March 9, 2007: Andy Cheng has seen it all. The scientist from Johns Hopkins' Applied Physics Lab has worked on the Galileo mission to Jupiter, the Cassini mission to Saturn, the NEAR mission to asteroid 433 Eros and many others during his decades-long career. Alien vistas are old hat to him.
But even he was amazed when he laid eyes on this photo of Io's Tvashtar volcano, taken Feb. 28th by the New Horizons spacecraft:science.nasa.gov/headlines/y2007/09mar_alienvolcano.htmTvashtar's plume dwarfed grand old Prometheus, rising 180 miles (290 km) above Io's surface. (For comparison, volcanoes on Earth spew their gas and dust just a few miles high.) "The patchy and filamentous structure seen in the Tvashtar plume suggests to me that condensation from gas to solid particulates is occurring," he says. In other words, the gas could be crystallizing in the cold space above Io to form a kind of sulfurous snow.
Volcanoes spewing snow? It is an alien world.
Tidal heating? to 180 miles? patchy and filamentous structure?