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.

                               2020 January 8

                            Galaxies in the River
   Image Credit & Copyright: Star Shadows Remote Observatory, PROMPT, CTIO

   Explanation: Large galaxies grow by eating small ones. Even our own
   galaxy engages in a sort of galactic cannibalism, absorbing small
   galaxies that are too close and are captured by the Milky Way's
   gravity. In fact, the practice is common in the universe and
   illustrated by this striking pair of interacting galaxies from the
   banks of the southern constellation Eridanus, The River. Located over
   50 million light years away, the large, distorted spiral NGC 1532 is
   seen locked in a gravitational struggle with dwarf galaxy NGC 1531
   (right of center), a struggle the smaller galaxy will eventually lose.
   Seen edge-on, spiral NGC 1532 spans about 100,000 light-years. Nicely
   detailed in this sharp image, the NGC 1532/1531 pair is thought to be
   similar to the well-studied system of face-on spiral and small
   companion known as M51.

                    Tomorrow's picture: happy perihelion
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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