Sunspots are among the many curious and mysterious aspects of the Sun. They are areas that concentrate large amounts of energy and the site of solar storms whose effects reach our planet and can have potentially harmful effects.
What are sunspots?
A sunspot is an area of the Sun where the temperature is lower than the surrounding areas, but with strong magnetic intensity and where the most explosive solar storms take place. As they are cooler, they emit less light, making them darker than the rest of the Sun’s surface (which is why they are called spots), although they shine between 10 to 50 times more brightly than the Moon at its brightest. This phenomenon is not limited to our Sun, but a feature of all suns.
Observation and study of sunspots is essential if we want to know when storms occur that can affect the Earth, and also to take them into account for space travel, because satellites and astronauts are also exposed to them in what we could refer to as the environment of space.
The number of sunspots at any time varies and it has been observed that there are periods with increased sunspot activity that occur approximately every 11 years.
What effects do solar storms have on the Earth?
Solar storms, also referred to as geomagnetic storms, are episodes with high emission of solar wind that, when they are strong enough, cause changes to the Earth’s magnetosphere.
The solar wind is a stream or current of electrically charged particles (mainly electrons and protons) that the Sun continuously radiates out into space in all directions. Solar storms occur when this flow is more intense than normal.
The main effect of a solar storm depends on its magnitude, and we can appreciate this most significantly in the increase of polar auroras. When, however, a solar storm is particularly intense, it can cause interference in radio communications (short wave radiocommunications), damage the electronics of satellites, which affects navigation systems that use GPS and can even cause blackouts in electricity grids around the planet.
This is why these sunspots are monitored and studied constantly, to provide a warning or limit the effects that a major solar flare could have on the operations of everyday life on Earth.
Why we should protect ourselves from the Sun’s rays
As we have seen, the Sun is constantly radiating large amounts of energy that reach the Earth and affect us. This energy arrives as different types: On the one hand, there is infra-red radiation which gives us heat, but also visible light and ultraviolet light, which we need to protect ourselves from because it burns our skin and kills our cells.
Infra-red radiation, visible light and ultraviolet light are all wavelengths on the electromagnetic spectrum, but they are different, and some contain more energy than others.
The infra-red waves have less energy that the visible light waves and are longer, with more space between each peak and trough. The ultraviolet waves have more energy than visible light and can harm us if we do not protect ourselves against them as we should.
If our skin is exposed to too much ultraviolet light for a long time, this light can damage the cells in our skin, causing our body to react as the skin becomes red and inflamed, causing us pain.
*Foto from NASA.