Where do the magnetic fields of planets and stars come from?

It's a good question with a fascinating answer.

Celebrating the 150th anniversary of Maxwell's equations we talk to physicist John Ellis about what they mean for modern technology and our understanding of the Universe.

You may have heard of quantum theory and you probably know what a field is. But what is quantum field theory? This article traces the development of quantum electrodynamics in the first half of the 20th century. Hair raising difficulties, heroic struggle and illustrious characters — this story has it all!