College Park, Md. -- NASA's close encounter with comet Hartley 2 found dry ice is the fuel for jets of gas and dust bursting from the comet's surface, U.S. researchers say.
Images from the University of Maryland-led EPOXI mission flyby show spectacular jets of gas and particles shooting from many distinct spots on the surface of the comet, a university release said Wednesday.
Spectral analysis of the materials coming from the jets shows primarily CO2 gas (carbon dioxide) and particles of dust and ice, researchers said.
"Previously it was thought that water vapor from water ice was the propulsive force behind jets of material coming off of the body, or nucleus, of the comet," UM astronomy professor Jessica Sunshine said.