This clock tells the time using set theory and 24-hour time. From the top down: the blinking yellow circle of light at the top indicates the passing seconds; on for even seconds and off for odd.

“Your clock is set to a 24-hour rhythm, though sometimes it’s a little shorter or longer,” she says. Essentially, the circadian rhythm is crucial to establishing what our body and mind do ...

The golf industry has historically backed making daylight saving time permanent, for lighter evenings, while sleep experts say it would be healthier to keep clocks permanently set back, for lighter ...