STARQUAKE!

Thank your lucky stars that a magnetar--a new type of star astronomers discovered earlier this year--lies 20,000 light years from Earth. (One light year is about 9.5 trillion kilometers or 5.9 trillion miles.) If the star strayed any closer than the moon, force of its magnetic field could suck the keys out of your pocket and might rip iron atoms right out of your blood.

For five minutes last August 27 (at 2:22 a.m. Pacific time), a magnetar's blast of deadly X rays and gamma rays (types of short wavelength radiation) bombarded Earth's upper atmosphere. The burst overloaded the sensors of research satellites orbiting Earth, and disrupted long-range radio transmissions. Fortunately, Earth's atmosphere absorbed the rays. But the cosmic blast startled astronomers--and instantly riveted their attention on a new magnetar. They've named their new find SGR 1900+14.

"You might call magnetars leftovers of giant stars," says Umran Inan, an engineering professor at Stanford University in Palo Alto, California, who studied the magnetar's blast. When huge stars--some eight times the size of our sun--burn out, they explode into a mammoth gas cloud called a supernova (see diagram). The supernova's core instantly condenses. If the core spins fast enough--at least 200 revolutions per second--the result is a new kind of star made of nuclear ash. Its magnetic field is so powerful it can crack and quake the star's surface. That's what happened on August 27: A magnetar "starquake" spewed streams of intense radiation into space.

Does that mean it's Adios, magnetar? Hardly. The magnetar, only 20 km (12 mi) across, contains more matter than the sun. One teaspoon of its nuclear ash would weigh a billion tons on Earth. Astronomers now think magnetars have a life span of about 10,000 years before they totally fizzle out in space. Magnetars probably litter the Milky Way by the millions, and generate magnetic fields hundreds of times more powerful than any other star in the universe. Talk about magnetic attraction!

How do scientists detect, magnetars? Telescopes. Since magnetars are steady sources of X rays, X-ray and gamma-ray telescopes lofted into space sleuth them out. And radio telescopes on Earth have detected magnetars' sound waves. But no one's spotted a magnetar with an ordinary optical telescope yet--the Milky Way's thick dust clouds make the star too hard to see. After all, magnetars don't twinkle. They just churn!