Scientists just designed the world’s most accurate clock

Physicists in Singapore have built an atomic clock so precise that it measures time down to the 19th decimal place. A machine with this level of accuracy could run for hundreds of billions of years—far longer than the entire age of the universe—without gaining or losing a single second. This leaves the world’s reigning timekeeping superpowers in the dust. Until now, the ultimate records belonged to elite laboratories in the U.S. and China, which spent years locked in an intense scientific...