The most massive planet in our solar system, with four
planet-sized moons and many smaller moons, Jupiter forms a kind of
miniature solar system. Jupiter resembles a star in composition. In
fact, if it had been about eighty times more massive, it would have
become a star rather than a planet.
On January 7, 1610, using his primitive telescope, astronomer
Galileo Galilei saw four small 'stars' near Jupiter. He had
discovered Jupiter's four largest moons, now called Io, Europa,
Ganymede, and Callisto. Collectively, these four moons are known
today as the Galilean satellites.
Galileo would be astonished at what we have learned about
Jupiter and its moons in the past 30 years. Io is the most
volcanically active body in our solar system. Ganymede is the
largest planetary moon and is the only moon in the solar system
known to have its own magnetic field. A liquid ocean may lie
beneath the frozen crust of Europa. Icy oceans may also lie deep
beneath the crusts of Callisto and Ganymede. In 2003 alone,
astronomers discovered 23 new moons orbiting the giant planet,
giving Jupiter a total moon count of 49 - the most in the solar
system. The numerous small outer moons may be asteroids captured by
the giant planet's gravity.
Other caches in this series:
GC15YAM
Solar System Challenge GC15YAR Cowboy Sun GC15YAT Cowboy
Mercury GC15YAY Cowboy Venus GC15YB1 Cowboy
Earth / Moon GC15YB5 Cowboy Mars GC15YB8 Cowboy
Saturn GC15YBA Cowboy Uranus GC15YBC Cowboy
Neptune GC15YBE Cowboy Pluto
FTF
"Contryguy" & "Morgie H" Sept 29th, 2007
Placed by a Nebraskache Member