Threadkiller

[Umbran]

Why could there not be two planets diametrically opposed in the same orbit?

Because, while your intuition may say otherwise, that's not a stable configuration. Even a small deviation will eventually blossom into one (or the other, or both) of the bodies falling out of such an arrangement.

"Clearing the neighborhood" is not an absolute thing - there are something like 10,000 near-Earth asteroids, for example. But, Pluto is orbiting around in the vicinity of many, many more Kuiper Belt objects. Its neighborhood isn't even remotely emptied.

 

[Scott DeWar]

Not to mention that Neptune and Pluto cross orbits I think I read. If those orbits are considered not cleared then Neptune should not be a planet by that standard.

 

[Leif]

Because, while your intuition may say otherwise, that's not a stable configuration. Even a small deviation will eventually blossom into one (or the other, or both) of the bodies falling out of such an arrangement.

"Clearing the neighborhood" is not an absolute thing - there are something like 10,000 near-Earth asteroids, for example. But, Pluto is orbiting around in the vicinity of many, many more Kuiper Belt objects. Its neighborhood isn't even remotely emptied.

Okay, okay, don't get all scientific on me, what I'm suggesting is something that might be an early stage in the construction of a 'Ringworld', a la Larry Niven. Clearly fictional, but cool to think about anyway. And some really cool inventions started out as science fiction....

 

[Scott DeWar]

Hey Leif, did you know Pluto orbits catawupus?

 

[Umbran]

Not to mention that Neptune and Pluto cross orbits I think I read. If those orbits are considered not cleared then Neptune should not be a planet by that standard.

There are periods when Pluto is closer to the Sun than Neptune is, but given the tilt of Pluto's orbit, their orbital paths never actually get near each other. So, no, this issue does not arise for Neptune.

And if they did come close to each other, Neptune is roughly 10,000 times more massive than Pluto. Pluto would be history, flung to the side with no never mind.

 

[Scott DeWar]

poor little under appreciated Pluto.

 

[Umbran]

poor little under appreciated Pluto.

Really. We sent the most advanced sensor package ever made, at the highest speeds ever achieved by man, and waited a decade to get a few days of data as it went whizzing by, at a cost of over half a billion dollars. Yeah, we don't appreciate it at all.

 

[Scott DeWar]

Nope! not even the least bit. I mean, we have to wait until tomorrow at 1030 EDT to find out what it looks like!

*dramatic exasperation pose*

I mean come on! just a little respect, please!

 

[Pendrake Utherman]

Nope! not even the least bit. I mean, we have to wait until tomorrow at 1030 EDT to find out what it looks like!

*dramatic exasperation pose*

I mean come on! just a little respect, please!

drama king much?

 

[Leif]

Yes, DeWar, I knew that Pluto's orbit is funky such that it is sometimes nearer to the sun than Neptune and sometimes farther away.