Slashdot Log In
Water Ice On Mars
Posted by
kdawson
on Sun Jun 22, 2008 07:07 PM
from the not-wet dept.
from the not-wet dept.
cathector sends along a story from SpaceWeather.com on the discovery of water ice on Mars.
"Scientists have figured out the mysterious white substance unearthed by NASA's Phoenix lander on Mars. It's frozen water. The breakthrough came last week when Phoenix's stereo camera caught the substance in the act of disappearing. Bathed in martian sunlight for four days, the white substance sublimated — i.e., it transformed from solid to gas without passing through the liquid state. This is how water behaves on Mars.... Some readers have asked, how do we know the white substance is not frozen CO2 (dry ice) instead of frozen water? Answer: Phoenix's landing site is too warm for dry ice. The average daily temperature is about -70 F while dry ice requires temperatures lower than about -109 F." The animated GIF showing the ice sublimating is pretty nice too.
Related Stories
[+]
NASA Announces Water Found On Mars 157 comments
s.bots writes "Straight from the horse's mouth, NASA's Phoenix Mars Lander has identified water in a soil sample. Hopefully this exciting news will boost interest in the space program and further exploration of the Martian surface." Clearly, this has long been suspected, but now Martian water's been (in the words of William Boynton, lead scientist for the Thermal and Evolved-Gas Analyzer) "touched and tasted."
This discussion has been archived.
No new comments can be posted.
The Fine Print: The following comments are owned by whoever posted them. We are not responsible for them in any way.
Full
Abbreviated
Hidden
Loading... please wait.
Snow (Score:5, Interesting)
Re:Snow (Score:5, Interesting)
No, martian air is way too dry to form snow. There is water in the athmosphere, but IIRC it is something like a layer 1mm thick if all the water would condense on the ground. What happens is that some of that water freezes to/in the ground if it gets cold enough.
What I learned from following the press conferences online, is that since mars doesn't have a large moon, the axis of rotation changes much more than earth does, so if it is directed towards the sun, the ice could actually melt.
Parent
Re:Snow (Score:5, Interesting)
Parent
Dupe from Thursday (Score:5, Informative)
Water sublimating (Score:5, Interesting)
Re:Water sublimating (Score:5, Interesting)
Is water the only material that can sublimate? If not, why should we be so sure this has to be water just because we want it to be?
Parent
Re:Water sublimating (Score:5, Insightful)
Parent
Re:Water sublimating (Score:5, Informative)
Doesn't really need to be under low air pressure, if ice is in the presence of low vapor-pressure it will sublimate (see icecube tray in your freezer).
Parent
Re:Water sublimating (Score:5, Informative)
water sublimation doesn't need to be exotic; it happens in your freezer all the time.
you know how ice cubes gradually lose their sharp edges and finally become just little puddle-shaped lumps in the bottom of the ice try ? that's sublimation too.
Parent
Better picture (Score:5, Informative)
Martian ice is really big news, folks! (Score:5, Funny)
Re:Martian ice is really big news, folks! (Score:5, Funny)
Sorry - it's a Scotch joke.
Parent
Interesting press coverage of this. (Score:5, Insightful)
I've noticed that almost all of the news headlines covering this are qualified statements like "Lander finds water on Mars, according to scientists". As if they're afraid to actually say something straightforward like "Water found on Mars" and they have to make it clear that they're just reporting what someone else is saying (with the implication that maybe they don't really believe it). At the same time they seem to have no problem with other headlines like "Celebrity Arrested Drunk" without the need to qualify it as "Celebrity Arrested Drunk According To Police" etc.
Maybe it's just me, but I mind it a bit irksome that so many big news outlets seem so detached from any sort of science reporting these days.
G.
In Other News... (Score:5, Funny)
More at 8.
Parent
average daily temperature (Score:5, Insightful)
Could we have this important information in units used by, I don't know, the rest of the world?
Re:average daily temperature (Score:5, Funny)
Send your own fucking probe if you can't be bothered to subtract 32 and multiply by 4/9.
Parent
Re:average daily temperature (Score:5, Funny)
Parent
One Problem: (Score:5, Informative)
Here's the problem: We still don't know conclusively. Yes, we have observations which are highly suggestive, but we don't have a chemical composition of the substance, so we don't know for sure.
Science is a hard mistress; she demands proof before making such claims.
ice on Mars is nothing new (Score:5, Insightful)
Finding water was one of the key goals of the Phoenix mission.
That is a bizarre statement. Large quantities of ice have been observed in numerous ways already. Even the Viking lander observed water frost directly in the 1970's:
http://en.wikipedia.org/wiki/Viking_2 [wikipedia.org]
http://www.solarviews.com/cap/mars/frost.htm [solarviews.com]
That frost sublimated just like this ice did.
Here are other observations:
http://science.nasa.gov/headlines/y2002/28may_marsice.htm [nasa.gov]
Here you can see a frozen crater lake:
http://esamultimedia.esa.int/images/marsexpress/210-010705-1343-6-co-01-CraterIce_H.jpg [esa.int]
http://www.esa.int/SPECIALS/Mars_Express/SEMGKA808BE_0.html [esa.int]
Not only is that ice, it may actually be an outflow.
What makes the results from Phoenix exciting is that the actual experiments that Phoenix is supposed to perform depend on having landed on ice. But finding ice somewhere on Mars is not a surprise.
How come the water is so white/clean? (Score:5, Interesting)
First, I think the best evidence so far that this is water is not this picture, but the fact that the Mars Orbiter's spectrometer determined that that is was a lot of hydrogen in the ground near the poles.
That some white stuff vanishes is poor evidence. They need to get the white stuff in an oven and test it.
Let's assume it is water.
What really puzzles me is how clean the water is. It is covered with what would make a dirty mud if it ever melted together. Also on earth, you never have clean water if you have flash floods like what you see as a result of a volcanic eruption or meteroid impact. You only have clean water/ice in snow and still lakes/oceans.
This implies:
1. The ice has not melted after the dust blew over it.(A long time)
2. It used to be a lake/ocean or snow
So the purity of the ice might be a bigger discovery than the fact that it is ice there.
Re:Wow (Score:5, Funny)
You're absolutelly right, all we need now is some Martian Whisky and the social lives of any future human expedition is well and truly sorted out.
Parent
Re:Wind? (Score:5, Informative)
It was at the bottom of a trench. Plus, wind doesn't selecticely blow white rocks away while letting the rest of the scene untouched. Plus, you can also see some white areas at the end of the trench getting smaller.
It's ice. Definitely.
Parent
Re:Wind? (Score:5, Informative)
Parent
Re:Wind? (Score:5, Insightful)
Parent
Re:Stupid terraforming.. (Score:5, Informative)
Parent