Post by Seth Drakin of Monster Crap on Aug 24, 2006 11:09:25 GMT -5
After a tumultuous week of clashing over the essence of the cosmos, leading astronomers Thursday 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.
The historic vote by the International Astronomical Union officially shrinks Earth’s neighborhood from the traditional nine planets to eight — forcing future revisions of science textbooks and classroom charts. But the scientists made clear they’re as sentimental as anyone else about the ninth rock from the sun.
Jocelyn Bell Burnell — a specialist in neutron stars from Northern Ireland who oversaw the proceedings in Prague — urged those who might be “quite disappointed” to look on the bright side.
“It could be argued that we are creating an umbrella called ’planet’ under which the dwarf planets exist,” she said, drawing laughter by waving a stuffed Pluto of Walt Disney fame beneath a real umbrella. Later, she hugged the doll as she stood at the dais.
“Many more Plutos wait to be discovered,” added Richard Binzel, a professor of planetary science at the Massachusetts Institute of Technology.
In fact, NASA’s New Horizons spacecraft is in the midst of a 9½-year journey to the solar system’s rim to study Pluto and a whole class of what are now known as "Plutonian objects." Louis Friedman, the executive director of the nonprofit Planetary Society, said in a statement that Pluto and its icy kin were still eminently worthy of study, regardless of their classification.
“Anytime we visit a new world — planet, moon, asteroid, comet, whatever — we make exciting and surprising new discoveries about the evolution of our solar system and about our own planet,” Friedman said.
Who belongs in the cosmic club?
The decision by the prestigious international group spells out the basic tests that celestial objects will have to meet before they can be considered for admission to the elite cosmic club.
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 — named for the god of the underworld — 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 that of much larger Neptune.
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.
Experts said there could be dozens of dwarf planets cataloged across the solar system in the next few years.
Dramatic reversal
The decision at a conference of 2,500 astronomers from 75 countries was a dramatic shift from just a week ago, when the group’s leaders floated a proposal that would have reaffirmed Pluto’s planetary status and made planets of its largest moon and two other objects.
That plan proved highly unpopular, splitting astronomers into factions and triggering days of sometimes combative debate that led to Pluto’s undoing. In the end, only about 300 astronomers cast ballots.
Now, two of the objects that at one point were cruising toward possible full-fledged planethood will join Pluto as dwarfs: the asteroid Ceres, which was a planet in the 1800s before it got demoted, and 2003 UB313, an icy object slightly larger than Pluto whose discoverer, Michael Brown of the California Institute of Technology, has nicknamed Xena.
Charon, the largest of Pluto’s three moons, is no longer under consideration for any special designation.
Brown was pleased by the decision. He had argued that Pluto and similar bodies didn’t deserve planet status, saying that would “take the magic out of the solar system.”
“UB313 is the largest dwarf planet. That’s kind of cool,” he said.
But as it all sank in, he added: “Deep down inside, I know this is the right thing to do. It’s sad. As of today, I have no longer discovered a planet.”
The historic vote by the International Astronomical Union officially shrinks Earth’s neighborhood from the traditional nine planets to eight — forcing future revisions of science textbooks and classroom charts. But the scientists made clear they’re as sentimental as anyone else about the ninth rock from the sun.
Jocelyn Bell Burnell — a specialist in neutron stars from Northern Ireland who oversaw the proceedings in Prague — urged those who might be “quite disappointed” to look on the bright side.
“It could be argued that we are creating an umbrella called ’planet’ under which the dwarf planets exist,” she said, drawing laughter by waving a stuffed Pluto of Walt Disney fame beneath a real umbrella. Later, she hugged the doll as she stood at the dais.
“Many more Plutos wait to be discovered,” added Richard Binzel, a professor of planetary science at the Massachusetts Institute of Technology.
In fact, NASA’s New Horizons spacecraft is in the midst of a 9½-year journey to the solar system’s rim to study Pluto and a whole class of what are now known as "Plutonian objects." Louis Friedman, the executive director of the nonprofit Planetary Society, said in a statement that Pluto and its icy kin were still eminently worthy of study, regardless of their classification.
“Anytime we visit a new world — planet, moon, asteroid, comet, whatever — we make exciting and surprising new discoveries about the evolution of our solar system and about our own planet,” Friedman said.
Who belongs in the cosmic club?
The decision by the prestigious international group spells out the basic tests that celestial objects will have to meet before they can be considered for admission to the elite cosmic club.
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 — named for the god of the underworld — 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 that of much larger Neptune.
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.
Experts said there could be dozens of dwarf planets cataloged across the solar system in the next few years.
Dramatic reversal
The decision at a conference of 2,500 astronomers from 75 countries was a dramatic shift from just a week ago, when the group’s leaders floated a proposal that would have reaffirmed Pluto’s planetary status and made planets of its largest moon and two other objects.
That plan proved highly unpopular, splitting astronomers into factions and triggering days of sometimes combative debate that led to Pluto’s undoing. In the end, only about 300 astronomers cast ballots.
Now, two of the objects that at one point were cruising toward possible full-fledged planethood will join Pluto as dwarfs: the asteroid Ceres, which was a planet in the 1800s before it got demoted, and 2003 UB313, an icy object slightly larger than Pluto whose discoverer, Michael Brown of the California Institute of Technology, has nicknamed Xena.
Charon, the largest of Pluto’s three moons, is no longer under consideration for any special designation.
Brown was pleased by the decision. He had argued that Pluto and similar bodies didn’t deserve planet status, saying that would “take the magic out of the solar system.”
“UB313 is the largest dwarf planet. That’s kind of cool,” he said.
But as it all sank in, he added: “Deep down inside, I know this is the right thing to do. It’s sad. As of today, I have no longer discovered a planet.”
Damn them. Damn them all to hell.
