I’m saying that (many) moons are planets too. Anything big enough to be round, but not big enough to burn hydrogen, should be a planet regardless of where it orbits.
But how round is round enough? What about the millions of asteroids floating in the asteroid belt, many of those are spherical. Should they be considered planets? No, of course not. We can’t just call everything that looks like a sphere a planet. That’s ridiculous.
It was decided that planets 1. should have a stable orbit around a star 2. have enough mass to become spherical (that’s your point) 3. massive enough to clear its orbit, which in our Solar System means there are 8 planets. Pluto is surrounded by millions of Pluto-like objects in the Kuiper belt. Pluto, as well as its buddies Eris, Makemake, etc. are classified as dwarf planets because they are not massive enough to have cleared their orbits.
Dwarf planets are cool too, they might even have life in subsurface oceans under all that ice :0
Moons are not planets because they don’t orbit a star. Stars are pretty well-defined, objects where there is enough mass for nuclear fusion to occur. Planets are definitely not stars, so moons are not planets.
You’re just repeating the definition that I’ve already made clear I disagree with. This definition isn’t science, it’s taxonomy. Taxonomy is just a tool; we group similar entities together so we can characterize them. A body’s orbit and neighbors aren’t as important for that purpose as other attributes like size and composition.
Should they be considered planets? No, of course not.
Why not?
how round is round enough?
I’m sure the IAU can come up with a suitable boundary. The lines are always fuzzy.
I’m saying that (many) moons are planets too. Anything big enough to be round, but not big enough to burn hydrogen, should be a planet regardless of where it orbits.
But how round is round enough? What about the millions of asteroids floating in the asteroid belt, many of those are spherical. Should they be considered planets? No, of course not. We can’t just call everything that looks like a sphere a planet. That’s ridiculous.
It was decided that planets 1. should have a stable orbit around a star 2. have enough mass to become spherical (that’s your point) 3. massive enough to clear its orbit, which in our Solar System means there are 8 planets. Pluto is surrounded by millions of Pluto-like objects in the Kuiper belt. Pluto, as well as its buddies Eris, Makemake, etc. are classified as dwarf planets because they are not massive enough to have cleared their orbits.
Dwarf planets are cool too, they might even have life in subsurface oceans under all that ice :0
Moons are not planets because they don’t orbit a star. Stars are pretty well-defined, objects where there is enough mass for nuclear fusion to occur. Planets are definitely not stars, so moons are not planets.
You’re just repeating the definition that I’ve already made clear I disagree with. This definition isn’t science, it’s taxonomy. Taxonomy is just a tool; we group similar entities together so we can characterize them. A body’s orbit and neighbors aren’t as important for that purpose as other attributes like size and composition.
Why not?
I’m sure the IAU can come up with a suitable boundary. The lines are always fuzzy.