Hypothetical Lobed Planet

[cubinator]

Like my mad MS Paint skills?

This is an idea for a hypothetical two-lobed planet. It starts as a binary system with similar planets, and the orbits decay, slowly bringing the two planets together. Eventually they come so close that they touch, and you get a rapidly spinning double planet, at least for a short time before it all melds together into one bigger planet. There was an article a while back about a star system doing this, so I wondered if it could happen with planets too. My question is could this planet exist, at least for a geologically short period of time, or would the tidal and gravitational forces be so great that both planets break apart before getting close enough to touch? Wouldn't it be weird to walk from one planet to another?

Edited December 12, 2015 by cubinator

[RainDreamer]

I think this would depend on a lot of factors, like the sizes of the planets, their mass, their velocities, and so on. In a few cases I imagine they won't orbit each other in such harmony, but just crashing into each other and the resulting debris will form a new planet eventually.

[NovaSilisko]

Hmmm... reminds me of something...

Edited December 12, 2015 by NovaSilisko

[Spaceception]

That would be a pretty cool place to live on, the thing is, what would the tides be like on a double planet like that?

[cubinator]

7 hours ago, Spaceception said:

That would be a pretty cool place to live on, the thing is, what would the tides be like on a double planet like that?

The oceans would probably just clump in the middle if there were any.

 

9 hours ago, RainDreamer said:

I think this would depend on a lot of factors, like the sizes of the planets, their mass, their velocities, and so on. In a few cases I imagine they won't orbit each other in such harmony, but just crashing into each other and the resulting debris will form a new planet eventually.

This probably would happen in most cases. For this instance we're assuming the planets have similar masses and densities, and their orbits are slowly decaying. If it decays slowly and steadily enough, they would eventually just touch and it would be a fast-spinning double planet. The only problem I see with this is that the gravitational forces would be stronger in the middle, so the planets would be prone to tearing each other apart. The material in the planets would want to clump at the barycenter, and the planets would likely deform and break.

Here is a picture of how this probably would turn out. The gravity is much greater on the inside, so the planets would be spinning faster in the middle than on the outside. This would lead to a lot of stress, probably enough to tear both planets apart. Then there would be a spinning disk of matter which eventually clumps back into a new planet.