I wouldn’t have known if Cath didn’t tell me.
Pluto is no longer a planet (click! click!). Apparently, my favorite little guy “isn’t big enough and strong enough to push anyone around.” It’s also not gravitationally strong enough to be round enough. Pluto is now officially just a dwarf-planet and is categorized along with the other less significant rocks in the solar system.
According to the new definition, a full-fledged planet is an object that orbits the sun and is large enough to have become round due to the force of its own gravity. In addition, a planet has to dominate the neighborhood around its orbit.
Pluto has been demoted because it does not dominate its neighborhood. Charon, its large “moon,” is only about half the size of Pluto, while all the true planets are far larger than their moons.
In addition, bodies that dominate their neighborhoods, “sweep up” asteroids, comets, and other debris, clearing a path along their orbits. By contrast, Pluto’s orbit is somewhat untidy.
Aww, we have one planet less. Dear Astronomers, find another one quick! Because if you guys have nothing to do but fight about names, labels, and definitions, then you definitely need another Mars to liven up the scene.