Water Ice On Mars 364
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.
POOL PARTY!!!! (Score:3, Funny)
Now we just need a little global warming.
Stupid terraforming.. (Score:2)
So, if we sent a bunch of robot tractors to Mars and uncovered the dirty ice caps, wouldn't they all sublimate and all that water vapor would warm the planet? Are we looking at a cheap way to terraform the planet?
Re:Stupid terraforming.. (Score:5, Informative)
Re: (Score:3, Interesting)
Actually, that argument can be made for any atmospheric gas constituent, not just water vapor.
There is less water in the Martian atmosphere oxygen while the water is more massive, so the oxygen would leave at a proportionally greater rate (assuming we are observing a long term steady state). One theory of the rapid loss has more to do with disassociation of H and O by UV radiation. H would quickly leave by your molecular motion argument leaving a relatively larger amount of O.
If that's the case, we'd be m
Re: (Score:3, Informative)
But you're right, either way the dissociated hydrogen is way lighter.
Personally (Score:3, Insightful)
Re:Personally (Score:4, Interesting)
Re: (Score:3, Funny)
You leave Mr. Stallman out of this!
$3,000,000 mint juleps at next year's derby (Score:4, Funny)
In other news, NASA announced today that a manned mission to Mars is planned to retreive the newly found ice in time for the 2012 Kentucky Derby. NASA plans to upstage Woodford Reserve's famous $1000 Mint Julep at the race with its own $3,000,000 version of the traditional cocktail. While plans are still being firmed up, the beverage will reportedly come in a limited edition collector's glass.
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.
Re: (Score:3, Interesting)
Re: (Score:3, Funny)
we should wisely remember that all these claims of ice or dry ice and so many other speculations are based on our earthly experience and so are limited to our sense perception. the fact is that every planet, all those millions that you can and cannot see in the sky are fully habitable and many many people are living there. this is the knowledge coming from the topmost intelligent people who have ever appeared on this planet and given fully scientific information about other planets. spending billions on
Re:Snow (Score:5, Interesting)
Dupe from Thursday (Score:5, Informative)
All that means... (Score:2)
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?
Re: (Score:2, Informative)
CO2 sublimes on earth of course, and many other substances do under different conditions. Per the summary, we know it could not be frozen CO2.
Re: (Score:2)
OK, cue the moth balls jokes...
Re:Water sublimating (Score:5, Insightful)
I know (Score:5, Funny)
Yep, Vodka.
Re:I know (Score:5, Funny)
Re: (Score:3, Funny)
Re:Water sublimating (Score:5, Informative)
To quote wikipedia: This can occur if the atmospheric pressure exerted on the substance is too low to stop the molecules from escaping from the solid state.
Atmospheric pressure is not as important as the partial pressure of the substance at its surface. That is, in this case, the vapour pressure of water which is practically zero on Mars. Therefore water, if it is not locked down in crystalline form, cannot exist in liquid form because it cannot form an equilibrium with its surroundings to form a 'triple point' (solid/liquid/vapour phase temperature).
It also depends, as far as I understand, on the interaction between molecules of the substance. If it is too weak, the range of temperatures at which the substance can be liquid is narrow (or practically zero). It's a fairly wide range for water, though.
I didn't study the topic beyond that and it was years ago.
PS. Iodine is another substance that sublimates.
Re:Water sublimating (Score:4, Informative)
All materials sublimate. The liquid phase doesn't exist beneath a substance's triple point, so at pressures beneath that level temperature increases cause the material to go directly from solid to gaseous (sublimate). http://en.wikipedia.org/wiki/Image:Phase-diag2.svga [wikipedia.org] has a good picture of what we're thinking about.
Re: (Score:3, Interesting)
All materials sublimate
Not sure about helium. If it can sublimate then it's going to be way up the phase diagram at enormous pressure at or close to the critical temperature. But it can definitely go straight from the superfluid state to the vapour state.
It's quite bizarre when you watch He4 transition to superfluid as you reduce the pressure. It's boiling away vigourously and then suddenly all the boiling stops (and it becomes quite difficult to see because it's refractive index is so close to 1)
Tim.
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).
Re:Water sublimating (Score:4, Informative)
Indeed it does, and it's probably better explained using a triple point diagram:
http://www.chemistrydaily.com/chemistry/Image:Phase-diag.png [chemistrydaily.com]
On earth (at higher pressures), increasing temperature goes from the solid, to liquid, and then to gas phases (the triple-point in the middle is at zero degress celcius)
The lower atmospheric pressure on Mars (~1% of sea-level earth pressure) means that you go straight from solid to gas. In fact, the liquid part is actually impossible (IANAChemist) unless you increase the pressure sufficiently.
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.
Re: (Score:3, Informative)
phase diagram (Score:3, Informative)
Here [wikipedia.org]
How to read them [wikipedia.org]
I feel that a great disservice was done to a lot of us early on with a simplistic view of the usual three phases of matter.
And yes, you're right. That is part of the explanation.
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.
Re: (Score:2)
How can it be neat, if you're going to put ice into it?
Re: (Score:2)
Re:Martian ice is really big news, folks! (Score:4, Funny)
Please call it by its proper name, would you?
Martch.
This is a dumb question, but... (Score:2)
A first glance, it doesn't look to me like ice "melting" any more than salt or some other finely-grained material blowing away (no, I'm not saying it's salt -- just something that could move). Is there no wind in that area or something?
Re: (Score:2, Informative)
Re: (Score:3, Informative)
If I understand correctly, the water is blowing away.. just not as crystals. It is blowing away as discreet water molecules much like evaporation. The crystals gain energy from the sun and a little from the impact of the atmospheric gases and then the water molecules lift from the crystal lattice and suspend in the atmospheric gas matrix.
If you visualize everything as tiny versions of the colored balls in a child's play pit, you will notice that each type of ball (atom) has a different weight and tends to
What about the pressure? (Score:2, Interesting)
dry ice requires temperatures lower than about -109 F.
But what about pressure? A look at the phase diagram [wikipedia.org] shows that carbon dioxide can be a solid (dry ice) at 25 C (room temperature), but at 10000 bar. I dunno what the pressure is on the surface of Mars, but temperature isn't the only thing that dictates if dry ice exists. Pressure is just as important. I doubt that Mars has that kind of pressure though.
And why are we using F? This is a science article, posted on a web site for nerds.
Re: (Score:2, Informative)
Re:What about the pressure? (Score:4, Informative)
You are also correct to assume that Martian pressure is nowhere near what is required for room-temperature dry ice. In fact it's about 1% that of earth's atmosphere. More reading here. [wikipedia.org]
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.
Perhaps they're waiting for NASA to weigh in (Score:3, Insightful)
In Other News... (Score:5, Funny)
More at 8.
Re: (Score:2)
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"
I think the reason is that the scientists technically have no proof it is actually water - what they have instead is a substance that looks like water, behaves like water and quacks like water. Whether it makes said something water, you be the judge.
On the other account, I totally agree - the media don't always seem so scrupulous in other areas :)
Re: (Score:3, Funny)
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: (Score:3, Insightful)
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.
Re:average daily temperature (Score:5, Funny)
Re:average daily temperature (Score:5, Funny)
Re:average daily temperature (Score:5, Informative)
Calculate your own conversion to attempt-by-the-French-to-regain-relevance-on-the-world-stage units.
Metric is the global standard. Get over it.
Re: (Score:3, Funny)
And yet they've succeeded in every bar in America. Checking the units used to measure wine and booze ... yep, metric.
Re:average daily temperature (Score:5, Funny)
Long live imperial units! I say, if God had wanted us to use metric, He would have given us ten fingers! ...
oh, crap.
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.
Re: (Score:2)
Correct, and further experiments will be undertaken to confirm that it is indeed water ice.
In the mean time, though, it's pretty safe to act under the assumption that there is indeed water on mars.
Re: (Score:3, Funny)
>> Science is a hard mistress; she demands proof before making such claims.
I shall have this woman.
Re: (Score:3, Insightful)
You know NASA has made a few major announcements that they have had to retract in the past few years. Remember the "river beds" that had no other possible origin? NASA later admitted that they were likely caused by the wind.
NASA doesn't let science get in the way of a good press release.
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.
Re:ice on Mars is nothing new (Score:4, Interesting)
Sweeet (Score:2)
Anybody else see Dan Quayle running around with his chest puffed up saying, "I Told You So".
Good for him :)
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.
not necessarily amazing (Score:5, Interesting)
there's a number of geological processes that can concentrate water like this
in areas on earth where a lot of freezing and thawing occurs on earth, rocks get concentrated neatly in rings according to size, as if someone sorted them
i'm not saying this process is anything like why the ice is so pure on mars, what i am saying is that there are plenty of natural processes out there that concentrate materials in orders that, contraintuitively, seem like it took intelligent concentration, but are in fact totally natural
i won't even begin to speculate what processes on mars could do this, but i wouldn't be surprised if someone more knowledgeable than me could describe such a natural mechanism for ice purification on mars
Four days apart (Score:4, Insightful)
So these two frames [spaceweather.com] were taken four days apart while the sublimation was taking place. My question would be - where are the rest of the frames? Does this lander really only "look around" every few days?
It would be nice to see it at even a 1-day resolution and get a 4-frame animation of the process. Those lumps should be seen to get smaller and vanish.
Not that I'm complaining, this is still very cool (no pun intended).
Standards.... (Score:5, Informative)
U.S needs to upgrade it's standards. A good start would to move from Fahrenheit to Celsius. After that you can move over to the metric system.
-70 F is -56 C
-109 F is -78 C
Conversion done with Google.
Seems to me... (Score:3, Informative)
are you absolutely sure? (Score:3, Funny)
You say you think it's sublimation
Well you know
that'd be out of this world
What else could explain the diminution
Well you know
that'd be out of this world
But when you talk about reduction
Don't you know ice ain't the only thing
Don't you know other substances are white [x3]
You say you got an aqueous solution
Well you know
We'd all want to see the proof
Martians might be liliputian
Well you know
Look for them if you can can
But if you want money for space probes that crater
All I can tell you is brother maybe later
Learn how to use metrics first, alright? [x4]
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.
Re: (Score:3, Funny)
Are they sure it's NOT martian whiskey? ;) Or some sort of liquid that looks like water when frozen?
Re:Wow (Score:5, Funny)
> Hopefully they are right about it.
Of course they're right about it, they have solid photographic evidence. [nasa.gov]
Re:Wow (Score:5, Funny)
Re:Wow (Score:5, Informative)
"Just like dry ice does here on Earth, water ice goes from solid to gas when the pressure is below 6.1 millibars and it gets heated (like it does in the Martian sun). It can also go straight from solid to gas above 6.1 millibars when the vapor pressure (amount of water vapor in the air) is low enough. This is because the molecules of water in solid form and gas form are not at equilibrium."
http://blog.wired.com/wiredscience/2008/06/answering-mars.html [wired.com]
Re:Wow (Score:4, Insightful)
It took many days to determine that the white stuff Phoenix uncovered was ice (and not salt). An astronaut on Mars would have made that determination within seconds.
Re: (Score:3, Interesting)
Does that make the robot less effective, or just slower?
Re: (Score:3, Insightful)
By virtue of being slower, it is automatically also less effective, since it has a limited amount of time to operate.
Re: (Score:3, Interesting)
Not necessarily - by not needing oxygen, and a way out, etc, it can prolong the stay. Maybe it can even more-than-compensate for its slowness.
So its not that clear-cut.
That's not water... (Score:3, Funny)
After looking at that fascinating GIF from the summary, I'm not sure it is water. It just kind of disappears. It's probably some sort of highly advanced life form that can change its shape at will and lives beneath the planet's surface most of the time. It then just came up for a little Martian sunshine and, upon noticing our probe went back to tell its buddies that the Earthlings sent more crap to their planet and that they should expect an invasion soon. Unless they can prove to us they don't have any
Re:Wow - not (Score:5, Insightful)
There is a fair bit of difference between believing and knowing!
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.
Re:Wind? (Score:5, Informative)
Re: (Score:2, Insightful)
True, wind doesn't selectively blow white rocks.
But it would selectively blow an ultrafine powder which happened to be white.
Comment removed (Score:5, Insightful)
Re:Wind? (Score:5, Funny)
Re: (Score:3, Funny)
Re:Wind? (Score:5, Insightful)
Neither, because NASA only hires smart people.
Re:Wind? (Score:4, Funny)
Re: (Score:3, Funny)
Re: (Score:2, Informative)
It's 1% of Earth's atmospheric pressure. At that point there is no water, only solid and gas. And the sublimation point is a lot lower because of the lower pressure. (Less pressure = less molecules keeping the other molecules tightly packed)
Re: (Score:3, Interesting)
Water freezes at zero degrees. :-p
But seriously, this is oversimplified. Water freezes at 0 degrees on Earth, at standard pressure. Furthermore, even when water freezes, there's still water vapor. Really, if you think about it, you can't have the physical states without multiple molecules. Liquids and solids require certain arrangements of multiple molecules. In either case, individual molecules can escape, thus sublimating. The energy from the sun was enough to cause these molecules to escape, even though
Re: (Score:2)
And here I thought the explanation of what sublimation was in the summary was superfluous.
Please see the phase diagram for H20. Martian atmospheric pressure is extremely low.
Re: (Score:2, Redundant)
the very same way that ice cubes sublimate in your freezer, even though your freezer temperature is below 32 degrees.
Re: (Score:2)
No, as the point they're making is that it doesn't get cold enough for dry ice to form. If it did, Mars' atmosphere would snow out.
Re:could be CO2? (Score:4, Informative)
Yes, still not cold enough as far as I can tell given this phase diagram [fsnet.co.uk] and these temperatures and pressures [wikipedia.org].
Re: (Score:3, Funny)
How much water have you found on Mars?
Uh-huh. I thought so...
Re:Life on Mars (Score:5, Funny)
Perhaps next mission they should take along some sugar. Put it out and see if it 'sublimates' as well.
By order of the Council of Elders, anyone caught consuming the sweet, sweet bait near the robotic invader from the blue planet is to have his gelsacs summarily pierced.
Signed,
K'Breel
Re:Life on Mars (Score:4, Funny)
Re:How does the ice exist this close to the surfac (Score:3, Informative)
PI'm just flabbergasted that the ice could exist so close to the surface without sublimating purely from solar warming of the soil.