Astronomy Picture of the Day
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August 4, 1995
Closeup of an Io Volcano
Credit: NASA, Voyager Project
In 1979, one of NASA's
spacecraft made a spectacular and unexpected
the innermost Galilean moon of Jupiter, was covered
with volcanoes and some of them were erupting! In all, Voyager 1 observed
nine volcanic eruptions during its encounter with the moon.
When Voyager 2 flew past four months
later it was able to confirm that at least six of them were still erupting.
This Voyager image of Ra Patera, a large shield volcano, shows colourful
flows up to about 200 miles long emanating from the
dark central volcanic vent.
For more information about volcanism on Io, see
`Views of the Solar System'
Tomorrow's picture: Geysers on Triton
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