Understanding the Three Body Problem

The theoretical questions have been around and worrying some of the greatest minds of all time, including Isaac Newton.

Taking our specific example of interest, Newton considered what appeared to be the stable rotational path or orbit of the Moon around the Earth and the Earth around the Sun.

These are the three bodies involved in what became known as the three-body problem.

My chat GBT visit further informed me that the three-body problem is a famous problem in physics and mathematics.

If three objects are pulling on each other through gravity, can we predict exactly how they will move forever? With two bodies, such as the Sun and Earth, Newton's laws give a beautifully predictable solution – Their paths are eclipses, ellipses, or more generally conic sections, and you can calculate their positions arbitrarily, far into the future.

Add a third gravitational interacting body, though, and things become dramatically harder.

This, of course, was the specific situation I'd been thinking about during the eclipse.

Predictions are based on calculations about the effects of the Earth producing the orbit of the Moon and the effects of the Sun producing the orbit of the Earth around the Sun.

Now, what had become obvious to humans during many thousands of years of observation is that there was a very stable repeated pattern as the sun apparently rose in the morning and set in each evening.

Likewise, there was a stable pattern of daylight over time and season and seasons over a year.

Sorting that out becomes the three-body problem which bothered philosophers and natural scientists before and after Isaac Newton died.