Our sleep cycle, or circadian rhythm, is based on the body's reaction to the daily rise and setting of the sun, producing more of the sleep-encouraging hormone melatonin in the dark hours and less after dawn.
The Slatest Week in Pictures A pilgrimage in Nepal, elections in Athens, war in Syria, fashion in Paris, and trash heaps in China.
What Happened at Slate This Week? Social media guru Lindsey Underwood highlights the most popular stories of the week, from the Patriots to Tom Petty.
He Never Touches the Balls Tom Brady may be the handsome face of the Pats, but the team’s heart and soul belong to defensive tackle Vince Wilfork.