Images: Astronomers see three new planets
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Jupiter and Saturn may move farther from the sun in a new lineup of planets proposed by the International Astronomical Union.rnrnrnrn
rnThe designated dozen would include Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune, and Pluto. The three newcomers would be Ceres, the largest known asteroid which orbits between Mars and Jupiter; Charon, which has been considered Pluto’s moon; and the recently discovered 2003 UB313, an object nicknamed Xena that was discovered in 2005 orbiting far beyond Pluto in the outer solar system.rnrn
This is an artist’s montage of an “expanded” solar system.
Ceres, named after the Roman goddess of agriculture, was discovered in 1801 by Giuseppe Piazzi. It was first called a planet, then demoted to asteroid status, and may be headed back to being a planet. Ceres, the largest object in the asteroid belt between Mars and Jupiter is about 600 miles in diameter–almost one fourth the size of the moon. It completes one orbit around the sun in about 4.6 years. rn
Earlier this year NASA cancelled, then reinstated, the Dawn mission which is now scheduled to launch in 2007. A probe will be sent on a four year journey to the minor planet Vesta where it will spend about a year before being sent to its next target, Ceres, where it will arrive in 2016.
This cutout view of Ceres shows that the potential planet may contain water. With no atmosphere, the possibility of life on Ceres is remote.
In 1978, Charon was discovered by James Christy who noted a bulge in images from the planet Pluto that moved, in this case, from the top to the bottom over time. Charon was named after a “ferryman of the dead” figure in Greek mythology.rnrn
Some astronomers are especially critical of giving new status to Charon, shown here to the right of Pluto. Charon’s new status would come because it is big enough for gravity to crush all other forces and make it round. But so are some of Jupiter’s and Saturn’s moons, as well as Earth’s.
On January 19, 2006 NASA launched the New Horizons spacecraft on a 3-billion mile journey to reach Pluto and Charon in the summer of 2015. The piano-sized craft, designed and built at Johns Hopkins University Applied Physics Laboratory, will travel at a record 36,000 miles per hour after bouncing off Jupiter’s gravity field in February 2007. After passing the two(?) planets, the craft will be directed toward one more object in the Kuiper belt.rnrn
Who knows what the probe may find. It has only been traveling for seven months and two new moons and a planet have appeared on its route.
The third new planet is officially named 2003 UB313 but is better known as Xena. It was discovered in 2005 from images taken in 2003 and is slightly larger than Pluto. rnrn
The name Xena comes from the TV series “Xena, Warrior Princess” and its moon is called Gabrielle, Xena’s sidekick.
