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.