Monday, June 18, 2007

Another Slap in the Face for Pluto

Last year, Pluto was “unceremoniously stripped of its status as a planet” by the International Astronomical Union (IAU). It was reduced to the status of “dwarf planet.” But at least it was the biggest dwarf planet. Until this week when new calculations showed rival dwarf, Eris, is 27 percent bigger than Pluto (check out coverage at Scientific American).

Like Pluto, Eris has an elliptical orbit around the sun, true planets on the other hand have circular orbits. Another thing Eris and Pluto have in common is their (likely) composition of ice and rock. One scientist referred to Eris as “covered in an almost perfectly uniform white frost… like a white billiard ball out there."

Eris’ irregular orbit takes it 3.5 to 10 billion miles from Earth. Interestingly enough, Pluto’s orbit stretches as far from the Earth as 5 billion miles, so Eris comes closer to us than Pluto for periods of its 560-year solar orbit. In contrast, Pluto takes 250 years to circle the sun.

With a diameter of 1,500 miles, Eris is roughly half the size of Earth’s moon. As far as diameter, Pluto is a mere 1,400 miles across.

There is one thing that Pluto will always have on Eris and the estimated 50 other dwarf planets in our solar system, Pluto was the first. And so far, it’s the only one with a Disney character named after it. But since we’re running out of Greek and Roman gods to name the planets in our system, and throughout the Galaxy, I’d bet Disney Characters and ancient politicians are next.

By the way, here are the
requirements for planet status, as agreed upon by the IAU:

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I started pound360 to channel my obsession with vitamins, running and the five senses. Eventually, I got bored focusing on all that stuff, so I came back from a one month hiatus in May of 2007 (one year after launching Pound360) and broadened my mumblings here to include all science.