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Mattia Famoso Liceo Boggio Lera, Catania, Italy [email protected]

NEWS Pluto isn’t a planet The International Astronomical Union (IAU) decided that Pluto should be downgraded to the status of dwarf planet. Our solar system has now eight planets only: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

During the General Assembly of the IAU, the new criteria that would give a new definition of a planet were decided. With the old criteria, Charon and Eris were planets on every aspect.

PLUTO AND ITS SATELLITES

In this way all the number of planets would not be sure, because it is possible other planets will be discov-

ered later.

After careful and long discussion it was decided to make a cut in the category of planets and classify Pluto, Eris and Charon dwarf planets.

Even after its discovery (which took place in 1930 by Clyde Tombaugh) had seen that it was a planet apparently imperfect, but above all very small.

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Strangely, Mike Brown (the discoverer of Eris) rather than being internationally known as its discoverer, voted in favour of downgrading Pluto.

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EPM History of Science and Technology It sounds quite strange that the Americans decided that, since Pluto was the only planet discovered by an American! But now astronomers have finally decided to stop at eight. Will it be the final decision?!

PLUTO AND CHARON

Meanwhile, on Jan 19th 2005, NASA launched a new interplanetary mission to explore Pluto and Charon. The trip will last nearly ten years: the arrival on Pluto is set for July 14th 2015, at that point it was estimated that the probe will be only 10,000 km from the planet. Then (from a distance of about 23000 km) will also sight Charon.

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Iconography http://win.defilippotovini.it/lavori2007.08/SCUOLA_APERTA/sa_raffaello/ MANUEL_SISTEMA%20SOLARE/ plutone.jpg http://astrocultura.uai.it/tesi/stella2004/ Chiara_Donadio/data/img/plutone.jpg www.repubblica.it/2003/e/gallerie/ scienzaetecnologia/lunepluto/ ap76526582302172736_big.jpg www.astronomia.com/wp-content/ uploads/2008/03/sole-da-mercurio.jpg

Bibliography www.ecoblog.it/post/1947/plutonedeclassato-non-e-piu-un-pianeta http:// siderumpulvis.blogspot.com/2006/08/ plutone-non-pi-un-pianeta.html

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