USA/ CZECH REPUBLIC: Astronomers strip Pluto of status as planet.

Scientists from around the world approved a new definition of a planet on Thursday (August 24), downgrading Pluto's status after 76 years, to leave just eight classical planets. Thousands of scientists and astronomers agreed at the International Astronomical Union General Assembly in the Czech capital Prague that Pluto, which has been called a planet since its discovery in 1930, would be put into a category of planets called "dwarf planets". The meeting agreed that to be called a planet, a celestial body must be in orbit around a star while not itself being a star. It also must be large enough in mass for its own gravity to pull it into a nearly spherical shape and have cleared the neighbourhood around its orbit. The new definition -- the first time the IAU has tried to define scientifically what a planet is -- means a second category of planets called "dwarf planets", has been created. It also creates a third category known as trans-Neptunian objects. There are now only eight classical planets, dwarf planets falling into a lesser category. At a news conference held after the decision, Richard Binzel, professor of Planetary Sciences at The Massachusetts of Technology and a member of the planet definition committee said it was an historic day. "It is the first time after a millennia that scientists have actually defined the word planet," Binzel said. "If we discover something completely new, completely different that completely changes our scientific view of our solar system or other solar systems that would be tremendously exciting so I look forward to the day when some new discovery forces us to rethink this definition and come up with a new one," he added. From now on -- or 'at least for the time being' -- traditional planets will be restricted to eight: Mercury, Venus. Earth, Mars, Jupiter, Saturn, Uranus and Neptune. For the Smithsonian Institution National Air and Space Museum, that means a lot of scrambling to change all their displays and exhibitions. Spokesman Mike Marcus said the decision means a lot of work. "We have several models of the solar system both in the museum and on the National Mall there is a scale model we have to re evaluate and see how we're going to adjust that to fit the new decision on Pluto being demoted," Marcus said. But for some of the visitors, Pluto's demotion was exciting. "I think it's fascinating because my daughter and I love to learn about the planets," said Judy Danaher who was visiting the planetary exhibition with her 6-year old daughter, Emma.

ITN Source | August 25, 2006

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