Wikipedia:Today's second feature/August 21, 2005
Today's featured picture
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The heliosphere is a bubble in space produced by the solar wind, the stream of charged particles emanating from the Sun. At some distance not exactly known, far beyond the orbit of Pluto, this supersonic wind slows down to meet the gases in the interstellar medium, producing several shock boundaries. This diagram shows the position of Voyager 1 as it crossed the termination shock and entered the heliosheath at a distance of 94 AU some time around December 2004.
Illustration credit: NASA