For those looking for the best places on the planet to stargaze, there's a new tool available -- an atlas of artificial skyglow.
A map shows the distribution of light pollution in North America. Photo by Falchi et al./Science AdvancesIn the biggest of cities, stars are nearly impossible to see. The skies are too polluted with artificial light, or artificial skyglow. On the opposite end of the spectrum are patches of wilderness miles from major cities. Here, the starry details of Milky Way are in full display.
A series of new maps, published in the journal Science Advances, reveals the full spectrum of stargazing potential.
"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," lead researcher Fabio Falchi, a scientist with the Italian Light Pollution Science and Technology Institute, said in a news release. "Unless careful consideration is given to LED color and lighting levels, this transition could unfortunately lead to a 2 to 3 fold increase in skyglow on clear nights."
As the maps reveal, much of the world features relatively few places untouched by light pollution. Among the nations analyzed by the study's authors, Italy and South Korea feature the highest levels of light pollution by area. Canada and Australia feature the least light pollution by area.
According to the study, the chances of an average household being able to see the Milky Way on a clear night is greatest in India and Germany. Residents of Saudi Arabia and South Korea are least likely to witness the galaxy's outstretched spiral arms.
Much of the research and subsequent map-plotting was made possible by science organizations that monitor and measure light pollution. But citizen scientists contributed a significant amount of data to the cause.