Body Problems

Three Body, Liu Cixin, 2006-2010

Modern Chinese Science Fiction about an Earth in a triple star system

A reasonable starting point for the many-body problem may be the question of how many bodies are required before we have a problem. Prof. G. E. Brown has pointed out that, for those interested in exact solutions, this can be answered by a look at history. In 18th century Newtonian mechanics, the 3-body problem was insoluble. With the birth of general relativity around 1910 and quantum electrodynamics around 1930, the 2- and 1-body problems become insoluble. And with quantum field theory, the problem of zero bodies (vacuum) is insoluble.

So if we are after exact solutions, no bodies at all is already too many.

-Richard Mattux on Interacting Particles