|Werner Heisenberg quantum mechanics
Werner Heisenberg declared a limit to what can be determined precisely. We don’t have this problem when talking about planets or billiard balls, only for elementary particles such as photons or protons. The more we know about one property of a particle, such as its position, the less we know about any related property, such as its momentum.
The standard deviations of position and momentum multiplied together is greater than or equal to half the reduced Planck constant.
You’d think this’d be easy but I’m not sure.