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Alien Life
Posted:   04/13/09

Summary: At the most recent NASA Astrobiology Science Conference, a panel of scientists discussed different types of planets where we might find alien life. In the final segment of this series, the panelists express their hopes about discovering evidence for aliens in our galaxy.
Certain types of modern scientific technology, such as stem cell research or the creation of genetically modified organisms, are highly controversial.
Image Credit: NC State University

Q: Let’s say we have identified life on other planets and other solar systems, and we have to make the decision of whether to engage with that life. Do you think our fear of the unknown or our religion would prevent us from really engaging? Just look what has happened with stem cell research, or genetically modified organisms or GMO crops, or human cloning. Don’t you think our primitive fears would prevent us from going beyond what we are comfortable with?

Jill Tarter: I think you described a good characterization of where we are today. I don’t mean to be too crude or too rude, but at some point humans have to grow up if we want to have a future. We have to distinguish between what is, what we’d like to be, and what needs to happen. If we don’t do ourselves in over the next 30 or 40 years, we should reassess our fears and how we can deal with them and what would be the benefits of overcoming them. It’s a type of cultural evolution, I think, as well as technical evolution.

Seth Shostak: Jill, what do you think are the possibilities that we might learn from extraterrestrial contact how to better behave?

Jill Tarter: I honestly don’t think that our future is going to be dependent on extraterrestrial salvation. We are going to have to deal with our own problems. There may be some additional motivation to do so by virtue of having understood that it is possible to overcome the technological infant stage that we are in. But I think we probably have to do the heavy lifting ourselves.

Q: Is the best hope for the Allen Telescope Array to pick up unintentional leakage from a civilization about like ours? If that’s its best hope, is it powerful enough to do that?

Jill Tarter: It’s much easier for technology that we design and build to find someone else’s technology. It’s more likely to succeed if somebody out there has put some gain into transmitting something that can be easily detected. Our television and radio broadcast leakage can only be detected out to the distance of the very nearest star, based on the best detection technology we can put together today. Our most powerful transmitter, on the large telescope in Puerto Rico, is a radar that makes a very narrow beam. If you happen to be in that beam, it could be detected halfway to the center of the galaxy. So an engineered signal whose audience is at a distance is much easier to detect than a signal which has a local at home audience and is just leaking away, because you engineer something with enough power to do the job and not any more.

Artist rendering of the Allen Telescope Array.
Credit: Isaac Gary
Q: Such an engineered signal would have to be highly directional, and so it would be a pure stroke of luck that it was pointing in our direction.

Jill Tarter: Yes, that is a problem if it’s a beam transmission. But if the other technology has long had something as wonderful as TPF or the Life Finder, or by doing the experiments on other planetary atmospheres that we’re talking about doing, they may already know that there’s biology on Earth and it is one of the places to point their transmitter.

Q: I’m interested in some of the motivations of the panel members. We’ve been looking for life, and we’ve concluded that there is probably no intelligent life in our solar system, and it’s unlikely that there is intelligent life in the nearest solar system. Why keep looking?

Tori Hoehler: SETI is the search for extraterrestrial intelligence. I like to think of myself as a SETL person. I’m just looking for life; it doesn’t have to be smart. I think it would be an astounding thing to find some evidence of any sort of life elsewhere, not just intelligent life. That’s a question that we have not yet had the technology to answer well in our own solar system, but the technology is going to get there. For me the motivation is that this is an extremely profound question that has been asked since people started wondering where they came from. The difference is, now we have the potential to answer it. The search for life elsewhere, or determining how life can even originate, will help us be more informed about what types of life could exist out there. If we find something that’s very different from our own forms of life here, then we’ve expanded our knowledge or understanding of how life could occur.

Artist representation of what our Milky Way Galaxy may look like from above, and the position of our star, the sun, within the galaxy. How many of the other 100 billion stars in our galaxy could host planets with life?
Peter Ward: I think we ought to keep SETI going. Wealthy people are willing to put up the bucks, so why not do it? Searching for signals is the cheapest and most efficient way to search for alien life. But my take on the solar system is different. I think we do need humans on Mars for the simple fact that it would be difficult for a machine to find a fossil on Mars. You have a much better chance of finding interesting history of billion-year-old Mars if you send a paleontologist. He may find stuff you would never find robotically. Chris McKay once said that Mars could have had an oxygenated atmosphere after its first billion years or 500 million years, so we may have metazoan fossils there from 3.5 billion years ago. How could you not go look?

Jill Tarter: The question of looking for a long time and looking extensively, I think we are so biased by our short life times. We have poorly explored our solar system, our local cosmic neighborhood. I look at all of the scientific excitement now about dark energy, about which we knew nothing 15 years ago. Who knows how long it will take to crack that puzzle? I think asking about life in the universe, asking about intelligent life, asking what the laws of chemistry and physics have created in the universe are fundamental questions. It’s as appropriate a scientific exploration as investigating dark energy or anything else. We want to know what our place in the universe is. Are we one, or are we one among many? Is there a lot of life and only a unique intelligence? Or is it the other way around?

The "Pale Blue Dot" is the name given to this photo of the Earth taken from Voyager 1 on Feb. 14, 1990, at a distance of 4 billion miles.
Credit: NASA/JPL
Q: If we do find some life somewhere else in the universe, what do you think we will do about it?

Jill Tarter: I’m going to drink some champagne.

Peter Ward: I think we’ll chop down trees and print things about it.

T.C. Onstott: Victoria should answer this question. We’ve started getting all this great spectroscopic data back about different planets out there. So now, how do you communicate that data to the rest of civilization in a way that they get really excited about that?

Victoria Meadows: The process of finding life is going to be more complicated than most people think. We’ll get this spectrum from a planet and see that it has abundant oxygen on it. It probably is a Slime World, but we’re going to have to look at it very carefully to make sure we aren’t fooled. Certainly we will drink champagne when the first data comes back down, and then one of the first things we will do is contact Jill. We’ll say that we just found this planet where there might be a Slime World or some kind of biology on it, and now we need to see if there is extraterrestrial intelligence on it as well. So there will be a lot of initial jubilation, and then a lot of really hard work from the scientists to make sure they got it right.

Artist conception of a "super-Earth" orbiting a red dwarf star 9,000 light-years away. The 13-Earth-mass planet was detected in 2006.
Credit: David A. Aguilar (Harvard-Smithsonian Center for Astrophysics)
Tori Hoehler: I think that Victoria makes a good point, which is if we discover something like a Slime World, if we’re not getting I Love Lucy on hydrogen times pi, people’s perception of what we see will be different. They’ll hear scientists debating, and if it seems likely that the oxygen on the planet’s atmosphere could only have come from life and there’s not enough of it to be accounted for by another thing, it will seem like a bit of a soft hit, I think, and not a hard hit. But for me personally, it would be a huge deal. I think it would be fantastic if we found life somewhere else.

Seth Shostak: I should mention that 11-1/2 years ago, scientists thought they had found dead martian microbes in a meteorite. It was an enormously big story. Finally, I want to thank our panelists for excellent presentations and responding to a highly heterogeneous set of questions.

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