What created this unusually textured rock on Mars?
Most probably: a volcano.
Dubbed Bumpy Boulder, the strange stone measuring just under a
half-meter high was found by the
robotic Spirit rover
currently rolling across Mars.
Pits on the
ragged rock are likely
vesicles and arise from hot gas bubbling out of
hot rock ejected by an active Martian volcano.
Several similar rocks are visible near Bumpy Boulder that
likely have a similar past.
The above true-color image was taken about one month ago.
The Spirit rover, now in its third year of operation on Mars,
is weathering the low sunlight winter of Mar's northern hemisphere on a
hillside slope in order to maximize the amount of absorbable