The view from Mars

Natural History, March, 2004 by Fred W. Chesson

Has anyone ever determined how bright Earth would appear to an observer oil Mars, as a morning or evening "star"? Would the Earth appear brighter from Mars than Venus does from Earth?

Fred W. Chesson

Waterbury, Connecticut

JOE RAO REPLIES: The Earth as seen from Mars would closely mimic how we on Earth see the planet Venus, as Fred Chesson suggests. Since Earth is closer in to the Sun than Mars is, Earth would be a brilliant "star" that would appear to follow the Sun down the sky after local sundown or to lead the Sun above the horizon before local sunrise. In addition, Earth would show phases, just as Venus does as seen from Earth.

This month the Earth rises in the martian morning sky ahead of the Sun. We would appear as a brilliant bluish-white star of magnitude--2.3, apparently hovering not too far from Venus. An observer on Mars would also be able to see our Moon, if not with the unaided eye, then with slight magnification. On May 8, 2003, the Mars Global Surveyor made the first image of the Earth-Moon system as seen from Mars; the result is fuzzy and somewhat humbling (see www.jpl.nasa.gov/ releases/2003/75.cfm).