This weekend the Earth is due to be hit by a pair of solar storms that might affect radio and satellite communication. But how and why does this happen?
What Does Solar Mean?
Anything that is related to a sun is commonly described as being solar. Our sun is a typical medium-sized yellow star which is about 5 billion years old. Its surface temperature is about 5,500°C, but even that isn’t as hot as its superheated centre. Some parts of the sun’s surface are cooler, with a temperature of between 2,700–4,200°C, and these appear darker when viewed through specialised telescopes. These cooler patches are caused by fluctuations in the sun’s magnetism and are called sun spots.
What are Solar Storms?
Occasionally a part of the sun will suddenly release a large amount of energy and electromagnetic radiation, including gamma rays and x-rays. This sudden explosion is called a solar flare and can be more powerful than a million nuclear bombs going off. A flare will often launch large amounts of magnetic energy known as Coronal Mass Ejections (CMEs) as well, and all this energy travels through space at high speed. When it encounters a planet we call it a solar storm. Solar flares and storms seem to reach a peak once every 11 years.
Are Solar Storms Harmful?
Not to us, no; Earth’s atmosphere is strongly magnetic and protects us from the impact of almost all solar storms. In fact, this is what causes the Northern and Southern lights (or Aurora borealis and Aurora Australis, to give them their proper names). The gas particles released from the sun react with the gases in our atmosphere, and the different colours are caused by the different kinds of particles colliding. Solar storms can affect astronauts and satellites, as they’re outside the protection of the atmosphere.
Why is This Weekend Particularly Interesting?
This week scientists have observed 2 solar flares from sunspot AR2518. The first was relatively small and the second extremely large, and because of the sun’s current position these flares and their CMEs are heading directly for Earth. It’s unusual to have 2 flares heading for us at the same time and scientists are interested to see how they interact with each other. It’s possible that the incoming storms may affect radio communications as well as satellite transmissions, but there’s no need to worry about ground-based electronics.