Sky-gazers as far south as the United Kingdom were treated to a spectacular show when the Northern Lights lit up the heavens Sunday night.
The luminous greens, reds and blues -- the aurora borealis -- are the result of a strong solar wind escaping from the sun. When the particles reach Earth, they interact with the planet's magnetic field to paint the sky in dazzling colors.
In the United States, sightings of the light show were reported from Maine to Massachusetts.
The U.S. National Oceanic and Atmospheric Administration classifies solar storms on a scale of one to five (one being the weakest; five being the most severe). The Sunday storm was forecast to be a G3 event, meaning it could have the strength to cause fluctuations in some power grids, intermittent radio blackouts in higher latitudes and possible GPS issues.
NOAA's Space Weather Prediction Center canceled a G1 storm warning for today and said "Earth's geomagnetic field is expected to be at quiet to unsettled levels with isolated periods of active conditions possible" for the remainder of the day.