Sunspots, Solar Flares and Coronal Mass Ejections

The surface of the sun is a very busy place. It has electrically charged gases that generate areas of powerful magnetic forces. These areas are called magnetic fields. The sun’s gases are constantly moving, which tangles, stretches and twists the magnetic fields. This motion creates a lot of activity on the sun’s surface, called solar activity. Sometimes the sun’s surface is very active. Other times are a bit quiter. The amount of solar activity changes with the stages in the solar cycle. Solar activity can have effects here on Earth, so scientists closely monitor solar activity every day. Sunspots are areas where the magnetic field is about 2,500 times stronger than Earth’s, much higher than anywhere else on the Sun. Because of the strong magnetic field, the magnetic pressure increases while the surrounding atmospheric pressure decreases. A solar flare is a tremendous explosion on the Sun that happens when energy stored in ’twisted’ magnetic fields (usually above sunspots) is suddenly released. In a matter of just a few minutes they heat material to many millions of degrees and produce a burst of radiation across the electromagnetic spectrum, including from radio waves to x-rays and gamma rays. Scientists classify solar flares according to their brightness in the x-ray wavelengths. There are three categories: X-class flares are big; they are major events that can trigger radio blackouts around the whole world and long-lasting radiation storms in the upper atmosphere. M-class flares are medium-sized; they generally cause brief radio blackouts that affect Earth’s polar regions. Minor radiation storms sometimes follow an M-class flare. Compared to X- and M-class events, C-class flares are small with few noticeable consequences here on Earth. A coronal mass ejection (CME) is an explosive outburst of plasma from the Sun. The blast of a CME carries about a billion tons of material out from the Sun at very high speeds of hundreds of kilometers per second. A CME contains particle radiation (mostly protons and electrons) and powerful magnetic fields stronger than what is normally present in the solar wind. CMEs travel outward through the solar system. Some are directed toward Earth, though many others miss our planet completely. The radiation storms that are a part of CMEs can be hazardous to spacecraft and astronauts. If a strong CME collides with Earth’s magnetosphere, the disturbance can send a burst of particle radiation into Earth’s upper atmosphere. As the radiation interacts with gas molecules in Earth’s atmosphere, it causes them to release light and essentially to glow, creating the magnificent light shows of the auroras (the northern and southern lights). Thanks for watching! #sunspot #solarflare #CME Images credit: NASA’s Goddard Space Flight Center, AIA/SDO/HMI Music credit: YouTube Audio Library Desert Planet - Quincas Moreira