People in Britain marveled at the unusual and spectacular sight of the northern lights on Friday night, the consequence of a severe solar storm that was brewing and was expected to continue over the coming days.

The northern lights — also known as aurora borealis — usually don’t reach that far south. They are most often seen in higher latitudes closer to the North Pole. People in other European countries, including Denmark and Germany, also reported seeing the lights.

Onlookers marveled at the sight, posting their surprise, delight and sometimes shock on social media. As one user wrote: “Aurora Borealis? At this time of year? At this time of day? In this part of the country? Localized entirely over Edinburgh?”

Another onlooker posted, “It really is gorgeous though.”

The northern lights also made appearances in North America, with some people reporting sightings in Maine on Friday night. They occur when the sun expels material from its surface.

The current solar storm is caused by a cluster of sunspots — dark, cool regions on the solar surface. The cluster is flaring and ejecting material every six to 12 hours.

Earlier Friday, the National Oceanic and Atmospheric Administration’s Space Weather Prediction Center issued a rare warning about the solar outburst, because it could disrupt communications and even power grids.