Pluto faces being sent to minor leagues
Pluto faces being sent to minor leagues
By Dennis Overbye
Copyright by The New York Times
Published: August 23, 2006
Pluto was looking more and more like a goner as astronomers meeting in Prague continued to debate the definition of a planet.
Under fire from other astronomers and the public, a committee appointed by the International Astronomical Union revised and then revised again a definition proposed last week that would have expanded the number of official planets to 12, locking in Pluto as well as the newly discovered Xena in the outer solar system, as well as the asteroid Ceres and Pluto's moon Charon.
The new definition offered Tuesday would set up a three-tiered classification scheme with eight "planets"; a group of "dwarf-planets" that would include Pluto, Ceres, Xena and many other icy balls in the outer solar system; and thousands of "smaller solar system bodies," like comets.
The bottom line, said the Harvard astronomer Owen Gingerich, chairman of the Planet Definition Committee of the astronomical union, is that in the new definition, "Pluto is not a planet."
"There's not happiness all around, believe me," he added.
The new proposal was hashed out in a couple of open meetings, the first of which was described by participants as tumultuous, and the second as more congenial. Astronomers are supposed to vote Thursday on this or some other definition, but whether a consensus is emerging depends on whom you ask. Some astronomers expressed anger that the original definition of a planet had been developed in isolation and then dropped on them only a week before the big vote. Others continued to question whether it was so important to decide the question now.
To many astronomers, Pluto's tiny size and unusually tilted orbit make it a better match to the icy balls floating in the outskirts of the solar system in what is known as the Kuiper Belt than to the traditional planets like Jupiter and Mars.
The issue has been forced on astronomers by the discovery of such a ball even larger than Pluto, nicknamed Xena by its discoverer, Michael Brown, of the California Institute of Technology.
If Pluto is a planet, Xena should be, too, Brown has argued.
The newest resolution includes the requirement for orbital dominance as a condition for full-fledged planethood, Gingerich said. That knocks out Pluto, which crosses the orbit of Neptune, Xena and Ceres.
Pluto was looking more and more like a goner as astronomers meeting in Prague continued to debate the definition of a planet.
Under fire from other astronomers and the public, a committee appointed by the International Astronomical Union revised and then revised again a definition proposed last week that would have expanded the number of official planets to 12, locking in Pluto as well as the newly discovered Xena in the outer solar system, as well as the asteroid Ceres and Pluto's moon Charon.
The new definition offered Tuesday would set up a three-tiered classification scheme with eight "planets"; a group of "dwarf-planets" that would include Pluto, Ceres, Xena and many other icy balls in the outer solar system; and thousands of "smaller solar system bodies," like comets.
The bottom line, said the Harvard astronomer Owen Gingerich, chairman of the Planet Definition Committee of the astronomical union, is that in the new definition, "Pluto is not a planet."
"There's not happiness all around, believe me," he added.
By Dennis Overbye
Copyright by The New York Times
Published: August 23, 2006
Pluto was looking more and more like a goner as astronomers meeting in Prague continued to debate the definition of a planet.
Under fire from other astronomers and the public, a committee appointed by the International Astronomical Union revised and then revised again a definition proposed last week that would have expanded the number of official planets to 12, locking in Pluto as well as the newly discovered Xena in the outer solar system, as well as the asteroid Ceres and Pluto's moon Charon.
The new definition offered Tuesday would set up a three-tiered classification scheme with eight "planets"; a group of "dwarf-planets" that would include Pluto, Ceres, Xena and many other icy balls in the outer solar system; and thousands of "smaller solar system bodies," like comets.
The bottom line, said the Harvard astronomer Owen Gingerich, chairman of the Planet Definition Committee of the astronomical union, is that in the new definition, "Pluto is not a planet."
"There's not happiness all around, believe me," he added.
The new proposal was hashed out in a couple of open meetings, the first of which was described by participants as tumultuous, and the second as more congenial. Astronomers are supposed to vote Thursday on this or some other definition, but whether a consensus is emerging depends on whom you ask. Some astronomers expressed anger that the original definition of a planet had been developed in isolation and then dropped on them only a week before the big vote. Others continued to question whether it was so important to decide the question now.
To many astronomers, Pluto's tiny size and unusually tilted orbit make it a better match to the icy balls floating in the outskirts of the solar system in what is known as the Kuiper Belt than to the traditional planets like Jupiter and Mars.
The issue has been forced on astronomers by the discovery of such a ball even larger than Pluto, nicknamed Xena by its discoverer, Michael Brown, of the California Institute of Technology.
If Pluto is a planet, Xena should be, too, Brown has argued.
The newest resolution includes the requirement for orbital dominance as a condition for full-fledged planethood, Gingerich said. That knocks out Pluto, which crosses the orbit of Neptune, Xena and Ceres.
Pluto was looking more and more like a goner as astronomers meeting in Prague continued to debate the definition of a planet.
Under fire from other astronomers and the public, a committee appointed by the International Astronomical Union revised and then revised again a definition proposed last week that would have expanded the number of official planets to 12, locking in Pluto as well as the newly discovered Xena in the outer solar system, as well as the asteroid Ceres and Pluto's moon Charon.
The new definition offered Tuesday would set up a three-tiered classification scheme with eight "planets"; a group of "dwarf-planets" that would include Pluto, Ceres, Xena and many other icy balls in the outer solar system; and thousands of "smaller solar system bodies," like comets.
The bottom line, said the Harvard astronomer Owen Gingerich, chairman of the Planet Definition Committee of the astronomical union, is that in the new definition, "Pluto is not a planet."
"There's not happiness all around, believe me," he added.
posted by Carlos T Mock at 6:50 AM
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