Gamma-ray bursts, the most powerful kinds of explosions known in the universe, can generate even more energetic light beams than astronomers previously realized, according to a set of new studies. The ...

Einstein’s claim that the speed of light is constant has survived more than a century of scrutiny—but scientists are still daring to test it. Some theories of quantum gravity suggest light might ...

Scientists at the X-ray free-electron laser SwissFEL have realized a long-pursued experimental goal in physics: to show how ...

Can we turn back time? Ask a savvy physicist, and the answer will be “it depends.” Schemes for retrograde time travel abound but usually involve irreconcilable paradoxes and rely on outlandish ...

While the terms "quantum physics" and "Theory of Relativity" are used casually every day, not many people know what they really mean. Yet these theories have had a profound impact not only on science ...