Discussion in 'General Science & Technology' started by SwedishFish, Jul 14, 2003.
this is a subject i know nothing about. someone please enlighten me. why is a moon not a planet?
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A planet is a planet becuase it orbits a star.
A moon is a moon becuase it orbits a planet.
That simple. I doubt theres any depthy explanation as to why
zxanth's very correct. and it doesn't get any simpler...
so they're really all big rocks? i don't think moons get enough respect.
does it strike anyone else as odd that there are these giant perfectly spherical rocks flying around in perfect orbit? i never thought of it that way before but it is mindboggling.
i always wonder when i jump up why i tend to come down. bummer!
They aren't perfectly spherical, and they don't fly around in perfect circular orbits. And they aren't all rocky, either.
Not all moons are rocky either. Europa, one of Jupiter's moons,
is completely covered in water ice, with crisscrossing tracks or
cracks in the ice. Many scientist believe there may be a vast
liquid water ocean under the ice, in which case there is the
possibility of life in the ocean.
and the Moon Titan has huge seas of natural gas!
I bet Enron would LOVE to get thier hands on that Moon..
oh poo in know that, i'm just saying. the universe is still an amazing thing to lay people like myself.
It was a debate for a while to name Pluto a moon because it has many characteristics of one but ultimatly they decided to keep it a planet because uh..well...it has a moon. Tritan, Pluto's moon, is the coldest known place in our solar system.
I thought titana was the coldest...
So the question becomes:
So then, what is the difference between a planet and an asteroid? They both orbit stars.
I'll grant the distinction between a planet and a comet. Cometary orbits are so eccentric that they're qualitatively different. But asteroids orbit in a more-or-less planetary manner. They're just small.
Several large moons are bigger than the smallest 2 planets. (3 planets if you include that new one)
Here's a really good site about this.
A Good Definition of the Word "Planet": Mission Impossible?
… and a natural body that orbits a moon is a moonlit?
Pluto and Charon orbit each other and some have assume them as a dual planet system with Pluto being the bigger of the to.
it would be called a Satelite.
Actualy, anything that orbits Anything else is a satelite.. the earth is a satelite of the sun, the sun is a satelite of the galactic core.. (the big black hole in the middle of the milkyway)
Anyone else think otherwise?
There is a case for the distinction in kind between moons and planets-
planets orbit stars, moons orbit planet- there is no known case of a moon having a natural satellite of its own; the distinction in this case is orbital based rather than size based.
In fact all bodies in space are on a more or less sliding scale, mass wise-
meteoroids blur into meteors blur into asteroids blur into planetoids blur into planets blur into brown dwarfs blur into red dwarfs blur into orange, yellow dwarfs, subgiants, giants, hypergiants;
each size grouping has many different compositions, but these compositions are determined by the history of the object and can be considered separately.
SF worldbuilding at
Planet vs. Asteroid
Nobody ever spoke to my question about what defines the difference between a planet and an asteroid.
If a planet orbits a star and a moon orbits a planet...
(No, I am not going to ask what orbits a moon)
Why do people say that Pluto is not a planet, but a moon?
Is there an actual scientific debate on this, or are these just people that are listening to crackpots?
A planet is bigger than an asteroid. That's the only difference, I think.
<i>Why do people say that Pluto is not a planet, but a moon?</i>
Who says that?
Separate names with a comma.