Microscopic View of Gritty, Grainy Soil
View a larger image (66 kB) or learn about other sol 8 images.
Members of the science team were really excited to see soil grains
on the surface close-up for the first time. The
(a camera that's mounted on the end of the robotic arm), can provide a
picture of the soil grains with 30 times more resolution than any
previous camera sent to Mars.
That accuracy pays off, as scientist Lutz Richter will tell you.
"You can tell a lot by studying the shape, size, and brightness of
the grains like the ones in this image," says Lutz. "What we
see here suggests that water probably flowed at the site in the
For geologists, the irregular shape of the particles and their random
sizes suggest that water deposited the material, not wind. That's
because water can carry larger bits of material, while wind can only
transport and deposit very small particles. The grains that can be seen
in this stamp-sized image range in size between about 200 micrometers
(the size of beach sand) and 12 millimeters (the size of gravel). The
various brightnesses of the particles indicate that they are made of
different minerals, formed by different processes. Further studies of this
image and others like it will help determine how the soil formed and was
later deposited. That will tell us a lot more about the geologic and
climatic history of this region.