Imagine a star with a magnetic field so strong it can suck pens out of your pocket and demagnetize your credit cards from as far away as half the distance to the moon. 

A newly discovered type of neutron star called a "magnetar" has just such a field—so intense that if it were 160,000 miles away, it would be as strong as a refrigerator magnet is up close. 

Before this year, these magnetars were just a theory, first proposed in 1992 by Christopher Thompson, assistant professor of physics and astronomy at Carolina, and Robert Duncan of the University of Texas at Austin. The theory suggested an explanation for an enormous outburst of soft gamma rays in 1979 from a source that continued to burst sporadically for several years. 

"We found that the only way of explaining the burst was with the idea of intense magnetism," Thompson says. And as a result of the source's intense magnetism, its rate of spin was predicted to slow down at an extremely rapid pace. 

Their theory, however, lacked sufficient evidence until earlier this year, when Chryssa Kouveliotou and colleagues at the Universities Space Research Association found evidence to support the magnetar theory. By observing another "soft gamma repeater" (SGR), they found that this particular star was slowing down at an unusually fast pace. "It was the slow rotation that convinced people that these sources really are magnetars," Thompson says. 

Then, on August 27, Kouveliotou and colleagues witnessed another immense burst that rivaled the 1979 burst in terms of energy that was radiated. These bursts can put out as much energy in one second as the sun does in an entire year. This recent discovery lent further support for the magnetar model, Thompson says. 

So far, strong evidence suggests the existence of four SGRs that could be magnetars. These stars are either in our galaxy or the Large Magellanic Cloud, a satellite galaxy that orbits our Milky Way. A half dozen other SGRs are very similar to magnetars, but they have never burst, Thompson says. 

But don't worry about these powerful stars bursting near the earth. "The chance of any of these sources coming near to the earth is as likely as a meteor hitting your house," Thompson says. 

"The new data not only tied up some questions about the nature of these sources, but they have also pointed to new directions," Thompson says. "This raises a whole host of interesting questions of how neutron stars behave in their interiors. We now have an outline of what their properties are, but many of the details remain to be filled in."