NASA's Mars rover finds key traces of water | Hacker News Reader

NASA's Mars rover finds key traces of water

zdnet.co.uk

26 pointsowlmusic8 comments

This is an incredible achievement.

The "key traces of water" is awe inspiring in itself. However, what is more impressive is that Opportunity is still chugging along 7 years longer than predicted and making these discoveries. Unfortunately, NASA is pretty bad at displaying successes and explaining why it is important.

The press release: http://marsrover.nasa.gov/newsroom/pressreleases/20111207a.h...

I used to kid people that Spirit and Opportunity's longevity were themselves a problem.

They were built in an era of faster, better, cheaper and at the beginning of that time, the theory was that it was better to have more spacecraft even if some failed than to build expensive too big to tail projects that consumed the entire budgets.

That Spirit and Opportunity went far beyond their 90 day requirements was a indication of overengineering, and wouldn't it have been better to have had 20, or 40 Spirits and Opportunities launched, even if 1/2 of them failed?

(Now their longevity could be, not because of gross over-engineering but because the minimum engineering required to bring them to 90 - 120 days naturally makes a 5-10 year lifespan easy....)

We seem to have since gone back to wanting huge, too big, we're too afraid to let them fail projects.

I haven't followed it closely, but I am saddened that apparently Curiosity is a one off, and not part of a dual, triple, twenty member fleet. It could also be that I am just unaware of NASA's planned follow on to Curiosity.

The problem with faster better cheaper is programs are cut until just before they become irrelevant. If you want to send 20 identical robots someone is going to come along and say, what's the harm if we only send 1/2 that. But they will do the same thing if you only want to send 10. Sending 2 is vary defensible because 'you want some redundancy' but funding is not appropriated based on bang for the buck.

PS: ITER is a great example of this. Initially the goal was to test a full scale power plant with turbines etc. But, they kept cutting until it was exactly on the threshold between useful and toy without generating any power whatsoever.

Can someone in the know please comment on the prospects for bacterial life on Mars?

I know nothing about biology or astronomy, but the case for life on Mars seems extremely good. I'm basing this on:

* Repeated offhand comments by Neil deGrasse Tyson (admittedly not a scientific source)

* Articles in popular newspapers about "Mars Farts" (I haven't read any scientific publications on the topic)

* Relatively recent (2009) reports about AL84001 (again, as understood by a layman)

What are the accepted scientific opinions about those last two items?

> astrology

Astronomy is the correct word here. Astrology is horoscopes and the like.

Whoops, fixed that. Thanks.

There is little likelihood of finding life on Mars or evidence that it existed in the past. If life was so easy to start that it arose independently on two planets in the same solar system, then we would expect it to start on literally billions of planets in the Milky Way. Since it would take much less than the age of the Milky Way to colonize it, we would expect the Milky Way to be colonized long ago (or for there to be some evidence that life arose elsewhere).

There are a million caveats here. For instance, it's possible that life is easy to start but intelligent life is absurdly difficult to form. But this seems much less likely, given the development of life on Earth. Smart money is on no life.

Here's a bit to get you started.

http://en.wikipedia.org/wiki/Great_Filter

I don't believe the 'prospects', a fairly imprecise term, have changed at all, however the probability that life has existed there has gone up substantially.

Many scientists see liquid water as a pre-requisite for life because chemical processes that we associate with life happen in the presence of it. So the question of liquid water on Mars informs the probability of life there, no liquid water, lower probability, liquid water, higher probability.

Much of the scientific community is on board with the idea that liquid water existed on Mars at 'some' time, and a few are in the 'recently' camp, and a small number are in the 'now' camp. It is subterranean, if it is there, because liquid water cannot exist under the current surface conditions.

The 'farts' was the detection of the presence of methane in Mars' atmosphere. That is significant because methane is not stable in Mars' atmosphere and so unless it is being created some how it should not exist. Its presence, especially waxing and waning, says there is a mechanism on Mars that creates methane and releases it into the atmosphere.

Now on Earth there are many biological processes which create methane and a few geological ones. The presence improves the probability that it may be caused by some form of bacteria but its creation is not required to be from biologic means.

Much of the 'fossil' bacteria hoopla in the Mars meteorite was objected to on first principals (life has to exist there, prove that first). In light of its re-examination it is slightly more probable that it represents fossilized bacteria.

So the argument in favor of their being life on (or under the surface of) Mars has picked up some facts to help out its case. It will remain a probability until such time as someone (or something) directly observes it. And of course someone else repeats that observation.

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