What is a solar flare?
A solar flare is a sudden, intense burst of energy and radiation from the Sun's surface, caused by the release of magnetic energy. Large flares can disrupt radio communications and satellites on Earth.
The Sun's surface is covered with powerful, twisted magnetic fields, especially around sunspots. When these fields snap and reconnect, they release huge amounts of energy in minutes, equal to millions of nuclear bombs. The flare sends out light across the spectrum, from radio waves to X-rays.
Flares are classified by their X-ray brightness as A, B, C, M or X class, with X being the strongest. Flares are often linked to coronal mass ejections, giant clouds of charged particles that can hit Earth's magnetic field a day or more later, causing geomagnetic storms and bright auroras.
Effects on Earth
Strong solar storms can disrupt GPS, radio communications and power grids and increase radiation risks for astronauts. In 1989, a solar storm caused a nine-hour blackout in Quebec, Canada. Space agencies monitor the Sun to provide warnings. Solar activity rises and falls in an 11-year cycle.
Did You Know?
The most powerful solar storm on record, the Carrington Event of 1859, caused telegraph wires to spark and produced auroras visible near the equator.