Post by gogonutz on Aug 24, 2006 10:43:08 GMT -5
Astronomers will next week vote on a redefinition of the term "planet" that will allow three celestial bodies in our solar system to be counted as planets for the first time.
But Pluto will be downgraded to a second-tier planet, joining new entrants Ceres, Charon and Xena as "plutons".
The new definitions will leave eight "classical planets" - Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Everything else, including Pluto, named as the ninth planet when it was discovered in 1930, will be a pluton.
Under the proposal put forward by a seven-member Planet Definition Committee, plutons will be considered objects in the outer regions of the solar system that are Pluto-sized or bigger. They also have orbits different from their classical counterparts, and typically take more than 200 years to orbit the sun.
The new draft definition states that two conditions must be met for an object to be called a planet: it must orbit a star and be big enough for its own gravity to pull it into a spherical shape.
The committee's resolution - presented yesterday at the International Astronomical Union meeting in the Czech capital of Prague - will be voted on next week by members of the 9000-strong body. Australia has 200 members of the IAU.
If the resolution is passed, original committee member Chris Tinney - an astronomer with the Anglo-Australian Observatory in Sydney - will be delighted. "I will be deliriously happy when I no longer have to spend a moment of my time worrying about the definition of the word planet," Dr Tinney said last year when The Australian flagged the resolution.
IAU president Ron Ekers said from Prague the new definition of a planet was necessary because of the recent discovery of objects such as Xena, which are bigger than Pluto. "These discoveries have rightfully called into question whether or not they should be considered new planets," said Professor Ekers, foundation director of the CSIRO Australia Telescope National Facility in Sydney.
Committee chairman Owen Gingerich said Pluto was a particular sticking point in the debate, largely because of widespread public sentiment towards the distant planet.
Committee members were worried they would be unable to reach consensus at the July meeting, the Harvard University astronomer said. "But by the end of a long day, the miracle had happened. We had reached a unanimous agreement."
But Pluto will be downgraded to a second-tier planet, joining new entrants Ceres, Charon and Xena as "plutons".
The new definitions will leave eight "classical planets" - Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Everything else, including Pluto, named as the ninth planet when it was discovered in 1930, will be a pluton.
Under the proposal put forward by a seven-member Planet Definition Committee, plutons will be considered objects in the outer regions of the solar system that are Pluto-sized or bigger. They also have orbits different from their classical counterparts, and typically take more than 200 years to orbit the sun.
The new draft definition states that two conditions must be met for an object to be called a planet: it must orbit a star and be big enough for its own gravity to pull it into a spherical shape.
The committee's resolution - presented yesterday at the International Astronomical Union meeting in the Czech capital of Prague - will be voted on next week by members of the 9000-strong body. Australia has 200 members of the IAU.
If the resolution is passed, original committee member Chris Tinney - an astronomer with the Anglo-Australian Observatory in Sydney - will be delighted. "I will be deliriously happy when I no longer have to spend a moment of my time worrying about the definition of the word planet," Dr Tinney said last year when The Australian flagged the resolution.
IAU president Ron Ekers said from Prague the new definition of a planet was necessary because of the recent discovery of objects such as Xena, which are bigger than Pluto. "These discoveries have rightfully called into question whether or not they should be considered new planets," said Professor Ekers, foundation director of the CSIRO Australia Telescope National Facility in Sydney.
Committee chairman Owen Gingerich said Pluto was a particular sticking point in the debate, largely because of widespread public sentiment towards the distant planet.
Committee members were worried they would be unable to reach consensus at the July meeting, the Harvard University astronomer said. "But by the end of a long day, the miracle had happened. We had reached a unanimous agreement."
. I'd also like to know if anybody has an HD copy of Lifehouse at Pinkpop 2003. BY far their best concert ever