OK, it's not Earth and "Counter-Earth"...

[FreeTrav]

http://www.newscientist.com/article/dn20160-two-planets-found-sharing-one-orbit.html

Unfortunately, the article doesn't go much beyond "Wow, they're in the same orbit, in the Trojan points!", but at least now there's something you can point to and say "Yes, you CAN have two worlds sharing an orbit, not just a planet and a bunch of little rocks.".

 

[rancke]

http://www.newscientist.com/article/dn20160-two-planets-found-sharing-one-orbit.html

Unfortunately, the article doesn't go much beyond "Wow, they're in the same orbit, in the Trojan points!", but at least now there's something you can point to and say "Yes, you CAN have two worlds sharing an orbit, not just a planet and a bunch of little rocks.".

Although Cruithne IS only a little rock, I don't think there's any reason why two bodies of comparable size couldn't be co-orbital bodies in a similar orbit. If I ever do get around to doing a full writeup of Heya, I'm going to resolve the problem with it's so-called moon, Heya-minor, by making it a quasi-moon like Cruthne.


Hans

 

[Space Hamster]

If you live on one, you would hope they are orbiting in exactly the same speed. If not, you don’t want to be on either when they meet. :rofl:

 

[rancke]

If you live on one, you would hope they are orbiting in exactly the same speed. If not, you don’t want to be on either when they meet. :rofl:

They won't meet. That's what so cool about co-orbital bodies. Check out Janus and Epimetheus, two moons of Saturn whose mean orbital distances from Saturn differs by about 50 km, less that the diameter of either of them.


Hans

 

[Meteoric Assault]

Well that is good news

It makes the galaxy a bit more interesting.

 

[Frankymole]

That's right. Don't they "donate" orbital (kinetic? Potential?) energy to each other via gravity as they grow nearer, moving into slightly higher or lower orbits once acted upon by the other body's gravity, meaning the foremost body accelerates again whilst the approaching one decelerates, in a constant oscillation?