Our solar system once had nine planets, which we all learned helped mnemonics like "Mother Very Thoughtfully Made A Jelly Sandwich Under No Protest." (T for Terra, us, thank you.) Then Pluto got kicked to the curb.
The International Astronomical Union, which gets to say what is a planet and what isn't, stripped distant Pluto of its planet status in 2006.
Pluto was told to go sit in the corner, and was summarily downgraded to the second-class status of "dwarf planet."
The public wasn't happy after all those years of memorizing the planet names, and many planetary scientists said the IAU decision was arbitrary.
To be a planet, the IAU said, a celestial body has to orbit the sun, has to be round or close to it, and has to have sufficient gravity to clear the neighborhood of its orbit of other objects.
Pluto, at least in the eyes of the IAU, failed the third test because it's too small to have cleared neighboring space rocks from out of its way in its long journeys around the sun.
Not so fast, said the Harvard-Smithsonian Center for Astrophysics, which joined the debate and on Sept. 18 presented both pros and cons -- and then allowed a public audience attending the debate to vote.
The response was loud and clear; as far as the public is concerned, Pluto is a full-fledged planet.
The non-binding vote doesn't mean Pluto is suddenly a planet again, but could be considered a demonstration of a desire to have our solar system as it once was.
The public apparently agreed with Dimitar Sasselov, head of the Harvard Origins of Life Initiative, who argued in the debate that a planet is "the smallest spherical lump of matter that formed around stars or stellar remnants."
Pluto may be small -- with a radius of just 750 miles and a circumference of around 4,500 miles, making it smaller that Earth's moon -- but it's definitely spherical and formed around a star, our sun, those plumping for reinstatement of Pluto's former status argued.
Its size shouldn't be held against it, they said.
Or as the Harvard-Smithsonian Center put it, "a dwarf fruit tree is still a small fruit tree, and a dwarf hamster is still a small hamster."
At least one expert said he preferred the public's view to those of many of his fellow scientists.
"I think the public is better suited to this than astronomers, at least," said Alan Stern, principal investigator for NASA's New Horizons spacecraft on its way to Pluto, the first space probe ever sent toward the planet.
"The IAU should never have pretended to have the expertise to enter into this debate," he said. "It's a matter for planetary scientists, not astronomers."
