Last week, I made a prediction to a friend that, alas, has come true. My prediction was that by this week, NASA’s look at Pluto and Charon would have fallen out of the news as being too old, and the ‘news’ programs will have returned to dissecting and analyzing some politician’s speech or statement made last week... or even earlier. As exciting as the Pluto/Charon photos and info are, the people analyzing that information are scientists who want to be sure they understand what they have before making any big announcements like “Life found on Pluto!” or “Charon a huge alien generation ship!”
I find Pluto and Charon far more interesting than all this way-too-early political jibber-jabber we’ve been getting for what seems like the past decade. So I’ll take this opportunity to go through my reasons why I feel Pluto (& Charon) should go through yet another reclassification.
In my research reading the past couple of days, it seems there is no upper size limit to ‘dwarf planet’. One article actually said that if an object larger than Mercury were found in the Keiper Belt, it would be classified as a dwarf planet, because it has not substantially cleared out its neighborhood of debris. Can you imagine? If Earth were located in the asteroid belt, it would be a ‘dwarf planet’!
The lower size limit of ‘dwarf planet’ is pretty fuzzy, too, but from what I gathered, the lower size for a rocky planet is about a radius of 372 miles.
Pluto’s radius is 1,430 miles, about half the size of Mercury, and definitely bigger than that lower limit. NASA’s new photos show it as round and rocky/icy. But look at this; Charon’s radius is 751 miles (about half Pluto’s size), also bigger than that lower limit, and it is also round and rocky/icy. So, why is it still considered by most to be a moon and not a dwarf planet?
Technically, Charon does not revolve around Pluto. Both Charon and Pluto revolve around a common point that is located outside Pluto’s body. If Earth and Mars were in the same orbit and both revolving around a common point, they would be a binary planet. Why not just jump in and classify Pluto/Charon a binary dwarf planet?
I have to imagine that Pluto’s ‘other’ 4 moons probably revolve around that same point, or run the risk of slamming into Charon. If they’re small enough, they could zip around Pluto inside Charon’s ‘orbit’, but from what I understand, Pluto and Charon are pretty close.
The European Space Agency referred to Earth/Moon as a binary planet, and the moon is 1/4 the size of Earth. Another website said that unequivocally, Earth/Moon is not a binary planet, because the moon does not orbit the sun, as set forth in the current definition of planet. Really? How does the moon orbit Earth and not go around the sun at the same time? By that reasoning, binary planets are impossible, because their primary orbit would not be around their star. So, what would they be?
To be fair, I did glimpse some websites that indicate there are others who - like me - think Pluto and Charon are a binary dwarf planet. I hope the idea spreads. Pluto deserves to be somewhat special, in my mind.
What do you think?