Pluto and the plutons.It's a planet! No, it's not! Yes, it is! No, it's not! It sounds like a schoolyard spat, but astronomers have been debating for years whether Pluto is truly a planet. Many people want to keep Pluto in the planet family. So, astronomers are now considering a way to define "planet" so that Pluto remains one. But this means that other bodies in the solar system solar system, the sun and the surrounding planets, natural satellites, dwarf planets, asteroids, meteoroids, and comets that are bound by its gravity. The sun is by far the most massive part of the solar system, containing almost 99.9% of the system's total mass. would also qualify to be called planets. If the new definition is approved by astronomers, the official number of planets will go from 9 to 12. Eventually, there may be dozens more. According to according to prep. 1. As stated or indicated by; on the authority of: according to historians. 2. In keeping with: according to instructions. 3. a panel of seven astronomers, writers, and historians, a planet is an object that orbits a star, but it is not itself a star or a satellite (moon) that orbits a planet. The object must also have enough gravity that its shape is round. "We finally have a definition of a planet after 2,500 years," says Neil deGrasse Tyson Neil deGrasse Tyson (b. October 5, 1958 in New York City) is an astrophysicist and, since 1996, the Frederick P. Rose Director of the Hayden Planetarium at the American Museum of Natural History on Manhattan's Upper West Side. , director of the Hayden Planetarium The Hayden Planetarium is a public planetarium located on Central Park West, New York City, next to and organizationally part of the American Museum of Natural History. in New York City New York City: see New York, city. New York City City (pop., 2000: 8,008,278), southeastern New York, at the mouth of the Hudson River. The largest city in the U.S. . "I applaud any definition that gives us an unambiguous answer." For more than 75 years, textbooks have taught kids to memorize, in order from the sun, the names of the nine planets of the solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune and Pluto. Then, in 1992, astronomers started finding large objects in the outer solar system--a region called the Kuiper belt Kuiper belt: see comet; Kuiper, Gerard Peter. Kuiper belt or Edgeworth-Kuiper belt Disk-shaped belt of billions of small icy bodies orbiting the Sun beyond the orbit of Neptune, mostly at distances 30–50 times Earth's distance , which lies beyond Neptune. The Kuiper belt contains nearly 1,000 objects, including Pluto. Experts have debated Pluto's status as a planet because, compared to other planets, Pluto is pretty weird. Its orbit is oddly shaped. It's also smaller than its planetary peers. Then, last year, astronomers found an object in the belt that's larger than Pluto. This object is called 2003 UB313 (unofficially named Xena). No one seems willing to take away Pluto's planethood. Instead, the panel suggests keeping Pluto and adding anything like Pluto to the list. One such object is Charon, presently considered Pluto's moon. The panel suggests that Charon is big enough that Charon and Pluto together should count as a "double planet." Charon has 15 percent the mass of Pluto. Under the new proposal, 2003 UB313 would also become a planet. Along with Pluto and Charon, it would belong to a new group, called icy plutons. Scientists have discovered at least 41 objects at the edges of the solar system that would eventually become part of this group. There are probably many more icy plutons still waiting to found. Some scientists worry that the new definition will confuse the public. Others just want to get the decision made and over with. The General Assembly of the International Astronomical Union “IAU” redirects here. For other uses, see IAU (disambiguation). The International Astronomical Union (IAU) unites national astronomical societies from around the world. (IAU IAU abbr. 1. International Association of Universities 2. International Astronomical Union ) will soon vote on the proposal in Prague, Czech Republic Czech Republic, Czech Česká Republika (2005 est. pop. 10,241,000), republic, 29,677 sq mi (78,864 sq km), central Europe. It is bordered by Slovakia on the east, Austria on the south, Germany on the west, and Poland on the north. . If the vote is "yes," astronomy textbook publishers may have to add a few extra pages to their planet chapters. http://www.sciencenewsforkids.org/articles/20060823/Note3.asp From Science News for Kids Aug. 23, 2006. |
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