Increasing levels of light pollution means Earth's surface has almost no practical locations for astronomical observatories, a group of astronomers said on Monday.
Artificial light emitted from buildings, streetlights, and reflected from satellite constellations are making the night sky brighter for earth-bound skywatchers. The Milky Way was visible to pretty much everyone less than 100 years ago, but is now drowned out by human-made light to most, according to the International Dark Sky Association.
New ground-based telescopes are being built in increasingly secluded areas, but even in those out of the way locations a clear view of the dark sky is hard to find.
"Today, due to the rise of light pollution, there are almost no more remote places available on Earth that simultaneously meet all the characteristics needed to install an observatory (namely, the absence of light pollution, a high number of clear nights, and good seeing)," a team of astronomers said in Nature Astronomy.
The authors urged astronomers, companies, politicians, and lawmakers around the world to work together to reach a global agreement to limit artificial light. Light pollution should be treated in the same way that other types of pollutants, like greenhouse gases, they argued. Governments around the world should and can tackle light pollution in the same ways they address climate change: with international treaties and goals to restrict levels of other pollutants.