The northern lights lit up the night sky with rare sightings across the UK and Europe.
The aurora borealis was spotted in Whitley Bay on the north east coast; Essex; Cambridgeshire; and Wokingham in Berkshire.
Kathleen Cunnea, in Great Horkesley, Essex, said: “It was absolutely amazing to see.”
Met Office spokesman Stephen Dixon said on Friday it was likely that the northern lights could be seen.
He said: “Although the shorter nights will limit the visibility window, there is a good chance of seeing the aurora, especially on Friday night and particularly in Scotland, Ireland and parts of northern England and Wales.
“There can even be visibility further south if you have the right equipment.
“Those conditions could continue on Saturday night, but we still need to work out details on where exactly that will be.”
Dixon said the combination of clear skies and increased activity from the sun reaching Earth will improve the chances of seeing the display.
Aurora displays occur when charged particles collide with gases in the Earth’s atmosphere around the magnetic poles.
In the Northern Hemisphere, most of this activity occurs within a band known as the aurora oval, which covers latitudes between 60 and 75 degrees.
When activity is strong, it expands to cover a larger area – so displays can sometimes be seen as far south as the UK.
In the US, the National Oceanic and Atmospheric Administration (NOAA) issued a rare severe geomagnetic storm warning on Friday. It warned operators of power plants and spacecraft in orbit to take precautions. NOAA says the storm could produce northern lights as far south as Alabama and northern California.
“For most people here on planet Earth, they won’t have to do anything,” said Rob Steenburgh, a scientist with NOAA’s Space Weather Center. “This is really the gift of space weather – the aurora.”
Steenburgh and his colleagues said the best aurora views might come from phone cameras, which could capture light better than the naked eye.
Even when the storm is over, signals between GPS satellites and ground receivers can become scrambled or lost, according to NOAA. But there are so many navigation satellites that any outages shouldn’t last long, Steenburgh said.
The flares appear to be associated with a sunspot 16 times the diameter of Earth, according to NOAA. This is all part of the solar activity that increases as the sun approaches the peak of its 11-year cycle.
Nasa said the storm posed no serious threat to the seven astronauts on board the International Space Station. The main concern was increased radiation levels, and the crew could move to a better shielded part of the station if necessary, according to Steenburgh.
Increased radiation could also threaten some of Nasa’s science satellites. Extremely sensitive instruments will be turned off if necessary to avoid damage, said Antti Pulkkinen, director of the space agency’s heliophysics science division. Several sun-focused spacecraft watched all the action.
“These are exactly the kinds of things we want to observe,” Pulkkinen said.
With PA Media and Associated Press
