There is no mud without water

I always thought that Opportunity landed in a mud.

There is no mud without water, and I have recently seen the confirmation
of my layman's intuition in a report of the Lunar/Planetary Science
meeting. Reporting from the conference, Bruce Moomaw for SpaceDaily.com
writes in
http://www.spacedaily.com/news/mars-...rintready.html


Sulfuric acid, is extremely "hydrophilic" -- it's powerfully chemically
drawn to blend with the rest of Mars' surface water, whether liquid or
frozen. And mixtures of sulfuric acid and water can have amazingly low
melting points. In fact, as such an acid-water mixture drops to temperature
levels enough to refreeze part of the water in it, the remaining liquid
portion of the mixture becomes a more and more concentrated liquid solution
of sulfuric acid until it finally becomes about 39% H2SO4 -- at which point
it will remain liquid down to temperatures as low as -74 deg C (-101 deg F),
10 deg C lower than the lowest average yearly surface temperature on Mars at
the current time.

Moreover, such an acid solution is so eagerly chemically attracted to more
molecules of water vapor in the air that -- even in modern Mars' near-vacuum
trace of air -- it will not evaporate; it pulls more water vapor molecules
out of the thin air as fast as it releases them into it.

In short, it appears increasingly likely that small moist traces of sulfuric
acid solution may frequently exist on or near the surface of many parts of
Mars right now, even far from any volcanic vents, remaining stubbornly
liquid even in the planet's current hostile environment.


So, there is water at the surface of Mars.