Astronomy Picture of the Day
Discover the cosmos!
Each day a different image or photograph of our fascinating universe is
featured, along with a brief explanation written by a professional
astronomer.
August 3, 1995
Io: A Volcanic Moon
Credit: NASA, Voyager Project
Explanation:
In 1610,
Galileo
turned his telescope to the heavens and discovered that
the planet Jupiter had four bright moons. The innermost of these
Galilean moons,
Io,
turned out to be one of the most exotic objects in
the solar system. About the size of the earth's moon, Io is covered
with volcanoes, many of which are currently active.
The material expelled in the volcanic eruptions may contain compounds
of Sulfur which take on a variety of colours and could account for
its mottled, "pizza-like" appearance.
For a report of a recent eruption of an Io volcano,
see the NASA Infrared Telescope Facility
press release
and
photo .
Tomorrow's picture: Closeup of an Io Volcano.
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Authors & editors:
Robert Nemiroff
(MTU) &
Jerry
Bonnell (USRA)
NASA Technical Rep.:
Jay Norris.
Specific rights apply.
A service of:
LHEA
at
NASA/
GSFC
&:
Michigan Tech. U.
