What’s a “moon” versus a “planet”? Earth is a moon of Sol, is it not?
We already have the word "satellite" for "things that go around other things" right? I think "moon" is just "satellite of a planet" for convenience in discussing that subset.
Why is having a lot of planets a problem in the first place?
I think keeping the number manageable is explicitly something we keep around to help kids grasp the main entities in the solar system. If we just said "there are 235 planets" it would be silly to try to teach them all, so we'd probably just settle for "The top 10 biggest planets" or something. Having a definition instead of a number to bound the set isn't much less arbitrary than teaching the "top 10," but since the long tail clearly starts after #8, "Top 8" would be the only guaranteed stable set to give special treatment to, which is what we've arrived at with the official definition.
No. The sun is a star, so it doesn't get to have moons. It has planets. If Jupiter started generating heat from nuclear fusion reactions, we'd call Io a planet right before we boiled to death, and with our dying breath we'd add "and also, it's no longer a moon".
Putting a leash on a cat doesn't make it a dog, and both of those creatures have four legs even if you call the tails of each a leg. A planet revolves around a star, a moon revolves around a planet (revolving around a star). There's further elements which make Ceres and Ed White's lost glove not a planet or a moon, respectively, but planets and moons are distinct and non-overlapping categories.
Why would we be boiling to death in this situation? Jupiter is much further from Earth than the sun is and Jupiter is also much smaller. Heat would increase, but probably not that much.
I would rather expect Earth to not have a stable orbit. Either ripped apart from fluctuating tidal forces, flung away or in one of suns (thus boiling would happen, briefly) or just generally a much more extreme place compared to now.
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What’s a “moon” versus a “planet”? Earth is a moon of Sol, is it not?
We already have the word "satellite" for "things that go around other things" right? I think "moon" is just "satellite of a planet" for convenience in discussing that subset.
I think keeping the number manageable is explicitly something we keep around to help kids grasp the main entities in the solar system. If we just said "there are 235 planets" it would be silly to try to teach them all, so we'd probably just settle for "The top 10 biggest planets" or something. Having a definition instead of a number to bound the set isn't much less arbitrary than teaching the "top 10," but since the long tail clearly starts after #8, "Top 8" would be the only guaranteed stable set to give special treatment to, which is what we've arrived at with the official definition.
No. The sun is a star, so it doesn't get to have moons. It has planets. If Jupiter started generating heat from nuclear fusion reactions, we'd call Io a planet right before we boiled to death, and with our dying breath we'd add "and also, it's no longer a moon".
Putting a leash on a cat doesn't make it a dog, and both of those creatures have four legs even if you call the tails of each a leg. A planet revolves around a star, a moon revolves around a planet (revolving around a star). There's further elements which make Ceres and Ed White's lost glove not a planet or a moon, respectively, but planets and moons are distinct and non-overlapping categories.
Why would we be boiling to death in this situation? Jupiter is much further from Earth than the sun is and Jupiter is also much smaller. Heat would increase, but probably not that much.
I would rather expect Earth to not have a stable orbit. Either ripped apart from fluctuating tidal forces, flung away or in one of suns (thus boiling would happen, briefly) or just generally a much more extreme place compared to now.