They’ve long been seen as a way to prevent cognitive decline—but experts say the real key to brain health goes far beyond word games. An elderly person works on a crossword puzzle. These games can ...

At 3.3 billion light-years across, the ring may challenge the “cosmological principle” that the universe looks uniform at sufficiently large scales.

Gravity is supposed to be the most familiar force in nature, yet at the deepest level it remains the least understood. A bold ...

A hundred years ago, quantum mechanics was a radical theory that baffled even the brightest minds. Today, it's the backbone of technologies that shape ...

Physics pioneer Dr. Marlan Scully explores how century-old ideas are now lasers, quantum computers and detectors that can find ripples in spacetime.

China has quietly solved a problem that only becomes obvious once you try to live and work off-world: clocks on the moon do ...

Wormholes are often imagined as tunnels through space or time—shortcuts across the universe. But this image rests on a ...

Last week's challenge was a numerical one from Ed Pegg Jr., who runs the website mathpuzzle.com. Take the nine digits -- 1, 2, 3, 4, 5, 6, 7, 8, 9. You can group some ...

Today's puzzle is called "Pet Theory." Every answer is a familiar two-word phrase or name in which the first word start starts PE- and the second word starts T-. (Ex. What walkways at intersections ...

Albert Einstein was intrigued by a simple puzzle: an old car must travel 2 miles at an average of 30 mph. The twist? Its structure makes the solution impossible. Can you solve it?