Thursday, August 24, 2006
The International Astronomical Union approved new guidelines Thursday that downsize the solar system from nine planets to eight.
The leading astronomers, meeting in Prague, Czech Republic, stripped Pluto of the planetary status it has held since 1930, when it was discovered.
In doing so, the group provided a new definition of what is and what isn't a planet.
Astronomers have been trying to draw a distinction between the eight "classical planets" -- Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune -- and Pluto, which is smaller than Earth's moon and has an eccentric orbit.
In January, NASA sent a probe known as New Horizons on the way to Pluto. It is expected to reach the object in 2015.