‘Dry Ice’ Snowflakes Seen On Mars

‘Dry Ice’ Snowflakes Seen On Mars, The carbon dioxide snowfall happened near the red planet’s south pole, scientists say. A spacecraft orbiting Mars has detected carbon dioxide snow falling on the Red Planet, making Mars the only body in the solar system known to host this weird weather phenomenon.

The snow on Mars fell from clouds around the planet’s south pole during the Martian winter spanning 2006 and 2007, with scientists discovering it only after sifting through observations by NASA’s Mars Reconnaissance Orbiter (MRO). The Martian south pole hosts a frozen carbon dioxide – or “dry ice” – cap year-round, and the new discovery may help explain how it formed and persists, researchers said.

“These are the first definitive detections of carbon-dioxide snow clouds,” lead author Paul Hayne, of NASA’s Jet Propulsion Laboratory (JPL) in Pasadena, Calif., said in a statement. “We firmly establish the clouds are composed of carbon dioxide – flakes of Martian air – and they are thick enough to result in snowfall accumulation at the surface.”

The find means Mars hosts two different kinds of snowfall. In 2008, NASA’s Phoenix lander observed water-ice snow – the stuff we’re familiar with here on Earth – falling near the Red Planet’s north pole,.

Hayne and his team studied data gathered by MRO’s Mars Climate Sounder instrument during the Red Planet’s southern winter in 2006-2007. This instrument measures brightness in nine different wavelengths of visible and infrared light, allowing scientists to learn key characteristics of the particles and gases in the Martian atmosphere, such as their sizes and concentrations.