                        Astronomy Picture of the Day

    Discover the cosmos! Each day a different image or photograph of our
      fascinating universe is featured, along with a brief explanation
                    written by a professional astronomer.

                                2023 April 11
        A bright star is seen in field of dimmer stars and pervasive
    light-brown dust. The star is the North Star: Polaris. Please see the
                 explanation for more detailed information.

                  North Star: Polaris and Surrounding Dust
                   Image Credit & Copyright: Javier Zayaz

   Explanation: Why is Polaris called the North Star? First, Polaris is
   the nearest bright star toward the north spin axis of the Earth.
   Therefore, as the Earth turns, stars appear to revolve around Polaris,
   but Polaris itself always stays in the same northerly direction --
   making it the North Star. Since no bright star is near the south spin
   axis of the Earth, there is currently no bright South Star. Thousands
   of years ago, Earth's spin axis pointed in a slightly different
   direction so that Vega was the North Star. Although Polaris is not the
   brightest star on the sky, it is easily located because it is nearly
   aligned with two stars in the cup of the Big Dipper. Polaris is near
   the center of the eight-degree wide featured image, a digital composite
   of hundreds of exposures that brings out faint gas and dust of the
   Integrated Flux Nebula (IFN) all over the frame as well as the globular
   star cluster NGC 188 on the far left. The surface of Cepheid Polaris
   slowly pulsates, causing the famous star to change its brightness by a
   few percent over the course of a few days.

                Explore Your Universe: Random APOD Generator
                       Tomorrow's picture: open space
     __________________________________________________________________

       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
                NASA Web Privacy Policy and Important Notices
                      A service of: ASD at NASA / GSFC,
                           NASA Science Activation
                             & Michigan Tech. U.

