The Milky Way is now invisible to one-third of the world's population due to light pollution, a new map reveals. This includes 80 percent of people living in North America.
The New World Atlas of Artificial Night Sky Brightness documents the effects of light pollution across the globe.
The Earth, along with the rest of our solar system, sits at the outer edge of our disk-shaped galaxy. As we look up from the ground, into the disk, we are able to see a fog of stars, stretching across the sky. However, this magnificent sight is best seen under dark skies, and artificial lights from cities and automobiles can easily wash out the image.
"The new atlas provides a critical documentation of the state of the night environment as we stand on the cusp of a worldwide transition to LED technology. Unless careful consideration is given to LED color and lighting levels, this transition could unfortunately lead to a 2-3 fold increase in skyglow on clear nights," Fabio Falchi of the Italian Light Pollution Science and Technology Institute (Istil) said.
Western Europe is one of the areas of the world most heavily affected by light pollution, where dark skies are few and far between. Locations in Spain, Austria, Norway, Scotland and Sweden are still dark enough to view our home galaxy, the map reveals.
Light pollution not only affects astronomers, but can also alter the natural patterns of wildlife and ecosystems.
The new study examines the fraction of people living in G20 countries who suffer from light pollution. Researchers found Australia and Canada were least affected by the phenomenon, while Italy and South Korea possess the least amount of dark sky conditions. Of all nations, South Korea showed the most light-polluted skies, a problem also found over much of Saudi Arabia. The darkest skies are found in India and Germany, according to the new study.
In 2001, researchers produced a map showing how light pollution affects populations around the globe. The Suomi NPP satellite currently in orbit is the first space-based observatory designed to measure light pollution on Earth. Data from this instrument was a great advance in this new data set compared with the earlier version of the graphic.
Amateur scientists also played a major role in data collection for the new map. A total of 20,865 sky quality meters around the globe were monitored by citizen scientists.
The map and analysis of light conditions around the world were published in the journal Science Advances.