Alan Stern is the principle investigator on NASA's New Horizons mission to Pluto and he thinks Pluto should be a planet. So do plenty of kids who write him letters.
The International Astronomical Union stripped Pluto of its planet status in 2006, because it only meets two of the three criteria in their new definition of a planet:
A celestial body that (a) is in orbit around the Sun, (b) has sufficient mass for its self-gravity to overcome rigid body forces so that it assumes a hydrostatic equilibrium (nearly round) shape, and (c) has cleared the neighbourhood around its orbit.
Pluto hasn't cleared its neighborhood, so it could no longer be called a planet. 😞
But Stern doesn't agree with the astronomers' decision.
"If you put Earth out beyond Neptune, you wouldn't be able to call it a planet because it couldn't clear its zone," Stern told BuzzFeed. "When you produce these awkward definitions, you get these weird consequences."
"As a planetary scientist, I don't know what else to call Pluto: It's big and round and thousands of miles wide" he says. "A miniature poodle is not not a dog, just because it's miniature."
Stern says he's received "dozens" of letters from kids who agree with him, without ever having asked for them.
This particular set of letters come via Janet Ivey, space science educator and founder of Janet's Planet, who is working on outreach for the New Horizon's mission and spoke to classes at an elementary school in Nashville, TN, earlier this month. When she went back the next week, the third grade teacher handed her an envelope full of letters addressed to "Mr Alan".
So here are some of the reasons kids think Pluto should be a planet again.
1. It is round.
2. It rotates on its axis.
3. And it orbits the sun.
4. Yes, it is very small compared to the other planets.
5. But it's big enough.
6. People probably couldn't survive on Pluto.
7. It might have some craters.
8. It's just different, ok?
9. But it's still a circle floating in space just like the other planets.
Of course not everyone in the class agreed that Pluto should be a planet. Some had valid reasons.
Some got a little personal.
And some just wanted answers.