For the more than 100,000 years humans have been on Earth, we have looked up at night and seen the stars and our celestial home, the Milky Way galaxy. Cultures all around the world have stories and records incorporating this majestic, sublime sight. However, nearly 3 billion people can no longer see the Milky Way when they look skyward at night.
In turn, their connection to the cosmos - and to the sense of deep time it represents - has also been lost. Light pollution is the culprit of this loss. But it is a relatively recent problem.
In fact, roughly a century ago, the skies above some of even the biggest cities in the world were still dark enough to see the gaseous clouds of the Milky Way and the infinite specks of flickering light shining in the farthest reaches of the universe. So, what happened? And what can we do to help darkness reign supreme again? The long legacy of lights Light pollution is the spill or glow of lights upward, into the sky. Lights help us see on the ground.
But for a variety of reasons - from poor design to inefficient lights and unnecessary lighting - light pollution in an area can grow fast. Light pollution also comes from a variety of sources. Much of it comes from streetlights.
They contribute 20 to 50 per cent of the light pollution in a city. But they are not the only source. Others include floodlights from ovals, billboards and lights at our homes - both inside and outside.
At night, when we see a large building or empty apartment building with.