Researchers from the University of San Francisco have introduced a term to express the sadness caused by losing the night sky to light pollution. They call it noctalgia, a yearning for the stars, and they also outline practical steps to address a challenge that harms both the environment and astronomical observation. The finding appears in Physics and Society.
Most light pollution originates from human-made sources on the ground, including streetlights, office complexes, and parking facilities. The spread of LED lighting, praised for efficiency and longevity, has intensified the issue because it can operate for long periods with relatively little energy input.
A second major contributor is the rapid expansion of space activity. In recent years, the number of satellite launches has surged to record levels. Man-made objects in orbit reduce the clarity of powerful telescopes and can reflect sunlight from solar panels, creating stray light. Researchers estimate that the abundance of orbiting objects has boosted the brightness of the night sky by roughly 10 percent over the last five decades.
Light pollution also affects wildlife, disturbing natural circadian rhythms and hindering the ability of animals and birds to detect predators or catch prey. To counter this, scientists advocate establishing dark sky reserves around the world where human activity is restricted to protect nocturnal environments. They also suggest advances in lighting design that automatically dim or shut off when not needed to minimize wasteful glow.
Limiting satellite operations is a more intricate issue that calls for international cooperation and increased pressure on major space actors to tighten orbit management. The researchers emphasize that success in this area would let people once again enjoy a truly visible starry sky.
Earlier assessments by astronomers suggested that the number of visible stars could fall by about two and a half times within an 18-year span, underscoring the urgency of coordinated action to preserve dark skies for science and the public’s wonder.