Day 525: Wherefore Art Thou, Pluto?

originally published June 8, 2013

Poor, poor Pluto. For many people, the demotion of Pluto from the ranks of the Elite Nine backing vocalists to the Sun’s great whizzbang show was nothing short of a tragedy. Rallies were held, people marched through the streets with pale orange warpaint smeared across their sweaty faces, and supporters across the globe lit their local Laundromats on fire in a misguided act of defiance. Myself, I refuse to acknowledge Micronesia as a nation until we can once again call Pluto a planet.

Well, bad news everyone. As much as we’d like to cling to the security blanket of our childhood science lessons – the few we remember, anyway – Pluto is not technically a planet. Nor is it sentient, nor is it even aware that it has been demoted. That chunk of ice-rock has had a brief flicker in the window of our awareness, and its ‘status’ has shifted a lot more often than this most recent re-classification.

Oh, and technically Micronesia is a region; the Federated States of Micronesia is a country. So my protest may have been in vain.

Back in the 1840’s, a suave fellow named Urbain Le Verrier noticed there were some quirky wiggles in Uranus’s orbit. ‘Quirky Wiggles’ is not the scientific term – in fact, it would be a great name for a clown at a kid’s party – but the point is, Uranus was acting a little wonky. Using what he learned from Isaac Newton’s lessons on mechanics (which is clearly more than I have learned from them), Le Verrier pinpointed where another planet might be. That planet turned out to be Neptune.

A few decades later, astronomers were noticing that Neptune still wasn’t accounting for all the bumps and stumbles in Uranus’s orbit. They figured there had to be another planet out there, mucking up the works. Percival Lowell, the wealthy astronomer who sketched out the canals of Mars (which don’t actually exist, but hey, technology makes for good hindsight), set off on a mission to discover Planet X in 1906.

Lowell’s search continued until his death in 1916, after which the great workings of his Flagstaff, Arizona observatory assumed a state of stasis as his widow grappled for her share of the space-money that was no doubt oozing from the observatory walls. Then in 1929, the job of finding Planet X was handed over to Lowell Observatory wunderkind Clyde Tombaugh, 23 years old. It took Clyde over a year, but in March of 1930 his discovery was confirmed.

The planet’s name was the first thing to figure out. Constance Lowell, the widow whose legal wrangling added fourteen years to the hunt for Planet X, suggested ‘Percival’, ‘Zeus’ and ‘Constance’. Those were tossed in the trash heap. It was eleven-year-old Venetia Burney, a schoolgirl in Oxford, who came up with the name Pluto. She knew him as the god of the underworld, and felt such a cold and dark place deserved an appropriately bitchin’ name.

The name was a lock, and the citizens of earth had a new neighbor, albeit a cold, hermit-type who lives at the far end of the street and doesn’t conform to the lifestyle (in this case, elliptical orbit) of everyone else. Walt Disney introduced Mickey Mouse’s dog companion that same year, seemingly naming it after the new planet. Disney animator Ben Sharpsteen, director of Pinocchio and Dumbo, claims that no one really confirmed that the dog was named after the planet, but since they both showed up in 1930 and it’s unlikely Walt would have named a cartoon dog after the god of the underworld, I think we can assume the dog’s name is a tribute. There’s no doubt that Glenn T. Seaborg named his new element, plutonium, after the planet.

That little chunk of rock was a Depression-era celebrity, bigger than Betty Boop.

It didn’t take long for Pluto to begin its Lindsay-Lohanian slide from beloved celebrity ice-chunk into the gutter of societal rejection. In 1931 Pluto was believed to be a kindred sister, the size and mass of earth, craving our love and the warmth of the too-distant sun. In 1948, further calculations bumped her down to the size of Mars. In 1976, a trio of astronomical buzz-kills at the University of Hawaii figured out Pluto’s albedo was made of methane ice, and its luminosity had us all fooled – she couldn’t be bigger than 1% of Earth’s mass. Two years later, the discovery of Charon, Pluto’s moon, allowed for a proper calculation of the planet’s mass… 0.2% of earth. Hardly enough to shake up the orbital groove of Uranus.

So Pluto had suffered her licks, and the hunt resumed for the mysterious Planet X. This time it took until Voyager 2 cruised by Neptune in 1992. Yale prof Myles Standish was able to get a clearer picture of Neptune’s mass, and realized that our eighth planet was in fact the one messing about with Uranus all along. There was no Planet X.

Things were not looking good for that one-time starlet of the 30’s.

This was around when astronomers began referring to the Kuiper Belt as the area beyond Neptune, filled with the most distant debris of our solar system. They looked at Pluto, not with the adoring eyes of a world stretching the limits of its own discovery but with the clinical eyes of a post-Hubble perspective, when our eyes were straining to see the origins of the universe. Pluto, they reasoned, wasn’t much different than the rest of the population in the Kuiper Belt.

Then along came Eris, the grey shrew whose location – three times further from the sun than Pluto – had remained hidden all this time. Eris is 27% larger than Pluto, and likely more deserving of a higher rank. The International Astronomical Union finally had to sit down and decide what actually qualifies as a planet. They came up with three criteria:

  1. The object must be in orbit around the sun. Check.
  2. It must be large enough for its own gravitational force to have squished it into a sphere. Check.
  3. It must be the largest object in its orbit zone, having ‘cleared the neighborhood’ of anything else in its path. Uh oh.

Pluto didn’t meet the third criteria, and she was thusly relegated to the new class known as dwarf planets. So instead of being a part of the Illustrious Nine (now Eight), Pluto is in a class of five, along with Ceres in the asteroid belt, and Haumea, Makemake and Eris in the outer fringe of the solar system.

So don’t despair. Pluto may not be a planet, but she’s not alone. And no one’s changing the name of Mickey Mouse’s dog – Pluto’s place in history as a one-time star (well, planet) won’t be forgotten.

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