Hues of pink, purple and green streaked the skies in North America overnight in a dazzling display of Northern Lights.
Weather officials said the aurora, which was seen from California to New York, as far south as Arizona and north into Canada, was “fairly unusual”.
The event was categorised as a “severe geomagnetic storm” and received the second highest rating in strength, a G4. The strongest would be a G5.
A less severe storm is expected this weekend.
“We got more of an impact than we expected,” Bill Murtagh, programme co-ordinator at the National Oceanic and Atmospheric Administration Space Weather and Prediction Center, told the BBC.
Mr Murtagh explained that the Northern Lights phenomenon experienced last night was due to “several eruptions on the sun”, which released high energy particles that collided with Earth’s atmosphere “like a big magnet getting shot out of the sun”.
“When these clouds of particles and magnetic fields from the sun hit the Earth’s magnetic fields, we see these high energy particles will interact with the Earth’s upper atmosphere and that will create the Northern Lights,” he said.
An event like this will happen about 50 times every solar cycle, he said, which is 11 years. But this was the most severe geomagnetic storm in almost six years, according to spaceweather.com.
Mr Murtagh said we are currently approaching a point in the solar cycle where more eruptions on the sun will occur, in a period defined as the solar maximum.
Throughout the solar minimum, when activity on the sun is lower, less severe geomagnetic storms more commonly occur, and are typically seen in northern states like New England and along the Canadian border, he said.
But more frequent high level solar storms are on the way.
“The next coming years we are going to see the most solar activity,” he said.
Source : BBC
