Sun: More sunspots than in 20 years

We can tell whether the sun is particularly active or not by the so-called sunspots. There are currently a particularly large number of them – more than there have been for 20 years.

“We are currently at the maximum of a relatively strong solar cycle,” explains solar physicist Achim Gandorfer from the Max Planck Institute for Solar System Research in Göttingen to the German Press Agency.

The cause is strong temperature differences

The spots appear repeatedly in an eleven-year cycle and then gradually disappear (sunspot cycle). Gandorfer: “It is currently impossible to say whether we are already at the end of the cycle or whether there will be a further increase.”

The Sun is a ball of gas and consists mainly of helium and hydrogen. While its surface is around 6000 degrees hot, its interior is a hellish 15 million degrees and under enormous pressure. As a result, gases from the interior are constantly swirling up to the surface, sometimes causing huge eruptions. In some places, the sun's magnetic field prevents these gases from being repelled.

At these points, the temperature of the material drops suddenly. This makes dark spots visible that are around 2000 degrees cooler than their surroundings and therefore stand out visually from the rest of the sun's surface. Gandorfer: “The spots are still very, very hot, but in contrast they appear darker because the surroundings are even hotter and brighter.”

Solar flares

Because the sun is so active, the probability of solar flares increases. These so-called Solar storms Billions of tons of high-energy particles are thrown into space, which can also reach the earth. This can cause damage to satellites, among other things. Positive side effect: This makes the northern lights more visible, even in areas where they would not otherwise be seen.

Sunspots were first sighted in the early 1600s, with the invention of the telescope. They have been systematically documented since the mid-18th century.