Roughly one-third of the globe can no longer see the Milky Way thanks to artificial light at night. The impact of light pollution has long been obvious, but scientists are now exploring the role of constant exposure to light on health, and a study in the journal Current Biology adds both good and bad news.
Researchers in Holland say the absence of natural light-and-dark rhythms can lead "to severe disruption of a wide variety of health parameters"—including a loss of bone density.
The conditions were extreme: They were studying mice subjected to constant artificial light for six months, which is a torture technique, notes the Independent. The good news, as delivered by researcher Johanna Meijer at Eureka Alert: "These negative effects on health are reversible when the ... light-dark cycle is restored." To study the impact of so much light, the team implanted electrodes in the parts of the brain that control circadian rhythms and observed neuron activity in the mice.