Expert: Courtney Seligman - 2/17/2010

Question
/bows thank you for your time.  I never see rover pics from Mars at night, but I love the sunrise image. What do the moons look like from the surface of Mars?  Do they go through phases?  Are they visable at the same time?  What would our own moon look like with a dark regolith from earth?  (I imagine it would still shine as it would reflect light, but also absorb some.)

Answer
I think they power down the rovers at night, to save on battery power, and because it gets so cold things might not work properly, even if power weren't a concern.

Deimos is so small that it would just be a bright dot in the sky, so you wouldn't be able to see any phases; but Phobos is not only a little bigger, but a lot closer, so it would be an oblong-shaped object about 10% the size of our moon, and would go through phases. In fact, it would change phase during a single night, because its position would change substantially, relative to the sun, during the time it took to cross the sky.

I'm not sure what you mean about putting a dark regolith on the Moon. But the Moon is much darker than the Earth anyway, reflecting only a tenth as much light, overall, and we can still see it even during the day, because the lit part is in full sunlight, and even a little reflection is enough to make it visible.