Explanation:
How did this unusual Martian rock form?
The atypical two-toned rock, visible in the lower right of the above image, was photographed a few days ago by the
robotic Spirit rover
currently rolling across
Mars.
For now, the
environmental processes
that created the rock remain a matter of
speculation.
Finding unusual rocks is not unusual for
Spirit or its twin rover
Opportunity, however.
Over the past two years, for example, the rovers have unexpectedly discovered very
small gray pebbles dubbed
blueberries, and a rock out in the
middle of nowhere
now thought to be a
meteorite.
Having investigated
alien terrain and having found clear
evidence that part of Mars had a
wet past, the Earth-launched Martian rovers
are now entering their
third spectacular year exploring the red planet.
