Show Notes

• • Paper in Science on Arsenic Life (pdf)
  • News article on the paper — Universe Today
  • Backlash/Feedback on NASA’s Arsenic Findings — Universe Today
  • Arsenic Bacteria — a post-mortem, a review and some navel-gazing — Ed Yong from Not Exactly rocket Science
  • Periodic Table website
  • Scientists from Arsenic Bacteria Paper Respond to Criticisms
  • Mono Lake
  • xkcd comic on the media frenzy
  • “This Paper Should Not Have Been Published” -a review by Carl Zimmer — Slate
  • Titan’s Methane Cycle — Astrobiology Magazine
  • Water Bears
  • Donate to Astronomy Cast
  • AstroGear

Transcript: Exotic Life

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Fraser: Astronomy Cast Episode 209 for Monday November 29, 2010, Exotic Life. Welcome to Astronomy Cast, our weekly facts-based journey through the cosmos, where we help you understand not only what we know, but how we know what we know. My name is Fraser Cain, I’m the publisher of Universe Today, and with me is Dr. Pamela Gay, a professor at Southern Illinois University Edwardsville. Hi, Pamela, how are you doing?

Pamela: I’m doing well. How are you doing, Fraser?

Fraser: Doing great! So you’re back safe and sound from TAM Australia and other trips.

Pamela: I am back, and now I’m getting ready to leave to go to the American Geophysical Union meeting where hopefully I’ll get to see some of the people out in the audience, but I have to admit I’m going to be trapped inside the conference center and unable to leave, so…

Fraser: [missing audio]

Pamela: Yeah, exactly.

Fraser: And I was recently on “The Skeptic’s Guide to the Universe” as a special guest when they did a live show in Vancouver, and I got to handle the “Science or Fiction.” But I don’t want to ruin the show for you, so give it a listen.

Pamela: Awesome.

Fraser: Now, we don’t like to cover news on Astronomy Cast, but sometimes there’s a news story that’s so interesting and complicated and rapidly-unfolding—and it happens to cover an area that we haven’t really talked much about—that we just got to talk about it. So today we thought we’d cover the discovery of arsenic-based life and exotic forms of life in general. Maybe we need to redefine our definition of life, or maybe we just got introduced into some distance cousins, or maybe it’s just not that interesting at all. Nah… I think it’s interesting. [missing audio] This has changed everything! No… it hasn’t changed much…

Pamela: No, no not really.

Fraser: [missing audio] …speculation up to this discovery and then all of the skepticism and counter-arguments afterwards. It’s fun to go through this process. I mean… I watch… I know how it’s going to unfold now. We’ve done so many stories on Universe Today that I know how it’s going to unfold every time. So, NASA had a big meeting where they were going to discover something very, very important. And the speculation ran rampant on the internet on what that thing was going to be… and the discovery was…

Pamela: …that it is believed by a group of researchers—with confirmation awaiting from other researchers—that there is a bacteria from a lake in California (and it never surprises me when aliens come from California) that this particular bacteria is capable of replacing phosphorus in DNA with arsenic… which is kinda cool.

Fraser: [missing audio] So, this is a bacteria, not a space alien with many tentacles. This is a single-cell bacteria. So the environment is very important, though, right? It’s a California lake. Something strange about California?

Pamela: Well, it’s more something strange about this particular lake. It was locked off from having fresh water coming into it a number of years ago, and so all of the nasties in the lake have been able to get denser and denser and denser as the waters become more concentrated. So kinda think it’s the Dead Sea of arsenic. It’s just a very arsenic-rich lake… Mono Lake in California.

Fraser: [missing audio] …doesn’t have the combinations of life… the basic building blocks of life that we understand that you might find in a regular lake. You’ve got nice clean water, you’ve got nutrients, you’ve got sunlight… you’ve got a lake that would essentially be poisonous to most life forms.

Pamela: Yeah, that whole arsenic and lace thing… people are long-known for dying sudden deaths when “enriched” with arsenic, you might say. So they went looking specifically to see if they could find, in this arsenic-rich environment, a critter capable of making this particular substitution. This is actually something that wasn’t just done on a wild whim, but rather there was a study done a number of years ago called “The Limits of Organic Life in Planetary Systems.” It was a large committee put together by the National Research Council to try to figure out if we’re trying to figure out if there is alien life elsewhere in the universe, where do we go looking for this potential alien life? They came out with a bunch of specific recommendations, and one of their specific recommendations was—and here I’m quoting from the paper—“to search for life that can extract essential nutrients such as phosphorus, iron, and other metals from rocks such as pyrite and apatite.” Then they wanted to figure out if those key minerals could be used as key nutrients where they also said to search for organisms from environments that are limited, including limits in phosphorus and iron, such that these organisms can substitute these other elements such as arsenic for phosphorus. So, the study actually recommended finding critters that make the substitution of arsenic for phosphorus. So they were specifically looking for something based on a recommendation made by the wisest people in the field of astrobiology, we hope.

Fraser: [missing audio] …of that paper here on Astronomy Cast because of our policy of not talking about news. But we actually got interviewed for Skepticality… it was a couple of years ago actually… so we actually went in for about an hour with Swoopy talking about this information. It really brings things around… it’s quite neat because you’ve now got, back then, the recommendation to the scientists to go look for these environments where various pieces of the puzzle are restricted and see if life has found a way to deal with that. Now there’s more implications in this original study talking about how you could replace…. could you have instead of a carbon-based life form… what other molecules will do the trick? Ammonia-based life forms and all these different exotic forms of life… silicon, etc. [missing audio] …this is one of those things with NASA… they do a pretty good job of going forward in a very deliberate manner. If you look at their research, when they’re searching for life on Mars it follows the same process. They’re looking for evidence of past water. They’re looking for evidence of current water. They’re looking for evidence of biologically-produced compounds. They’re inching towards life in a way that when the scientific evidence is found, it’s very good.

Pamela: This all goes back to the idea of extraordinary things require extraordinary evidence. The search for non terrestrial-based life is one of those things that when it’s finally found, that is going to be the most controversial claim ever made in science, unless some little green or grey dude comes and talks to us directly. No one really thinks that’s going to be how we find life. It’s going to be via a signal, it’s going to be via an atmospheric signature, it’s going to be via some indirect detection. So we’re working on trying to figure out how do we make that indirect detection locally with bacteria that may exist on other planets. Where do we look, what do we look for, and then how do we look outside of our solar system.

Fraser: [missing audio] Can you explain in more detail exactly what this little critter is doing?

Pamela: Within our body, human beings require phosphate… one phosphorus atom and four oxygen atoms forming a molecule… for a whole lot of different stuff. Any of you who ever took high school advanced-placement biology got to memorize the ADP cycle within the body which includes phosphate as one of the major constituents of the process. One of the backbones of forming the DNA molecule, that twisted helix that defines who each of us are genetically, one of the backbones of forming that molecule is phosphate. Now the reason that people talk about making a substitution with arsenic is that if you pull out your periodic table or Google one, which is what I did, there’s a really good one at www.ptable.com… a horrible name but an excellent periodic table. When you look down the columns, the reason that the periodic table has all the strange gaps that it does… the first row only has hydrogen and helium, the next row has a limited number of things… it has two things on the left and six things on the right. That pattern of the periodic table is actually built on the pattern of orbiting electrons, so in hydrogen and helium you only have two possibilities of where to stick electrons. So you have these two items. Then with each successive movement down the list you add more possibilities for these electrons. Each column in the periodic table represents how many gaps are left in the outer-most orbital, the outer-most layer that electrons can live within. So when you’re looking at oxygen, when you’re looking at sulfur, when you’re looking at selenium, tellurium, polonium, all of these different elements that just happen to make up column 16, they all have six electrons living happily out in their outermost orbital shell and they can fit two more out there.

Fraser: [missing audio] …eight.

Pamela: Yeah. Well, this particular orbital always goes in rings of eight. So with those six happily living electrons in that particular shell, those six electrons are just waiting to bond with something else, and just waiting for something else to come along and bond with them.

Fraser: [missing audio] …share them or steal them from somebody, but to make that outer ring be balanced.

Pamela: Right. So when we’re looking at phosphorus, in that outer-most level it has five electrons out there. If you go next down the list to arsenic, again you have five in that last orbital. So the idea is that both of them are able to form a similar molecule. With phosphate you have phosphorus and four oxygens. Then they also formed… in the mix that they fed these particular critters that they got from Mono Lake… they created a molecule that was instead arsenic and four oxygens.

Fraser: Right, so it’s almost like a puzzle piece that both phosphorus and arsenic have the same puzzle piece so they can connect to oxygen in exactly the same way.

Pamela: Right. We hope… we think… Now the thing is, while chemistry is something I last took in 10th grade… having tested out of it… I have taken lots of quantum mechanics and physical chemistry which avoids a lot of the types of things that you worry about with biologicals. But what it does talk about is bonding angles… the probability that things exist… how they come together. One of the things that does change is the links of the bonds in these molecules. The exact geometry of how they form is just slightly different when you’re forming it with arsenic. So it’s a similar critter… a similar molecule, rather. But it’s not absolutely identical. The question is… can that slightly rescaled molecule get forced to buckle itself in… twist itself just a little bit to fit in and replace the phosphate in these DNA strands.

Fraser: And the initial evidence seems to be… yes.

Pamela: Yes. Now there’s been a lot of people being vocal, to say the least, about this. So the reason that you have a lot of people being vocal about this is first of all, it’s highly controversial. So, you want to prove them wrong… because that’s how science works. Someone says something new and you poke holes in what they said if you can. Now the other reason that they’re doing this is what they were feeding the bacteria that they were working with was a salt that did contain trace amounts of phosphate. So the question is were they metabolizing using this arsenic replacement molecule, or were they simply figuring out how to metabolize just enough using these trace, trace, trace amounts of phosphate. There is life that is known to exist that metabolizes phosphate at even lower levels than what existed in this particular salt.

Fraser: Or maybe it’s figured out some kind of blend. If it’s a folding problem, maybe you can use as much phosphate as you can, then you have to use arsenic. So it could be something in-between.

Pamela: Right. So there’s lots of possibilities. One of the things that is on the list of things that scientists are going to be doing next is figuring out how to image the DNA to actually see is the arsenic via some sort of… it’s not going to be a direct image… you don’t take an electron scanning microscope to look for arsenic… but they’re going to be looking to most likely use radioactive isotopes of arsenic to trace is the arsenic getting used to form the DNA molecules.

Fraser: So then what are the implications? We’re still going to find out whether this is true or not, and whether this is really doing this or not doing this. But as we talked about, this goes back to this study that NASA did a few years ago where they’re really taking another look at the concept of what it means to be life. There are many other molecules, many other solvents that you can use to make what would appear to us in all ways to be life.

Pamela: Right. So, the question basically boils down to can life find a way, when everything else goes to pot, to still exist. Can the substitutions dreamed about in Star Trek actually be made. There’s a number of different substitutions that we worry about. The one that most people have heard about is the substitution from carbon, which has four electrons in its outer-most shell, to silicon, which also has four electrons in its outer-most shell.

Fraser: And that’s good because I think a lot of people say oh, is this not a carbon-based life form but an arsenic-based life form? That’s not what’s been discovered.

Pamela: No, this is still carbon molecules forming most of the structure of the bacterium. It’s still carbon-based organic life. It’s just one particular process that you have a phosphorus to arsenic substitution instead. Bodies are filled with all sorts of things and you require phosphorus… maybe…

Fraser: Maybe… or arsenic…

Pamela: But the reason that we’re pretty sure that life on Earth is using carbon and oxygen and using phosphorus instead of arsenic is the cosmic abundances of all of these things. Here on Earth, carbon is much more prevalent than silicon so it just seems natural that that was what ended up forming life. Now when it comes to phosphorus versus arsenic… again, much more prevalent here on Earth than the arsenic. But it’s possible that even though cosmically you expect the same sorts of ratios that we see on the earth, it’s possible that via some sort of weirdo process you end up with a planet that has a deficit in one of these particular atoms. Wouldn’t it be cool if even in these environments where the atoms that we use are much rarer… what if life could still find a way to exist in these environments, those Mono Lakes of the universe?

Fraser: And what NASA identified is that there are many different places… I mean we assume carbon, water, some kind of energy source… you’ve got life. But, maybe it doesn’t have to be carbon, maybe it could be silicon… maybe it could be some other element. In fact, as we’re seeing with this, maybe you can replace some of the different elements that go into the DNA with different elements… replacing phosphorus with arsenic. But the other one that’s really important is the actual medium… the solvent that the life does its work in. For us, it’s water…. you hear that we’re bags of mostly water. That’s another one that could be completely different.

Pamela: And that’s one of the ones that’s even more exciting in the context of our own solar system because if we look out to Saturn’s moon Titan, which is what rumor had it that this was going to be a discovery about if you read some of the rumors, on Titan, instead of having a water cycle there’s a methane cycle where you have the planet rains methane, there’s methane lakes on the surface. It’s a combination of at that low of gravity, at that low of a temperature, methane is able to persist and have all of these different functions within the environment. You’re at what’s called the triple point for methane. Now recently people have been, within the past ten years, working very hard
to redefine what it takes to form life. And I love that the definition I learned in elementary school is now completely replaced and this is information that has made it all the way down to the 5 year olds asking questions at events. Now we think that what it takes for life is, just as you were saying, a solvent… not necessarily water but anything that will dissolve stuff within it. You need not sunlight… that’s what we learned in school… but instead you need an energy gradient. We say energy gradient because we now know that the thermal vents at the bottom of the ocean can sustain life. And we no longer say it has to be carbon… it could be something else. We’re now much more open-minded in our chemistry.

Fraser: So how do these changes, as you say… the definition of life, how does that change our search for life here in the solar system? Where are the scientists starting to look?

Pamela: Well, once upon a time we were only willing to spend the money searching for life in places where we knew liquid water could exist. On the planet Mars we’re still desperately searching for where are there places that in reality really salty water could exist? They’re seeking brine water on Mars through a lot of theoretical models. But it means that within the solar system, on Titan where you have a methane atmosphere or methane water cycle, you have the potential for life. So we’re going to go look there hopefully. We don’t know what the sea of Europa might be made of, but we know there’s probably liquid there and there’s not enough sunlight but there’s the possibility for geothermal heating. That’s in fact where the ocean comes from. So that’s someplace else we want to go look for life. So here we have something other than water on Titan, we have something other than sunlight on Europa, and we’ve opened our eyes to the possibility that life could exist just about anywhere.

Fraser: Now would you say… I know one of the descriptions of this was that it was aliens found on Earth… there was alien life on Earth. And again, that’s really just not a good description.

Pamela: No. The problem is that people like to run with things and write sensationalistic titles. We’ve all been guilty of it at one point or another…

Fraser: No we have not! Universe Today has a policy of never ever being sensationalist. Just the science, please…

Pamela: Ok, so I’ve been “punny” with my titles… I admit that. I don’t think I’ve ever been sensationalistic, I’ve just been silly…. which is different. And Universe Today… ok, fine… you guys behave well.

Fraser: We don’t… but anyway…

Pamela: Anyway, it’s easy as a journalist when you’re trying to get people to click your link rather than somebody else’s link…

Fraser: But don’t you people see… this is just like Star Trek! But real! Yeah, that’s the angle that we take a lot.

Pamela: So NASA wrote a perfectly reasonable press release that said this will affect our search for alien life… which is true. But then didn’t give either enough information to squash rumors or enough information to give away the results. So it was one of these things of… we’re not going to tell you anything, we’re saving it for the press release…. that allowed wild speculation to occur.

Fraser: Yeah. Again, we absolutely could’ve watched this unfold and… but the point here is that it’s a very interesting evolutionary adaptation to a hostile environment but it is definitely not… I’m sure that we’ll be able to trace the lineage to a common ancestor with regular life as we know it.

Pamela: And I have to say that some of the criticisms being leveled at this paper are completely reasonable. The concern that if the DNA molecules were actually built with an arsenic-based molecular structure they should dissolve much more readily in water than they are. That’s a reasonable scientific argument. But I’ve seen other people just sort of stomp their foot and say that this was science by press release. Science by press release refers to times when people… and this happened with cold fusion, we’ve talked about this before… when people put their results out during a press conference without there being a peer-reviewed paper accepted for publication. This wasn’t one of those cases. These scientists wrote a paper, they got as much confirmation as they knew how to get for their first round of work. They submitted a paper to Science. It went out for peer review. They got referees’ comments back. They reacted to the referees’ comments. The paper was revised. It was accepted for publication. The day the paper was published was the day of the press release, so everyone could review all of the results. They said from the very beginning that this was preliminary. We want our competitors to replicate what we’ve done and either prove it or show us what we did wrong. That’s not science by press release. That’s just science at the edge of what we understand.

Fraser: Real science. Perfectly well-done.

Pamela: Yeah.

Fraser: Yeah. Absolutely. So then does this have any implications, do you think, for the search for life in some of the other ways that we search for life? I mean we’ve talked about SETI, we’ve talked about the terrestrial planet finder type mission where you’re analyzing the atmospheres of distant planets, does this have any implications for that, do you think?

Pamela: Potentially. So right now one of the more interesting ways that we could identify not intelligent life but simply life on another planet is by looking for molecular oxygen within a certain pattern of molecules in alien atmospheres. Molecular oxygen isn’t something that likes to exist by itself. It just has a tendency to do things like form carbon dioxide and carbon monoxide. So when you have that molecular oxygen signature, you probably have algae or plants or something else that we just haven’t thought of. But the question is if you can have silicon-based life, if you can have arsenic-based DNA, what sorts of metabolisms do we have to think about? What sorts of chemical respiration processes do we have to think about that might lead to a different, unique signature of life within an atmosphere? This is where the astrobiologists are having a lot of fun is trying to figure out what are the different ways that life can respirate?

Fraser: And you can imagine some space mission being developed which is highly tuned to discover free oxygen in some atmosphere in some distant planet and doesn’t find any oxygen in these planets but, in fact, if they had just run all the models and figured out every possible chemical outcome and then built that into the telescope, then you could say no, it doesn’t have free oxygen… oh, and it doesn’t have… I don’t know… some kind of methane output and it doesn’t have ammonia in the atmosphere. You could run through this whole checklist and imagine every possible chemical outcome and really be comprehensive about it. Or, you could say look, we found silicon oxide in the atmosphere… I’m not sure if that’s one of them but… something that would have to be sustained by a biological life form. So I think this is great because it’s really expanding the tool set and giving the new telescope developers more things to look for.

Pamela: And it’s always good to find reaffirming data saying life really can exist anywhere. We started from the premise of life is hard… it’s difficult to get life. No… difficult to get intelligence is our remaining theory. But life itself… if you’ve never Googled the phrase “water bear,” it’s this little tiny silly looks like an overly-legged gummy bear bacteria that… or I guess microbe is the correct term… you can launch these suckers on the outside of a spacecraft, orbit them around the planet for a little while, then de-orbit them through the atmosphere where they get exceedingly hot and once they’re back down on Earth, they’re perfectly happy to reproduce and go on being living creatures.

Fraser: It’s funny because one of the most important scientific discoveries of possibly all time… the discovery of life other than on Earth… is being chipped away by the scientific research in other ways. So that by the time that you actually get there, you know… Life is found on Mars! Well, yeah, but we kinda knew it was there… we could see the methane… we’ve got a much wider understanding of what life is so it’s not really that surprising and looks like it’s related to us… Life is found on Europa! Well, you know there’s water and there’s vents and we were expecting that… Life is found on another planet! Well, you know we know they’re in the solar system with us and particles get from one solar system to another solar system, and it looks like they’re related. It’s almost like it will be not surprising by the time the most important discovery of science ever is made.

Pamela: And what I love about this particular story is prior to launching spacecraft to go look at Mars up close, everyone just kind of assumed that the seasonal variations on the surface of Mars were at least partially related to plants, animals, life on Mars. We take a close-up look at Mars with a spacecraft, let out a community-wide sigh and/or expletive and kill off our thought of life anywhere in the solar system… anywhere in the universe.

Fraser: But the hope is coming back.

Pamela: The hope is coming back. Hope springs eternal… life springs eternal.

Fraser: Well, that’s great! Thanks a lot, Pamela, and of course if there is any more really interesting discoveries and changes, we’ll re-address the topic again in the future.

Pamela: And one more thing as we’re taking off… we are ending a tax year soon here in the United States. It’s very sad and exciting because it means paperwork.

Fraser: I’ll just take your word for it.

Pamela: Yeah, yeah, yeah. But, if you are looking for a tax deduction, it is within my job requirement to remind you that we are tax-deductible. I would challenge everyone out there that for the year 2011, which is about to start, donate $20.11 or at least something that ends in 11 cents so that we know that the reason you’re donating is you heard this plea. We can’t keep paying our student unless you donate, so please donate… please help…

Fraser: Ooohhh… or buy our stuff at astrogear.org.

Pamela: That works, too.

Fraser: …AND buy our stuff. Alright, well thanks, Pamela! We’ll talk to you next week.

Pamela: Thank you Fraser. I’ll talk to you later.

Shownotes

Things that didn’t die in space:

• Earth microbes on the Moon — Science@NASA
• Water Bears Survive Space Vacuum — New Scientist

Astrobiology (aka Exobiology)

• NASA’s Astrobiology website
• NASA’s Astrobiology Magazine
• Exobiology @ NASA
• Life’s Little Essentials — PBS
• Solvents – Wiki
• Life Seeks out Energy Sources — Science Frontiers
• Energy Sources and Life (paper) — NASA/Harvard Smithsonian
• The Limits of Organic Life in Planetary Systems — free pdf book
• Miller-Urey Experiements – Duke University
• Miller-Urey Experiments (with Video) — UCSD
• Peter Ward
• Book:  The Life and Death of Planet Earth: How the New Science of Astrobiology Charts the Ultimate Fate of Our World by Peter Ward & Donald Brownlee
• Peter Ward Talks Mass Extinctions on TED
• Alternatives to Carbon Based Life
• Hypothetical Types of Biochemistry — Wiki
• Viking Mars Landers and the search for life – UTK
• Viking Mission to Mars – GSFC
• Looking for Life in All the Wrong Places — Air & Space Magazine
• Phoenix Mars Mission :  Habitability and Biology
• Mars Science Laboratory (“Curiosity”)
• Ground-Based Telescopes Observe Atmospheres of Exoplanets -- Universe Today
• Carbon Dioxide Detected on Exoplanet — Universe Today
• Large Quantities of Methane Being Replenished on Mars — Universe Today
• RTG: Radioisotope Thermoelectric Generator – Wiki

Transcript: Astrobiology

Download the transcript

Fraser Cain: I wanted to let people know, and you may have noticed now that we’ve got new album art and a whole new logo for AstronomyCast. This was designed by one of our listeners, Luke Fielding. Luke has also designed some CD cover art and we are going to be coming out with some CDs in the near future.

We’ll give you more details when that actually happens. Thanks to Luke and if you haven’t seen it you can come to our website but you should be able to even see it right on your iPod or on iTunes.

As you’ve noticed, publishing has been sporadic. Pamela’s travel schedule has been absolutely crazy. We have these days where we record four episodes in a day. Then she’s off on some other trip, other people edit them and so we’re doing the best we can.

Dr. Pamela Gay: The International Year of Astronomy will end on December 31, 2009 and then all of you will have my highest priority again. We’re so sorry.

Fraser: We know there’s life in the universe, we see it all around us here on Earth but is there life anywhere else? By studying the extreme that life can take here on Earth scientists are learning just how hardy and adaptable life can really be.

When you consider other ways that life might function, the options open up considerably. This week we’ll discuss the study of life, extreme life here on Earth and the possibility of finding life on other worlds. Just how hardy is life?

Pamela: That’s a kind of broad question. What we do know is

Fraser: Well okay let me ask you a more specific question. How hardy is the life we found here on Earth?

Pamela: There are things that really don’t want to die.

Fraser: [Laughter] Right other than me and you [laughter] I know what you mean. Things that live in places that would kill us in an instant right?

Pamela: Not only that but there are critters that have adhered themselves to the outsides of spacecraft, gone up, come back down and they’re still going strong. There are these little tiny invertebrates called water bears – they look like gummy bears with vicious claws – but they’re really little tiny microscopic organisms.

You’d only really consider one bear sized if you were a millimeter tall. You can’t kill them. They are happy with outer space. They are happier here on Earth. These fall into the category of things that will not die.

Fraser: Yeah, radiation is fine, make it hot or cold, it’s all good.

Pamela: Yeah they just turn themselves off when it gets too harsh and re-animate themselves when life is back to being more like what they want.

Fraser: What has the search for extreme life on Earth – I know there’s been sort of a revolution of that in the last few years – what is sort of the history of that then?

Pamela: The normal thing that we learn in elementary school is that life requires water, sunlight, oxygen and it requires moderate ph. It requires moderate temperatures. Life in general we learn is fragile.

Anyone who takes their first fish and over-feeds it or dumps it in the water too fast knows fish die really easy. This reinforces the idea that life is fragile. What’s fragile is complex life. What’s fragile is intelligent life.

Once you start getting down to the little critters the single-celled organisms then you start getting into finding things that can live anywhere. We have found organisms at the highest and lowest ph values. We have found them in the coldest and hottest places on the surface of the Earth.

We find them at high altitudes and very deep underground. It seems that the smallest organisms are fully capable of adapting themselves to live in just about any environment.

Fraser: This obviously then is sort of leading to the search for life on other worlds?

Pamela: We’ve developed this entire new field of biology called astrobiology or in older sci-fi it was called exobiology. They’re really the exact same thing.

What we’re trying to do is define okay we know here on Earth we’re finding life in all these crazy venues. Once we start relieving the well life requires, what is actually required? Where in the universe can we find those actual requirements which still exist but are much looser in their criteria?

Fraser: How is that criteria changed?

Pamela: Nowadays instead of saying that life requires liquid water, instead life requires liquid solvents, things that can facilitate different chemical reactions. Things that can facilitate things dissolving for instance with the restrictions strictly looking for liquid solvents.

That means that we can look for life that perhaps lives off of sulphuric acid. It opens up Venus as a place where life might be possible in a way that doesn’t exist here on Earth at all.

Fraser: What’s a solvent?

Pamela: A solvent is any chemical that will break molecules apart. When you pull out the nail polish remover that is a solvent that tears apart nail polish. Water can be a solvent as well.

Consider all sorts of different random dirt, random molecules that just fall apart – sugar dissolves in water. Anything that causes molecules to dissolve, causes compounds to dissolve, that’s a solvent.

Fraser: How is that important for life? How is life using the solvent?

Pamela: Our body is nothing more than a large bucket of different chemical reactions. We need that water to facilitate all the different chemical reactions from just eating our food through to dissolving the fat in our body to sloshing the blood in our veins around in our body. All of these things require a liquid.

Within our blood it’s not so much as a solvent as it is we need plasma to keep things moving. Liquid in general is facilitating all of these chemical reactions taking place that keeps the body moving.

It keeps the body energized and allows the body to take base compounds and transition them into being energy that the body can use to then do locomotion and other activities.

Fraser: I see it’s almost like if you have some chemical process in your body and you need to change the chemical. Or you use energy or get access to one of the atoms on the chain you need solvents so you can kind of take it apart.

You can let the atoms and molecules float around so that you can recombine them in different places. If you don’t have a solvent then it’s all just kind of locked together and there’s no easy way to move things around.

Pamela: That’s exactly what’s happening.

Fraser: What else then? We’ve got solvent so what else have scientists changed their attitudes about?

Pamela: Instead of strictly saying that we need sunlight and food we’ve changed that into simply: you need an energy source. In general some sort of a thermal gradient helps.

Fraser: Whoa, thermal gradient?

Pamela: This is where you have hot and you have cold. That’s not as required. That just helps get the chemical reactions going. In general all we really need is an energy source of some sort.

Fraser: That could be sunlight.

Pamela: Volcanoes under the ocean.

Fraser: Right and that could even be electricity or solar power, right? With plants? [Laughter]

Pamela: Compression. At this stage basically we need an energy source and a liquid solvent. Then you need the raw stuff. Even what that raw stuff is has changed.

Instead of saying strictly we need organic molecules based on carbon, nitrogen, oxygen, now we’re saying maybe it’s possible to have life that’s built on ammonia.

Maybe it’s possible to have life that’s built on silicon or plays. We’re changing our ideas of what sorts of base materials are needed to build up these life forms.

Fraser: Yeah because at the end of the day you need to be able to have some way to extract the energy from the environment. You need some way to move your molecules around into some other and then use it for something.

That’s it. If you’ve got an energy source then you can power it all up. If you’ve got a solvent you can move those molecules and atoms around and recombine them in different ways.

Pamela: What’s interesting is we’ve been trying to experimentally figure out what are the limits on where life can exist? Also under what circumstances can the types of molecules that we find in life form?

The experiments that we’re all most familiar with are the Miller-Urey experiments that took place back in the ‘50s. They used electricity and a bunch of organic molecules and water and they stirred things up and mixed it around.

They looked to see what organics they could create that were more complex to see if they could perhaps synthesize amino acids. What’s cool though is those aren’t the only experiments that have led to creating these complex molecules.

Stanley Miller one of the two who was involved in this experiment also took and created a frozen experiment. He mixed a vial of ammonia and cyanide and kept it at minus 108 degrees for 25 years. That’s minus 108 Fahrenheit. For 25 years he kept this vial extremely cold.

You’d think at that low of a temperature there would be no chemical reactions going on. This is a temperature like you find out on Europa – one of Jupiter’s icy moons that we think has liquid water.

What he found was after 25 years the ammonia and cyanide had very, very slowly undergone chemical reactions and had started to form complex organic molecules. Even in extremely cold environments you can still get chemical reactions taking place, just at a slower rate.

Fraser: As long as you’re not at absolute zero there can be a temperature gradient that can help the process move forward. You just have to redefine your idea of time.

How does this then apply to search for life at least here in the solar system? How have scientists applied this so far?

Pamela: There is a scientist called Peter Ward. He’s an astrobiologist. He’s been working to try and find first of all what vocabulary can we use to start storing any new life forms that we have?

Here on the planet Earth we have the whole tree of life that we all memorized in about 10^th grade. It assumes everything is based on DNA here on the planet Earth.

He’s been trying to think outside the box and figure out as we move around the solar system instead of looking for our normal carbon-nitrogen-oxygen life, what other things can we look for? What he’s identified is in the inner solar system instead of looking for water-based life let’s look for life that might be based on sulphuric acid.

As we move further out in the solar system why don’t we look for things that are based on methane? We know here on the planet Earth in fact we used to have methane-based life as one of our primary life forms.

As you move even further out can we maybe envision life that lives off of liquid nitrogen or even colder yet, liquid hydrogen? He’s working to figure out what are the chemical environments in which you can start to get chemical reactions.

You have the solvents and what are the specific places and temperatures where each of these different solvents, are they going to play the role of water here on the planet Earth.

He’s also looked to say what are the different types of elements on which you can build life? We look primarily at carbon and silicon as the atoms that form the rich molecules that may be capable of supporting life.

He’s working to define like I said the solvents and also trying to figure out what are the different energy sources that we can consider. What are the different habitats?

Everything from maybe we can get life living in the Venusian’s clouds or we can get it living in the ices of Triton out orbiting around Neptune. Trying to define the places to look and the chemical reactions to look for is a good starting place.

Without knowing what chemical reactions to look for we can’t actually test for life. We have to start by figuring out what is possible and then go out and look for it.

Fraser: I guess that was my next question. How would you actually try to find it? What would you need to equip a spacecraft or a rover to be able to find this kind of life, or any life?

Pamela: [Laughter] That’s one of the really great questions. The Viking probes when they landed on Mars attempted to look for life. We had thought that certain organic molecules only occurred in the presence of life.

We thought that when you made certain mixtures they would give off oxygen if life was present. Then people thought about it and realized that there are all sorts of other things that can cause the same outcomes.

Fraser: What happened with the Viking mission? I know that the Viking landers were equipped with a little scoop and they could dig up a little bit of dirt.

Then they put in food, like some kind of mixture into the dirt and detected to see if there are any chemical processes that would be indicated for life. The results were inconclusive, right?

Pamela: The results were inconclusive because they failed to consider all the different compounds that could exist in the soils on Mars. The problem they ran into is they got a positive result but they couldn’t figure out if it was a positive result because of the stuff that exists within the Martian soils or because there was life.

When they started looking for organics they couldn’t find organics at that point. It was one of these things where they got the chemicals released that you’d expect to be released if there was life.

But then when they searched for the organic molecules that would make up the life they couldn’t find them. That’s where the inconclusive results came back.

Fraser: Some of the following stuff, nothing else has been as equipped to search for life almost as the Viking landers.

I know that Spirit and Opportunity have no way to search for life. I don’t even think the Mars polar lander can do it.

Pamela: No and this is where things have gotten controversial. There are a lot of scientists that are like we just want to go look for life! And really you can’t blame them. That would be so cool.

At the same time that’s expensive and controversial. What we’re doing instead is we’re slowly building up the laboratory picture of okay, assuming that we’re looking for life that’s like anything that exists on Earth, let’s go out and let’s look for organic molecules.

Let’s go out and look for water. Let’s go out and look for all of the building blocks that you would expect to find here on Earth if you were probing either Antarctica or the Atacoma desert or some other really harsh environment to see if it was capable of supporting life.

One of the really intriguing results was yes. Mars is capable today of supporting life. Now we just need to define what experiments can you run to took for that life? Here we’re talking about single-celled organisms nothing complicated.

Fraser: Right. We’re definitely not talking about Martian civilizations with canals.

Pamela: No, we’re talking about like single-celled amoeba happily existing in the sands of Mars.

Fraser: Okay so what are some of the future experiments that are going to be heading towards Mars?

Pamela: The next best chance we have for looking for not necessarily critters but the type of stuff that you get when you have critters is the Mars Science Laboratory which is also known as Curiosity.

It’s an upcoming rover. It is huge by rover standards. It’s probably going to insert itself into orbit sometime around 2012. It is hoped that it will last about 690 Earth days, so it’s going to last a couple of years basically.

It’s heavy, about 2,000 pounds and it’s going to carry a whole bunch of different instruments on it. One of those instruments is a chem-cam. It’s a suite of remote-sensing instruments that will include things like a laser-induced breakdown spectroscopy system.

That’s a big mouth full for saying they’re going to heat things up with lasers and see what they can excite that will allow them to tell what elements are involved.

Fraser: This is going to be a robot with lasers on Mars zapping rocks.

Pamela: Yeah, vaporizing rocks. They’ve stepped beyond zapping. This means that they are going to finally be able to do detailed analysis of what sorts of minerals are there down on the surface.

They’re also going to have a chemistry and mineralogy x-ray and x-ray fluorescent instrument. They will be able to look in amazing detail at minerals in all sorts of different ways.

Beyond that they’re also going to have a gas chromatograph that’s going to start to allow them to vaporize things and get out what are the ratios of the different elements within the samples. All of these things are tuned to allow them to look at isotopic ratios.

We know life prefers specific isotopes. It’s going to allow us to look for different organic molecules. We’re going to get a better and better idea of what are all the chemicals all of the molecules that you can find at the surface of Mars.

We know if you vaporize basically an anthill you’re going to have certain organics given off. We’re not going to be vaporizing anthills on Mars. If there are signs of life we’ll be able to see the increase of ratio one isotope of carbon over another isotope.

We’ll be able to see here there is a whole bunch of organics; over here there’s not. We’ll be able to see the differences from place to place in the chemical compositions of the soils.

Fraser: Right and so we’re going to have to wait just a couple more years until that mission gets to the surface of Mars. I know it’s not going to work the same way as the rovers because they have big solar panels while this one is going to actually have a nuclear reactor onboard.

Pamela: One of NASA’s very last.

Fraser: Sort of the same thing as on Voyager and Cassini.

Pamela: Right and this is going to allow it to have much more powerful – it’s going to allow it to have lasers – and blast things apart. That’s just cool.

Fraser: Yeah, work in the winter and work in the summer and just keep working. We talked a bit about molecules in space.

Do you think that some of the new research that’s been done in terms of astrobiology and thinking about extreme life?

Some of that could help astronomers could pitch in actually detect some of that stuff with their telescopes.

Pamela: This is actually one of the most promising ways of looking for life. I think just like digging through the Atacoma desert wouldn’t lead you to easily find life here on Earth even though there is life in the Atacoma desert. The easiest way to find life on Earth is to look at our atmosphere.

Look for the oxygen signature of the plant life. Look for the pollutants that are created by humans. By looking for molecules in atmospheres that don’t occur there unless there is life putting those molecules and compounds in the atmosphere we’re able to get a much better sense of what exists on the surface of the planet.

One scoop of soil may not have any life in it. One scoop or I guess one breath’s worth of oxygen from the planet Earth proves to us that there’s life on the planet Earth.

We’re at the stage where we can start looking for different molecules, different gases in the atmospheres of alien worlds. We’re working to build higher resolution spectrographs.

We’re working to build spectrographs that are capable of better distinguishing the light of a parent star from the light of its planets to better block out the light of that parent star so we can see the planets in isolation.

All of these different things will allow us to get a better sense of what are these alien worlds and do any of them contain life in either a methanogen form or in something that deals with oxygen or in an intelligent polluting form.

Fraser: We will soon have the technology. There will soon be the equipment to – soon being within the next decade – to image the atmospheres of planets going around other stars and to be able to analyze the constituents of Earth-sized worlds going around other stars.

Pamela: We just need to find them.

Fraser: Right we need to find the worlds, analyze their atmospheres and then we say if we see a world like Venus we’re like oh, runaway greenhouse effect.

If we see a world like Mars we could say, oh lost its atmosphere, very thin carbon dioxide atmosphere.

Maybe if we see a world like Earth and we see large amounts of oxygen, then that would have to come from some form of life keeping the oxygen in the atmosphere.

I guess all this additional work to come up with these other chemical process could then either then look at an atmosphere and say oh, that’s one that’s using silicon and putting out different kinds of constituents.

As you said, also pollution so you could look at a world, see high amounts of hydrocarbons in the atmosphere or certain amounts of ozone or even other very specific compounds that are produced by pollution and say oh, that’s a world that’s starting to use plastics. [Laughter]

Pamela: It’s all basic chemistry. We know that things like methane fall apart in the sunlight. We know that things like oxygen like to bond with things like carbon.

By knowing the basic this does not exist in free-form except for limited periods of time. By knowing the rules of how long things can last before they get bonded or destroyed we’re able to say we have this amount of certainty that we’ve now found life.

We haven’t found it yet.

Fraser: There’s something pretty close with Mars now, right with the discovery of methane in the atmosphere?

Pamela: Yeah, but there the issue is methane can only exist for a small amount of time before the sunlight destroys it. Methane can come from two different sources.

It can either come from a planet out gassing because it was hot chemical reactions took place deep in the soil, deep inside the planet. As the planet outgases it releases methane.

You could end up with methanogens down in the soil that is also releasing methane. Methanogens are the same type of critters that exist in the guts of humans and cows and cause them to make rooms stinky occasionally.

If it is methanogen, that’s kind of cool but it could have a geophysical cause so we can’t say anything with certainty as long as the world is active.

Fraser: At the same time both answers – in the case of Mars anyway – are interesting. Scientists aren’t sure what the geological state of Mars is either.

If you can trace it back and say you know it’s still volcanically active that’s kind of interesting.

Pamela: Yeah, Mars is a very interesting curiosity and there are lots of people chomping at the bit to go dig in its soil and explore it firsthand.

Fraser: Yeah, I can’t wait until the next rover. I’m having trouble calling it Curiosity I have to say. [Laughter]

Pamela: Well we got used to Spirit and Opportunity.

Fraser: I know so I guess we will get used to calling it Opportunity – I’m sorry calling it Curiosity. It doesn’t roll off the tongue for me yet.

Pamela: No, it’s a laboratory.

Fraser: Alright thanks a lot Pamela.

This transcript is not an exact match to the audio file. It has been edited for clarity. Transcription and editing by Cindy Leonard.

Shownotes

Links:

• SETI’s Website
• SETI’s History – Planetary Society
• Drake Equation
• Project Ozma – Internet Encyclopedia of Science
• Allen Telescope Array
• SETI’s Virtual Visit to the Allen Telescope Array
• John McCain and “Overhead projectors” — Universe Today
• Wow Signal – Cosmic Log
• NASA’s Near Earth Object Program
• Point to Point Communication – Wiki
• SETI Optical Telescope/ Harvard University – Planetary Society
• Voyager I & II
• Voyager Record
• How to Find Extrasolar Planets — ESA
• Do Advanced Civilizations Communicate With Neutrinos? — Universe Today
• SETI@Home
• Seth Shostak of SETI answers Universe Today readers questions
• Could it be dangerous to send messages to other worlds? — Seed Magazine
• METI: Messages to Extra Terrestrial Intelligence
• Messages to Earth Sent to Alien World – Universe Today
• WETI:  Waiting for Extra Terrestrial Intelligence
• Join the “Effortless Action Committee” and get your personal certificate of participation
• Terrestrial Planet Finder
• SIM Planet Quest mission
• Hubble Measures the atmosphere of an extra solar planet

Video:

• Carl Sagan:  Our Place in the Universe
• Jill Tartar, Director of SETI:  SETI and Our Place in the Universe
• Fraser wants to give visiting aliens a beer.  What kind would they like?

Books:

• Cosmic Company:  The Search for Life in the Universe by Seth Shostak and Alex Barnett
• Sharing the Universe by Seth Shostak
• Beyond Contact:  A Guide to SETI and Communicating With Alien Civilizations by Brian McConnell

Transcript: The Search For Extraterrestrial Intelligence

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Fraser Cain: You know what this show needs?

Dr. Pamela Gay: I don’t know. What does it need?

Fraser: More Aliens. [Sigh] Since we don’t seem to have any visiting right now, we’re going to have to find some. SETI is an acronym that stands for the Search for Extraterrestrial Intelligence.

But there’s more to SETI than just putting up a radio telescope and hoping to catch a glimpse of an Alien television broadcast. Pamela, with SETI – I’m sure people have heard quite a lot about this – people who have seen UFOs and think that they’re being abducted all the time, but there is legitimate Science being done to search for Aliens.

And that is SETI. So, what is sort of the history of the search for Aliens?

Pamela: Well it basically occurred to people that we’re sending out radio signals all the time. As we generate television, as we generate radio the signals are traveling out into Space and getting carried off to nearby Stars.

It’s possible that there are other societies out there, other civilizations out there and they might also be working in radio. They might also be perhaps even shooting laser beams our direction; pulses of radio light in our direction.

And maybe just maybe we can find those other civilizations by just going out and looking at the nearby Stars that just might be capable of having Planets that support life.

Fraser: Right so here on Earth we’ve been broadcasting in radio signals for the last 50 or 60 years and those signals are moving away from the Earth at the speed of light.

So, there is a sphere 60 light years on a side – where the radius is 60 light years – that if you’re inside that ball, that sphere, then you would be able to detect signals coming from Earth.

If you’re outside of that then our signals just haven’t reached that point yet.

Pamela: What’s scary is I think we’re both feeling our age because it was in the 1930s it was basically more than 70 years ago that the first television signals went out. So, we’ve been sending things out for a long time and those signals could be now hitting a lot of Stars.

Fraser: Right, that sphere holds probably hundreds if not thousands of Stars.

Pamela: And so some of these Stars do have Planets. We KNOW some of these Stars have Planets – we just don’t think they have habitable Planets yet because what we’re seeing is hot Jupiters.

Fraser: Then in vice-versa, there could be Alien civilizations that have been around for thousands or even millions of years who have been broadcasting like this and maybe are broadcasting through the entire Galaxy. It only takes like 60,000 light years to get from any point of the Galaxy outside. So you can imagine they have a big transmitter and they are able to reach every point of the Galaxy.

Pamela: In 1960, Cornel University Astronomer Frank Drake – the guy who brought us the wonderful Drake equation to try and figure out how many Alien citizens there just might be out there on Alien worlds – went out and made the first modern SETI experiment called Project Ozma after the queen of Oz from the Wizard of Oz series. He didn’t find anything.

What I find amusing is one of the Stars he looked at Epsilon Aridante actually has a Planet going around it. So even back then before we knew that there was a Planet there he was out there looking to see if there could be life in that system. He also looked at Calseti and it was a start. Since then we’ve looked at thousands of Stars.

What makes SETI a reasonable expenditure of money is as you’re out there looking at all of these nearby Stars, you’re gathering data on how these Stars are behaving in radio light. This is data that can be used for scientific explorations as well.

It’s not completely a waste of telescope time. It is telescope time that is spent going “okay, radio quiet, okay, still radio quiet.” But we’re learning the characteristics of all of these different Stars in radio light.

Fraser: What exactly is a SETI researcher looking for?

Pamela: In general what you’re looking for is a burst of intensity that you’re scanning across the Sky listening to Bland radio Star, Bland radio Star and then all of a sudden you see a signal that’s either higher intensity or has a pattern to the signal that’s coming off of it that’s not just noise.

Television signals, radio signals, all of these have modulations in the signal that your radio and television are able to turn into voices, music and pictures. As you’re listening to these Stars, what you’re looking for is changes in the modulation of the radio that are not nonsense, not white noise but have statistical significance. You can then go “aha, this just might have meaning” and try and come out of it, tweeze out of it with some sort of a coherent signal. The question is as we start thinking about perhaps we can start sending signals out and help our own Planet be discovered, what sort of signals might we be looking for? Anyone who has paid attention to how they encode the new Hi-Definition Television Signals knows that there’s been all sorts of arguments over how do you encode it; how do you phase the data.

Anyone who has done graphics knows that there’s multiple ways to compress an image. Once we find something that looks coherent, it’s going to be a matter of reverse-engineering the format of essentially this intergalactic file that has been sent towards us.

Fraser: Right, okay if you point your radio telescope at a Star today – even the Sun – you’re just going to get a sort of a cracking popping random fluctuation that should stay within a very normal parameter, right?

Pamela: Tune your radio or television to a channel that doesn’t exist. What you experience is what we get when we look at something that is giving off white noise.

Fraser: And so, if there was some kind of intelligent signal happening then it might still sorta seem like white noise but there will be a pattern to the noise that will say “okay, there’s no possible way that nature generated this pattern.”

Pamela: Right, we’ll get something that we may not understand but we know this isn’t completely random. You can imagine someone rolling 8 different weighted dice.

You’re going to notice that “wow, these don’t behave quite right” but if you’re mixing up which dice is which one each roll, it’s going to take you awhile to sort out how the 8 different dice are weighted.

Fraser: Okay, so what does the modern search for extraterrestrial intelligence look like?

Pamela: SETI has been forced to struggle. It used to be that they were funded in part by NASA. Now they’re completely funded through private donations. Since 1994 NASA hasn’t spent any money on the search for extraterrestrial intelligence. They’ve only spent money on astrobiology which is basically the search for extraterrestrial microbes.

What the SETI Institute out in California has done is they work to raise money to build the Allen array a radio telescope system that is going to be dedicated strictly to the search for extraterrestrial intelligence. There has also been other one off projects.

For instance Harvard has a project that is piggy-backing on the back of one of their optical telescopes and as the telescope goes about doing its normal research this instrument that’s mounted on top is looking for pulses of laser light that might be coming from other Stars.

Fraser: That strikes me as crazy that there’s no Science funding for this search. I mean it’s kind of like THE most important question you could possibly ask scientifically.

Why is that? Why is there not official backing and the poor folks at the SETI Institute have had to go and do pledge drives and raise money from private individuals.

Pamela: It’s politics. Far too many things come down to that very simple sentence. It’s politics. There are crazy people out there – many of us know some of them – who believe they’ve been abducted by Aliens, they believe they’ve been probed. They believe things that we have no scientific way of testing to say “yes you are right” there’s no evidence to say “yes you are right”.

These people have given the entire Search for Extraterrestrial Intelligence Program a really bad rap. So when Congress is out there and Senators and Representatives are trying to get on their high horse and say that we’re spending money appropriately, they will often go through NASA, the National Science Foundation, and the National Institutes for Health expenditures and start pulling out things that have names they can make fun of.

For instance, when I was at McDonald Observatory, we had a project called HEMP which stood for the Hobby-Eberly Telescopes Echo Mapping Project. It was a project to map the cores of Galaxies with actively feeding Black Holes. They saw the name HEMP and the project almost got cancelled.

Fraser: Hmm… Poor naming choice.

Pamela: Yeah. So, SETI – Search for Extraterrestrials, little ETs – that’s easy to make fun of sort of the way McCain has been making fun of the Adler Overhead Projector. The name and what’s being funded – well what’s being funded is significant. You can name something silly and make fun of it.

Fraser: Okay so before I interrupted you, we were talking about the Allen Array. How does the Allen Array work?

Pamela: The Allen Array is still in the process of getting built. It was formerly called the One Hectare Telescope. It’s paid for by Paul Allen which is where the name comes from. It’s in northern California.

This system is going to have 350 radio dishes on it that work together. It’s made as much as possible with off the shelf technologies to keep the price low. You can sort of imagine they went out and bought 350 satellite dishes that you might use to get old style pre-dish network, back yard satellite signals for your television. They have all of these commercially available dishes.

They’ve strung them together in their own miniaturized – but with more scopes – version of the very large array. This allows them to collect a lot of signals. It also means that they’re going to be able to have higher resolution. It means that they’re going to be able to if they want to, tune their dishes to a lot of different frequencies and it also means that they have a lot of redundancy.

There was one signal caught once called the Wild Signal. It was caught with one telescope and only one of the two detectors on that one telescope was able to catch it at moment. We don’t know if that one signal was real; if it was a fake or if it was something from the Earth or Space.

With the Allen telescope they will be able to say “yes, this signal was caught by this many telescopes; it was caught this different set of frequencies with all sorts of different types of coverage” and it will allow a better sense of what is real and what isn’t.

Fraser: If Astronomers have been searching for signals from Extraterrestrials for 30 years, why haven’t they found anything yet? I mean I think maybe that is where the funding is getting cut.

You’ve been at it for 30 years, how hard is it [Laughter] just to point a radio telescope up at the Sky and point it at all the different nearby Stars and call it a day.

Pamela: So here where I live in rural Southern Illinois, we don’t have a channel 2. So if I have a television that I bought in Boston where we did have a channel 2, and I came out here and every knob except for channel 2 on my television was broken, I would conclude that there is no intelligence producing television in Southern Illinois.

And I’d be wrong. The problem is I’ve only done my experiment on one narrow channel. As we search the Sky for signals, for all we know they could be using any one of hundreds and hundreds of different radio frequencies. So we have to look at all of these different frequencies.

Not only that, but the Sky is a really big place. We have to search all these different Stars and all these different frequencies. We haven’t been doing it continuously for 50 years. The first attempt to detect something was made in 1960. We’ve been hit or miss doing it now and then with this scope and that scope as time is made available.

There hasn’t been a search of the entire Sky in even one frequency. There are all these different frequencies that we can try looking in. There’s a lot of Space and we’ve only probed a small part of it.

Fraser: Right so there’s the problem, right? There are hundreds of millions of Stars in the Milky Way and you would have to watch each Star on every single frequency – because you don’t know what frequency the Aliens would be broadcasting on.

Pamela: And you’d have to do it more than just once. You can imagine someone looks in the direction of the Planet Earth and the moment in time that they capture corresponds to the moment in time that we were behind the Sun.

So you have to go back more than once to really rule out a Solar System and look for more than a brief instance. All these pieces together means this is a project that’s going to take a long time for us to do.

It’s something that has to be done in both the northern and southern hemisphere. The Allen telescopes can at least get us the northern hemisphere. But that’s still only half the Sky.

Fraser: If I remember and I was trying to dig this up before the show and I was unable to find it but Seth Shostak who works at the SETI Institute said that it would take something like the Allen Array or even something bigger working for a few dozen years to do a comprehensive search in the radio spectrum for all the Stars that are appropriate within a certain range of us to really say okay we’ve searched the radio spectrum and we haven’t found any signals. We’ve really right now just scratched the surface.

It’s almost like decoding the human DNA on one person and now you’ve got to do everybody else. Or like finding Asteroids, NASA feels pretty confident that they have located most of the Planet-killing Asteroids and plotted their locations.

But there are still millions of potentially dangerous Asteroids out there that they haven’t even found yet. It’s just scratched the surface of this project.

Pamela: The thing that you always have to wonder about is once you’ve done all of this work in the radio, well what if you’re dealing mostly with societies that never developed radio. What if you’re dealing with societies that went straight to encoding things in microwaves and doing point-to-point communications?

Fraser: So are there any plans to search for that kind of thing?

Pamela: Not that I know of but that doesn’t mean they don’t exist The problem with point-to-point communications is it doesn’t exactly leak through the Atmosphere so here you have to start hoping that we’re having signals beamed toward us.

Fraser: Right I think with SETI the expectation is that we’re not eavesdropping on a civilization that’s just broadcasting television shows. There is a very advanced civilization that has a lot of energy at its disposal and is pumping a lot of that energy into broadcasting a signal out so that it can be heard on another Star. Right?

Pamela: This is one of the things that I actually find really remarkable. If you use the right color of laser and you focus it using basically a 10 meter telescope – something like the very large telescopes that they have down in Chile – you can focus a laser beam such that a Planet orbiting another Star detects it will see for a brief moment that laser beam appear a thousand times brighter than the Sun.

So, it actually makes sense for us to not just – if we want two-way communications – to not just go out and listen but to also be beaming signals as we go. It’s kind of a waste of a 10 meter telescope to dedicate it strictly to shooting laser beams out to other worlds, but you can almost imagine a system that observes a Star, observes a Star, discovers a Doppler-shifting Planet and then says “ah, found you!” and beams it with a laser beam briefly.

Fraser: So are people searching for these beamed laser beams?

Pamela: There is a program at Harvard University – the one I mentioned earlier – that’s piggybacked on their Optical Telescope and it’s out there looking at thousands of Stars just paying attention while the telescope is off doing its own Science looking for these potential laser beams from other Worlds.

Fraser: So it’s exactly that, right? We’re hoping that some Alien species has found us, knows that there’s a civilization here and is occasionally zapping at us with a laser beam to see if we’re paying attention.

Pamela: And even though the Sky is a really big place to try and explore, we can actually increase the probabilities of success on these active projects by looking at how we discover Planets. The places in the Sky that people are most likely to realize “wait that Solar System over there has Planets.” And the places that are most likely to try and actively send us signals are on a very narrow band around the Sky.

The way we detect Planets is we look for Doppler-shifting of the Sun. With the Sun to be the Alien Sun in this case to be yanked around by its largest Planets causing it to have these wobbles in its motion that we detect a slight variations to the red and blue of individual spectral lines. We also look for Eclipses. We look for the hot Jupiters to pass in front of their parent Star and cause the light to dim in some cases just a hundredth of a magnitude. But we can see these slight changes and if we look at the parts of the Sky where Aliens on Alien Worlds would see Jupiter Eclipsing our Sun would see our Sun’s wobble at its most pronounced due to all of the Planets pulling on it.

Those are the places that are most likely to know about us if they’re finding Planets the same way we are. We can focus our energy quite literally on shooting laser beams and shooting radio signals at those potential Worlds and increase our odds of having this actually work.

Fraser: The assumption would be that those Worlds would be doing the same. It’s almost like if we can find Earth-sized Planets around other Stars, then we start zapping at them and we can almost assume that they’re going to be zapping at us. We would do a much better search of those Worlds than some random Red Star. We talked about radio mostly. We’ve talked a little bit about optical. Are there any other ways that maybe civilizations are attempting to communicate?

Pamela: Well, one way – and we’ve actually done this a bit ourselves – that you can try and communicate to other species is you just send them your junk. Not literally, but if you think about it by the time Voyager One and Voyager Two which both contain information about the Planet Earth on them, by the time they reach other Solar Systems they’re going to be a bit beat up.

They’re going to no longer really be functioning and just sort of traveling through Space as very technologically advanced pieces of scrap metal. But it didn’t take a lot of energy to put those systems together. As they explored our Solar Systems they did a lot of really great Science. They served a purpose.

Now they’re just on their way outside of the Solar System. Someday they might get scooped up by an Alien race and they’re carrying a lot of information with them encoded on records and engraved on their surfaces.

Fraser: I’ve heard that it will take whatever, 77,000 years for the Voyager Spacecraft to reach the nearest Star. If you’re an Alien civilization that’s maybe been around for millions of years, what’s a few tens of thousands of years to do some communicating.

You can imagine a civilization just going with the absolute lowest amount of energy possible and just hurling very clever little robots in all directions. One per Star and the robot lands and then just starts communicating.

Pamela: You have to wonder is this a really good way to use resources right now but once we start being able to easily mine the Asteroid Belt, it starts to become much more feasible to think about sending little chunks of rock out in all directions carrying some sort of message.

This is where we have to start thinking carefully about what sort of signal do we want to send. How do you communicate with someone that isn’t going to have the same basis of language? How do you communicate numbers? There are a lot of very intelligent people from many different fields who’ve gotten together at different points in time to figure out how to encode things.

What I love most is one of the things that was sent on the record on one of the Voyager missions – I don’t remember which – was the sound of a beating human heart. These are just fascinating things that we’ve decided are representative of our World that we wish to communicate.

The way that we always come down to settling on how we are going to communicate is with mathematics. So hopefully, some things truly are universal.

Fraser: Right but I think that if we found an object, we would know right of way that it was made from an Extraterrestrial Intelligence. You wouldn’t necessarily need to communicate but if it was made of something or had properties that we had never seen before.

Even something sent from our future, like if you sent something made out of Carbon Nanotubes or even things that we’ve only developed in the last ten or twenty years, it would be very indicative to people here that someone else made this. We don’t have this technology yet.

We talked about Matter being sent, there’s one article that we did on Universe Today a little while ago about civilizations using Neutrinos to communicate.

Pamela: This is where you have to start getting the civilizations far more advanced than our own. We’re just figuring out how to detect Neutrinos effectively. The idea of communicating effectively with them is still beyond us.

We know that you can get bursts of Neutrinos from extremely distant sources. Then it just becomes a matter of trying to figure out how to send these things that don’t weigh a lot so if you move it very close to the speed of light that don’t get absorbed really – these things don’t like to react via the electromagnetic spectrum – so you can basically shoot them through Planets and Stars.

How do you effectively communicate with them and code information in them? Especially with the way they change varieties at will it appears.

Fraser: Right but as we mentioned these are the nearly massless particles that are streaming out of the Sun right now.

We mentioned that Neutrinos would go through nearly a light year’s worth of solid lead before finally getting stopped. If you had a way to generate them – I mean don’t we generate Neutrinos in Nuclear Reactors here on Earth?

Pamela: Right, so we know how to generate them fairly easily. The problem that we have is figuring out how to detect them consistently. You can imagine that you can basically send out smoke signals with Neutrinos where you get bursts of Neutrinos coming through.

You’re able to detect those bursts of Neutrinos and get information out of the size of the burst. Or other ways perhaps that some advanced civilization will figure out how to encode information in these patterns of arriving really tiny particles.

Fraser: Now, I had two things that I want to talk about before we wrap this show up. One is talk just for a second about SETI at Home which is awesome. It’s been going for quite a few years now. If you have a computer with some idle CPU time you can install this screensaver called SETI at Home which lets your computer help crunch through all of those gigabytes of data that are drawn down by those telescopes.

And you can search for some kind of signal from an Extraterrestrial Intelligence which is just great, such a great use of your computer time and processor power so don’t e-mail us we know about SETI at home. [Laughter] We think it’s great.

Pamela: And it’s FREE!

Fraser: It’s free, yeah. But I think the last thing I wanted to talk about was: “Is it dangerous for us to be sending signals out into Space?”

Pamela: I think this is where we start getting into Philosophy and it comes down to the question: “Do you really want to find Aliens?” If the answer is yes, then are you worried that they might be dangerous?

I’m not so much worried about other Aliens coming and destroying the Planet Earth. I’m probably a little bit Pollyanna in that. But once we discover Aliens, I don’t know what that will do for our society. I don’t know what consequences that will have philosophically. There are religious implications.

There are so many different things where you can sort of think of the movie Independence Day where you had people on the tops of buildings offering themselves up to UFOs. You can think of the book “Contact” where you had people lining up at the fences of the VLA and yes these were fictions, but I think in this case you have very intelligent writers that imagined what this sort of a discovery would do in our society that has from everyone from the truly crazy to the truly brilliant.

Unfortunately it’s not an even distribution by numbers across that. I’m not sure we necessarily want to find Aliens right now. Then there is always the issue of if the Aliens just really want to come and take our resources and turn us into slaves.

Again, I’m not particularly worried about that being likely. Space is a big place. You cannot travel at the speed of light. We’re a long way from the nearest Star that could potentially have a habitable World. So, I’m not really worried about that.

Fraser: So, you’re not worried about Aliens coming and stealing our resources and turning us into slaves and so on. It’s sort of like it’s just way too expensive to make that trip. [Laughter]

Pamela: Yes. Exactly, it’s too expensive.

Fraser: It’s like buying a super tanker so that you can go across a lake to steal somebody’s lunch.

Pamela: It is in fact more like the Seinfeld episode where they discovered that there is a ten-cent deposit on aluminum cans in Massachusetts. So they rent a truck, fill it with aluminum cans and try and drive them all to Massachusetts to get their deposits back.

You’re going to spend too much money on gas. Just stay at home and take them to the recycling facility.

Fraser: Exactly, go mine another Asteroid. Grow another Space Cow. Okay, but then you are worried that you think that our fragile emotional state can’t handle the comprehension that there is another intelligent species out there.

Pamela: I admit to thinking there will be momentary mass chaos and far too many organizations forming cults. It’s just not something I’m excited to live through.

Fraser: But should people hide the knowledge?

Pamela: No. I’m for full disclosure if you find something. I’m for full scientific honesty and openness.

Fraser: So you’re just kind of bracing for impact.

Pamela: Yeah, yeah there’s part of me that thinks this is so cool and we definitely need to keep looking. But if we can hold off finding something until I don’t have to deal with the chaos, I’m okay with that.

Fraser: And I think there would be no chaos. Not only that, it would become mundane. [Laughter] It would be like BORING. Like do we have to hear about those Aliens again and their Alien TV shows? They’re not very good. [Laughter]

I think that within a very short period of time it would become a very mundane thing. There are so many amazing things that have already happened that we as human societies have incorporated into our psyches.

We just kinda like whatever, those cars they drive are really fast and people can fly in the air without wings, that any amazing thing becomes mundane very quickly. So I wouldn’t be worried about it at all. Bring on the Aliens.

Pamela: But for now, I’m going to maintain that I’m a very strong proponent of WETI and a proponent of SETI but not perhaps strong….

Fraser: Oh, WETI, that’s right. We’ve totally forgotten to talk about WETI. Let’s talk about WETI which is the [Laughter] last kind of search for Extraterrestrial Intelligence. So what is WETI?

Pamela: WETI is: Waiting for Extraterrestrial Intelligence. Just sort of hanging out, sitting on your sofa waiting to see if the Extraterrestrial Aliens show up. It’s the effortless action committee is the way they put it. [Laughter]

Fraser: So don’t build Spaceships, don’t build telescopes, don’t send signals, Matter or build Neutrino detection devices, just sit on your sofa and wait for some Alien to come in and sit down beside you and ask for a beer.

Pamela: Exactly this is my way of searching for Aliens every day of the week. I am totally a member of WETI and in fact, you can sign up to be a part of their effortless action committee on their website.

I’m for SETI – they’re getting really good science out of what they’re doing. If we do find Aliens, well okay, but it’s important knowledge. It means something to know if we are or aren’t alone in our Galaxy. We can’t answer that question if we don’t look.

Fraser: Yeah, I think that if I were in charge of priorities, I would make the search for Extraterrestrial Intelligence one of the highest possible priorities. Personally I would throw a lot of resources at both SETI and things like the Terrestrial Planet Finder which would be searching for Earth-like Planets orbiting other Stars.

That is the most fundamental important question in Science right now is: Are we alone? To find out, why not just listen and see if we can find them. If we don’t find them, that’s fine.

That tells us something, that life is rare and that our Earth and our civilization are rare and we have a duty to preserve life and peace and try to help explore the Universe. It’s like if you find out that the Universe is populated with tons of civilizations and they’re all busy then it takes a little of the pressure off of us to keep life going. [Laughter]

But if we can’t find a signal then I think that means a lot to us and shows that we have a lot of responsibility as a __35:26 race in the Universe to get out there and explore and do our job.

Pamela: While SETI is out there actively looking for Extraterrestrial Intelligence, NASA through many of its different programs and the Astronomy community through many of its different programs are looking for ways to look for plant life, microbial life and looking at the imprints of just organic life forms affecting the Atmosphere in which they live.

We’re trying to define new ways as we’re finding these new Planets orbiting other Stars to say yes, that World clearly has something affecting its Atmosphere. Yes there is life out there. I hope we really find that type of life in the next ten years.

Fraser: And we can so let’s just do it. So stop cutting the Terrestrial Planet Finder.

Pamela: Yeah, build it and Darwin.

Fraser: Yes, Darwin. Oh if I could run NASA. [Laughter] All right, thank you Pamela and we’ll talk to you next week.