Pluto Demoted!

Some planetary scientists, such as New Horizons’ Alan Stern and the Dawn mission’s Mark Sykes, aren’t buying the “size matters” argument. They think that any object that orbits the sun and has enough gravity to pull itself into a spherical shape should be called a planet. “When they get that size, that’s when geology turns on,” Sykes told Popular Science during an interview in January.

Scientists on this side of the debate don’t like the IAU’s definition since it depends on a world’s neighborhood instead of its intrinsic properties. If Earth were placed in Pluto’s position, it wouldn’t clear its orbit either, says Stern.

And although Earth’s diameter is five times larger than Pluto’s and that may seem like a big difference, Saturn and Jupiter are 9.5 and 11 times the size of Earth, respectively. Going off of just size alone, the line that separates real planets from minor planets could easily be drawn to exclude Earth.

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Tide1986 said:

Here's a current article on the Pluto debate:

http://www.popsci.com/pluto-has-atm...geological-activity-can-we-call-it-planet-now

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Bamaro said:

Can its orbit be considered spherical?

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Some planetary scientists, such as New Horizons’ Alan Stern and the Dawn mission’s Mark Sykes, aren’t buying the “size matters” argument. They think that any object that orbits the sun and has enough gravity to pull itself into a spherical shape should be called a planet. “When they get that size, that’s when geology turns on,” Sykes told Popular Science during an interview in January.

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Catfish said:

I don't think any planet's orbit is spherical, or not exactly spherical. I think they were talking about the shape of the planet itself, not it's orbit.

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Bamaro said:

Yeah, I misread it.
I heard Neil deGrasse Tyson talking about it the other day and he was saying about how its orbit significantly more oblong than the 8 planets (actually goes inside Neptunes for around 20 years) and its plane was significantly different.

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NationalTitles15 said:

Not a fan of Tyson. At all. And beyond the voting irregularities that took place with demoting Pluto, the criteria are stupid and the IAU should not be deciding the issue. Planetary scientists should. Pluto ought to be a planet and still is in my book.

Article on the issue: http://www.politifact.com/punditfac...-advocates-say-even-earth-would-not-count-pl/

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