BOULDER- Black holes, time travel and E= mc^2. They are all related to Albert Einstein's Theory of Relativity. How many of us, though, can actually explain any of it? This year, Einstein's theory ...

Many theories are rock-solid: Scientists have just as much confidence in the theories of relativity, quantum mechanics, ...

Solar eclipses occasion lots of excitement and pique the public's interest in astronomical phenomena. Eclipses can also expand our understanding of the universe in profound ways. In fact, astronomical ...

For over 100 years, two theories have shaped our understanding of the universe: quantum mechanics and Einstein’s general relativity. One explains the tiny world of particles; the other describes ...

The French philosopher Renee Descartes took some time before convincing himself that he really existed. Or, in his words, “Cogito, ergo sum,” which is Latin for I think, therefore I am. While most of ...

"GW250114 is the loudest gravitational wave event we have detected to date; it was like a whisper becoming a shout." ...

Einstein’s Theory of General Relativity, an immensely important update to Newton's Law of Universal Gravitation, is currently ...

For over a century, Einstein's general theory of relativity has been key to understanding gravity. But new research suggests this theory "glitches" in the farthest reaches of space. That doesn't mean ...

As the universe expands, it feels like it must be spreading out from some initial point. But a physicist explains why that’s ...

Access more than 20 years of online content Manage which e-mail newsletters you want to receive Read about the big breakthroughs and innovations across 13 scientific topics Explore the key issues and ...

Researchers at Hiroshima University have developed a realistic, highly sensitive method to detect the Unruh effect—a ...