The Harvard-Smithsonian Center for Astrophysics opened one of those cans of worms that refuse to go away any time soon: Is in fact Pluto a planet or not?
The organization had 3 distinguished scientists present the case for and against Pluto. Pluto’s planet status you may recall has been redefined and questioned since about 2006 when the International Astronomical Union (IAU) set a definition of what it meant to be a planet. The current, official definition says that a planet is a celestial body that:
1. is in orbit around the Sun,
2. is round or nearly round, and
3. has “cleared the neighborhood” around its orbit.
This definition excluded Pluto and reclassified it as a "dwarf planet."
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“But this definition baffled the public and classrooms around the country. For one thing, it only applied to planets in our solar system. What about all those exoplanets orbiting other stars? Are they planets? And Pluto was booted from the planet club and called a dwarf planet. Is a dwarf planet a small planet? Not according to the IAU. Even though a dwarf fruit tree is still a small fruit tree, and a dwarf hamster is still a small hamster,” according to the Harvard-Smithsonian.
Anyway, in an effort to semi-quell this controversy the Harvard-Smithsonian detailed the recent event and it went like this:
Science historian Dr. Owen Gingerich, who chaired the International Astronomical Union (IAU) planet definition committee, presented the historical viewpoint. Dr. Gareth Williams, associate director of the Minor Planet Center, presented the IAU’s viewpoint. And Dr. Dimitar Sasselov, director of the Harvard Origins of Life Initiative, presented the exoplanet scientist’s viewpoint.
Gingerich argued that “a planet is a culturally defined word that changes over time,” and that Pluto is a planet. Williams defended the IAU definition, which declares that Pluto is not a planet. And Sasselov defined a planet as “the smallest spherical lump of matter that formed around stars or stellar remnants,” which means Pluto is a planet.
After these experts made their best case, the audience got to vote on what a planet is or isn’t and whether Pluto is in or out.
The results are in, with no hanging chads in sight.
According to the audience, Sasselov’s definition won the day, and Pluto IS a planet.
So will that informal vote mitigate the dispute? Not likely. Though perhaps when NASA’s New Horizons spacecraft examines Pluto next year some more definitive science will sway the argument one way or the other.
Then again. What do you think?
If you want to watch the whole thing take a look:
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