A huge blast from deep space buffeted the Earth for months, scientists have revealed. The mysterious eruption has been traced to one of the most powerful magnets in the universe – a rare and mysterious death star.
A surge of X-rays from the explosion triggered an alarm on NASA’s Swift satellite on August 22 last year. Other space telescopes, including Europe’s XMM-Newton and Integral space observatories, quickly swung into action to monitor the radiation.
The outburst lasted for four months during which hundreds of smaller blasts were also recorded. Astronomers identified the source as a magnetar – one of only 15 known in the Milky Way.
Its magnetic pull is 10,000 million times stronger than the Earth’s magnetic field which directs compasses. If it lay half as far away as the Moon, it would wipe the details off the magnetic strips on every credit card in existence. Fortunately the magnetar, now labelled SGR 0501+4516, lies much further away – around 15,000 light-years distant – and it was not known of before the “shock waves” from last year’s outburst hit the Earth.
Astronomers believe the explosion, reported in the Monthly Notices of the Royal Astronomical Society, happened when the dead star’s unstable magnetic field pulled on its crust, producing an exotic volcanic eruption.
A magnetar outburst can send as much energy to Earth as a solar flare, despite the fact they are far across our galaxy, whereas the Sun is right on our doorstep, relatively speaking. Another magnetar was spotted exploding like a firecracker later last year until early in 2009.
There are two theories to explain magnetars. Some believe they are the tiny cores left after a highly magnetic star dies. Others think they may form after the demise of a normal star when the spin of its central core speeds up.
Picture: An artist’s impression of a magnetar. (Image: Robert S. Mallozzi, University of Alabama in Huntsville, and NASA Marshall Space Flight Center).
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