Does light have weight? Newton thought so. His laws predicted that gravity would bend light, two centuries before Einstein's revolution.

Why (some) physicists want to modify Einstein's general theory of relativity.

Cormac O' Raifeartaigh recently made a surprising discovery – an unpublished paper by Albert Einstein that sheds light on how Einstein's thinking about the Universe changed as he tackled some of the big questions in cosmology at the time.

This is the second article in our four-part series exploring quantum electrodynamics. After successfully applying quantum mechanics to the electromagnetic field, physicists faced a problem of boundless proportions: every calculation they made returned infinity as the answer.

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!

What a lovely coincidence! Pi day (the 14th of March, written 3/14 in the US) is also Albert Einstein's birthday. How are you going to celebrate? .