A new measurement offers insights on the density of the mysterious force driving the Universe’s expansion.

Here’s why the answer may forever elude scientists.

Wolfgang Pauli was a brilliant, well-liked physicist and a scathing critic of balderdash.

Physicists have yet to pinpoint the hypothetical matter that keeps galaxies from flying apart. Now they have a new focus.

Thanks to observations of gravitational waves, scientists were able to settle a longstanding debate over the speed of gravity.

Few could match the famous physicist in his ability to communicate difficult-to-understand concepts in a simple and warm fashion.