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 May 1

                             A View Toward M106
                    Image Credit & Copyright: Joonhwa Lee

   Explanation: Big, bright, beautiful spiral, Messier 106 dominates this
   cosmic vista. The nearly two degree wide telescopic field of view looks
   toward the well-trained constellation Canes Venatici, near the handle
   of the Big Dipper. Also known as NGC 4258, M106 is about 80,000
   light-years across and 23.5 million light-years away, the largest
   member of the Canes II galaxy group. For a far far away galaxy, the
   distance to M106 is well-known in part because it can be directly
   measured by tracking this galaxy's remarkable maser, or microwave laser
   emission. Very rare but naturally occurring, the maser emission is
   produced by water molecules in molecular clouds orbiting its active
   galactic nucleus. Another prominent spiral galaxy on the scene, viewed
   nearly edge-on, is NGC 4217 below and right of M106. The distance to
   NGC 4217 is much less well-known, estimated to be about 60 million
   light-years, but the bright spiky stars are in the foreground, well
   inside our own Milky Way galaxy. Even the existence of galaxies beyond
   the Milky Way was questioned 100 years ago in astronomy's Great Debate.

   Experts Debate: How will humanity first discover extraterrestrial life?
                      Tomorrow's picture: light-weekend
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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