When the sky lights up colorfully in the middle of the night: then it’s the northern lights. From time to time they can also be seen in Germany. It could stay that way for a while.
Over Germany the sky rarely burns red and green, sometimes yellow or purple. Because northern lights are usually hardly visible in this country. But in the past few months some have appeared several times. Whether they appear depends on certain activities of the sun. And these are likely to continue for some time.
Everything starts with the sun. When it coughs forcefully, it throws electrically charged particles into space. Experts from the German Aerospace Center, for example, speak of a coronal mass ejection. If these particles move towards Earth, they arrive at the planet about one and a half to three days later. The magnetic field shields the earth’s surface from most of the particles. But if the sun is particularly strong, the particles can penetrate into the earth’s atmosphere. There the particles stimulate the air molecules to glow.
Because the sun is particularly active right now. The US space agency NASA speaks of an activity maximum. Every eleven years, at the peak of the solar cycle, the sun’s magnetic poles reverse – as if the north and south poles swap places on Earth. At this time, the sun goes from a calm state to an active and stormy state – and that’s where we are right now. According to NASA, this phase could take about a year.
The further north or the further south on Earth, the more likely you are to see the celestial phenomenon. By the way, the lights in the northern hemisphere are called Aurora Borealis, or Northern Lights, and in the Southern Hemisphere, Aurora Australis, or Southern Lights. But even those who are beyond the Arctic Circle don’t see the northern lights every night. “But the probability is much, much higher there,” says Uwe Pilz from the Sternfreunde association.
They are also called the Northern Lights, which is why you should look north. That’s where they appear first. “At first you usually see a reddish glow, like distant fire, as if something was burning there,” explains Pilz. “When they are larger, they appear green and halfway up.” When the northern lights are particularly visible, the green even moves – “it looks like curtains that move very slowly in a weak breeze.” Only particularly large northern lights fill the entire sky.
And by the way: Such an eruption from the sun doesn’t last forever. It may be that nothing is visible at first, and an hour later the northern lights appear.
More in the north than in the south. Even a few hundred kilometers can make a difference. If you want to react spontaneously, you can also find out if the northern lights are likely to appear soon. There are special northern light warning apps for this purpose. However, these are only precise half an hour in advance – when satellites around a million kilometers away can measure the charged particles. Just from observing the sun, science currently doesn’t know exactly when and how strongly the particles hit the Earth.
“It’s best to use a modern smartphone,” advises Pilz. “It can even be done by hand, without a tripod.” Normal mid-range cell phones have a night mode. For example, he would then take many short recordings within ten seconds and put them together. “If you move a little bit, the phone compensates for it.” The experienced skygazer says: Just hold it up to the sky and press it.
Such images often show more and brighter northern lights than are visible to the naked eye. Because camera sensors are more sensitive to light. “Sometimes you can’t see anything with your eyes, but the camera shows the northern lights,” says Pilz.