Water Ice On Mars

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.

Comments

Interesting press coverage of this.

[Gavin Scott]

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.

average daily temperature

[Swampash]

Could we have this important information in units used by, I don't know, the rest of the world?

Re:average daily temperature

[Bill, Shooter of Bul]

Well, as soon as a country from a part of that world, then you'll get your pronouncements to the public in metric. You have to remember that NASA is publicly funded. They need the public engaged in their discoveries, in order to maintain their funding. So, it only makes sense that they report their public findings to the media in units that average ( and the not so average members of congress) understand. I'm sure there are those a NASA that thinks they should be trying to convince the American public to use Metric, but technically that's NIST's job

Perhaps they're waiting for NASA to weigh in

[cpu_fusion]

Although I agree with you in principle, I think it might be due to the anticipation of NASA's announcement, which could do away with the "according to scientists [working on the project]" caveat.

ice on Mars is nothing new

[speedtux]

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

http://www.solarviews.com/cap/mars/frost.htm

That frost sublimated just like this ice did.

Here are other observations:

http://science.nasa.gov/headlines/y2002/28may_marsice.htm

Here you can see a frozen crater lake:

http://esamultimedia.esa.int/images/marsexpress/210-010705-1343-6-co-01-CraterIce_H.jpg

http://www.esa.int/SPECIALS/Mars_Express/SEMGKA808BE_0.html

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:Wind?

[Anonymous Coward]

True, wind doesn't selectively blow white rocks.

But it would selectively blow an ultrafine powder which happened to be white.

Re:Water sublimating

[PieSquared]

Pretty much anything can sublimate under the proper conditions. But when you say "a white solid that sublimates at -70 degrees F and martian surface pressure and is found in macroscopic quantities naturally" you narrow down the field quite a bit. In this case, to exactly one reasonable possibility.

Re:Wind?

[Jafafa Hots]

OK, we admit it - none of the NASA scientists are as smart as you are, the whole "powder" thing just never occurred to them. Doh!

Re:One Problem:

[SetupWeasel]

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.

Four days apart

[Trogre]

So these two frames 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).

Re:Wind?

[Free the Cowards]

Neither, because NASA only hires smart people.

Personally

[WindBourne]

I would rather use the nukes to bring a few asteroids to impact mars. Some of those contain a load of ammonia. Ammonia is a great great house gas. Of course, that would disassociate over time, leaving N2 in the atmosphere.

Re:Wow - not

[ThePeices]

There is a fair bit of difference between believing and knowing!

Re:Wow

[Bombula]

Your joke reveals another truth: the limitations of remote instruments. Countless debates in slashdot threads have been had about human versus robotic space exploration. Many folks argue that robots are just as effective as people. Well, certainly they are more cost-effective, but as this Phoenix episode shows they are certainly NOT more effective in practical terms.

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:Wow

[bonehead]

By virtue of being slower, it is automatically also less effective, since it has a limited amount of time to operate.