Jul 29 2005
From The Space Library
A group of astronomers led by Michael E. Brown of the California Institute of Technology announced the discovery of a new planet in the solar system. The scientists had temporarily called the planet 2003 UB3 13 until the International Astronomic Union could formally approve the name that the scientists had proposed, but had not yet disclosed to the public. Although the scientists did not yet know the planet's exact size, they believed it was larger than Pluto, which astronomers estimate is 1,400 miles (2,300 kilometers) in diameter. In addition, the newly discovered planet, which the scientists believed to be composed of rock and ice, was the furthest known object in the solar system, with a 560-year elliptical orbit around the Sun at distances ranging from 3.3 to 9 billion miles (5.3 to 14 billion kilometers) from the Sun. By comparison, Pluto's orbit ranges from 2.7 to 4.6 billion miles (4.3 to 7.4 billion kilometers) from the Sun. The astronomers had also discovered that the orbit of 2003 UB3 13 is quite different from that of most planets in the solar system~it possesses an orbit skewed at an angle 44º from Earth's orbit, whereas most planets orbit in planes that are close to that of Earth. (Kenneth Chang and Dennis Overbye, “Planet or Not, Pluto Has Far-Out Rival,” New York Times, 30 July 2005; NASA, “World Book at NASA: Pluto,” http://www.nasa.gov/worldbook/plutoworldbook.html (accessed 2 July 2009); Richard A. Kerr, “Newfound 'Tenth Planet' Puts Pluto Behind the Eight Ball,” Science 309, 5736 (5 August 2005): 859.)
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