Astronomy Picture of the Day

  MWC 922: The Red Square Nebula Credit & Copyright: Peter Tuthill (Sydney U.) & James Lloyd (Cornell) Explanation: What could cause a nebula to appear square? No one is quite sure. The hot star system known as MWC 922, however, appears to be embedded in a nebula with just such a shape. The above image combines infraredexposures from the Hale Telescope on Mt. Palomar in California, and the Keck-2 Telescope on Mauna Kea in Hawaii. A leading progenitor hypothesis for ... Full Story