Paul Dirac hypothesized that in the early moments of the universe, when electromagnetism arose, so-called Magnetic Monopoles were created in abundant quantities. These are a heavier version of the electron (10^20 times heavier…) but with a magnetic rather than electric charge. This hypothesis is not experimentally verified: we should be inundated with monopoles, which would contribute 10^26 times more than stars to the mass of the universe.
