The physics that suggests there is a new force of nature
Scientists say they have found "strong evidence" for the existence of a new force of nature.
They have found that sub-atomic particles, called muons, are not behaving in the way predicted by the current theory of sub-atomic physics.
There are four fundamental forces of nature. One for gravity, another for electricity and magnetism, and two nuclear forces. Together they explain how the world works. But, as the BBC's science correspondent Pallab Ghosh explains, this new discovery could rewrite scientific theory.
