Dec 18, 2013 07:25 AM EST
Massive Stars Reveal Milky Way's 'Missing' Four Arms
Astronomers have debated exactly how many arms our Milky Way Galaxy has. While some were certain that our galaxy had four spiral arms, images taken by NASA's Spitzer Space Telescope showed only two arms. Now, scientists have reaffirmed that our galaxy has four spiral arms, paving the way to future s...