Is Pluto a Planet?

Image courtesy of mage courtesy of Image courtesy of NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research Institute.




Joel Kontinen


Pluto lost its planetary status in 2006. At that time, several trans-Neptunian objects beat it for size.

At the time, a planet was defined by 1) It must orbit the sun, 2) it must be massive enough that its gravity pulls it more or less into a spherical shape, and 3) it must clear the neighbourhood around its orbit.

Now, in the journal Icarus, Michael Metzger takes the line that “the third criterion did not match historical usage by scientists and should be revoked.”

Needless to say, Pluto is looking young.

And, as Merzger says. Pluto is "more dynamic and alive than Mars.”

Source:

Bartels, Meghan. 2018 Is Pluto a Planet? New Paper Adds to Decade-Long Debate. Space.com. (September 10).