Surprising Further Evidence for a Wet Mars 192
Riding with Robots writes "When the robotic geologist Spirit found the latest evidence for a wet Mars, 'You could hear people gasp in astonishment,' said Steve Squyres, the lead scientist for the Mars rovers. 'This is a remarkable discovery. And the fact that we found something this new and different after nearly 1,200 days on Mars makes it even more remarkable. It makes you wonder what else is still out there.' The latest discovery, announced today, adds compelling new evidence for ancient conditions that might have been favorable for life, according to the rover team."
Re:Sand? (Score:5, Informative)
Silica [wikipedia.org] or Silicon dioxide, is the most common constituent of sand in inland continental settings and non-tropical coastal settings is silica, usually in the form of quartz because the considerable hardness of this mineral resists erosion. However, the composition of sand varies according to local rock sources and conditions.
Re:Ok great... (Score:5, Informative)
Ice on the poles, a given. Easy. There are even some moons who're thought to have it. This, though, means that there was water there, liquid water, in larger quantities, far from the poles. And this water could have been the engine for life. Long, long time ago, granted, but still.
It's not that there was water, it's where they found it.
Re:Solvents (Score:5, Informative)
Re:Solvents (Score:3, Informative)
Actually, both water and ammonia should dissolve a glass bottle. At room temperature they just do it very very very slowly.
Re:Looks like ... (Score:5, Informative)
While this does appear to be an interplanetary bug-as-a-feature, the rovers' wheels were actually designed to be able to scrape off the top layer of soil and expose what's underneath.
Obviously, not to the degree this disabled wheel has, but still, they very much had plans to scratch below the surface of Mars.
- RG>
Re:Sand? (Score:1, Informative)
Re:Banth and mad Zitidor tracks (Score:1, Informative)
Re:Looks like ... (Score:2, Informative)
Perhaps they already did [marsanomalyresearch.com].
Re:I'm no rocket scientist, but... (Score:1, Informative)
1. When a bolide collides with Mars it will release a lot of energy. A colliding asteroid/comet would disperse the silica over a wide area, smashing it to various sized pieces, mix it with other materials, and vaporize then re-condense the rest of it during the collision.
2. The silica in question was not quartz. Fairly pure silica that isn't quartz can be several things: glass, such as the familiar volcanic glass we call obsidian; opal, which is formed by deposition through aqueous processes; leaching of other material from less silica rich rock by groundwater in the appropriate chemical regimes leaving relatively pure silica behind; and the various mineral polymorphs of quartz such as tridymite, cristobalite, etc...
3. There is the problem of how the purified silica would have made it in to an asteroid or comet in the first place. There is no shortage of silica in the solar system, but relatively few ways to purify it (that don't result in quartz) in the absence of water and certain chemical conditions, and very few that could be imagined occurring on a comet or asteroid. These materials are unlikely to form on a comet or asteroid because the processes responsible for forming them probably can't occur there.
4. The material observed on Mars was homogeneous and well sorted. Aside from explaining the material's composition, any hypothesis to account for the deposit must explain its purity and texture. A collision with an asteroid or comet would shatter a large impactor in to many pieces of different sizes; it is not an effective means of sorting or purifying granular material.
We have no sensible idea how a comet or asteroid could do this, but there are other models more consistent with the evidence that are readily available. In short, attributing it to an asteroid or comet just doesn't make any sense from any perspective.
There are lots of ways to explain things that don't make any sense, aren't supported by any evidence, and generally have no explanatory power. By necessity science ignores such alternatives.