Double-A wrote:
Raving Loonie wrote:
Double-A wrote:
Raving Loonie wrote:
O.K. How about water-ice on Mercury ? We could visit the poles !
' Man lands on Mercury ' ... now wouldn't THAT be something ?
'=2E. Mercury's axis of rotation is oriented nearly perpendicular to the
planet's orbit, so that in the polar regions sunlight strikes the
surface at a constant grazing angle. The interiors of large craters at
the poles are permanently shadowed and remain perpetually cold, below
-212=BAC (-350=B0 F). Radar images of the polar regions, first obtained
in 1991, show that the large craters' interiors are highly reflective
at radar wavelengths. The most common material that could explain this
behavior is -- ice! On the planet closest to the Sun! The tiny flow of
ice from infalling comets and meteorites could be cold-trapped in these
Mercurial polar deposits over billions of years, or water vapor might
outgas from the planet's interior and be frozen out at the poles.... '
See
http://messenger.jhuapl.edu/why_mercury/
Keeping cool while getting there may be problematic ?
RL