochemical reactions, and then, there has to be some form of replication. Now I think those are the six properties of life that we really need to look for.

Graihagh - Now we have our six things needed for life but it took a long time for it to come about on Earth…

Nick - There’s a lot of arguments about it, a kind of glib answer would be about four billion years ago. There are fractionated isotopes of carbon and so on in ancient rock from about 3.9 billion years ago. There’s a lot of debate about whether that signifies life or not, but I think most people think on balance, it probably does. I think we’ll never know exactly how life started on Earth but what we can know, what are the principles that lead to the origin of life from a non-living environment, and that’s what we’re looking for in trying to understand the origin of life here.

Graihagh - So, if we’re looking for life elsewhere then, it’s likely to be the same.

Nick - I think that’s actually a good argument to say that life could end up, at least at the bacterial level, remarkably similar. I mean, there’s a strong argument to say that carbon is really better than anything else. It’s much better than silicon, for example, at forming, you know, complex bonds between molecules and it’s also available. You know, carbon is far more available in the universe than silicon and also there are gaseous carbon oxides, carbon dioxides, and so on. It’s like a Lego brick, whereas silicon oxides are, you know, sands and so on, you can’t really boot-strap yourself up from the ground with sand. You can’t build on sand.

Graihagh - That’s because the rules of physics and chemistry are universal and, therefore, exactly the same constraints will exist wherever you live in the Milky Way or even the Andromeda galaxy. To Nick then, it’s likely you’re going end up following the same sorts of evolutionary pathways.

Nick - I think, yes, it’s possible. We can conceive that life could’ve operated in different ways but if you think about the probability of finding life, carbon, water, the kind of rocks that are required for hydrothermal systems and so on. They are all very common, so the kind of life that we have here is likely to be the kind of life that we find elsewhere as well.

UFO in space

13:16 - How we could track down ET

It may be light years away but scientists have developed a nifty way to see if planets around other stars could have evolved life...

How we could track down ET
with Dr. Carole A. Haswell, The Open University

It may be light years away but scientists have developed a nifty way to see if planets around other stars could have evolved life. Carole Haswell told Graihagh about how she does it...

Graihagh - It’s the Naked Scientists, with me Graihagh Jackson - the search for extraterrestrials - are we alone in the universe? Now, as Nick has just said, in order to be considered to be alive, you need parasitise your environment to make copies of yourself and then you excrete stuff. So could we track the elements cells excrete, this metabolic activity? A bit like a biosignature? Here’s Jim Al-Khalili, professor of physics at the university of surrey...

Jim -  So certain types...only created by living organisms.

Graihagh - That’s all very well but the Andromeda galaxy is far, far away. It’s a nearest neighbour and is still a whopping 2.5 MILLION light years away. So let’s stick to our patch of sky - how are we then looking for biosignatures around stars say, a hundred lightyears from home?

Carole - My name is Carole Haswell. I’m an astrophysicist at the Open University where I do research on exoplanets.

Graihagh - Exoplanets are just planets outside our solar system. Exo being greek for outside.

Carole - As a very young child I knew that I wanted to be an astronomer and, like many young people, I thought that I wanted to do cosmology just because seemed like the ultimate thing to do. And then, I think, as I got older and actually started studying at university, then I realised that actually, cosmology seemed to me to be a little bit abstract and removed from things that I could identify with and so, at that point, I decided that I wanted to work instead on things closer to home. So, I in fact started my research career still doing something that’s quite far out. I was working on accretion around black hole binary star systems and I did enjoy that but in, I think it was about 2003, I saw a paper which had observed an exoplanet using the Hubble space telescope.  And when a planet passes in front of a star from our point of view, it blocks say 1% of the light from the star and produces a very subtle dip every time it goes round the orbit.  But this particular paper, they had used the Hubble space telescope to look in the ultraviolet and they had seen, instead of a 1% very subtle dip, a 15% diminishing in the light from the star and this told us that the planet was actually surrounded by a huge cloud of hydrogen.  And, at that point, I thought this is just too exciting and exoplanets are the way to go.

Graihagh - I mean obviously it had a profound importance for you but what was the importance of that discovery more generally in the scientific community I’m thinking?

Carole - What that paved the way for was the whole field of being able to actually assess the chemical composition of exoplanets.  So, here you have a planet orbiting a distant star and because the planet is surrounded by some gas, which is translucent. The gas is made up of atoms and ions which absorb light at particular wavelengths.

Graihagh - I think of it like a looking at a rainbow. Whilst  hydrogen may block one frequency of light - red let’s say -  methane might block green. So you have a rainbow - or spectrum of light - that goes mm and YELLOW and PINK and mm! PURPLE and ORANGE and BLUE! And by looking at what’s colours are missing you can work out what elements are found in the atmosphere of this extremely, distant planet. Soooooo coool.

Carole - So it really opened the field for being able to actually measure what planets outside our own solar system are made of or at least what their atmospheres and the surround gas cloud is made of.

Graihagh - What I find absolutely insane is that these exoplanets are a long, long, way away.  I mean, how far are we talking in light years?

Carole - Well the very, very closest star is about 4 light years away and, obviously, most stars are very much further away than that - hundreds or more light years away. So the transit method has found thousands planets or planet candidates.  Not all of them have been completely verified but it’s been extremely successful at finding planets.

Astronaut above Earth

19:29 - Could we send humans to inspect Mars?

To prove life once existed on Mars, we may need to send humans. But what's life like in microgravity?

Could we send humans to inspect Mars?
with Jim Al-Khalili, University of Surrey and Stanley G Love, NASA Astronaut

To prove life once existed on Mars, we may need to send humans. But what's it like to live in microgravity? NASA Astronaut Stanley G Love spoke to Graihagh Jackson about his experience...

Jim Al-Khalili - We don’t believe there’s life on Mars now of any form, but there is a strong possibility that Mars did harbour life. Billions of years ago Mars was much more like Earth, it had an atmosphere, the climate was a bit more conducive to live, it was warmer. So life could have existed there and jury is still out on whether life existed there.
I do remember back in the 90s, there was a huge surge of excitement when it was thought that we’d found evidence of fossilised microbes in a meteorite that was discovered on Earth that we believe came from Mars. And studying it under an electron microscope it was thought that we could see this fossilised remains of a little organism, and that made headline news around the world. But then, of course, they realised that actually it was some inorganic crystalline structure that could have emerged without any evidence of life, so that was a huge disappointment.

Graihagh - But getting to the Red Planet will be tricky and that’s largely because of the daunting conditions of space but also the amount of time you’re out there - 9 months if you’re heading to Mars. NASA astronaut Stanley G Love spent 2 short weeks in space and it was enough to play havoc on his body…

Stanley - You get strapped in 2.5 to 3 hours before you launch. You'll get plenty of time to think about whether that was really a good idea.

Graihagh - What was going through your mind?

Stanley - Well, there are two sort-of astronaut’s prayers where the standard one is 'I really hope I don’t screw up' and not everybody admits but many people are also hoping they don’t get blown up.

Launching from the ground to reaching orbit takes about 8 minutes. During that time, there are milestones that you're sort of checking off – places where you say, “Okay, from this point on, if we lose an engine, we’re going to fly across the Atlantic and land in Africa whereas before that, if we lost an engine, we would’ve tried to turn around and land back in Florida.” There's also a milestone that my commander read off to us over the headsets. He made a little congratulatory statement for us rookies on-board, congratulating us on making it to space and officially becoming astronauts. When the engines cut-off and you're floating in orbit, that’s 40 per cent of the risk and your entire space mission has just been retired in those 8 minutes. So, you get a good feeling thinking, “This just got about twice as safe as it used to be when I was sitting on a pad 8 minutes ago.” So, that’s a great feeling. Floating in your straps is just amazing and then the next thought to hit you is, it is now time to get to work.

Graihagh - Paint me a picture of life in space. I imagine microgravity plays havoc on all sorts of things in terms of how you sleep but also how you eat and shower, and all that sort of thing.

Stanley - Yes, shower. Who said anything about showers?

Graihagh - Two weeks without a shower?

Stanley - Imagine turning off the gravity and turning on the shower. Water would go flying everywhere. So, if you want to take a bath, it’s going to be a sponge bath. But you're right. daily life really has a lot of changes when you're in microgravity especially at first when it’s disorienting. I mean, there's a few fine aspects especially after a couple of days, you'll get used to it. So, you can actually put your pants on both legs at the same time in microgravity, but getting into bed, setting up a bed takes a long time. you're setting up a sleeping bag basically that’s attached to the wall or the floor, or the ceiling if you like. Changing clothes is hard, eating is hard. Most of our foods are in sort of packets and you kind of cut open a corner and kind of nibble or if it’s a liquid stuff, you kind of suck the contents out. It just takes a long time to get anything done. Going to the bathroom can take half an hour especially the first couple of times. The biggest surprise on the whole flight for me was not during the flight but after landing. As your system gets used to being in gravity again, you can be very dizzy like your head is spinning. I didn’t quite expect that. I expected some of the other effects to feel kind of weak, maybe sick to my stomach. I did not expect to be dizzy. But in general, we were very, very well prepared for our flight and folks who had been there came back and told us about their experiences so there were not very many surprises.

Graihagh - You're mentioning the effects of microgravity there and there's lots of talk about the effects on bone density and muscle wastage, was this something you encountered after 2 weeks after you returned back to Earth?

Stanley - Absolutely, but I was a bad astronaut and I did not do my exercise. But I had ample time to regret that when I came home. So, I lost 8 pounds of muscle, almost all out of my legs. If I went again, I would not blow off my exercise because it made a huge difference. And that was only 2 weeks. You can imagine if you were up there for 12 times longer than that, being up there for 6 months.

Graihagh - How long did it take you to recover those 8 pounds of muscle?

Stanley - Several months. I have this memory of being finished with the spacewalk waiting outside the airlock to come back inside and our shuttle’s orbit took us up over the Pacific Ocean and across the western part of the United States and just having that immense tableau of scenery of all the world that I'd known growing up and having that just come rolling up underneath me as we were finishing that spacewalk and feeling good about it. That was a wonderful, wonderful experience and something I’ll remember for the rest of my life.

Graihagh - Sounds beautiful.

Stanley - It is, I like to say and this is a strong statement coming from somebody with a background in astronomy that the Earth is the most interesting thing in space. So, I'm hoping that in the future, more and more people can see what it’s like to be in orbit, look down at the Earth, see what it really looks like and observe our homes as a planet rather than just something you drive around to work and back every day. I think it will make us all better people to have that experience.

Mars Rover

26:14 - Sending robots to to the Red Planet

...but it's not all easy. Space is a dangerous and inhospitable place but if successful, we can look for microbial life on the Red Planet.

Sending robots to to the Red Planet
with Paul Meacham, Airbus Defence and Professor Jim Al-Khalili, University of Surrey

Getting to Mars is a tricky business. Space is a dangerous and inhospitable place but if we're successful, we can look for microbial life on the red planet. Paul Meacham works on the ExoMars prototype rover, Bruno and he explained to Graihagh Jackson what it takes to get to Mars...

Paul - Mars is not the easiest place to get to. It’s actually very demanding. Even just getting off the surface of the Earth is difficult because our gravity, it doesn’t feel very strong to us. But it is an incredible force to overcome.

Graihagh - And then getting there I imagine is what, 9 months?

Paul - It is a very long time, yes. Nine months in cruise and of course, during that whole time, you're away from the Earth’s protective layer. So, you're subject to the full elements of space. It’s quite tricky to overcome that.
Graihagh - To give you an idea - to get off the surface of the Earth, you need tremendous amounts of power.

So, if you're strapped on top of a rocket, it’s not a very pleasant place to be. You are getting blasted with lots of vibrations, lots of soundwaves. So, you’ve got to build your spacecraft to be able to withstand all those forces and not transmit too many of them to the actual passengers.

Graihagh - How do you test that?

Paul - Essentially, you’ve just got environmental test facilities. Where you have a big table that shakes the spacecraft. We even have a room where we do an acoustic test. So essentially, we stick the spacecraft in there and then we blast it with sound waves. It’s not a particularly pleasant place to be because if you were a person in that room when we were testing one of our spacecraft, you would be killed.

Graihagh -  That’s not all, the radiation can wreak havoc on your electronics. In the Apollo missions, something like 3 days in space was the equivalent of 12 chest x-rays.

Paul - That’s right. They flew through what we called Van Allen belts which are belts of radiation that surround the Earth. It’s particularly a high energy environment. But yes, as you say, that was only 3 days and we’re talking 9 months. So, the equivalent dose is much, much higher.

Graihagh - Not to mention temperature…

Paul - The rover’s main structure is called a bathtub and it has this space equivalent of double glazing in order to create a thermal barrier through which heat can't get in and heat can't get out. And then when you do that, you can create quite a habitable microenvironment within that cocoon.

Graihagh - And then there’s the landing. It’s not only ExoMars that have struggled to land rovers on the surface; back in 2003, the Beagle probe famously didn’t manage to open its solar panels and power up.  What I’m trying to say is It’s one big job for people like Paul.

Paul - We certainly do and that’s why facilities like the Mars Yard are so important because it allows us to practice everything we’re going to need to worry about when we get to Mars on Earth.

Graihagh - This is the weirdest place I've ever been. I don’t know quite how to describe it.

Lost for words I was, but imagine a giant sand pit filled with bright orange sand and a mixture of real rocks and polystyrene boulders taped to the walls were vistas of Mars. Bar the lack of weightlessness, the scorching effects of radiation, and the bountiful levels of oxygen, I did feel like I was traipsing around Mars. This is the Mars Yard and no, it isn’t a film set. It’s where scientists like Paul test out prototypes of the ExoMars rover which will be sent to the red planet in 2018 for more scientific tests. The latest prototype is rather fondly referred to as Bruno.

Paul - Bruno has on him all the sensors the real rover will need to drive itself autonomously as the cameras and all the sensors in the wheels and that sort of thing. so essentially, we practice driving the rover by itself in this Mars Yard.

Graihagh - Can we take him out for a spin?

Paul - Yes, we certainly can.

Graihagh - Am I allowed to tread on the sand?

Paul - You can.

Graihagh - And away Bruno goes. Bruno looks like a giraffe. Instead of 4 legs, he has 6 wheels and the wheels resemble the sort of things you get on tanks.

It’s painfully slow going. But hopefully in 2020 when the rover launches for real, one hopes we’ll be able to answer the question of whether there once was microbial life on Mars.

Bacteria is one thing, but what about intelligent life? Jim Al-Khalili again...

Jim - Well, one way is point our radio telescopes to listen out for signals from space. After all, we’ve been broadcasting our presence into the universe ever since we invented radio and television a hundred years ago. So, whether it’s an accidental or deliberate signal from any alien civilisation, we’re listening out for those signals. So this is what SETI, the Search for Extraterrestrial Intelligence is all about, but that is looking at life that has advanced enough to become technologically able to send out signals.

ET phones home

30:59 - ET is out there, according to maths

If you fill out Drake's equation, life beyond Earth is highly probable...

ET is out there, according to maths
with Patrick Short, Sanger Institute and Professor Jim Al-Khalili, University of Surrey

If you fill out Drake's equation, life beyond Earth is highly probable. Patrick Short and Graihagh Jackson do the math...

Patrick - ...he actually didn’t intend it to really be his legacy or to be the thing that he was remembered for.  It was basically intended to drum up conversation at a conference and the idea was basically to put a rough, back of the envelope calculation on what is the probability that we find life somewhere in our galaxy.

Graihagh - At this stage, I think it would be a really good idea to go through Drake’s equation to understand a bit more about what these limitations are.  So what is the first item in the equation?

Patrick - So the first item is the rate of star formation in the galaxy.  So they express this in terms of the number of stars per year.  So the Milky Way is about 13 billion years old and Drake puts his first estimate at 1 star per year.  So that’s the first step.

Graihagh - So 13 billion - let’s write that down.

Patrick - So this would be 'n' and star I guess…

Graihagh - OK.  What next?

Patrick - So next is what proportion of these stars have planets around them. So not all stars have planets and Drake put this at somewhere between ⅕ and ½.  And then we’ve also got the number of planets per star.  So given that it’s got a planet, how many does it have in general and he puts this at somewhere between one and five. Given that you’ve got a star that’s got planets we’ll assume conservatively that it’s got one planet and we’ll assume aggressively that it’s got five habitable planets per star.

Graihagh - And when we’re talking habitable we mean the right sort of temperature, that it’s got an atmosphere, and it doesn’t spin too fast or spin too slowly.  All these types of things that are needed for life.
Patrick - Yes, exactly.

Graihagh - So we’ve got the number of stars and then how many habitable planets around those stars. So what’s next after that?

Patrick - Then we’ve got the probability that a habitable planet will result in life.  So, I guess, you can consider it the probability that given all the right conditions to find that habitable planet that life will arise on that planet and Drake puts that at one.  So he’s quite an optimist - he says if we’ve got a star with a habitable planet then life will arise on that planet.  And then this follows quite closely by the second term which is the probability that that life will develop into intelligent life, which Drake also puts at one.  So he thinks that it’s inevitable that if life is created it follows to intelligent life.

Graihagh - After this, there’s still more isn’t there?

Patrick - Yes.  So then there’s the probability that they don’t develop communication skills so Drake was specifically interested in looking for civilisations that would have made contact with us or that we could make contact with.  And he puts their probability of developing communication at between 1/10  and ⅕, so 0.1 and 0.2.

Graihagh - OK - communication. Surely that’s the final one?

Patrick - No - we’ve actually got one more.  So Drake has factored in exactly how long these communications will last. We’ve been doing our search for extraterrestrial intelligence listening not broadcasting but only for a few decades so he places his lower bound and upper bound between somewhere between 1,000 and 100 million years.

Graihagh - OK. So if we take this equation and we do the conservative estimate, what do we get?

Patrick - So the conservative estimate which is: 13 billion stars, ⅕ of which have planets, one of which is habitable in which we develop life 100% of the time, intelligent life another 100% of the time,  10% of the time they develop communication tools and they only use these communication tools for 1,000 years.  Then Drake estimates that we would have actually only have about 20 habitable planets in our galaxy, which is the Milky Way.

Graihagh - That doesn’t seem like very many.  What about on the other end of the spectrum?

Patrick - On the other end of the spectrum if you want to go with Drake’s most optimistic estimates, then Drake arrives at a maximum of 50 million intelligent species within our galaxy and again, that’s just within the Milky Way. So we’ve got another hundred billion of these galaxies out there so, even if we pick Drake’s lowest estimate which is 20, then we’ve got in the order of 2 trillion intelligent species that we could get in contact with.

Graihagh - I mean that sounds incredibly high so why the heck have we not been able to make contact with any of these civilisations or, indeed, they make contact with us?

Patrick - Yes, so that opens up a whole other famous chapter of physics history. So this question was asked by Enrico Fermi, he’s a physicist and, I think the exact terminology he used is “if this is the case then where is everybody.” And his point being that if we accept that somewhere between this conservative and aggressive estimate of the amount of life out there that surely either we should have heard somebody, detected something or had somebody get in contact with us.  And especially the extra layer of evidence is that we’re actually somewhat young in terms of the history of the universe.  So, if we can imagine our society fast forwarding just a few hundred million years, then we should most certainly be able to colonise the galaxy and do all these intergalactic travels and certainly communication but, the fact of the matter is, we haven’t heard from anybody. So the paradox here is if we can accept that the universe is teeming with life then what are the possible explanations for why we haven’t heard from anybody?

Graihagh - Jim Al-Khalili thinks the answer lies in the sheer size of the Universe.

Jim - ...despite searching for so many decades, we are only sampling a tiny, tiny fraction of what is out there. After all, we are only looking towards star systems that are close enough to us - you know, hundred or so light years away or nearer. That’s only our little neighbourhood within the Milky Way galaxy. Just because we may never find evidence of life elsewhere doesn’t mean there isn’t life out there.
Just from the laws of probability, the universe is big enough that it must be teeming with life. It’s just whether there’s anything close enough to us that has evolved and become sentient, and developed civilisations, and developed technology enabling it to send signals out to us. So there are lots of steps along the way that would explain why we’ve heard nothing yet.

Tarantula Nebula

39:19 - How big is the Universe?

...and could it explain why we haven't found any evidence of life beyond Earth?

How big is the Universe?
with Professor Neil deGrasse Tyson, The Hayden Planetarium

The Universe is astronomically large, says Neil deGrasse Tyson and as he explained to Graihagh Jackson, it might tell us why we haven't found any evidence of life elsewhere...

Graihagh - It’s the Naked Scientists here, with me Graihagh Jackson and today, are we alone in the universe? Why haven’t we found any evidence of life elsewhere? Well, half the problem is the the universe is a big place… but how big is big…

Neil - Astronomical. You know that’s our word - right? People have used that word to describe how big national debts have been or how large things are. But let me use it in the way it was intended, the way nature had always planned to use it - the universe is astronomically large - there’s no other way to say it.

Graihagh - Meet Neil deGrasse Tyson.

Neil - An astrophysicist and co- author of Welcome to the Universe, and as my day job I serve as Director of New York City's Hayden Planetarium, which is part of the American Museum of Natural History.

Graihagh - I suppose it’s kind of hard to wrap your head around, so how big is astronomical?

Neil - You raise an interesting philosophical point because when normally when we describe our life experiences, we compare them to other things that are of commensurate intensity, or size, or weight. You know you'd say "how big was that hailstone?" "Oh it was as big as a golf ball." So you would compare two things that already exist in your life experience. But since the size of the universe falls outside of our life experience, there’s no easy corresponding thing to say "the universe is so big. It’s as big as a…" See that’s the end of the sentence. There’s nothing you can add or bring to the cause. So the way we try to do this is you try to build up from things that are familiar - how big the universe is, and you rapidly enter realms that are inaccessible. But you have a thread, however thin, that takes you back to something that you do recognise and that you do understand. And so that’s how this basically works. I’ll give you an example: If you take a school room globe - a foot across maybe - and ask people "if this is the size of the Earth where would you put the Moon?" Like how far away is the Moon. People typically put it at most a metre away - okay. But, in fact, on that scale the Moon is ten metres away. Ten metres away from a globe that size. And how far away is Mars on that scale? Well, it is many kilometers away. And you start building and building and building. How big is the Sun compared to Earth? Well, if you hollowed out the Sun, you could pour more than a million Earths into the Sun and still have room left over. So, oh my God, the Sun is huge. And so this is the kind of exercise you go through and that gives us some hope of grasping the sheer scale and size of things.

Graihagh - But that's only our solar system. We're talking about the whole universe here. So talking about understanding the universe, there’s theories out there that suggest actually there may be many universes and, actually, we can only see a section of our universe. But, within our universe, how many galaxies are there, how many stars within those galaxies, planets?

Neil - So the observable universe contains approximately 100 billion galaxies, and a galaxy contains upward of a 100 billion stars. And planets, we have come to recognise, are quite common and when you put in some good estimates you get about 1.8 billion planets in the galaxy.

Graihagh - Not a small number then?

Neil - No, not a small number.

Graihagh - And we talk a lot about Drake's equation. This is trying to calculate how much life or intelligent life could be out there. You say 1.8 billion planets - what number of those could be what we would consider habitable?

Neil - Just because you're a planet doesn't mean there’s life on them. And, by the way, this conversation could go both ways. Well, you could say you're not going to have life on all of those planets. Well, actually some planets have moons, and the moons themselves could have life, as an example. There are estimates ranging anywhere from one, which is just us, to I would say several hundred. Some cases of a few thousand but if you’re going to be sort of middle of the road conservative, you’d say several hundred civilisations in the galaxy.

Graihagh - Where do you site on that spectrum youself? Are you a more conservative estimate or are you thinking there might be much more life out there?

Neil - I don't know that I’m actually on the spectrum. I’m a little bit off the spectrum. I have a slightly unorthodox view and it's: who is deciding that we humans are intelligent? Cause we're looking for other lifeforms like us, but who decided that we are intelligent? Well - we did, so we say we’re intelligent. And the other life forms on Earth - no, just us, just us! So I keep wondering, could there be lifeforms out there that are vastly more intelligent than we are on a level where they would not rate us as intelligent? Consider us not even interesting enough to put on their list of a civilisation worthy of their attention. I think about this all the time.

Graihagh - I mean, most people are wondering about what they’re going to have for lunch you know. Ok, so if we loosen our definition of intelligence to include…

Neil - All big brained mammals right? Mammals are a branch of life that only really took a foothold by luck because the dinosaurs went extinct by an asteroid, so they had bad luck. But that pried open ecosystems enabling early mammals to take footholds in places where they previously just would have been h’orderves for the terrible lizards that we call dinosaurs. So the asteroids are bad for dinosaurs - good or mammals. So we rise up and now we are basically some of the most intelligent creatures on Earth. Rats and mice, and chimps and humans, and dolphins and whales, and the domesticated animals - dogs and cats. So if that branch never took hold then mammals would have never risen to what we now see. And that was only 65 million years ago out of a 3.5 billion year history of life on Earth. So the contingency of the existence of our intelligence is something that is not clear would just duplicate in another planetary system, because it's not obvious that what you need to develop intelligence is as important for survival like other things like: can you run fast, do you have big teeth, can you hide, do you have camouflage. There are plenty of ways you can dominate your ecosystem and thrive that have nothing to do with what we think of as intelligence. So I don’t see why most planets that have life would just have plenty of life just happily coming along, susceptible to the forces of natural selection and evolution of course, but without intelligence every arising up. I think there'll be plenty of such places are doing just fine in the galaxy and across the universe. Now, if you do happen to develop intelligence, and you did it earlier ago than mammal intelligence developed on Earth, then maybe you've had a billion years to develop intelligence instead of our measly 65 million years from the branch of life called mammals. So, imagine a life form that’s been developing intelligence far longer than ours. We could end up looking like no greater than worms slithering in the street in the presence of their intellect. I think about that all the time.

Graihagh - I have one final question for you and that is - if you ever got the chance to meet an alien, an extraterrestrial, what would you say?

Neil - Here's what I would do. I would show the alien - I'd assume they could see - and I would show the alien our periodic table of elements. I would find out how they count; they’ve got to be able to count. Once we learn how to count, once we learn about the elements, then we can do some rudimentary mathematics. Do they have representation for the value of Pi? Pi is very important mathematically and it's practically important. How do they present Pi? Then I compare my representations, our representations, with them? So you build a vocabulary from things we have in common. I'm not teaching them English - that’s not happening. And then I would ask how you have solved these various problems? I would ask for help because for sure human civilisation in 2016 needs help. Now I'd hope that they’re benign and kind, because if we were they, we would come upon civilisation less advanced than we are and we would just round them up into reservations, or kill them, or enslave them. Like I said - put them in a zoo as research curiosities. So I would hope they don’t treat us the way I know we would treat them.

Person looking at night sky

48:44 - How life would change if ET phoned home

What if we found life beyond the Earth?

How life would change if ET phoned home
with Jim Al-Khalili, University of Surrey

Jim Al-Khalili discusses what it would mean to find life beyond the Earth with Graihagh Jackson...

Jim - I use to think that it would render world religion obsolete, certainly those religions that their philosophy, ideology is about us humans being special and being created by a divine being that created us in his image. And all the stuff, for example, in the Abrahamic religions, is that all sort of thrown up in the air if we discovered we’re not special? But I think, talking to other people, I'm now inclined to agree with them that religions are probably more versatile than I thought. They would roll with this punch in the same way that the more enlightened religions are quite happy to have acknowledged that the Earth isn’t the centre of the universe post Copernicus and Galileo. So I think discovering life elsewhere won’t do away with religions but it will certainly, I think, change our perception of our place in the universe in a far more profound way than I think people think now.

I just use as an example the false alarm back in the late 90s of the discovery of the fossilised microbe on Mars. Bill Clinton went out on the White House lawn and said "this will be the most significant discovery in the history of mankind." Well, you know, I wouldn’t disagree with him there, I think it would be profoundly important.

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