Does the Earth's blue sky have anything to do with the light-scattering
properties of oxygen molecules? What do we expect the Martian sky to look
like as a consequence of the atmospheric composition of Mars?
I've seen pictures from Spirit showing a red sky, and websites suggesting
that the colour balance has been (deliberately!?) distorted. Other versions
of the same pictures show a blue or a white sky.
Looking out of my window through the bare trees outside, I observe that the
earth sky is grey!