All products featured here are independently selected by our editors and writers. If you buy something through links on our site, Mashable may earn an affiliate commission. Alarm clocks might seem ...

Atomic clocks. They almost sound like something out of science fiction, or an experiment confined to some elite physics lab, but in reality, they’ve been around since the 1950s in one form or another.

The Earth has rhythm. Every 24 hours, the planet pirouettes on its axis, bathing its surface alternately in sunlight and darkness. Organisms from algae to people have evolved to keep time with the ...