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Ice Lake on Mars
DecoDragon writes "The ESA's Mars Express discovered an ice lake on Mars. The ESA has a number of images and an explanation of what was found. The lake was found in an unnamed crater. The report says it can't be carbon dioxide, because carbon dioxide ice had already disappeared from the northern polar cap at the time the image was taken." Coverage from the BBC also available. From the article: "The team has also been able to detect faint traces of water ice along the rim of the crater and on the crater walls. Mars is covered with deep gorges, apparently carved out by rivers and glaciers, although most of the water vanished millions of years ago. "
Nice pictures. I think the article has one thing wrong, though. It should be possible for the ice to sublimate away above -103 F on Mars. Unless, of course this particular crater never gets that hot...
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Well, the only evidence of life is that which exists on Earth. On Earth, where there be water, there be life. The statement "All life needs water" is supported by the evidence. The evidences scope, however, is rather narrow.
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Not a joke, still from the Astronomy Picture of the Day site, is this picture, which according to the page text, was actually taken back in February, and reported in the June 2005 issue of Nature. So while it's news, it's not new news.
Likewise if humans were going to set up a permanent presence on Mars, they'd probably want to do it near the equator, where the cold wouldn't be so devastating.
Hmm, I would think that a difference of 50 degrees (-50 C vs. -100 C) would not be as much of a problem as being near to vs. far away from your life sustaining ice supply. Which is why everyone has been thinking that the first base should be at the south pole. However, craters like this would certainly expand the possibilities and make a base near the equator more practical...
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really. IANARS*, but how did previous missions miss that? haven't we already imaged most or all of the martian surface from orbit at a resolution high enough to see this glaringly obvious bullseye?
Well, this patch of ice looks like it has a surface area of what, 75 square km? All of Mars is about 145 million square km, so we're talking about 0.00005% of the surface -- I can kinda see how that might take a while to notice.
Basically, planets are big -- Mars may be smaller than the earth, but since there's no ocean, it has about the same land area.
Try jpeg2000 in lossless mode.
Another decent overview is available at O'Reilly.
2000's lossy mode is superior to jpg as well.
Was originally an Astronomy Picture Of the Day. (http://antwrp.gsfc.nasa.gov/apod/ap050720.html) This is a good site or backgrounds!
P.S. For other good/neat pics goto http://epod.usra.edu/archive.php3 (Earth Science Picture Of the Day)
The GEEK shall inherit the earth...
Assuming that meteorites strike Mars fairly evenly, it should be possible to guess how old the ice lake is. It is certainly newer than the crater it is in (duh!) and from the lack of craters on the ice or in the crater the ice is in, there must be a very definite upper limit to how old it can be.
There are two possible sources for the water (an issue the ESA and NASA don't really discuss on their sites): We know there's an underground ice lake, for a start. It is possible that when the impact occured, it burst through to such a lake, melting the water temporarily. The water would reach the surface and re-freeze.
The second possibility is that the surface has indeed been warm enough for liquid water, despite evidence from those with martian meteorites. This is possible, as the meteorites may well have been from a cold part of Mars. It could well be that Mars couldn't -sustain- warm temperatures, so warm regions were geologically active regions. Water takes finite time to freeze, especially when flowing, allowing for water-formed features even outside regions that would have sustained liquid water.
The latter explanation would be great for those looking for life, but the ice-spray on the rim of the crater, along with the bulge of land under the ice, is more indicitive of the former. Rats!
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When you decrease the atmospheric pressure, you change the freezing and boiling point of water. Under pressure, water favors being a liquid. Without such pressure, the melting point and boiling point would come closer together.
For more info see this PDF (in particular, figure 5.1). It illustrates the triple point.
Except for the fact that the average surface temperature of Mars is -63 C, the atmospheric pressure is 100x lower than earth and the O2 composition of the atmoshpere is about 1,000,000x less.
"When Nature Calls We All Shall Drown" Johan Edlund
It's pretty clear that life requires a solvent of some kind to form the complex molecules needed for life. Try and imagine amino acids forming in ice or some other solid. Water is regarded as the universal solvent since virtually everything will dissolve in it. Add to that that water is pH neutral and it provides a very hospitable environment for these molcules.
Also, water has the unique property of being less dense in solid form than liquid form, hence ice floats. Thus, when bodies of water freeze, the ice settles on top of it. In other words, water freezes from the surface down, unlike other liquids. This action provides an insulating layer which allows life to flourish under the surface instead of being driven to the surface by ice forming from the bottom up.
Water also has strong surface tension due to the hydrogen bonding between water molucules. This allows for capillary action in which plant can pull water up against gravity. This isn't necessary for the formation of primitive life, but it's difficult to imagine higher forms of life without it.
No, all science points to water being the one molecule which is able to nurture and sustain life. It's an amazing compound despite the fact that it's so prevalent that we tend to take it for granted.
"War is God's way of teaching Americans geography." -- Ambrose Bierce
That implies that they are there ;)
Take a look at Robert Zubrin's book The Case for Mars as a counterargument. It's a bit dated, and he gets a bit personal in attacks on NASA, but the facts are that much of what you stated above is wrong. Zubrin knows what he's talking about (fomrer engineer for Martin Marietta).
It looks like an artifact of either graphics compression or a glitch in the sensor data to me:
- The shapes are very angular, unlike everything else in the image.
- It's only there in the blue channel. If it were really present, there should be *some* trace of it in red or green, but if you remove the blue channel the shapes disappear.
- If I re-compress the image as a minimum-quality JPG, the amount of green "tendrils" dramatically increases.
My best guess is that it's a JPG artifact due to the extreme colour change at the rock/ice boundary.
"...always new atoms but always doing the same dance, remembering what the dance was yesterday." -Richard Feynman
After looking at the highest resolution color version I noticed that you can see the square patterns of the pixels, or more likely sets of compressed pixels. This happens often with JPEG images that have been compressed a little too much. Each square of X pixels gets compressed separately and some information is lost, so that when the same square is uncompressed it doesn't always blend smoothly into the surrounding squares with regard to color and lightness. I believe this is referred to as posterization, a loss of smoothness in the color transitions where it changes in steps that can be clearly seen rather than in tiny increments.
If you look at the patterns of squares, the image seems to have been tilted counter-clockwise about ten degrees, so the vertical and horizontal lines aren't straight up and down or left and right. Oddly enough, the long green "tendrils" seem to line up very well with the lines of squares, especially the big one in the bottom left. Notice how the tendril is very straight. Looks like those areas were supposed to be slightly blue-greenish but because of the compression the color jump is a little too much and they appear to be somehow different than the colors that surround them. I don't think they were meant to be that color.
You can see the posterization, or compression artifacts, most clearly in the transitions between light and dark colors. And you'll only see it when you view the image at 100% pixel-for-pixel on your screen. If you have Photoshop or Elements open the levels dialog and drag the black slider up to about 200. The green areas will turn black and it will become very apparent that they are perfectly straight in many areas. There are some horizontal ones and some vertical ones and some nice 90-degree angles in there. Life forms of course do not make perfectly straight patterns, especially on a large scale.
Humans to Mars is completely realistic. Here's why all your showstoppers don't hold up.
Yes, launch windows are only every 26 months and you have to spend over a year on mars before returning, but that's not a bad thing. You want to maximize the amount of time you spend studying the planet.
No, you don't have to take fuel for the return trip. You produce it on Mars by extracting carbon from the CO2 atmosphere and combining it with a small store of hydrogen you bring with you. Then you have methane, a perfectly respectable rocket fuel. The oxidizer gets extracted from the CO2 atmosphere as well. You bring a smallish nuclear reactor with you to power all this.
Yeah, you need a big heavy lift vehicle. We've made those before; remember Saturn V? Variants of the Space Shuttle stack can also be used. You can fit all the supplies and cargo and astronauts on one launch to Mars, and send them their return vehicle on a separate launch.
Radiation in space can be dealt with perhaps by circulating water through the hull of the spaceship. For protection from the occasional solar flare, astronauts can cram into a small central heavily shielded area of the craft. Radiation on Mars isn't toooo much of a worry becuase it's got an atmosphere, albeit a thin one, and bags of Martian sand can be laid across the top of the habitat for extra protection.
Yeah, there's a problem with the low gravity in space, but you're only in space for six months at a time. Astronauts recover pretty quickly from six month tours on space stations. Mars itself has over a third of Earth's gravity, so we're *hoping* that should suffice when combined with regular exercise.