Mysterious 'Magnetar' Might Be The Largest-Known Magnetic Field In The Universe

Astronomers have discovered the mysterious source of what might be the largest source of magnetism in the universe, inside the core of an unlikely dead star.

Using the European Space Agency's XMM-Newton Space Telescope, researchers in Italy examined the "magnetar" SGR 0418, which is located within our galaxy about 6,500 light years from Earth.

Above: Magnetic loop on magnetar SGR 0418

Magnetars are a type of dead star, in which the core of a sun is compacted into extraordinarily small spaces - in this case, the mass of our sun is packed within a ball about 20km across.

They are named for the intense magnetic fields - trillions of times as strong as a hospital MRI scan - formed by their super-dense cores. Magnetars exist only briefly but sporadically burst with massive amounts of high-energy radiation while they do.

SGR 0418 was discovered in 2009 when Nasa's Fermi telescope detected a sudden burst of X-rays and gamma rays.

Based on three years of study it had been thought SGR 0418 had an unusually weak magnetic field, judged by the rate at which its rotation speed declined.

However new research was able to examine how X-rays from the object change as it rotates, and all indications are now that the object is far, far more magnetic than previously thought.

In fact, said Norbert Schartel at ESA, it is "one of the largest values ever measured in the Universe".

The picture painted by this more detailed study is truly mind-blowing.

"To explain our observations, this magnetar must have a super-strong, twisted magnetic field reaching 10 to the power of 15 Gauss across small regions on the surface, spanning only a few hundred metres across," said Andrea Tiengo of the Istituto Universitario di Studi Superiori.

"On average, the field can appear fairly weak, as earlier results have suggested. But we are now able to probe sub-structure on the surface and see that the field is very strong locally."

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