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Physics News
Phillip F. Schew
November 27, 1990
A sodium nebula around Jupiter may be the largest object ever recorded on film. A group of astronomers at Boston University, working at the McDonald Observatory in Texas, have detected a neutral cloud of sodium out to distances beyond 400 Jovian radii. The Boston astronomers believe that the shape of the nebula will provide information about Jupiter's magnetosphere and that their technique of measuring non-spherical neutral clouds may be applicable to the study of other planetary magnetospheres.
Physics News
Phillip F. Schewe and Ben Stein
November 9, 1999
Astronomers have previously known of a sodium cloud which precedes the moon Io in its orbit around Jupiter. The cloud is believed to arise from slow escape of sodium from Io. Now the Galileo spacecraft is providing details of another sodium feature at Io, more of a fast-escaping spray or jet, thought to come about when Io plows through Jupiter's potent magnetic field, a process which induces mega-amp currents through Io's atmosphere... New pictures, reported by scientists at the University of Colorado... and Boston University (Jody Wilson), localize the source of the sodium to a region smaller than Io's diameter, suggesting that Io's atmosphere might not be global; that is, the atmosphere might be patchy and not extend all the way to the poles.

Joint News Release
Boston University
Center for Space Physics
and American Geophysical Union
1 June 1999
Boston University astronomers announced today the discovery of an enormous tail of sodium gas stretching to great distances from the moon. The observations were made at the McDonald Observatory in Fort Davis, Texas, on nights following the Leonid meteor shower of November 1998. The tail of sodium gas was seen to distances of at least 500,000 miles from the moon, changing its appearance over three consecutive nights... Ten years ago, groundbased telescopes revealed that sodium gas (Na) was in the lunar atmosphere, an element that can be used to trace the shape and behavior of such a thin atmosphere... The BU team considered several theories that could explain these unusual features, ruling out a comet, the impact of Leonid meteors upon dust in the solar system, and even possible instrumentation problems... [T]he August observations without meteors and the November observations with meteors imply that the daily flux of micrometeors that strikes the moon's surface creates an extended tail at all times; it was just so enhanced during the strong Leonid storm that it was observed rather easily.