OK, time for me to post a question that reveals my sheer ignorance of astrophysics, but that’s still been preying on my mind for awhile…
Here’s the setup: I want to add a second Earth-type planet in our solar system. It’d be the same size, density, ecosphere, etc. as the first Earth. But I’m not going to have it suddenly enter the solar system from the outside, like a comet or anything…I’m going to have it suddenly appear in place, like magic. But otherwise, there’d be nothing supernatural about the way it interacted with the rest of the universe from that point on. (But I would make sure it started out moving at the proper speed so it’d maintain it’s orbit around the sun.)
(For the sake of clarity, I’ll just call this new planet “Deuce” from now on.)
My question is…how close could I put planet Deuce to Earth, without screwing up Earth’s orbit? Could the two planets “share” the same orbit around the sun, but still remain constantly visible to each other, or could Deuce have a slightly wider or smaller orbit than Earth, (Say, a little more or a little elss than 1 AU) but still be able to “keep pace” with Earth as it orbited the sun? I’d want to have Deuce look about as big in Earth’s sky as our moon does, for most or all of the year…would that be possible, without bringing around disastrous side effects (Like the moon being ripped out of it’s orbit; or Deuce and Earth drawing each other into a collision; or Earth getting it’s rotation or axial tilt changed, bad stuff like that.)? How close could you put Deuce to Earth, without any major ill effects?
Well, thanks for your time,
(::Walks off, muttering something about cutting back on watching “Escaflowne”: