Satellites Threaten Night Sky, Disrupt Life

Proposals to deploy reflective satellites and a significant increase in low Earth orbit constellations are raising alarms among sleep and circadian rhythm researchers. These plans could fundamentally alter the Earth's natural night-time light environment on a global scale, according to scientific societies representing thousands of researchers. Such changes risk disrupting biological clocks essential for sleep, hormone secretion, and migration patterns in both humans and animals.

Companies like Reflect Orbital aim to use reflective mirrors to illuminate areas on demand, while SpaceX plans vast satellite networks for AI. Scientists emphasize that even subtle increases in night sky brightness, like those already observed from existing satellites, can affect biological systems sensitive to light.

Experts are urging regulators to conduct thorough environmental reviews and establish limits on satellite reflectivity and cumulative sky brightness. They compare the potential impact to other planetary-scale changes like climate change, stressing that the light-dark cycle is a fundamental organizing principle for life on Earth.