That was interesting. I thought I'd look up 'diameter of an electron' and found sizes between 10^-13 m and 10^-18 m.

The 'classical' radius is

Although all that really tells you is that you can't say how big an electron is, because unlike a rock it doesn't have hard edges. Instead it's defined by how much it bounces when you bang it with something else.

Curiously, football pitches also seem to suffer from quantum indeterminacy - very bad news for science journalists.

The official FIFA dimensions are '90-120m' wide and '45-90m' tall. Goal dimensions are defined as 7.32m x 2.44m, which presmably requires precision laser range-finding to make sure they're accurate to the nearest mm.

So - it's unlikely we'll ever know exactly how many electrons fit into a football pitch.

A bit unfortunate, that, but there it is.