Explanation:
What's creating light-toned deposits on Mars?
Quite possibly -- water!
Images of the same parts of
mid-latitude Mars taken over the years but
released only last week have shown unexpected new light-toned deposits
where there were none before.
One clear case is
shown above,
where the same crater on Mars is shown as photographed in 1999 August and again in 2005 September.
The unusual deposit is visible only on the more recent photograph.
Apparent tributaries near the bottom bolster the
leading hypothesis
that water gushed out of the crater wall, flowed down the crater,
and soon evaporated into the thin
Martian atmosphere.
Although
frozen water-ice has been known near the
Martian poles for years,
free flowing surface water like this was not expected to be seen in the mid-latitudes of
Mars.
If confirmed, such water springs might make more of
Mars hospitable to life and
human visitation than previously believed.