Science / Medicine : Mars Atmosphere Loss Laid to Comets

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.

In the past, astronomers have advanced several theories about how Mars might have lost much of its atmosphere, but “none of these proposals has gained general acceptance,” said H.J. Melosh and A.M. Vickery of the University of Arizona’s lunar and planetary laboratory.

In a study published in the British journal Nature, the researchers presented computer calculations that they said indicated collisions with large, fast-moving bodies, such as comets, may have triggered Mars’s atmospheric loss.