Astronomer Interview: Seth Shostak

Interview with SETI's Senior Astronomer Seth Shostak

We opened the floor for the community to ask questions of Seth about astronomy and the SETI pursuit. Here are his responses to your questions.


10heattj: What exactly does SETI look for?

The Search for Extraterrestrial Intelligence (SETI) is just that: a scientific hunt for proof that thinking beings exist elsewhere in the cosmos.

Most SETI experiments are efforts to pick up signals from advanced civilizations - radio, or flashes of light. It's also conceivable that we might find evidence for aliens by tripping across some mammoth engineering projects - structures that a highly sophisticated society might build and that might be visible in our telescopes.

LuckyPierre: Besides listening or watching for E.T.'s signal, what else does the SETI Institute do?

The Institute has a broad research program in a subject called "astrobiology". This sounds as if it's about life around other stars, which of course is treu. But a lot of astrobiology research concerns life on Earth: how did it get started, and when?

Other research areas include learning where could life survive, and how might we find hidden biology on Mars or some of the moons of the outer solar system. So the SETI Institute is about more than just looking for communicating aliens -- it's also about extraterrestrial critters that might not be clever, but whose existence would tell us a lot about whether life is extremely rare or very common. The Institute also has extensive programs for education and outreach, including a weekly science radio program, "Are We Alone?"

Falthron: Could you elaborate on the Wow signal?

The celebrated Wow Signal was picked up in 1977 with the Ohio State Radio Observatory's large antenna. Ohio State's "Big Ear" was being used in an automatic mode to search for signals, and one morning, when astronomer Jerry Ehman arrived at the scope to look over the printer output, he saw a big spike of radio noise. He wrote "Wow" next to it, hence the signal's famous name.

But it wasn't seen again, even though the telescope was set up to look at the same piece of sky only about a minute later. The signal's not been seen since, either. Most likely it was just some earthly radio interference, although it's possible it was ET sending us a very short ping. If we don't find it again, we'll never know.

s7ryk3r: I am curious what your thoughts are on the radio signal found emanating from Saturn as the Cassini probe passed by in 2004?

Indeed, Saturn makes a lot of radio noise. But so does Jupiter, Earth and the Sun. Frankly, it's likely that any rotating body with a magnetic field will do this. In the case of Saturn, if you shift the frequencies of the radio noise, and then speed up the recording a bit, it sounds like some sort of zombie trying to order a burger at a fast-food drive-through. But this would be true of just about ANY radio static. Our ears and brain are designed to hear voices, in the same way our eyes and brain can see faces in clouds. It doesn't mean that Saturn is talking to us, and I doubt that it is!

Zombieontherise: What if SETI makes successful contact? What would be their first priority?

The first thing to do after first detecting a signal is to check it eight ways from Sunday. Are we sure it's ET on the line, and not just more human-made interference? If we convinced ourselves it was real, we'd let the world know - and in particular, the world's astronomers. We'd want them to collect all the data they could.

Toastas: Is it possible that life could adapt to an environment like the moon?

The moon is about as sterile as most college-dorm political discussions. The real difficulty for lunar life, aside from the wild swings in temperature and lack of any real atmosphere, is that there's no liquid water - either on the surface or, as far as we know, beneath it. It's tough to do chemistry (which is what life is, after all) without some liquid to speed things along.

jakec88: In 2008 we discovered frozen water on Mars. Do you think some life exists on Mars?

It's possible, but it's not yet proven. There are tantalizing hints that lying a few hundred feet under Mars' unappealing surface are aquifers of liquid water. There might be some microbes down there, enjoying life in the rock without either sunlight or much fun. The discovery of methane on Mars might be another indicator of hidden life.

Aweirdgamer: What planet, outside of our own solar system, is the best candidate for life as we know it?

There are none that are wonderfully good candidates, but the best bet so far is a planet with the nifty name, Gliese 581c. This planet is roughly twice the diameter of the Earth, and is orbiting a star about 20 light-years away in the direction of the constellation Libra. Does it have oceans and an atmosphere? We still don't know.

Didzo: Are there any plans to send a probe to Europa to search for life in the near future, or will SETI's efforts remain focused on the search for ET radio waves?

The SETI Institute has scientists (one is Cynthia Phillips) who are hoping that sometime within the next two decades, a robotic spacecraft will be sent to this icy moon. The idea is to drill a hole through the ice (maybe 10 miles thick) and drop a submarine-like probe through it to look for life swimming in Europa's velvet-dark seas. If it's there, it's probably microscopic, and nowhere near the size of a tuna.

Dananddna: I have often wondered what sort of biochemistry might develop on an alien planet. What sort of alternatives might there be to biomolecules like proteins or nucleic acids?

It would be life as we don't know it! But, rather obviously, that means we can't say too much about it. Nonetheless, there are possibilities for life to be silicon-based (on hot worlds, this might work better), or to develop in liquids other than water. There might be some sort of weird life floating in the methane-ethane lakes of Saturn's moon, Titan. Would they have DNA or some other biological blueprint? If you have the answer, you can expect to hear from the Nobel Prize committee...

Soliton: What if significantly advanced civilizations, (or even civilizations on a par with our own) don't communicate via radio and/or use a method of communication that we have yet to discover - and further assume that any other civilization uses their method of communication?

This could be happening, and of course, we don't know what to do about it. After all, if E.T. is communicating with weird fudnick waves, we won't hear him. But of course, you can always make this argument, and just sit on your hands and not undertake a search. But that's silly. If you don't look, you really have no chance of finding anything.

Crocoofdoom: Do you think E.T.s are angry about how we portray them in movies, videogames etc...?

I don't think they watch our movies or play our video games! This isn't because they can't afford either the popcorn or an X-Box. Our TV broadcasts have only reached 50 or 60 light-years into space so far, and it's not very likely that there are any extraterrestrials that close.

Michaelknapp: What is your personal theory about what's outside our universe?

Keep in mind that the Big Bang didn't happen in a pre-existing, huge empty room. The Bang that began our cosmos created the space you enjoy today. So it's easiest to say that your question doesn't really make sense, because there is no "outside" to the universe. On the other hand, it may be that our universe is just one of zillions of parallel universes, all sitting in a kind of "super-space" made of material quite unlike the stuff that makes up our own cosmos. Physicists are speculating about this possibility.

OspreyGBR: It's an often cited belief that the first interstellar transmissions that could prove the existence of life beyond Earth would be a sequence of prime numbers. Is there any likelihood that if interstellar communication could be established with other life forms, that we could ever get beyond sequences of frequencies or numbers and establish a method of linguistic communication without the immersion that is required to bridge language barriers on Earth? Is the idea of a 'universal translator' far-fetched?

A universal translator - if not "far-fetched" - is at least far in the future! The aliens wouldn't have to send us prime numbers or the value of pi to prove that they're really on the air: the nature and direction of the signal would be good enough for that. As for communication, well they could send us the equivalent of their internet web - all those pictures and texts, no matter whether they were in Klingon or some other language - would be a pretty good way to start communication.

Meadowhawk: I'm curious as to how within your SETI program you determine the validity of an "intelligent" signal? What criteria do you follow to separate potentially intelligent signals from the mish-mash of background noise?

It all boils down to something simple: a real signal from E.T. would come from a place on the sky that moves the way the stars do. Transmitters on Earth are bolted to the ground (so they don't move) or are in airplanes, satellites, trains or cars - none of which move with the stars.

steak89: On a different note, how close would you say Spore's space stage is compared to the current REAL galactic situation? Steve and Grox aside, can we envision the world outside ours as (more or less) how Spore depicts it?

Hey! I'm still in the Darwinian "warm little pond"! But colonizing the Galaxy might be more than a little difficult for biologic intelligence - lifetimes are short, and the distances are long. It may be our artificial-intelligence successors that can really travel to the far reaches of the Milky Way.

Rectangle: What will happen on the 21st of December, 2012? I heard there is going to be a change of the north and south poles positioning.

I think what will happen is that a lot of people are going to be disappointed that ... nothing much happened! The Mayan calendar flips over, but our calendar does the same thing on December 31 of every year, and about the only drama is a lot of people having too much to drink at late-night parties. Earth's poles do occasionally wander, but the moon keeps this from being overly traumatic. It doesn't happen overnight, and the pole doesn't go too far. I wouldn't hesitate to make dinner plans for December 22.

WintersKnight: I recently heard a lot about M-Theory: the super-string theory-the theory of everything. Correct me if I'm wrong, but the theory suggests that there are an infinite number of parallel universes and these coexist and collide with one another; that it is very small and infinite at the same time. How is this emerging theory changing the world of modern astronomy?

So far, such speculations about M-theory are ... just that: speculations based on some complex mathematics and good ideas. The trouble with string theory (and superstring theory, too) is that until now no one has been able to prove that any of it is true. It's a difficult task because to see most of the predicted effects requires instruments that are far beyond what we can build today. So maybe string theorists are like Democritis, talking about atoms two thousand years before anyone could prove that atoms exist! These theories haven't yet very much influenced astronomy. Wait a while.

Candymanld: Warp field theory. Are we any closer to making it happen? Do you think we ever will? Do you know if any one is working on it now?

Warp field theory? I think you may be referring to the underlying principle behind warp drive, famously used in Star Trek for touring the Galaxy at faster-than-light speed. Physicists have proposed schemes that mimic this capability, involving bending space with exotic matter or black holes to create "shortcuts" for hi-tech rockets. It's still a bit unclear whether you can make this work theoretically or not. But even if warp drive works on blackboards, the difficulties with making it a reality - actually building a warp-capable rocket - are either incredibly daunting or impossible, depending on which physicist you talk to!