Hazy Skies and Flowing Ice
July 24th, 2015, 6:01PMNew information keeps pouring in from New Horizons, now outbound from Pluto but still looking over its shoulder to get as much data as it can before it turns its attention to the Kuiper Belt. Using LORRI, its Long Range Reconnaissance Imager, the spacecraft saw sunlight streaming through two distinct layers of haze--one at an altitude of about 30 miles and the other at 50 miles. Scientists believe that the haze forms when ultraviolet light from the sun breaks up the methane gas in Pluto’s atmosphere, which causes heavier complex hydrocarbons to build up and fall to the colder, lower parts of the atmosphere, where they condense into a haze. The UV light then converts the gas haze into tholins, molecules with a reddish-brown color, which explains the surprising color of Pluto’s surface. In addition to that discovery, New Horizons also shows large sheets of ice that might still be flowing, the way glaciers move on Earth.