Hey everybody, welcome back to explain that in five. The podcast always take the questions you always wanted to ask and talk about them in a way that's easy to understand. We are your hosts. I'm Tim.
And I'm Kevin. So Kevin, today we are diving into one of the most perplexing puzzles in physics and astronomy, and it's called the three body problem. What exactly is this problem? So in simple terms, the three body problem involves trying to predict the motion of actually three celestial bodies moving under the influence under mutual gravity.
So you can try to forecast how three planets, or maybe a planet with two moons, will move and interact over time. And even though it sounds kind of straightforward, it's really not. Why not? Can you explain that in five that part?
Yeah, so the difficulty lies in the chaotic nature of the system. With two bodies, you can predict their positions at any future time. But with three, their gravitational interactions creates a system that's highly sensitive to their initial positions. And so, tiny differences can actually lead to vastly different outcomes, making long-term prediction practically impossible.
You know, for example, if you have objects A and B in space pull on each other because of gravity, we've got this one down pretty easily because the math is relatively straightforward and very, very predictable. Now you add a third object, right? So we know how A and B pull on each other. But wait, now C is also pulling on A and B.
So I got to redo all the math because of that. And then wait, so A is also pulling on C too. So that changes things again. So you can recalculate it on B on C and so on and so on.
It's just a lot of calculations to try to predict what's going on here. I got a picture. And so this problem has been wobbling many bright minds for a number of centuries, right? Oh, yeah.
I mean, I think since the time of Isaac Newton, scientists have tried to crack this problem. And Newton himself could solve the motion of two bodies in space, you know, like the earth and the moon using his laws of motion and universal gravitation. And just one more body to this mix and a whole problem becomes incredibly, incredibly complicated. So who was the first to try to attempt to solve it?
So the first significant attempts were made by the French mathematician Henry Poincaré in the late 19th century. Well, he showed us there's no simple one-size-and-subsolution to this problem, revealing the system's inherent chaos. And this is actually a groundbreaking insight into field of dynamical systems and chaos theory. Can you give us a real-world example of where this exists?
Sure. You know, the earth moon sun system is actually a classic example. Well, we all think simplify calculations by considering just two bodies at a time to get more accurate predictions like those needed for a sort of eclipses. They actually require taking into account the gravitational effects of all three bodies.
I see. And it actually goes beyond physics. It's not just in physics, which we can use the free body problem. There are other fields too, right?
Yeah, that's right. The principles underlying the three body problem and chaos theory in general have implications across various fields from engineering to even economics. They basically help us understand complex systems, whether it's the stock market or like weather patterns. And what about the connection to chaos theory?
You mentioned that. Yeah, yeah. So the three body problem is just it's a classic example of a chaotic system. And this means that we technically know how the system behaves and can simulate its future states.
But, you know, a very, very small change in any input variable can just drastically change everything. And by drastically we mean like a small change can affect the final result to the point of the original calculation is actually totally meaningless. This means to perfectly predict such a system into the far future. Well, we have to calculate its current state to effectively infinite precision, which is impractical and borderline impossible.
I see. That's helpful to understand. And as a result, the free body problem has sort of made its way into culture and science fiction as well. Oh, yeah.
Oh, yeah. Most notably in Leo C. Sheen's novel called Santi, which literally means three body in Chinese. The story cleverly integrates this scientific concept into its plot, too.
It explores this alien civilization of a planet with a three star system. And it's actually the unpredictable orbits that creates quite a fascinating backdrop for the whole story. And so in 2012, it was first described as one of China's most successful full-length novels. And then the English translation by Ken Leos also published by Tor Books in 2014.
And now in English language, Netflix series adaptation called the three body problem was actually recently released in March 2024. And just to end with, is there really any solar system out there like described in the book in Netflix series? Oh, so there really is a three star solar system about four light years away from us. Very much like that described in the three body problem.
It's called Alpha Centauri and it's an A triple star system about four light years away from Earth. Very interesting. Do you want something new? If you did, send us an email.
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