By ROB WAUGH
After an unusually long quiet period, the sun unleashed a solar flare on May 17 this year – but scientists are now puzzling over what happened on Earth. Neutron monitors all round the world lit up in response to the blast for the first time in six years, despite the fact it was an M-Class, or moderate, flare.
The ‘answering’ pulse shouldn’t have happened at all. Now scientists are trying to unravel what happened – and why our planet ‘pulsed’ in response.
James Ryan, an astrophysicist at the UNH Space Science Center said, ‘This solar flare was most unimpressive and the associated CME was only slightly more energetic. And looking at it optically, it was remarkably dim, it was, all things considered, a ninety-eight pound weakling of solar events.’
Scientists are now analysing the data using a satellite which scans an range of bizarre particles invisible to other spacecraft – PAMELA, a European spacecraft dedicated to watching rays from space.
Launched in 2006 and dedicated to studying cosmic rays, just two weeks before the most recent blast from the Sun PAMELA was retasked to focus on solar physics due to the Sun’s ever-increasing activity.
For decades, there has been strong debate as to what complex processes produce the extremely energetic particles that are registered on the ground; is it the shockwave in front of a CME or do the particles come from the solar flare itself?
The most recent event will allow the study of the evolution of the flare from low to high energies without interruption.
‘The PAMELA satellite provides us with a bridge that has never existed before,’ says Ryan, ‘a bridge between solar energetic particles measured by other spacecraft and those made on the ground by neutron monitors, like the one we’ve operated here in Durham for decades. Spanning that gap has opened up new opportunities.’