Spectacular aurora displays seen across the northern hemisphere in recent days have been caused by a huge solar flare with the energy of a billion hydrogen bombs, UK scientists have said.
The largest solar flare for more than 12 years - and the eighth-largest since modern records began in 1996 - erupted from the sun on Wednesday and has been captured in high detail by a team of researchers from the University of Sheffield and Queen's University Belfast.
The massive burst of radiation, one of three so called X-category flares observed over a 48-hour period, continues to produce spectacular aurora displays across northern latitudes.
A team from a consortium of UK universities, including the University of Sheffield and Queen's University Belfast, observed the huge coronal mass ejections in extremely high detail using the Swedish Solar Telescope on the island of La Palma, in The Canaries.
The scientists said the data collected will help predict when and where X-class flares might occur in the future and this information can be channelled into the multi-billion pound space weather industry to better protect satellites from the dangers of the sun.
The team said flare observation using ground-based telescopes is difficult because X-class flares can form and reach their peak intensities in little more than five minutes.
Dr Chris Nelson, from the University of Sheffield's School of Maths and Statistics, said: "It's very unusual to observe the opening minutes of a flare's life. We can only observe about 1/250th of the solar surface at any one time using the Swedish Solar Telescope, so to be in the right place at the right time requires a lot of luck
"To observe the rise phases of three X-classes over two days is just unheard of."
Dr Aaron Reid, from Queen's University Belfast's Astrophysics Research Centre, said: "The sun is currently in what we call solar minimum. The number of Active Regions, where flares occur, is low, so to have X-class flares so close together is very usual. These observations can tell us how and why these flares formed so we can better predict them in the future."
The Swedish 1 m Solar Telescope is operated on the island of La Palma by the Institute for Solar Physics (ISP) of Stockholm University at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofisica de Canarias.
UK access to the SST is funded by the Science and the Technology Facilities Council, Armagh Observatory, Northumbria University, Queen's University Belfast and the University of Sheffield.