Life on Mars?

A press conference is currently being conducted by NASA scientists. Here's a story from Voice of America announcing the press conference. Strong evidence has been discovered that there was once enough water on Mars to support life.Do you think the rovers will eventually uncover even more compelling evidence that life may have once existed there? I do, but regardless this is a fascinating story. I think the mars rover program has been a huge success. I hope Americans will continue to support NASA.

Yaro writes:

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I remember watching a documentary were they sugested that at some point in mars's history, it lost it's atmospheric pressure. It was said that perhapse a near miss comet 'sucked' it away as it sped by.

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I probably missed that documentary, but I remember reading something about this years ago. If I remember correctly, some scientists speculated that Mars once might have had a reducing atmosphere, but that something unexplained had happened to destroy it.Question: isn't a reducing atmosphere rich in ammonia? At one time, earth had such an atmosphere, right?

NosyNed writes:

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The current sites were chosen (this is off the top of my head) for:

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low enough latitude to supply solar power

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safe enough terrain to give the lander a chance not to get mashed on rocks

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sites that suggested from orbit that there was a chance of finding evidence for water

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Nothing to disagree with here, but I would put your last criterion first. From what I've read and seen about this mission I think the technology which culminated in these landers was developed to deliver what scientists most needed and wanted. In other words, scientists chose where they wanted to go on Mars first, then the engineers designed the landers and, working with the scientists, chose the precise locations according to your first two (and probably many other) criteria.

MSNBC reports today that scientists now believe that the site currently being explored by the Opportunity rover was once the bottom of a salty sea. This is helpful in the search for a fossil record of any life that may once have existed there.In other words, scientists are now apparently certain that the site was not merely a groundwater spring but rather a full-blown sea like the ones we have here on earth.

Am I to understand that you believe life might once have been possible on one of the gas giants? Can you explain your idea in laymen's terms? I'm interested, but I'm not sure I'm understanding you correctly.

Does anyone know why it is that we can't send a spacecraft to Mars, scoop up a few of these rocks and bring them back to earth? Do scientists think that would be of less value than what these rovers are doing, or is there some technological hurdle that hasn't yet been surmounted? Would the cost of such a project be much higher than the rover project?I ask because it seems to me that, given the fact that we launched a manned craft from the surface of the moon 35 years ago, there should be some hope of successfully launching an unmanned craft from the martian surface by now. Of course I realize that there are dramatic differences in the moon and Mars, but since we can land a delicate instrument on Mars without damaging it why can't we build something that could launch itself back to earth?I remember reading something about this idea years ago, but I can't seem to find anything on it just now.

I have no idea if the source is credible, but if this is true we could be starting something we won't be able to stop. What do you folks make of it?

What you're talking about sounds fascinating, Brad, but I think you're grossly overestimating my knowledge of planetary science. Your brain is about a light-year or so ahead of mine. In order that I might fully understand you, I hope you'll answer a couple questions.1. Can you briefly (and in dumbed-down language) describe Cohen's work on Newton?2. What is the Kantian question you're referring to? Is it simply "why do we have 3-D space?" or is there more to it than that? I remember that Kant was an 18th century philosopher and that Kantian questions always seem to be existential, but I can't remember specifically what it is that makes a question Kantian.3. In what way do you think Einstein might have been wrong? If it is related to relativity, please make it extra simple as I don't fully understand that concept.

Seems that some NASA scientists think it's possible that life exists today on Mars, based on fluctuating levels of atmospheric methane. From space.com.

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