What is the 3 Body Problem in physics? Is there a solution to it?

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I recently finished watching the 3 Body Problem on Netflix so this question came to mind. Can anyone explain (in simple terms) why the 3 body problem was deemed unsolvable even by the advanced alien race in the series? Even better, can anyone here simplify what the 3 Body Problem actually is in Physics? It really got my curiosity. Thanks! 🙂

In: Physics

24 Answers

Anonymous 0 Comments

Two bodies orbiting each other under gravity have a general analytical solution for their orbital dynamics. As such, if you know the starting conditions, you know how they are going to move going forward with certainty for all time.

However, no such general analytical solution exists for the movement of three bodies. There are lots of special cases with approximate solutions that are analytical or semi-analytical, but all of them require certain simplifications, so in realistic systems you end up with chaos, instabilities, and overall qualitative changes in the movement patterns over time. One way to deal with it is to use basically brute force and solve the orbital dynamics numerically with computers – but there, again, you run into the issue of having limits to accuracy and resolution.

In short: The two body problem can be solved exactly, the three body problem is impossible to be solved exactly.

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