Tracking space weather

In early March 2022, the ESA/NASA Solar Orbiter spacecraft got a feel for how a future space weather forecasting system might work. On 10 March, a solar flare produced a coronal mass ejection (CME) that was directed at Earth. The cameras on the ESA/NASA mission SOHO (Solar and Heliospheric Observer) recorded the event at around 22:06 UT. Solar Orbiter also observed it from its viewpoint about 67 million km from the Sun.

Late on 11 March, the CME arrived at Solar Orbiter’s position to be detected by the magnetometer (MAG). The readings could be used to calculate the time the CME would strike Earth’s magnetic field and the possible severity of the CME’s effects when it did. Solar Orbiter’s Solar Wind Analyser (SWA) instrument also recorded the event as a change in properties of the solar wind.

On 13 March, the lumbering CME finally passed over several spacecraft, including NASA’s Wind, stationed at the L1 point, which is 99% of the Earth’s distance from the Sun, about 1.5 million km from Earth. About an hour later, the CME struck Earth and sparked aurorae in the skies of Earth.

Thanks to the data from Solar Orbiter MAG, Christian Möstl, Space Research Institute, Austrian Academy of Sciences, Austria, had been able to predict the aurora. He posted a prediction on social media on 12 March 18:26 UT. This was seen by J Bant Sexson IV, who set up cameras at Eklutna Lake near Anchorage, Alaska. At around 5 am local time on the morning of 13 March, as twilight was starting to creep into the sky, he was rewarded with a brief but exciting display of the northern lights, that he posted to social media.

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