Magnetars II

StarDate: March 6, 2009

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Passing close to a magnetar would be an unpleasant experience. From a quarter million miles -- the distance from Earth to the Moon -- it would rip the wristwatch from your arm and erase the magnetic strips on your credit cards. And from inside one thousand miles, it'd rip the iron in your red blood cells out of your body. Fortunately, though, the nearest known magnetar is thousands of light-years away.

A magnetar is the corpse of a once-mighty star that blasted itself apart as a supernova. Its core was crushed so tightly that even though it contains several times as much mass as the Sun, it's no bigger than a city.

Such a stellar remnant is known as a neutron star, and there are probably millions of them scattered through the galaxy. Most of them are old and lifeless. But a few of the young ones spin rapidly, beaming energy into space like a lighthouse.

And if they spin fast enough, they generate monstrously powerful magnetic fields -- up to a million billion times as powerful as Earth's magnetic field. These are the objects known as magnetars.

The magnetic field creates enormous stress on the star. This can crack the star's crust, creating a fireball that briefly shines brighter than billions of normal stars.

The magnetic field also acts as a brake, slowing the star's rotation. Within a few thousand years, it slows down so much that it loses most of the magnetic field. The magnetar is dead, but the neutron star continues on, skulking silently through the galaxy.

Script by Damond Benningfield, Copyright 2009

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