The Milky Way galaxy that is home to Earth, has two arms of stars, not four as previously thought astronomers, as revealed in the images provided by the Spitzer Space Telescope NASA. The theory of stellar four arms had been impossible to confirm until now precisely because of the fact that the Earth is inside. Our Sun is between Perseus and Sagittarius But now Spitzer has provided a new basis to reconsider the whole structure of the Milky Way, said Robert Benjamin, an astronomer at the University of Wisconsin, during a press conference in St. Louis, Missouri.
"We will continue our picture editing (Galaxy) in the same way that early explorers sailing around the world corrected their maps," he said in a report submitted to the Astronomical Society of the United States.
Since 1950, astronomers had models based on observations of galactic cosmic gases that suggested a spiral structure with four arms of stars, called Norma, Scutum-Centaurus, Sagittarius and Perseus. Our Sun is between Perseus and Sagittarius.
800,000
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For many years, created maps of the galaxy on the study of a section or a single method, Benjamin said in a statement released by the Jet Propulsion Laboratory (JPL) of NASA.
"Unfortunately, when comparing these models did not match. It was like studying an elephant blindfolded," he said. But observations by infrared instruments made in the past decade led to reconsider those structures.
With Spitzer, astronomers have now got a much broader picture of the galaxy with a mosaic of 800,000 pieces which includes 110 million stars, JPL said. To further these observations, Benjamin has developed software that allowed him to count the stars and measure the density of stars. And when he looked toward group Scutum-Centaurus, found, as expected, an increase in the number of stars. But by focusing on Sagittarius and Norma, no such increase was stellar. Perseus is at the opposite end of the galaxy and can not be seen in Spitzer images.
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