Slashdot Mirror
Brine on Mars?
Bagels writes "A new article on MSNBC (coming originally from Space.com) reports that the both Rovers may have struck water in the form of brine. The Opportunity rover found hints of salty water in the trench that it dug, and scientists note that the Spirit rover is currently digging a trench of its own to investigate the soil that clings to its treads, suggesting the possibility of moisture. The brine would only be small amounts of water mixed with salt, which can exist in liquid form at very low temperatures. More images are available over at NASA's rover site." Reader
frovingslosh would like to add: "I'm just hoping that when you get around to posting one of the many stories that the rover has found mud on Mars that you might include a link to the slashdot article where I predicted this but got moderated as 'funny'." Done!
Here's a New Scientist article from January which argues for the presence of brine.
It's never too late to have a happy childhood.
That's why they're not looking for water on the surface. Water mixed with rock, sand, or salt, or even just underground, would not evaporate.
The parent is right; the "+5 informative" grandparent is just wrong. We have known for some time that at least the north polar cap was composed mostly of water ice.
r _040123.html
References:
http://www.nature.com/nsu/030210/030210-9.html
http://www.space.com/missionlaunches/express_wate
The same reason they are speculating that it can exist in liquid form at such low temperatures: the phase diagram of a solution can be radically different from the pure substance. In hand-waving terms, the attracion between the salt molecules and the water molecules increases the energy required to evaporate the liquid. This is why they are theorising that it is highly concentrated brine - because if it were not highly concentrated, it could not exist under the temperatures and pressures on Mars. I'm probably not being unrealistic in suggesting that the scientists have thought this all through before publishing the press release.
If I seem short sighted, it is because I stand on the shoulders of midgets
No need to thank me, just not doing my (real) job.
"The very small particle size of Martian dust makes it likely that it sticks due to static charge. If the soil were moisture laden you would expect it to rapidly dry out and crust over (change appearance) on the wheels of the rover."
No. The amount they are talking about causing this is much much smaller than the amount it would require to saturate it to the point of an observable change in appearance after exposure.
It may even be the result of no water in it now but the result of residual salts left behind by existance of water at some point. Theoretically this could display these properties as well.
Indeed, I've found an abstract from the Lunar and Planetary Science Conference on the subject.
Right.
m l.
The brine speculation is coming from people not involved on the project, which space.com is reporting uncritically. The news conference where the project scientists are presenting their information mention nothing about brine.
See the entry for Thursday, February 19, 2004 at http://www.spaceflightnow.com/mars/mera/status.ht
HCG 50a = 2MASX J11170638+5455016
11h17m06.4s +54d55m02s
Gases do move into outer space. Gravity slows down the process, but it doesn't stop it. When you get to the outer atmosphere, the velocity of gas atoms and molecules follow a predictable statistical distribution, dependent on their atomic mass and average temperature. Many atoms and molecules will reach escape velocity, and diffuse away from the planet. What do you think happened to the atmospheric helium on Earth?
Mea navis aericumbens anguillis abundat
Most of it probably has. One process could be groundwater carrying dissolved mineral salts being drawn to the surface by capillary action. The water evaporates into the very low pressure Martian atmosphere, leaving the salt as a deposit.
Similar processes take place on Earth where they deposit salt and iron oxides in deserts.
Best wishes,
Mike.
It is definitely a microscope - going down to 30 microns per pixel. A hair is around about 100 microns in diameter.
Sorry I don't have a precise magnification.
If there were things the size of microorganisms in the briny reaches, could we see them?
The objects seen in the ALH84001 meteorite were only between 20 and 100 nanometres (0.02 to 0.1 micrometres) and needed a scanning electron microscope to be seen. So MER can't hope to see them. Terrestrial bacteria are 2 to 10 microns (generally) in size - so the majority of them would also be invisible. There are some much larger bacteria; the largest known Epulopiscium fishelsoni is a whopping 250 microns in diameter.
But it should be remembered that this is not a biological microscope - it was designed for petrological work which rarely requires such extreme magnification.
Best wishes,
Mike.