A strange form of matter called a time crystal has fascinated physicists for about a decade. These systems move in repeating cycles, even without a steady external push.

A team at New York University has discovered a new form of time crystal that hovers using sound waves. Unlike ordinary matter, these crystals seem to behave in ways that don’t align with Newton’s ...

Although few people ever get the chance to travel at the speed of sound, it is an alluring flight goal and an impressive technological feat. Though average people have flown at high speeds on ...