When Samyukta Manikumar sets out into nature on foot, it is mostly in the dark. She is neither looking for wild animals nor beautiful scenery, but the night sky. “There are very few places where the sky is as clear, and constellations as impressive, as right here”, recounts the 28-year-old from Kenya who, close to Nairobi, can only occasionally spot the Big Dipper or the Milky Way. Apart from that, it is mostly the high beams of cars and streetlights that dominate the views of the sky.
Light pollution is the name for this phenomenon – when artificial light sources outshine the light of the stars and the moon. “Those who want to enjoy an undisturbed view of the stars must leave civilization behind”, advises Manikumar. As a tour guide, she takes people with her on her night walks. Together, they lie on the ground and gaze at the shining stars through their binoculars or cameras, or simply with the naked eye. “In the beginning, some can’t stop being amazed as they experience true darkness for the very first time.”
Exposed to light smogNeon lights, floodlights and industrial lighting, as well as car lights, generate light domes in the night which brighten the sky within a radius of several kilometers. Even a seemingly clear night sky is affected by light scatter which becomes evident through astrophotography and its extended exposure times. “Whereas in a deep dark environment, the naked eye should be able to detect more than 6,000 stars, it is often only dozens within cities”, says Manikumar. Since most people live in settlements or cities, up to 80 percent of the world population, and 99 percent of those living in Europe, are directly affected by light smog.
Furthermore, multiple studies have been able to demonstrate the negative effects on humans and on nature. For example, the nightly exposure to light influences our hormone balance. The release of the sleep hormone melatonin is delayed, which makes falling asleep in the evening, as well as waking up in the morning, more difficult. Problems sleeping may contribute to the onset of diabetes, hypertension, obesity or depression. And, according to a report issued by the European Commission, there may even exist a connection with an elevated risk of cancer.