Top Story: August 18, 2010

Pluto Killer


This will be our last article on SETIcon this week, we promise, but we did save the best for the last: Pluto, everybody’s favorite (non) planet.

There were three sessions on Pluto over the weekend, including the very fun and informative “How I Killed Pluto and Why it Had it Coming” with Mike Brown on Sunday.

If you don’t know who Mike Brown is, known as @plutokiller on Twitter, he’s the guy responsible for demoting Pluto to a dwarf planet. But really, it’s only because he cares.

Brown studies objects in the Kuiper Belt—the stuff beyond Neptune—which now number in the 1200s. In fact, as tweeted just today by @plutokiller, one of the larger objects, Sedna, just got its own Wikipedia page. From Sunday’s discussion, Brown said, “It’s the coldest thing we know in the solar system and takes 12,000 years to go around the sun” Wow! By comparison, Pluto only takes 248 years to orbit the sun.

The Kuiper Belt was discovered in 1992 and it and its objects are truly to blame for Pluto’s demotion. There are several objects close to Pluto’s size, and one, Eris, is even larger. In addition, one third of the objects have moons. They all orbit the sun, but on very titled orbits. Eris’ orbit is tilted by 45 degrees.

But we didn’t really lose a planet, we gained a belt. We just have to change our definition of what the Solar System is according to Brown. Now instead of nine planets, we have eight planets, the asteroid belt and the Kuiper Belt.

And in fact, this makes Pluto even more important. The dwarf planet and its neighbors have been around since the beginning of our Solar System. In fact, he said, the Kuiper Belt holds “the fossil record of the birth of the sun.” Who knows what we’ll find there in the next few years?

At the end of the session, we asked Andrew Fraknoi, who helped organized SETIcon, what Pluto had to do with the search for extraterrestrial intelligence. He admitted nothing, really, but that the organizers thought it would be fun. That it was!

Image credit: NASA and A. Feild (Space Telescope Science Institute)


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