Globe at Night

Mapping light pollution in the night sky.

    About this project

    A little more than 100 years ago, you could walk outside at night even in a city and see the Milky Way galaxy arch across the night sky. Being able to see thousands of stars was part of everyday life, inspiring artists like Van Gogh or musical composers like Holst or writers like Shakespeare. By allowing artificial lights to wash out our starry night skies, we are losing touch with our cultural heritage (e.g., what has made us who we are). We are also losing touch with what could inspire future generations.


    With more than half of the world’s population now living in cities, 3 out of every 4 people in cities have never experienced the wonderment of pristinely dark skies. How do you explain the importance of what they’ve lost to light pollution? How can you make them aware that light pollution is a concern on many fronts: safety, energy conservation, cost, health and effects on wildlife, as well as our ability to view the stars? Finally, how do you convince them that it’s worthwhile to take even small steps, to help fix this problem?

    The Globe at Night program is an international citizen science campaign to raise public awareness of the impact of light pollution by inviting citizen scientists to measure their night sky brightness and submit their observations from a computer or smartphone.  By participating in the project and taking as many measurements as you can from different locations, you will be promoting awareness and helping to monitor light pollution levels locally.


    More than 100,000 measurements have been contributed from people in 115 countries during the campaigns each winter/spring over the last 9 years, making Globe at Night the most successful light pollution awareness campaign to date. The worldwide database is used to compare trends over years and with other data sets (like on animals) to see what effects light pollution has on them.