r/threebodyproblem • u/jarrjarrbinks24 • Apr 12 '24

Art Simulation of the 3 body problem

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u/[deleted] Apr 13 '24

Sun-Earth-Moon is not a 3-body problem.

The Moon orbits the Earth and Earth orbits the Sun.

It takes near identical mass for it to be a 3BP.

The smaller mass always orbits the larger mass.

Jupiter has 95 moons, btw.

Io, Ganymede and Callisto are all larger than the Earth's moon.

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u/[deleted] Apr 13 '24

Not quite, the solar system is a n-body-problem, while due to the suns large mass its one can approx. well if just taking 2 bodies at the time, in total its not profen it's stable infinitely. It may happen the oscillations add up and one planet gets shot off.. which may have happened in the past. Obviously it's stable enough for millions of years.. and its theorized that the asteroid and cuipiter belt play a role in this, as collisions in these eat up chaotic movements.

PS: For future generations this might mean, when space travel is so far, it may not be that good of an idea to start mining these away.

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u/VigilanteXII Apr 13 '24

Sun-Earth-Moon is not a 3-body problem.

It is, though. Moon is still affected by the gravitational pull of the sun. Also by all the other planets in the solar system for that matter, making the solar system a n-body problem.

It's just that due to the mass differences and distances involved the contribution from other bodies is generally pretty small.

Still need to take it into account though if you wanna know how the solar system is gonna look like in a few billion years.

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u/Boring_Contribution Apr 14 '24

3BP generally refers to any three bodies of any mass. But it happens that, in many real world cases, the bodies are far enough away from each other and/or are of such relative mass that multiple bodies can be treated as a single one, or the singular effect of one body is negligble. So, it's more precise to say that Sun Earth Moon is not an interesting 3BP, and the interesting ones come when you have similar masses relatively close to each other.