Solar flares

Solar flares are great bursts of light and radiation due to the release of magnetic energy on the sun. Flares are by far the biggest explosions in the solar system, with energy releases comparable to billions of hydrogen bombs. The radiation from the flare travels at the speed of light, and so reaches Earth within eight minutes. The energy is generally absorbed by Earth's atmosphere, which protects humans on Earth, however, the energy can cause radio blackouts on Earth for minutes or, in the worst cases, hours at a time. The radiation from a flare would also be harmful to astronauts outside of Earth's atmosphere. Some, but by no means all, flares have an associated coronal mass ejection (CME).