Present - day Mars is a cold and dry planet with less than 1 % of Earth's atmospheric pressure at the surface. (sciencedaily.com)
The red region shows the habitable zone as extended inward for dry planets, with minimal surface water, a low water - vapor atmospheric abundance, and low atmospheric relative humidity and hence a smaller greenhouse effect. (hdstvision.org)
«We would like to know whether in other planetary systems Kuiper belts exist with large quantities of water that could be added to otherwise dry planets,» he said. (keckobservatory.org)