Artificial Light at Night Harms Humans and Wildlife, Scientists Warn

The sun gives us light during the day, and darkness at night.

But people have added lots of electric lights outside, like streetlights and shop signs.

Scientists call too much bright light at night 'light pollution.'

It is different from dirty air or water because it doesn't leave any mess behind, but it can still cause problems.

Our bodies have an invisible clock that tells us when to sleep.

Bright light at night can trick that clock and stop a special sleep hormone called melatonin from working.

Animals are affected too - insects fly toward lights, birds get confused, and some animals hide from bright areas.

Even plants can change how they grow because of extra light.

Scientists don't want us to turn off all lights, because we need them to stay safe.

They just want us to use the right amount of light, in the right place, at the right time.