From the Nature Abstract[1]: Indirect evidence for water on Mars was found by detecting the presence of salts that absorb atmospheric water vapour, and suggest that transient brines form in the upper 15cm of the martian subsurface.
The crux of the problem with Mars is that its magnetic field is smaller than its atmosphere. All water gets blown away by the solar wind. Venus has a similar situation, and it's reacting somewhat similarly, having lightweight particles blown away by solar wind.
Indeed, the Earth is the only one of the 3 with a larger magnetic field than its atmosphere. We look like a small gas giant by comparison - our magnetic field reaches far out into space, more than half as big as Neptune or Uranis' magnetic fields. This protects our water and other environmental factors.
Sadly, this means that seeding the planet with water, perhaps by towing an ice-asteroid into orbit and knocking it to the planet, would be a temporary fix at best. Eventually all of that water would just evaporate away and join the Heliopause.
My understanding is that "temporary" in this case means, like, "one million years or more."
While I appreciate that that's a very short span of time by both geological and evolutionary standards, I don't think it's meaningfully "temporary" by human standards.
> However, many scientists believe Mars was much warmer and wetter billions of years ago, when it may have had a thicker atmosphere to help trap heat.
This is both fascinating and horrifying. Given the timeline of the solar system thus far, it would seem plausible that an entire evolution of species, including the rise and demise of intelligent life, could have already started and finished on Mars.
The Long Mars (by Pratchett/Baxter) explores some ideas like that on a trip through parallel universes, though it's 3 books into a series that doesn't lend itself to skipping around.
Taking this one step further, it is also possible that life has been exchanged between our two worlds. Large meteor collisions in the past have moved parts of Mars to Earth, and possibly also Earth to Mars. And some small life can exist clung to rocks in space (we know of such creatures here on Earth)! So perhaps, Mars was once wet and warm and full of life. Perhaps it suffered a large impact of some kind billions of years ago, and perhaps that impact flung Mars rocks with little tiny Martians on them towards Earth. In fact, this could have happened thousands of times.
It's possible, anyway. You know, while we're speculating.
It's a pitty we are not digging in the underground of the planet yet; imagine the amount of fossils and history one could find if the planet had been habitated before.
Terra forming Mars has never been something which I imagined we would do. I always thought we'd be living in greenhouses and digging for minerals and fossils.
A little less than half the surface of Mars has pressures above the triple point of water, so wherever the temperatures dip above 0C, maybe a few hours a day in the equatorial regions, liquid water can exist. Deeper craters closer to the equator or seasonally in the northern lowlands or the southern Hellas or Argyre region.
Because this is far from the first evidence. There is plenty of evidence for liquid water on Mars both past and present. In fairness, the article mentions this. In spite of the headline, it only claims the first direct evidence. Personally, I think even that is a bit of an overstatement. To me, this is simply one more bit of evidence that supports the current scientific consensus.
This would be the first time they state there's liquid water naturally under one of our machines. For a starter, this is a huge problem regarding environmental protection. Regardless of the other factors against letting something like Conan the Bacterium take residence a few cm under the surface, I suspect if this had been suspected earlier (or those that suspected it were taken seriously), we wouldn't have sent the same kind of probes to the same areas, possibly not even having a Mars ground exploration program at all until we understood better how to do it without polluting the planet with terrestrial life.
16 comments
[ 40.1 ms ] story [ 770 ms ] threadIt's fairly exciting news.
http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo24...
Sadly, this means that seeding the planet with water, perhaps by towing an ice-asteroid into orbit and knocking it to the planet, would be a temporary fix at best. Eventually all of that water would just evaporate away and join the Heliopause.
While I appreciate that that's a very short span of time by both geological and evolutionary standards, I don't think it's meaningfully "temporary" by human standards.
This is both fascinating and horrifying. Given the timeline of the solar system thus far, it would seem plausible that an entire evolution of species, including the rise and demise of intelligent life, could have already started and finished on Mars.
It's possible, anyway. You know, while we're speculating.
Terra forming Mars has never been something which I imagined we would do. I always thought we'd be living in greenhouses and digging for minerals and fossils.