Is Pluto Going To Make a Planetary Come-Back? - Page 2
1. Orbits the Sun. This means it cannot be a star unto itself, and cannot orbit as a moon around another planet. Sorry, Titan, Triton, Ganymede and the other 60 moons hanging out with Jupiter. Some of these moons, by the way, are larger even than Mercury.
2. Has a nearly circular shape. This requires sufficient mass to create its own gravity and overcome the forces of other celestial bodies desiring to “steal” mass from it.
3. Has cleared all debris from its orbital path. This means its gravity well has pulled in all little rocks and bits of dust hanging out nearby, and can reliably continue on its way forevermore, unimpeded.
Because of these new rules, Pluto was relegated to the newly created dwarf planet status, along with Ceres, Haumea, Makemake and new-found 2003 UB313, now known as Eris. Over a hundred more dwarf planets in our Solar System will officially join this status as they are more thoroughly studied.
Is there new-found hope for Pluto?
With the IAU meeting again this year in China, the question has arisen once again. The original IAU definition is only good for celestial objects found inside our own Solar System, and astronomers looking well beyond our neighborhood want to know how to uniformly categorize planet-like objects found around distant stars. Since the last meeting, advanced technologies have allowed astronomers to also find planets that don’t even orbit stars, clouding the defining issue further.
Something’s gotta give here, and ultimately astronomers are going to have to be given a much broader brush to paint the beautiful, silent sentries they see through Hubble or ground-based arrays, or “listen” to through radio-based devices.
Let’s hope they come up with something lasting and easy to use. Although I can understand it remaining in its dwarf status, I kind of miss Pluto being a planet.