We tend to see the Sun as mass of flaming heat, but like everything that is alive, its status is ever changing and can actually have spots that are colder than others. Of course, that concept is relative considering the fact that most of the Sun’s surface has been measured at about 5,800°C and the cooler spots we are talking about still reach somewhere between 3,000 and 4,500°C. The thing that scientists have not been able to figure out just until now is why these spots that are cooler appear or why when they do they last so long.
But they have finally come up with a theory that might actually explain this mystery once and for all. To do this, they had to first figure out what a Sun spot really was, as it is easy to just call it a cooler area of the Sun, but that does not define the actual characteristics.
Scientists finally figure out what causes Sun spots
As we have stated, Sun spots are a relatively cooler area on the Sun where magnetic activity is more intense than in the rest of the star. When pictures are taken of the area, these regions look darker because they are not radiating as much heat and light as their surroundings, making them really visible. This might have been the reason why it took so long to figure out how they work, as scientists were relying on oversimplified models to explain them, assuming that the spots were motionless, had neatly symmetric magnetic fields, and behaved in a very orderly way.
While this might have not harmed anything in the beginning, as we wanted to learn more about Sun spots these assumptions put a lot of constraints, which, considering that the Sun is massive ball of plasma, is not a good thing. But since technology grows leaps and bounds every year, scientists decided to use the GREGOR solar telescope along with some next-level algorithms to cut through atmospheric noise and get a much clearer picture of what is actually happening on the surface of the star.
To do this, they took precise measurements of the magnetic fields in and around these Sun spots and they discovered that, despite being in one of the most unstable and extreme environments imaginable, Sun spots are actually incredibly balanced structures and that surprisingly, around the outer edge of a Sun spot, the magnetic fields and plasma pressures are in near-perfect harmony.
This effect has a name, the Lorentz force, which is a magnetic tension which keeps everything from flying apart in a very delicate balance. It is the existence of a push and pull, and the magnetic force offsets the internal gas pressure so well that the whole thing stays stable. Scientists call this magnetohydrostatic equilibrium.
The fact that everything is in equilibrium is what makes the Sun spots be able to stay present on the surface of the Sun for days and even weeks, as it makes it harder for the pocket that is created to be dispersed by the surrounding solar chaos. Having said that, this equilibrium does not go on forever, eventually the force of the Sun forces a dispersal, and the cold spot disappears as if it was never there to begin with.
This is just one of the mysteries that the universe presents, and it has taken very long to get solved because of its complexity, but there is still a lot that we do not know and we cannot wait until all mysteries in the universe are unveiled. Who knows what the next answer will be?