EARTH CHANGES

Brightest galactic flash ever detected hits earth

A huge explosion halfway across the galaxy packed so much power it briefly altered Earth's upper atmosphere in December, astronomers said Friday. The blast originated about 50,000 light-years away and was detected Dec. 27
No known eruption beyond our solar system has ever appeared as bright upon arrival.
In gamma rays, the event equaled the brightness of the full Moon's reflected visible light.
The commotion was caused by a special variety of neutron star known as a magnetar. These fast-spinning, compact stellar corpses -- no larger than a big city -- create intense magnetic fields that trigger explosions. The blast was 100 times more powerful than any other similar eruption witnessed.
The star, named SGR 1806-20, spins once every 7.5 seconds, and is surrounded by a magnetic field more powerful than any other object in the universe.
Millions of neutron stars fill the Milky Way galaxy. A dozen or so are ultra-magnetic neutron stars -- magnetars. The magnetic field around one is about 1,000 trillion gauss, strong enough to strip information from a credit card at a distance halfway to the Moon, scientists say.

"Had this happened within 10 light-years of us, it would have severely damaged our atmosphere and possibly have triggered a mass extinction," said Bryan Gaensler of the Harvard-Smithsonian Center for Astrophysics.
Gaensler and two other astronomers the strength of the tempest has them wondering if major species die-offs in the past might have been triggered by stellar explosions.