# Is dust the only reason why the Martian sky is so bright?

The atmospheric pressure on the surface of Mars is 0.00609 atm on average and 0.012 atm at most in the Hellas Basin. On Earth, at these pressures, which are found at altitudes about 30-35 km (19-22 mi), the sky is very black and full of stars. On the Martian surface however the sky is still bright (namely orange) and no stars/planets are visible in daytime from what is considered the sea level (except the Sun and maybe the Earth). Is this due to the many dust in the Martian atmosphere only or are there other reasons too for why the sky is not black but still orange at these pressures?

• +1 I always include the title or some other identifying information when I link to a paper. That way if the link breaks for some reason it's at least possible to find another copy. I also linked to some related SE posts, Feel free to roll back or edit further. – uhoh Oct 2 '20 at 1:21