by David K. Randall
In 1994, an earthquake knocked out electricity in Los Angeles, delivering previously unknown darkness to many residents. Some were alarmed by a silvery light in the black sky. Until then, apparently, the only Milky Way they had ever seen was a candy bar. But perhaps they got some good shut-eye that night.
It wasn’t always this way, Randall writes. People evolved to sleep long hours in a world that got very dark and stayed that way, every night. But modern conditions and lifestyles have left many people short on sleep. Ambient light — which sabotages release of sleep-inducing melatonin — is just one of the many risk factors that Randall investigates in making the case for getting more sleep.