Alien Hunters: The Search for ET

In March this year, the US BICEP team of astronomers claimed to have found the long-sought evidence for cosmic inflation - one of the mechanisms that underpin what happened in a fraction of a second after the Big Bang when the Universe began. Inflation has been theorised for decades and the results caused a big  stir in the scientific community, with talk of Nobel prizes being awarded to the American astronomers. But, just this week, these findings have been called into question, as Europe's Planck satellite published data suggesting the BICEP results could have been caused by cosmic dust contamination. Graihagh Jackson has been looking at this story and told Chris Smith the latestdevelopments...

Chris - So, what's first of all the background to this?

Graihagh - As you mentioned already, inflation was a theory developed in the 80s to help explain what happened in the first trillionth of a trillionth of a trillionth of a second after the Big Bang, and what happened in inflation is that space expanded very, very fast, faster than the speed of light from something the size of a proton, so, smaller than an atom, all the way to what we now see as the observable universe and this happened all in the fraction of a second. So, according to this theory, the expansion would have caused a sort of ripple in space and time, waves of gravity, and these waves and ripples have left like a pattern on the sky, so to speak, that we could potentially now see and this is what BICEP have claimed to have seen. This polarised cosmic micro background radiation or CMB.

Chris - So, if these waves are there, then it lends credence to the theory of inflation. It tells us what must have happened in the early epoch of the universe during those very, very early times when it was growing rapidly.

Graihagh - Precisely, yeah. It puts us that much closer to seeing the origins of our universe and how it came to be, and I've heard about physicists talking about this could be, you know, discovery of their lifetime sort of thing. So, it's caused a really big stir in the scientific community.

Chris - A ripple even.

Graihagh - A ripple. Yes, precisely!

Chris - It's not just in space-time. And what has Planck now done, because to put this into perspective, Planck is a satellite mission that launched from the European Space Agency 2009, I think it was, wasn't it, to try and probe some of these and other questions. So, what is the Planck probe saying?

Graihagh - It's worth just stepping back a little bit here and talking about what BICEP did. So, BICEP looks at a very small sections of sky and is looking at one frequency or color and that's what they were monitoring in the sky, whereas Planck looks at a huge area in the sky and is looking at multiple frequencies, and these frequencies that the Planck is looking at are much more sensitive to things like cosmic dust, the dust in the sky from asteroids, comets, and when stars explode. So, what Planck have now done is they've looked at exactly the same area of sky that BICEP have looked at and they now think that actually, there's much more dust than they previously thought, and this dust is imitating the polarised CMB.

Chris - The shortfall of the BICEP mission - we actually had them on this program at the beginning of the year when they made this announcement - was that they looked at just this one discreet frequency because we asked them why didn't you look at others, and they said, well our instrument's set up to look at that particular color of light. Planck now say, they've looked at other colors, you're saying, and that actually you may be able to explain those initial observations on the basis of dust. So, what do the BICEP people say about it?

Graihagh - BICEP have always been wanting to corroborate these results. It's just only that now that the Planck satellites come available to actually look at this segment of the sky. So, they haven't commented on it, so to speak, it's always been in the pipeline that they're going to come together and look at results together to see whether actually it is this sort of cosmic dust that's causing this, this signature in the sky or whether actually we really are seeing a signature of the beginning of our universe.

Chris - Ironic, that the guys who discovered the Cosmic Microwave Background radiation, and it won them a Nobel prize in the 1960s, this is Wilson and Penzias. And they actually first of all thought that pigeon poo on their antenna was the cause of this funny signal they were seeing, and it turned out that was the after-glow of the Big Bang. Now these guys might actually done the reverse and claimed to have seen something that is caused by the space equivalent of pigeon poo, cosmic dust. So what does this actually mean then, in real time terms? Are they now saying we're going to go and do some more studies or what?

Graihagh - So the Planck people and BICEP people are now coming together to look at results because as I said before they're quite different data sets, apples and oranges if you like, so they're now looking to put these results together, see what the results are, and we should actually see something coming out at the end of the year. Whether really, it was dust or whether we are seeing the beginning of our universe.

Chris - So there may still be a Nobel prize up for grabs. Graihagh, thank you very much. Graihagh Jackson. And Planck's data that Graihagh was describing was published just this Monday in the online journal Archive.

According to the government's chief medical officer, Dame Sally Davies, the danger posed by bacteria becoming resistant to antibiotics should be ranked along with terrorism on a list of threats to the nation. We need to tackle this problem head-on by creating new antibiotic drugs, by using the ones we got more carefully, and developing new strategies to stop superbugs taking hold in the first place. This was the message at a conference in Cambridge entitled "one bug one drug".

Representatives of pharmaceutical companies and drug discovery ventures got together to develop a plan of action. Chris Smith went along to meet some of them to hear about the approaches they're taking. Dame Sally Davies wasn't there this time, but her deputy, David Walker, was...

David - We're facing a very important problem here. Progressively, bacteria are becoming resistant to antibiotics. Over the last 20 years, we've seen a decline in the production of new antibiotics and so we face a problem in that we are having fewer and fewer antibiotics to treat more and more infections.

Chris - And if we take this to its logical conclusion, what's the end of the story?

David - Well, if we're not able to produce a steady supply of new antibiotic products, then more and more infections are going to become more difficult to treat and some of the more conventional procedures we use in medicine are going to become much more risky. Things like transplantation, joint replacements, and of course, the treatment of classical infections will become very difficult.

Chris - Is there any evidence that this is actually happening?

David - Yes. Well, we are seeing increasing numbers of infections by resistant organisms and these not only have worse outcomes, they're also much more expensive to treat.

Chris - Let's talk to a group of people who are actually working on pioneering the next generation of treatments to address the issues that David's raised.

Michael - I'm Michael McArthur, Procarta Biosystems. What we're trying to develop is a new class of antibacterials. We do this by taking small fragments of the bacteria's own DNA and these bind to key proteins called transcription factors that control gene expression. Without that ability, they're unable to cause disease and they rapidly die.

Chris - So in a normal bacterial cell, they will make these chemicals called transcription factors which go on to their DNA and turn genes on and off that the bacteria needs to control. You're saying if you put in bits of the bacterial DNA artificially, they could, what, soak up all these transcription factors so they don't go where they're supposed to and this is going to disrupt the ability of the bacteria to control themselves.

Michael - That's right. It's a very simple approach.

Chris - This means then that because you know what the genetic sequence of the bug you want to treat is, you could make little pieces of DNA, which means that they will exclusively target that microorganism, which would leave the good bacteria in the body untouched.

Michael - That's right, yes. We can develop bespoke antibacterials with a very narrow and defined spectrum.

Chris - Where are you with this? Is it ready to go?

Michael - So, we're in the process of taking things into animal models. So that puts us about four or five years out from what we'd hope would be successful clinical trials.

Ewan - My name is Ewan Harrison and I'm a researcher in the Department of Veterinary Medicine in the University of Cambridge. We're working on MRSA, which is Methicillin- resistant Staphylococcus aureus. One form is a hospital super bug that's caused massive problems. We're also interested in this because there are some kinds of MRSA that now are starting to become a problem, particularly in continental Europe, and we think this is coming from animal populations, in particular, pigs. We're working using genomics, so this is sequencing  the DNA of the bacteria to look at how the bacteria is moving from animal populations into people, and so to do this, we construct a family tree of bacteria and we look for the direction that we think that the bacteria are moving.

Vanya - Hello, I'm Vanya Gant. I'm consultant microbiologist at UCLH in London. I'm leading a group to develop some diagnostics whereby you can find those antibiotic-resistant bugs more quickly, but my other interest which I think really, really does need to be followed up relates to probiotics. These are the so-called good bacteria and they live in our bowels and one of the things they do is they keep the bad bacteria out. I have a very strong suspicion that it might be possible to keep the bad bacteria out by feeding people large amounts of probiotics.

Chris - This will outcompete the bad guys but only in the intestines, surely, if one of your patients is already got an infection in their brain or in their chest, you can feed them all the bugs that you like but it's not going to treat their chest infection.

Vanya - Yes, that's true, but in my field of work, I'd say well over three quarters of the life-threatening infections arise from those bugs that live in the intestines and when you haven't got any immunity they then end up in the blood, and the brain, and wherever else they can cause trouble.

Chris - Have you got a strategy that will enable us to do this?

Vanya - Well, yes, I have got a strategy. The big problem with probiotics is that 98% of them, as you buy them over the counter, just do not work.

Chris - Because you eat them. They go into your stomach, the acid kills them and they don't actually ever end up in your intestines to do you any good. So, people are wasting their money effectively, aren't they?

Vanya - That's exactly right. I know of one or possibly only two compounds in liquid form in this country that survive stomach acid and actually do what they say on the tin. We have to do a proper trial whereby half the patients get the probiotics and the other half don't, and we have a look for positive health benefits in terms of controlling antibiotic resistance and possibly even being able to get rid of the bad bugs that have set up home in these patient's intestines.

Chris - UCL's Vanya Gant with what sounds like pretty damning indictments of most probiotics.

This week, we're looking for life beyond Earth: is there anybody out there? Remarkably, we're making progress in answering that question. In the last few years, we've discovered that our galaxy is teeming with alien planets but the big question remains - do any of them harbour life? Coming up, how do we define life and how did it begin; what can we tell about planets thousands of light years away and how many alien civilisations they might be home to? Now to many people, astrobiology means the hunt for alien life, but a big part of this is understanding what life actually is, and what's needed for it to exist. 

Everywhere we look on earth, there's life in an endless variety of shapes and sizes- from microbes to elephants. But how do we define it? What is life and how is it different from non-life?  Nick Lane is a biochemist and he spoke to Chris Smith about the origins of life.

 Chris - So, how do we tell what's alive like a mouse from a brick? Because chemically they're both made of very similar things.

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

Chris - You said that there has to be a carbon source. To what extent is the life we see here on Earth so unique to this environment that you're not going to find it anywhere else or do you think if another planet Earth-like environment exists out there that life would take exactly the same pathway of evolution that it has here and we will be looking at our mirror image out there, somewhere.

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.

Chris - So, you're sort of saying that because the rules of physics and chemistry are universal throughout the universe, therefore, exactly the same constraints will exist wherever you live - Milky way or even the Andromeda galaxy and therefore, you're gonna' end up following the same sorts of 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.

Chris - The Earth's four and a half billion years old, so how long after the Earth formed, did life first pop up?

Nick - Well, we don't really know. 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.

Chris - Where do you think that life came from? What sorts of theories are out there to explain how life arose? Did it arrive de novo, in other words, from scratch here or is it possible that it could have had some kind of injection of some processes from, say, outer space. 

Nick - Well, we know for sure that there've been plenty of organic molecules delivered from space on meteorites, there's no question about that. Whether that prompted life on Earth in some way, conceptually what it does really is stock a soup, and so conceptually, it's not really any different to say the Miller-Urey experiment from 50-60 years ago, showing that lightning and UV radiation and so on, can also produce organic molecules, so can hydrothermal vent systems. It's actually remarkably easy in some ways to produce organic molecules and remarkably difficult to get beyond a soup.

Chris - So, would you be in favor then of the idea that life just spontaneously started, or do think that actually that there is credence to this idea that there could have been life coming from elsewhere, maybe intact life coming from elsewhere in the universe.

Nick - There's no evidence to suggest that it did, and actually I think it's a pointless theory in the sense that if it did come from somewhere else, well we still don't know any more about how life started elsewhere. 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. And panspermia, the delivery of life from space, it just moves the problem somewhere else so it's pointless.

How can we tell if a distant planet is potentially habitable when it's light years away across the Milky Way? One way is by looking in the Goldilocks zone - this is the planetary zone around a star where it's not too hot or too cold - and measuring how the spectrum - or colour - of light from the star changes when it passes through the atmospheres of any planets. This can tell you what's in those atmospheres, as Cambridge astrophysicist Eleanor Bacchus explained to Chris Smith.

Eleanor - So certain molecules you have, or certain elements, they absorb and re-emit different colors of wavelengths, so if you imagine looking at a white light source and you split this light up into different colors like you would if you're seeing a rainbow. We're looking for colors that are missing or colors that are more intense than we might otherwise expect them to be and that will give us an indication of what sort of elements or compounds are in the atmospheres of these planets.

Chris - I mentioned the light coming through the atmosphere. Do we only look in that way or could we look at the reflected light from an orbiting planet and do the same thing?

Eleanor - Yes. So that's a lot more difficult but what you basically have here are two different methods of looking at a spectrum of a planet. The one where you have the light coming through the atmosphere is known as transiting, so you're looking at the planet as it passes in front of the star, and then the other method that was mentioned is actually what I work on which is called direct imaging and we're looking for the light that's coming specifically from the planet and this light, in the cases where the planet's habitable, will be light reflected off the exoplanet's atmosphere that's actually coming from the star.

Chris - How far away are the objects you're studying?

Eleanor - So the nearest star is maybe about four light years away and we do think there's a planet around there but we can't, sort of maybe... ten light years at most at the moment. So, it's really very, very close by in terms of the size of the galaxy, let alone the size of the universe.

Chris - How do you do these experiments? Because I would think that the light that's coming from the star is tremendously bright, compared with anything that's reflected off a little planet next door, so how do you get away the light from the star compared with the planet itself?

Eleanor - With an awful lot of difficulty really.

Chris - You're shaking your head.

Eleanor - Yeah, it's incredibly hard. So, it's this very, very, very complicated instrumentation involved which to be honest it took me about a year to get my own head around. But fundamentally we can focus the light from the star into a specific region on telescope instead of channel it away, and then hopefully, after an awful lot of post-processing, and complicated computer algorithms, get like a couple of pixels which is a tiny blob and you point at that, and you go, "That's probably a planet, maybe, we hope."

Chris - So there's a little way to go at the moment you're sort of saying.

Eleanor - Yes.

Chris - But if I were to look at a planet, how would I tell whether the molecules in the atmosphere are indicating a planet which could be home to life or could provide a hospitable environment from one which wouldn't? What sort of parameters are you looking at?

Eleanor - I mentioned earlier something called bio-signatures and these are really the important things we're looking for and in terms of looking at exoplanets, we're looking for specific gases really in the atmosphere that can only really be created by life. So the common examples that people often use are things like oxygen and methane in our atmosphere where they're sort of metabolic byproducts and we can't produce them in the labs that we see in our atmosphere by any sort of geological or photochemical processes, they have to be produced biologically.

Chris - There was some controversy on Mars though, wasn't there? With these methane seeps. People said, "Oh look! This is perhaps evidence of subsurface microorganisms or something like that." They've largely backed down from that theory, so that still leaves you in the same sort of situation doesn't it? Because all you can see is literally the signature of a chemical, you can't distinguish between, say different heavier or lighter forms which a life scientist could do on Earth to distinguish a life-giving process versus a non-life generating process.

Eleanor - Yeah. It's incredibly difficult, so a lot of  work at the moment is going into coming up with what possible biosignatures we might have and to be honest, I don't think we have any at the moment that are definitively, if you saw this you would know there was life there. All of them have a kind of false-positive scenario which we would have to sort of try and rule out by just looking at maybe other elements that we can see in the atmosphere, or trying to find out sort of more fundamental parameters about the planet, so, where it is in the habitable zone.

If it's highly unlikely that we'll ever be able to detect intelligent life, should we continue on in our efforts to find ET? Would the money, time and effort not be better directed elsewhere? Chris Smith put these questions to Eleanor Bacchus, Lewis Dartnell and Nick Lane, and started by asking Eleanor if there are any spin-off technologies from astrobiology developments...

Eleanor - There's an awful lot of funding around for exoplanets at the moment because it's a really - well, it's a really trendy subject in astrophysics. There's a lot of grants for it and this is pushing our technology because it's such a difficult problem. It's pushing technology to sort of limits that people couldn't really imagine before and this has just spun off into medical uses as well. So, there are some of our telescope technology is actually used in looking at people's eyes. There's one of these that I came across that I wasn't aware of before which was pretty astounding.

Chris - It's ironic to think of turning the telescope around, isn't it?

Eleanor - Yeah.

Chris - We're taking something very powerful to look at something very miniscule. I think also, someone said to me that if it wasn't for astronomy and astrophysics, we wouldn't have Wi-Fi that we all use on the internet every day and of course the SKA, the Square Kilometer Array, world's most powerful telescope they're building. That's gonna generate as much data in a day as the whole world generates in a year at the moment, so we've got to marshal big data better. Nick Lane, what do you think about this whole business of looking for life out there? Do you think we should be looking for life in Cambridge, or we should be looking for life elsewhere in the universe?

Nick - Yeah. I think, I think it's overwhelmingly likely that life will arise on more or less any wet rocky planet, including Mars. I would agree with Lewis. I would be very disappointed if it hadn't, but complex life like ourselves, I think that's far, far more rare. All complex life on Earth only arose once in 4 billion years and so that's highly improbable for whatever reasons that we're trying to understand. Should we therefore look for complex life out in the rest of the universe? I would say, yes, because we don't understand what the reasons are here. We're trying to get at it but again, observational data is the only that's going to give us any kind of an answer.

Chris - And Lewis Dartnell, thirty seconds. So, SETI? Yes or no?

Lewis - My personal belief is that SETI will not detect anything. There is no other intelligent civilization in our galaxy. However, I think we should still be looking for it because it's an incredibly cheap thing to do but the repercussions would be so incredibly profound if we find an interstellar text message tomorrow.