Threats to astronomy: light pollution, radio interference, and space debris

Light pollution is excess or misdirected artificial light, from streetlights, buildings, and signs, that brightens the night sky and washes out faint stars and galaxies; most people in the United States and Europe live where the Milky Way cannot be seen at night. It also wastes energy and disrupts wildlife, such as sea turtle hatchlings and migrating birds. Shielded fixtures that point light downward, warmer and dimmer bulbs, and turning lights off when they are not needed all help, and dark-sky parks protect some areas. Radio astronomers detect extremely faint radio signals, so emissions from cell phones, Wi-Fi, radar, and satellites can drown them out; some frequency bands are protected by international agreement, and major radio telescopes are built in remote radio quiet zones, like the one around the Green Bank Telescope in West Virginia. Space debris, or orbital debris, is dead satellites, spent rocket stages, and fragments from explosions and collisions left in orbit. Tens of thousands of tracked pieces and millions of smaller ones travel at about 8 kilometers per second in low Earth orbit, so even a small fragment can damage a spacecraft, and the International Space Station sometimes moves to avoid debris. Collisions create more debris, raising the risk of a chain reaction called the Kessler syndrome. Large constellations of thousands of satellites add to the crowding and leave bright streaks across telescope images. Removing satellites from orbit at the end of their missions, darker satellite coatings, and tracking debris to avoid it can limit these problems.

This explanation is AI-generated and can occasionally be wrong. 🚩 Report