By Dr. Robert Mallozzi, University of Alabama
Artist's conception of magnetic field lines
and plasma clouds surrounding a
newly discovered magnetar.
Gamma rays
blast Earth’s
atmosphere
Energy from a star
By Craig Gima
20,000 light years away
hits above Hawaii
Star-BulletinIt's the stuff of science fiction and comic books -- a massive, invisible blast of gamma rays from a mysterious magnetic star that hit the Earth's atmosphere above Hawaii last month.
Gamma rays are the highest energy form of electromagnetic radiation. They're about a million times stronger than visible light.
In comic books, gamma rays are the kind of radiation that turned scientist Bruce Banner into the Incredible Hulk.
But in the world of astrophysics, gamma rays are a clue to forces that even comic book and science fiction writers would find hard to imagine.
The blast that hit the Earth over the Pacific Ocean on the night of Aug. 27 was so intense that it turned night into day in the Earth's outer atmosphere. It was detected by at least seven satellites, and two of them shut down to protect their electronics from the burst of radiation.
But don't worry, scientists said.
Just as Earth's atmosphere protects us from dangerous radiation from the sun, by the time the gamma ray blast reached the surface, radiation exposure was less than a dental X-ray.
At a news briefing yesterday, NASA scientists told reporters the gamma rays apparently came from a newly discovered type of star called a magnetar in the constellation Aquila, some 20,000 light years away. A light year is the distance light travels in a year -- about 6 trillion miles.
It's the first time a gamma ray flare from a magnetar was detected hitting the Earth, and apparently confirms the existence of what may be the most unusual stars in the universe.
Magnetars are collapsed stars with a magnetic field hundreds of trillions of times that of Earth.
The magnetic field is so powerful it could erase the magnetic stripe from your credit card and pull keys from your pockets even if you were 160,000 miles away -- a distance about equivalent to the halfway point between the Earth and the moon.
If you were standing on a magnetar, the magnetic field would kill you by rearranging all the atoms and molecules in your body.
The burst of energy that hit the Earth may have been created by a starquake on the magnetar that broke open the crust of the star known as SGR 1900+4, and in five minutes released as much power as the sun will emit for the next 300 years -- or a billion billion times the energy of the world's nuclear arsenal, according to calculations by Kevin Hurley of the University of California at Berkeley.
"If we could somehow harness this energy on Earth, we would have enough power to take care of everything, power every city, every village, every light bulb, until the end of the universe and far beyond," Hurley said at the briefing.
"But believe me, you would not want this star to be your sun. It's extremely lethal."
A magnetar forms after a star collapses upon itself in a supernova. What's left is an extremely dense object called a neutron star.
"A neutron star is created when an entire star, which is normally about a million miles across, is crushed into a star about the size of Oahu," explained Fritz Osell, a Leeward Community College astronomy professor.
The gravity from a neutron star is strong enough to flatten the highest mountains on earth to about the height of an ant.
Scientists so far have identified only four magnetars, but many more may exist in the universe.
"There are a lot of things in the universe that we don't know and can't see," said George Herbig, an astronomer with the Institute for Astronomy at the University of Hawaii.
Herbig said gamma ray bursts were first discovered during the Cold War by spy satellites that originally were trying to detect gamma rays from nuclear tests.
Since then, more satellites have been launched to discover the source of the bursts.
Xerex Tata, a UH physics and astronomy professor, said other cosmic phenomena called gamma ray bursters release even more energy than magnetars and may be the most powerful objects in the universe.
"You're talking about completely unimaginable energies," he said. "We know there are these explosions that are occuring with tremendous amounts of energy, and compared to those, the magnetars are tiny."
Wire services contributed to this report.
