Successful New Landing on Mars

Those white scrape areas are intriguing. Can the lander re-scrape there and dig a little deeper? If it were ice, wouldn't it be dirty ice instead of white?

Looks like Mars may be made of marshmallow under the topsoil. Or styrofoam. Maybe we landed on an ancient Martian landfill.

I don't know if there are any plans to "re-scrape" the same locations or not. They do plan to dig deeper, but I haven't read anything about them doing it in the same scraped areas.

The first priority is probably to get the requisite number of samples from various locations into the ovens.

After the planned mission is complete (whatever that is), if this lander keeps working as long as the rovers are, maybe they'll just start using the shovel arm to scrape topsoil all around the lander and take pictures over and over again.

Spirit and Opportunity are running so long they're probably having trouble figuring out what to do with them.

Could it be dry-ice and not water-ice?

If it turns to vapor, how will they ever know its composition?

Maybe part of it was scooped up when they made the scrape, and made its way into the oven for analysis?

Oh, yeah. The oven would be air tight, likely. Another great mystery solved.

I still say maybe it was marshmallow, and was licked up by the Martian lifeforms when NASA wasn't looking.

Amy Winehouse saw it, thought it was cocain, and snorted it all the way through space.

Fancy arresting Amy. How low-life can they get?

And now Naomi has got 200 hours community service for assaulting two police officers with her handbag.

She should have got an MBE for not using her hat-pin.

The Wired Science blog has been flooded with comments and questions about yesterday's announcement that the Mars Phoenix Lander has observed ice on Mars. Some of these questions are so good that we can't let them go unanswered. So here's our Mars Ice FAQ. If you've got more questions, put them in the comments below!

How do you know it's water ice, not CO2 ice (aka 'dry ice')?

There is a lot of CO2 ice on Mars in the winter. However, Phoenix landed in the Martian arctic during the summer (because the lander is solar powered, the extra summer light is a necessity). In the Martian summer it is much too hot for dry ice to be solid. It would be like trying to keep water ice from melting on a 140-degree day here on Earth.

Carbon dioxide (CO2) will freeze on Mars at -125 C. Today's weather report from the Canadian weather station on Phoenix shows a low of -80 C -- way too hot for dry ice to stay solid right now. (Note the largest "pebbles" of ice were seen to stay solid for a day before disappearing).

Why not send instruments to detect life?

If you are going to make a claim like, "I have found life on Mars," you have to be prepared to show that there is NO chance your sample was contaminated with Earth bacteria before launch. To do that takes an incredible amount of sterilization. Don't worry -- they have already done a lot of sterilizing on the Mars Phoenix before launching it. But to really be sure they would have to go to extreme measures to be able to rule out any contamination, and doing that would have drastically increased the cost of the mission beyond its budget. So NASA and JPL plan missions that look for water and the conditions of life within the budgets they have now.

What about the bright white stuff in the sunshine?

The scientists said they are monitoring the bright patches in the sunshine for changes too. They are seeing some changes, but stay tuned for more explanation and details. As for how the "pebbles" that disappeared did so in the shade, one scientist did mention that the portion of the trench it was in was exposed to morning sunshine earlier in the day.

Why are the pictures not all in color?

Be patient. The first images sent out are the raw files from the lander. The science team is committed to getting us the images to us fresh off the presses, so they send out the raw (monochrome) images first. Typically if you wait a day, the team will release the image in full color once it has been processed (see above for full color version of yesterday's image).

How can water ice go straight from being a solid to being a gas (sublimation)?

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.

You might be surprised to know that the same thing happens here on Earth. If you have a frost-free freezer, you may have noticed that your ice cubes gradually shrink over a period of days. This is sublimation: the fan is constantly sucking water vapor out of the freezer so the ice cubes surrender more and more water molecules to the dry air over time.

The pressure on Mars is about 8 millibars, very close to the "triple point" of water, which is the point where it can easily exist as either a solid, a liquid or a gas (see the chart below). Since the vapor pressure is so low, water can easily sublime in the Martian atmosphere, especially as the surface heats up in the sunshine. When that happens, the soil can often get hotter than the air in the sunshine (think of a lizard sunbathing on a hot rock).



You can get a list of the daily weather reports from Mars on the Canadian Space Agency's webpage. It includes the temperature, pressure and visibility at the landing site.

Phoenix ice photos
Compare these two close-up pictures taken on sol 20 (left) and sol 24 of a trench dug in the Martian surface by NASA's Phoenix Lander. Those sols of the Phoenix Mission (a sol is a Martian day), correspond to June 15 and 18 on planet Earth. Light-colored, dice-sized chunks, visible in the lower left shadow region of the trench in the sol 20 image have vanished by sol 24 -- a strong indication that the chunks were ice uncovered by digging the shallow trench. The vanishing act likely demonstrates the sublimation of ice in the trench, a process similar to evaporation, in which the ice went directly from solid to gas after it was exposed to sunlight and the thin, dry Martian atmosphere.

http://www.nasa.gov/mission_pages/phoenix/images/press/sol_020_024_change_dodo_v3.html

BBB - that is interesting.

Re: Phoenix ice photos

I wonder why the exposed white patches didn't go away (sublimate)?

Why would small chunks of dirty material (which, if they are ice, one would assume broke off from the white patches) sublimate away, but in the same amount of time, the white patches seem unchanged?

I wish NASA would do a better job of explaining their conclusions.

one was ice, one was mineral?

They have overwhelming evidence that Mars used to be inhabited, megalithic structures, pyramids, villages and other inhabited places, ancient mechanical debris strewn across the sand, and NASA, which can't deal with the implications of all that to several of their basic theories, wants to land probes on the poles and look for water or microbes...