Did you hear that another moon of Pluto has been discovered? Yes! In grade school we learned our solar system has 9 planets circling the sun. Pluto was #9. Then a few years ago, Pluto was downgraded to a dwarf planet (i.e. a bigger than average icy rock). Shocking to Pluto lovers everywhere, I know, but we've adjusted.
Then just when we relaxed enough to admit to 8 planets circling the sun, last week a new moon of Pluto is discovered. Now it has 5, but still can't regain planetary status. NASA update on Pluto.
What gives? First, I thought only planets could have moons, so I checked. A moon is a solid object caught in the gravity of and circling a more massive object that is itself circling something bigger like a star. Sounds like Pluto, but it still can't be a planet again.
Apparently, Pluto and its moons are just a few of the thousands of ice balls and cosmic rocks found beyond the planets in the Kuiper Belt. The region is littered with objects left over from the Big Bang or resulting from collisions with larger objects. So the bottom line is that Pluto is still not a true planet even with its own moons. It is just part of the floating rock pile beyond our 8 planet solar system. Sigh...