Begin forwarded message: From: Joseph Lorenzo Hall <[EMAIL PROTECTED]> Date: August 24, 2006 11:54:00 AM EDT To: Dave Farber <[EMAIL PROTECTED]> Subject: We now have 12 planets... give or take... Reply-To: [EMAIL PROTECTED] The International Astronomical Union has voted (and passed) a new definition scheme as to what constitutes a "planet". The Final IAU Resolution on the definition of "planet" ready for voting. <http://www.spaceref.com/news/viewpr.html?pid=20674> A "planet" is an object orbiting the Sun that is large enough to form a rough sphere (when gravity balances pressure). Any object orbiting a planet is a satellite (unless the center of mass of their orbit is outside the primary object, like Pluto and Charon, which are now both dwarf planets). (There's some speculation that the definition involved would make Earth and Jupiter not actual planets because they haven't "cleared the neighbourhood around its orbit" (Near-Earth Objects and Trojan Asteroids respectively).) What are the other three "planets" that have been added to the traditional nine? Well, Pluto's "moon" [Charon][1] is now a planet. The asteroid [Ceres][2], which is large enough to be spherical and orbits the Sun is now a planet. Finally, a recently discovered large and round object that is larger than Pluto, [UB313][3], is also a planet. -Joe [1]: http://en.wikipedia.org/wiki/Charon_%28moon%29 [2]: http://en.wikipedia.org/wiki/1_Ceres [3]: http://en.wikipedia.org/wiki/2003_UB313 -- Joseph Lorenzo Hall PhD Student, UC Berkeley, School of Information <http://josephhall.org/> -- Joseph Lorenzo Hall PhD Student, UC Berkeley, School of Information <http://josephhall.org/> ------------------------------------- You are subscribed as [email protected] To manage your subscription, go to http://v2.listbox.com/member/?listname=ip Archives at: http://www.interesting-people.org/archives/interesting-people/
