Thursday, August 24, 2006


After a tumultuous week of clashing over the essence of the cosmos, the International Astronomical Union stripped Pluto of the planetary status it has held since its discovery in 1930. The new definition of what is and isn't a planet fills a centuries-old black hole for scientists who have labored since Copernicus without one.
For now, membership will be restricted to the eight "classical" planets in the solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.
Much-maligned Pluto doesn't make the grade under the new rules for a planet: "a celestial body that is in orbit around the sun, has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a nearly round shape, and has cleared the neighborhood around its orbit." Pluto is automatically disqualified because its oblong orbit overlaps with Neptune's.

Instead, it will be reclassified in a new category of "dwarf planets," similar to what long have been termed "minor planets." The definition also lays out a third class of lesser objects that orbit the sun, "small solar system bodies," a term that will apply to numerous asteroids, comets and other natural satellites.
story here
For Pluto size comparison, check this
Other Pluto articles of interest can be found here and here and here.
Beloved by all, Disney's Pluto retains status. He first appeared in The Chain Gang (1930). Again that year in The Picnic he was Minnie's dog named Rover. Finally, also 1930 in The Moose Hunt, he got his rightful name and since then Pluto has been Mickey's dog.