What powers magnetism, subatomic particles, and gravity? Science, please.

A magnet pulls or attracts. Earth magnets require no batteries, yet will attract forever. Ditto, Gravity. I know Einstein's theory on how Gravity works, but it is still just a theory. These forces cause work to be done in the form of attraction, planets orbit stars, a bar magnet grabs up iron filings some distance from a Petrie Dish. The sub atomic particles that make up everything material are always in motion. These forces seem to come from nowhere and don't run down. Is there a real, satisfactory, scientific theory that explains these forces in terms a layperson could grasp? I have not yet seen one, but I am not a scientist.