If you want to see the Northern Lights from below the Arctic Circle, be prepared to take to the dark skies during the first week of June. The strongest geomagnetic storm on Earth in more than two decades occurred between May 10 and 12, painting the skies in southern Florida and Mexico with colorful auroras; This is an extremely rare event.

This was the result of at least five solar storms hitting Earth simultaneously; these were all caused by a massive sunspot known as Active Area 3664 (also known as AR3664 and AR13664), a dark spot on the Sun more than 15 times the width of Earth. . A shower of charged particles collided with Earth’s magnetosphere, directing them towards the poles along magnetic field lines, creating bright auroras.

Most importantly, precipitation from solar storms occurred several nights after the new moon in May, at a time when there was no moonlight in the night sky, making it easy to see even the faint auroras.

Because the Sun rotates around its axis every 27 days, the sunspot disappeared after about a week but did not stop producing solar flares. On May 20, it produced an X12 solar flare that was the most powerful since September 2017. Observed by the European Space Agency’s Solar Orbiter spacecraft.

AR3664/AR13664 is now visible again as the Sun returns and will return to Earth again during the new moon on June 6.

“It will line up nicely,” Ryan French, a solar system physicist at the National Solar Observatory (NSO) in Boulder, Colorado, told Live Science. “As soon as sunspots begin to appear, we will enter a window of opportunity [для спостереження за полярними сяйвами]”.