Here is why we should hope they find no life on mars. http://www.nickbostrom.com/extraterrestrial.pdf (PDF) This is also an interesting discussion by Nick Bostrom on the Fermi paradox and why we may be alone in the galaxy.
Interesting read. One candidate I had heard for the Great Filter discussed in the paper is MMORPGs. A civilization advances to the point where they develop immersive games, then vanishes. I tried to track down the source of that idea. Anyone know?
One quote from that paper is interesting: "Considering that space travel was science fiction a mere half century ago..."
Space travel, in the terms the paper is talking about, is still arguably science fiction.
One thing I don't understand in all of these discussions about there having been life on Mars in the past: wouldn't it still be there today?
Even given that the planet's climate has changed entirely over time, as long as life had begun at some point and had a non-negligible amount of time to evolve it would have expanded into every available niche. There's life here on Earth in environments far less hospitable than those on Mars, isn't there?
Well, the article is about studying a meteorite for ancient fossils. If sufficient evidence is found, we will be pretty sure there was life, but it's not enough evidence that there still is life in a place like Mars, it does raise the possibility.
The thing about Earth is that there's water almost everywhere, which can provide a suitable protective environment, even if it's mostly frzen. Not the same with Mars. Also, Mars has just been so cold and dry for so long that it might be too long for life to last through.
Finding evidence of past life would be less expensive and still serve the purpose of showing that life is not unique to Earth. Trying to find those isolated ecological niches that may still hold life would be very challenging and expensive. Also, if we already know life existed on Mars before, the ideological breakthrough would have been made. Finding current life on Mars would still be interesting, but only scientifically, not in the social and ideological way that extraterrestrial life's existence at any time does.
> Also, if we already know life existed on Mars before, the ideological breakthrough would have been made. Finding current life on Mars would still be interesting, but only scientifically, not in the social and ideological way
I sort of agree, except that when it's "only" bacterium-level organisms, I think the social impact is still going to be minimal. If a Mars-trilobyte-equivalent fossil (or fish or velociraptor) was discovered, people/religions would freak out. But, I think the layman doesn't really consider bacteria to be life anyway (or maybe it's just that fossils of bacteria aren't too compelling).
On the other hand, I think it's freakin' awesome. I don't think the timing works, but wouldn't it be great if we turn out to be Martians? :)
