Do you think it likely that the first discovery of extraterrestrial life will be made by a rover?

MT: I’m not properly qualified to answer this question but I will anyways: Yes. There at least I kept my uninformed opinion short.

Now to our commentators:

Robert Zubrin:
No. it will be made by human explorers operating on the surface of Mars.

Dr. Robert Zubrin is an aerospace engineer, president of the Mars Society and author of The Case For Mars.

Peter Watts:
If by “rover” you mean one of those white-corpuscle thingies that Patrick McGoohan kept going down on in “The Prisoner”, I’d guess no; there’s only so much you can expect from a weather balloon. If you’re talking about an autonomous extraterrestrial vehicle of some kind, though, sure. But I do think we should widen our search image a bit. Keep looking at moons and planets, but also look at comets and molecular dust clouds. By all means scan for oxygen and methane in atmospheric spectra, but don’t limit yourself to familiar carbon-based signatures: program your probes to search for anomalous concentrations of any element that aren’t consistent with the usual entropic dispersal processes. Look for spikes against bell-shaped backgrounds. It’s easy to talk about how carbon is the be-all and end-all when our sample size equals one: but life, regardless of its chemical (or physical, or energetic) basis will be a phenomenon of pattern, regardless of the materials used to structure it. Pattern’s what we should be looking for. If you spend all your time looking out of your log cabin for telltale signs of wooden structures, you’ll miss anything built of steel or stone.

Peter Watts writes cool science fiction novels. Check out our recent interview with him.

Briam Pomeroy:
Although the sophistication and flexibility of the landers and rovers we send to other worlds is even increasing, we need a thorough understanding of a planet or moon before we can search for life there effectively. For instance, we began examining the Martian surface for life with the Viking lander and turned up nothing conclusive. But that was 30 years ago, and now that we know a lot more about Mars, scientists believe that organisms may live beneath the surface. Plus, we have much better technology. So a probe will have to be designed, built and launched with that specific purpose.

Perhaps the best chance for a lander/rover to discover life on another world is for it to bring back a substantial quantity of soil or surface liquid back to earth for examination. With such as sample directly available to them, scientists might spot evidence of life that would be hard for an unmanned probe to identify, such as fossil remains.

Brian Pomeroy, FutureWire

Lab Lemmming:
Rovers can’t find things that don’t exist. I don’t think there is any life out there for a rover to find. Here is why:

The simplest approximation of the probability of life on other planets is l/p, where l is the total number of environments in which life can develop and survive, and p is the total possible number of environments.

Throught its history, planetary science has consistently and regularly underestimating p. Every time we’ve characterized a new planet, we have found that it is stranger than our wildest prediction. Until Buzz, Neil, and Andrew brought back the first load of moon rocks, nobody imagined that the moon’s crust would be predominantly anorthosite (a rock consisting primarily of the mineral anorthite, CaAl2Si2O8). The volcanoes of Io, the smog of Titan, the craters of Mimas and Phobos, and the nitrogen geysers of Triton were way beyond the imagining of humanity’s collective creativity. Even the solar system’s two sets of twins, Earth and Venus, and Neptune and Uranus, ended up being vastly different to their partners upon closer study.

And that’s just our solar system. The discovery of extra-solar planets has shown that planetary sizes and configurations are far more diverse than anything we had previously imagined.

So, l/p. All the evidence is that p >> than our predictions. It may even be bigger than the largest value we can imagine. And if p is that much bigger, then l/p is that much smaller.

Take Mars. We’ve orbited it, mapped it to a resolution similar to google Earth, landed on it, driven around and probed, poked, and prodded. What have we learned?

It is cold, dry, oxidized, and the dirt has the spectral signature reminiscent of jarosite, a mineral found mainly in the slag of zinc smelters here on Earth. Even if you take the presence of it and hematite to indicate past water, it is a failure of the imagination to assume that because Mars was damp and oxidized early in its history, it must have been similar to Earth. After all, for the first 2 billion years of Earth history, that mineral assemblage would not have been stable on this planet, as sulphates do not appear in the sedimentary record until the Proterozoic. Even today, the Jarosite-hematite assemblage is not exactly common.

If the rest of planetary history is any guide, the occurrence of unusual minerals on the Martian surface is the _expression of processes and conditions totally alien to us, and not a signal that Mars was just like home. We simply don’t understand enough of the basic planetary evolution to be able to predict what the conditions were.

Expecting to find life on a planet we know so little about is like expecting a blind date to agree to bear your children before she gives you her name.

There are two things that make planetary science amazing. The first is the sheer bizarreness of the planets that we do know about. Every time we make a discovery, what we find is totally beyond our wildest expectations. The second is that, given enough of the right sort of data, physics and chemistry can actually explain much of this wild stuff that we see. To try to reduce the variability of the planets down to a simple question of life is both ignorant and hubristic. And attempts to answer that question without understanding the basic evolution of the planets we ask it on will almost certainly be as inconclusive as the first Viking experiments 30 years ago.

The Lab Lemming is the ghost in the machines of a geology and planetary science laborotory.

Dan Schrimpster:
Not really. I think the first piece of evidence may be found by a
rover. It may have already been found and is sitting on a hard drive
waiting for analysis. But the final conclusions will be made by
humans based on that evidence. Rovers are computers with wheels.
Computers are stupid. I know, I write software for a living.

Dan Schrimpsher, Space Pragmatism

Related

Author Mac Tonnies at Posthuman Blues responds with his thoughts on the subject

Paul Gilster posted this response over at Centauri Dreams

Biologist Dan Rhoads over at Migrations posted this response

This Brain Parade is just Charlie’s way of reopening our Manned vs Unmanned Brain Parade (I trounced him in the debate but he won’t admit it). If you haven’t seen it check it out it’s a gooder.

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