Astronomers have been dodging the question for decades, but it looks like they’ll finally have a decision by the end of the IAU (International Astronomical Union) meeting in Prague this summer.Pluto has a few things going for it:
- three moons
- an atmosphere (though it only appears in summer)
And in the negative column:
- not only is it much smaller than the other eight planets, it’s smaller than the Earth’s moon
- even more so, it’s smaller than another object out there, 2003 UB313 and astronomers might not want to open the floodgates for dozens of insignificant planets
- it resembles smaller objects like Triton (moon of Neptune), Sedna, and several other bodies discovered beyond Neptune more than it resembles any known planet
Clyde Tombaugh’s discovery of Pluto in 1930 was a fantastic accomplishment. There’s no doubt about that. It took decades for the next astronomer to discover the next Plutonian neighbor. But I think the IAU is going to disappoint the pro-Pluto crowd and drop our planet-number to eight. What this will do to astrologers, I don’t know. But the rest of us will get over it eventually.