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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.
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.
Could we have this important information in units used by, I don't know, the rest of the world?
I thought the lander was loaded with scientific equipment. None of it can detect water? The best they can do is take pictures?
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.
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.
True, wind doesn't selectively blow white rocks.
But it would selectively blow an ultrafine powder which happened to be white.
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.
Does a line appended to your comment give your post meaning in and of itself, or only in relation to those without?
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!
This space available.
Isn't it sad though that we can tell the composition of object hundreds of lightyears away including detecting water but even with a lander right there on Mars we can't confirm water even when the lander is staring right at it? There's something not right about the whole mission. The rovers use RAT tools to expose the virgin surface of rock so we could tell the composition but we can't detect water with a lander designed specifically for that one thing. The landers were a staggering success but this mission feels a bit embarassing. Honestly with the instruments on board could they confirm water if they landed in a pond? They expose frost and which is halfway there and we'll be debating for months or years to come what it really was. Do we need shots of a Martian taking a bath or selling bottled water to confirm it? Still wouldn't confirm anything because martians might bath and drink liguid CO2. I can think of a hundred low tech tests to confirm water. NASA seriously dropped the ball on this one. Apparently the only real test involves getting material into a pencil lead sized hole. By that standard an ice cube couldn't be tested for water. Here's a fun fact. If there are only trace amounts at the surface and the act of exposing it to the air to collect it causes it to evaporate does that mean we can't test for it? How about a heating element on an arm with a gas chromatograph? Stick heating element in soil, heat soil, test escaping gases. Repeat as needed.
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.
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).
"Nine times out of ten, starting a fire is not the best way to solve the problem." - my wife
- Form some sort of hypothesis (The white stuff in the picture is water ice.).
- Decide upon consequences of this hypothesis (Water ice will sublimate.).
- Perform test (Take pictures every day to see if it sublimates).
If the test succeeds then you have evidence that the hypothesis is correct, but NOT proof. The more evidence the more accepted as truth the hypothesis becomes. Unfortunately the test could have been flawed, there might be a more correct hypothesis, or other problems.
My favorite incorrect hypothesis supported by evidence and experiment is Tycho Brahe believing in the earth centric model. He made very careful measurements and expected to see some parallax if the sun centric model were correct. Since he couldn't detect it he decided that the earth centric model must be correct because his measurements supported that view. Of course his measurements weren't as accurate as we can make today so his data was off and his conclusion was incorrect.
In any case leave proof to the logicians and mathematicians. Science demands evidence and experiments.
Neither, because NASA only hires smart people.
If you mod me Overrated, you are admitting that you have no penis.
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.
I prefer the "u" in honour as it seems to be missing these days.
There is a fair bit of difference between believing and knowing!
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.
A-Bomb
By virtue of being slower, it is automatically also less effective, since it has a limited amount of time to operate.