Milky Way mislay two arms

On the left-hand side is an artist's interpretation of the revised structure of the Milky Way galaxy; on the right-hand side is a former sketches, displaying the four-armed structure. Since 1950s, scientists have sustained to revise their models of the Milky Way.

 By means of new infrared imaging from the Spitzer Space Telescope, NASA scientists declare our spiraled Milky Way galaxy is in reality made up of just two main arms. For Past years, astronomers have mapped out the galaxy with four crucial arms. The two arms on the chopping block--Norma and Sagittarius--haven't departed completely; they've now been demoted to the humble status of minor arm, according to NASA.

Scientists have studied parts and divisions of the galaxy for many years, but they speak telescopes tuned to sense infrared light provide them the best picture of its outline since they can make a way through dust. Infrared images taken in the 1990s led them to determine the huge bar of creamy nougat stars in the center of the galaxy. Spitzer's new-fangled infrared shots, joined with software that calculates stellar density, designate that Norma and Sagittarius aren't as thick as astronomers had thought.

"They will keep revising the picture in the similar method that early explorers sailing in the region of the globe had to continue revising the maps," said Robert Benjamin of the University of Wisconsin at Whitewater, who presented the results at a press conference Tuesday.

Gigantic 'star-quake' rocks Milky Way

Astronomers state that they have been taken aback by the amount of energy released in a star explosion on the distant side of our galaxy, 50,000 light-years away.

The spark of radiation on 27 December was so dominant that it bounced off the Moon and lit up the Earth's atmosphere.

The explosion occurred on the surface of an exotic kind of star - a super-magnetic neutron star called SGR 1806-20.

If the blast had been within just 10 light-years, Earth might have suffered a mass extinction, it is said.

"They figure that it's probably the biggest explosion observed by humans within our galaxy since Johannes Kepler saw his supernova in 1604," Dr Rob Fender, of Southampton University, UK, told the BBC News website.

One calculation has the giant flare on SGR 1806-20 unleashing about 10,000 trillion trillion trillion watts.

"This is a once-in-a-lifetime event. We have observed an object only 20km across, on the other side of our galaxy, releasing more energy in a 10th of a second than the Sun emits in 100,000 years," said Dr Fender.