Science : Mars’ Atmosphere Once Thicker
From Times staff and wire service reports
WASHINGTON —
New calculations show Mars may have been stripped of a thick atmosphere that allowed water to flow over the now-desolate planet because it was bombarded by comets or asteroids, scientists reported today.
Mars, the planet that is fourth closest to the sun, currently has a very thin atmosphere with a surface pressure less than one-hundredth of Earth’s. But geological forms on the red planet suggest it once had atmospheric pressure great enough for water to run over its surface.
H. J. Melosh and A. M. Vickery of the University of Arizona, in a study published in the British journal Nature, presented computer calculations they said showed that collisions with large, fast-moving bodies, such as comets, may have triggered Mars’s atmospheric loss.
