It's often discussed that you can fit all the planets in the space between the Earth and the Moon. But if they actually did teleport there instantly what would happen next?

Assuming their initial direction and velocity was the least problematic, the most likely to "work". Would they all smash together or fling apart? Or do we have any idea?


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    $\begingroup$ We don't normally answer questions involving impossible hypothetical scenarios on this site, since it's generally not possible to give a scientific answer to a scenario that throws out one or more laws of science. But I won't vote yet to close your question, I'll wait to see what others have to say about it. (But basically, everything would fall into Jupiter). $\endgroup$ – PM 2Ring Jan 23 '20 at 19:27
  • $\begingroup$ Fair enough about hypotheticals. I just joined the site. I will try to come back with better questions another day. But "fall into Jupiter" is plenty good enough for my purposes, thanks. I figured it would not be a very stable arrangement! $\endgroup$ – Philip Jan 23 '20 at 21:15

Talking about instantly teleporting planets isn't very meaningful if you want to get scientific answers, as PM 2Ring pointed out. But is is almost certainly not physically impossible for them to have trajectories that let them all pass between the earth and moon at the same time. But the earth and moon would have to start out farther apart than they are now because all the planets passing in between would pull them closer together, and we want them to be at the current distance just at the moment the planets pass between.

The biggest issue here is tidal forces. Planets pull harder on the near side of other objects than on the far side, and the effect is much stronger the closer you are. Whichever planet was almost touching Jupiter would be torn apart by this difference in force - Jupiter's gravity would be pulling on the near side faster than the far side could catch up. The only way to avoid this is to have the planet passing by very fast, so it would only be in the area of maximal tidal forces for a very short time.

What exactly happened would depend on the exact trajectories. Obviously there are an infinite number of ways a bunch of things can fly past each other. The reason everything doesn't fall into Jupiter in this scenario is that they are moving fast enough and in the right directions. They will all definitely curve towards it, though. Its gravity would dominate the situation, but the gravity of all the planets would have to be considered if you were a super-powerful civilization trying to make this happen.


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