Posted by tourdemars to Planetology at February 6, 2007 02:27 PM

Nighttime clouds detected for the first time on Mars help to keep the planet’s surface warm after sunset when temperatures drop, a new study suggests. The nocturnal clouds are five times thicker than their daytime counterparts and hover close to the ground, almost like a fog. The study, conducted by researchers at NASA and the National Oceanic and Atmospheric Administration (NOAA), is detailed in the Feb. 1 issue of Geophysical Research Letters.