Category: Astronomie

Did you know, the Northern lights or Aurora Borealis are created when the mythical Finnish ‘Firefox’ runs so quickly across the snow that its tail causes sparks to fly into the night sky? At least, that’s one of the stories that has been told in Finland about this beautiful phenomenon. Another that we love comes from the Sámi people of Finnish Lapland (among others), who describe them as plumes of water ejected by whales.

Today’s scientific explanation for the origin of the Aurora wasn’t thought up until the 20th Century, by the Norwegian scientist Kristian Birkeland. Charged particles, electrons and protons, are constantly emitted by the Sun, making up the solar wind. This wind slams into Earth’s ionosphere – sometimes sped up to vast speeds by solar storms – and the charged particles are deflected towards the poles by the magnetosphere.

Molecules in our atmosphere then absorb energy from these charged particles from the Sun, and re-release it in their own unique set of colours. Oxygen produces green, but at high altitudes can create red, nitrogen creates blues, and colours can overlap creating purple. Waves, twists and streams are caused by variations in Earth’s magnetic fields.
This striking video shows the Aurora over Kiruna, the northernmost city in Sweden. It’s composed of images taken by the Kiruna all-sky camera every minute for about ten hours over 18-19 September 2023.

The all-sky auroral camera is operated by the Kiruna Atmospheric and Geophysical Observatory (KAGO) within the Swedish Institute of Space Physics (IRF), and data from here is provided as part of ESA’s network of space weather services within the Agency’s Space Safety Programme.
A sequence of multiple coronal mass ejections – large, sudden ejections of plasma and magnetic field from the Sun – recently struck Earth, and we are still recovering from the passage of the last of them. The fastest was travelling at around 700 km/s, which is considered a small event.

Solar storms are causing an increase in geomagnetic activity; temporary disturbances in Earth’s magnetosphere, which has led to increased light shows at Earth’s poles.

Find out more about space weather: https://www.esa.int/Space_Safety/Space_weather
Sign up for free updates from ESA’s Space Weather Service Network: https://swe.ssa.esa.int/registration

Credits: All-sky camera, Kiruna Atmospheric and Geophysical Observatory (KAGO) within the Swedish Institute of Space Physics (IRF). Data provided as part of ESA’s Space Weather Service Network.

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