Dust Cloud Surrounds Jupiter’s Largest Moon, Scientists Discover

Ganymede, Jupiter’s largest moon, is surrounded by a cloud of microscopic dust particles kicked into orbit when small meteorites strike the surface of the moon, a German-American team reports in today’s Nature. Similar dust kicked up earlier in the solar system’s evolution probably formed Saturn’s famous rings, the team said.

The team discovered the dust using a detector on the Galileo spacecraft that has been orbiting Jupiter since December 1995. The dust particles are too small to be seen optically but are detected by their collision with a special device constructed at the Max Planck Institut fur Kernphysik in Heidelberg, Germany.

The meteorites hit the surface of the moon so hard and fast that they evaporate and explode, causing puffs of debris to be ejected at speeds high enough to escape the moon’s gravitational pull, the team said. The new results represent the first time the process has been studied on site.

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Compiled by Times medical writer Thomas H. Maugh II