September 20, 2012 16:11
A spacecraft orbiting Mars, fixed carbon dioxide snow falling on the red planet. Thus, Mars was the only body in the solar system, where possible this strange phenomenon.
Snow on Mars fell out of the clouds above the south pole of the planet during the Martian winter 2006-2007, when they found this effect only after a detailed analysis of the results of observations made by Mars research probe MRO. The Martian south pole is ice cap of frozen carbon dioxide, or dry ice, and the new discovery could explain how it was formed and remains unchanged.
"This is the first unambiguous observation carbon dioxide snow clouds — said study author Paul Hein of NASA's Jet Propulsion Laboratory in California, U.S.. — We clearly that clouds are made of carbon dioxide — flakes Martian atmosphere, and they are heavy enough to fall as a result of snow and accumulate on the surface of the planet. "
Discovery means that on Mars, there are two different types of snow. In 2008, the Mars probe "Phoenix" was watching the snow of water ice that fell near the north pole of the red planet. Since the phenomenon we know on Earth.
Hein and his colleagues reviewed data collected tool for climate MRO Mars during Martian winter 2006-2007. This instrument measures the brightness in nine different wavelengths in the visible and infrared light, which allows scientists to study the basic characteristics of the particles and gases in the atmosphere of Mars, such as their size and concentration.
The researchers analyzed the measurements made in the machine direction of the clouds in the vast area of 500 kilometers, from directly vertical to the horizontal direction. These observations clearly showed mixed snow from dry ice falling from the sky red planet.
"A proof of the presence of snow is that the carbon dioxide particles in the clouds are large enough to fall to the ground during the life of the clouds — said study co-author David Kass. — Further evidence lies in the observation, when the tool is aimed at the horizon, and not on the surface. The characteristic features of the clouds, visible in the infrared spectrum at an angle, clearly indicate the presence of particles of carbon dioxide ice, and they extend to the surface. With these observations the tool can distinguish between particles in the atmosphere of dry ice on the surface. "
Astronomers do not know exactly how dry ice accumulation occurred forming the ice cap at the south pole of Mars — the only place where there is a year-round carbon dioxide in frozen form on the surface of the planet. According to scientists, it could be caused by snowfall or substance formed after freezing at ground level.
According to researchers, snowfall means that the form of deposits — snowfall or freezing — something to do with maintaining a year-round ice cap. For the formation of dry ice requires a temperature of about minus 125 degrees Celsius, and this once again confirms the details of the extraordinary cold on the surface of Mars.