Astronomy: Northern lights to be seen at the weekend

Astronomers expect northern lights over Germany on Friday and Saturday evening.

Astronomy: Northern lights to be seen at the weekend

Astronomers expect northern lights over Germany on Friday and Saturday evening. The further north you are, the greater the chance of seeing them, said Carolin Liefke from the Haus der Astronomie in Heidelberg. Of course there is no guarantee that you will see something - but there is a certain probability.

The cause is solar storms that hit the Earth's magnetic field. In the past few days, several solar storms, so-called coronal mass ejections (CME), have been observed towards Earth, said astronomer Volker Bothmer from the University of Göttingen. “However, there was no extremely strong storm that could lead to power grid failures and other things,” he reassures.

The source region of the solar storms - a large sunspot cluster - is moving away from the Earth due to the sun's rotation, said Bothmer, "so that we are out of the line of fire."

High warning level

The sunspot cluster is about 16 times the diameter of the Earth, experts from the US weather agency NOAA (National Oceanic and Atmospheric Administration) said at a press conference. The operators of important infrastructure in the USA have been notified. It is the first time since 2005 that such a high warning level has been issued for a geomagnetic solar storm, said NOAA's Shawn Dahl. "This is quite extraordinary, a very rare occurrence." Due, among other things, to the long distance between the sun and the earth, there is always a very high degree of uncertainty in the forecast.

The sun goes through a so-called sunspot cycle lasting about eleven years with phases of weak and strong activity. At a minimum, no spots can be seen for months, at a maximum, hundreds. Since December 2019, the sun's activity has been steadily increasing, and it is currently nearing a maximum. As a result, northern lights have been seen over Germany again and again in recent months.

There is a trick that can be used to make the natural phenomenon visible: "Normally, it is enough to put a cell phone on the windowsill," Liefke explained at the end of March. Then you have to expose the photo for as long as possible. It should be as dark as possible. A clear view to the north is also important. "The colors usually come out in the photo," says Liefke. And that's despite the fact that there are no colors at all or only a colorless veil in the sky.

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