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Probable Water Ice Sighted On Mars
CraftyJack writes "Bright white chunks in the trenches dug by the Phoenix Lander have disappeared, leading Peter Smith & co. to believe that the chunks were ice that has since sublimated."
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http://adsabs.harvard.edu/abs/1992LPICo.787...18K
http://michaelsmith.id.au
I'm pretty sure the poster (and anyone else who would be browsing slashdot) knew that; the quote is from Dan Quayle, he's the one who needs help.
Another article about the same news: http://blog.wired.com/wiredscience/2008/06/mars-phoenix-tw.html
There is water ice on Mars within reach of the Mars Phoenix Lander, NASA scientists announced Thursday.
Photographic evidence settles the debate over the nature of the white material seen in photographs sent back by the craft. As seen in lower left of this image, chunks of the ice sublimed (changed directly from solid to gas) over the course of four days, after the lander's digging exposed them.
"It must be ice," said the Phoenix Lander's lead investigator, Peter Smith. "These little clumps completely disappearing over the course of a few days, that is perfect evidence that it's ice."
The confirmation that water ice exists in the area directly surrounding the lander is big and good news for the Martian mission. NASA's stated goal for the Mars Phoenix was to find exactly this -- water ice -- and then analyze it. With the latest news, the first step is accomplished. All that's left now is to get the water into the Phoenix's instruments, a task which has occasionally proven more difficult than anticipated.
Still, this is the best opportunity that humanity has ever had to analyze extraterrestrial water in any form. That had the Phoenix Lander's persona fired up.
"Are you ready to celebrate? Well, get ready: We have ICE!!!!! Yes, ICE, *WATER ICE* on Mars! w00t!!! Best day ever!!" the Mars Phoenix Lander tweeted at about 5:15 pm.
Their suspicions about water ice beneath the surface of Mars confirmed, scientists and the world will have renewed interest in the outcome of the soil analyses currently being conducted by the lander.
The samples are being examined for traces of organic molecules, among other substances, but the lander does not have instruments that could directly detect life.
See the full announcement from NASA.
You are correct. I had not realized just how low the air pressure was on Mars: it can be around 0.006 atm which is exactly the point where ice will sublimate.
Cool. Thanks !
Why the f*ck was I moderated troll ? I was wrong, but trolling ? Sheesh, get a life.
Yes it does and can, at low atmospheric pressures (such as there is on Mars).
Jeremy
H2O ice does sublimate. Here's an easy way to prove it. All you need is a freezer and an ice cube tray.
1. Fill ice cube tray with water (liquid, H2O water) and put it in freezer.
2. Go back in a day and mark the level of the ice in the tray.
3. Return later (preferably at least a week) and marvel at how the ice is below the level marked.
4. ???
5. Profit.
The ice was in the freezer the whole time, so it didn't melt (assuming the freezer was set correctly and continuously powered). Therefore, the solid water lost must have changed to water vapor.
It has been a nervous year, with people beginning to feel like Christian Scientists with appendicitis.
btw, I feel the need to mention that H2O ice doesn't sublimate, CO2 ice does.
And I feel the need to mention that Mars is not Standard Temperature and Pressure. The atmospheric pressure on Mars is about 1/100 that of Earth, I honestly don't know if that's reason enough for why H2O may experience sublimation like that, but I'm too tired right now to look it up and/or crunch some numbers and see if it does or not.
If i had one dollar for every brain you dont have, i would have $1.
(Okay, okay, I just looked it up: "sublimate" can also be used with ice, but "sublime" is preferred.)
rj
Like this one?
You probably want something steeper, though.
I'll refrain from making a reference to the relative spatial positions of you and the joke. ;)
But escape velocity isn't really a velocity, as your trajectory is irrelevant. (Assuming it's, you know, above the horizon...) As long as you're traveling above a given speed, you'll escape the gravity well whether you're pointed straight up or towards the horizon.
The reason we launch rockets vertically is to minimize the time spent in dense atmosphere. You get a lot of drag at low altitudes here on Earth, so it's better to climb quickly and get to where the air is thin as soon as possible.
Mars is another story: Air pressure at the top of Olympus Mons is only ~0.003 that of Earth sea level. Launching a payload at a shallow angle through that would be no huge waste of energy.
On the moon (or anywhere that lacks an atmosphere), you could lay the mass driver right down on the surface and it wouldn't make any difference.
How can I believe you when you tell me what I don't want to hear?
H2O ice does sublimate. Here's an easy way to prove it.
There is absolutely no need to prove that.
Just pull up a phase diagram of water (google is your friend), look at the lower-left
corner (i.e. low pressure and low temperature), and what do you see ?
A line where the solid phase borders on the vapor phase.
And what's a phase transition from solid phase to vapor phase called ?
Bingo. Sublimation.