NASA Needs to Pick A Planet Number
@DavidWeaver how many planets are there in our solar system? Officially NASA says 8 which means this was accomplished in 1989 #plutoflyby
— NASA Watch (@NASAWatch) July 15, 2015
@DavidWeaver how many planets are there in our solar system? Officially NASA says 8 which means this was accomplished in 1989 #plutoflyby
— NASA Watch (@NASAWatch) July 15, 2015
I’m comfortable with the 8-Planet Standard. The eight major planets all have circularized orbits in the plane of the ecliptic and are significantly larger and more massive than the other bodies in the solar system (even Mercury was probably closer to Mars in mass and size before an impact blew off much of its mantle, although it’s smaller than Ganymede now).
There’s not really going to be a hard-and-fast standard in any case, much like how there isn’t one with continents. Are there 7 continents, or three: Afro-Eurasia-America, Australia, and Antarctica?
Let’s compromise, Pluto is the 8-1/2 planet. 😉
8 “major” planets, plus a big and growing batch of “minor” planets.
Wordsmithing doesn’t change reality, as we all like to think it does.
Pluto was always the odd man out among planets, tiny, out of the ecliptic and actually crossing the orbit of Neptune. Now Pluto is at home, with Ceres, Eris, Haumea, Triton (by origin) and dozens of similar bodies.