Scientists find evidence of salt water flowing on Mars
blog.chron.com
blog.chron.com
It's the atmosphere that makes this a bit surprising. Martian atmospheric pressure is less than 1% that of earth in the deepest valleys, and about .006 atm on average. If you look at a phase diagram for water [0], you can see that at .006 atm and below, water goes directly from solid to gas ("sublimation"). Even slightly above that pressure, there's only a tiny temperature range in which liquid water will exist.
I would guess that's why they've theorized very salty water. Its lower freezing point is going to allow for liquid water in a bigger temperature range at typical Martian atmospheric pressures.
[0] http://www.cims.nyu.edu/~gladish/teaching/eao/week2.html - top of the page
Edit to add, the Martian southern hemisphere seasons are more extreme because the effects of its significant eccentricity and its axial tilt are additive there, while they counteract each other to moderate the seasons in the north.
I love this comment:
The Bible didn’t say anything about god creating life on Mars.
Works for me.
Comes to mind all too often when browsing comments on the net.
On each planet is something ice on one, sand, lava, on another, etc., This is where we get our weather from in some ways. Our Earth is in the solar system of these other planets revolving around them.
I'm just not sure that's how it works...
Personally, my gut instinct is that the chances of life having existed on Mars at some point are quite high, above 90%. But the evidence for such may be very hard to come by. What if all life on Mars had never advanced beyond a unicellular level? What if most/all life died out one or two billion years ago? How challenging will it be to find evidence of that life? Especially when we only have a few robotic explorers to work with?
These mats tend to build up in layers, and often form structures known as stromatolites. You can find some examples both at the NASA team's site (http://nai.arc.nasa.gov/students/this_month/page2.cfm) and here: http://www.evolutionaryresearch.org/stromatolites.htm
There used to be a page up, claiming to show the remains of actual stromatolites on Mars, but it seems to be completely gone now (Spirit Finds Stromatolites, http://www.xenotechresearch.com/marsstro.htm). The Wayback Machine has it at http://web.archive.org/web/20081120022703/http://www.xenotec... but I'd probably rank its credibility with the Face On Mars.
EDIT: Just to make it clear, all actual stromatolites in these links are definitely of terrestrial origin! (At least, I think they are)
Finding any life outside our planet would be a huge discovery; even if it's billions of years away from growing legs, we could learn so much about life in its early stages, which could answer some big questions about our own evolution.
I say we land there with humans, spend a few decades checking the place out, then begin with the terraforming.
I guess it's a function of cheap transport to LEO. If we get that, other things will follow. Go Space X!
I do not think terraforming need be terribly expensive, incidentally. We already map a great number of asteroids and comets out of awareness that if a sufficiently large one were to hit the Earth its impact would be devastating. Our best understanding at present of how to deal with the possibility of such an impact is to give the item a slight nudge that will alter its trajectory during a non-terminal interaction with Earth's gravitational field. We have already matched speeds with and made very close observations of asteroids, and our observational abilities are constantly improving. So to begin the work of terraforming Mars, I would begin looking for asteroids with large quantities of ice (or ammonia or other appropriate compounds) that are likely to intersect closely with Mars' orbit, and give them an encouraging nudge.
It annoys me that since the two rovers we've sent so far have worked so well, our response is to spend years developing a New and Better Rover at great expense, rather than launching launching a large number of rovers that use the existing design which is already known to work, and which can be done without any additional research whatsoever.
When we've only got one example and it's us, our estimate of the probability of life evolving on a given planet (given suitable conditions) could literally be anything from 100% to any arbitrarily low number you might like to think of.
If we check two life-plausible planets and find separate life on both, the probability is suddenly way biased towards the high end of the scale. (A statistician can figure that one out for me.)
In some ways, modern life does leave us out of touch with the complexities of the world and nature.
Rice was a lot more labor intensive in that it required more time in the field per food-for-one-person than wheat. It also doesn't store as well nor have bumper crops. So, if you have a bad year, it's hard to have a buffer with which to get by. As a result, the vast majority of the population had to get over themselves, cooperate and comply with spending most of their lives taking care of the rice or else people would starve. Troublemakers who did not cooperate were putting everyone else in clear, near-term risk and were dealt with harshly.
ALL THESE WORLDS ARE YOURS EXCEPT EUROPA. ATTEMPT NO LANDING THERE.The hive mind disagrees with my sense of humour today. Or maybe it was the ALLCAPS. I would have quoted Tom Swift but since we were talking about why we might not go to Europa (and I don't recall what book it was where he went to the moons of Jupiter)... shrug oh well.
More like, congratulations, you can be conditioned like Pavlov's dog.
Europa is so much further and just to look for the fish would require equipment to penetrate the surface for the off chance there is water underneath.