                        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.

                               2025 January 30

                           Hydrogen Clouds of M33
                     Image Credit & Copyright: Pea Mauro

   Explanation: Gorgeous spiral galaxy Messier 33 seems to have more than
   its fair share of glowing hydrogen gas. A prominent member of the local
   group of galaxies, M33 is also known as the Triangulum Galaxy and lies
   a mere 3 million light-years away. The galaxy's central 60,000
   light-years or so are shown in this sharp galaxy portrait. The portrait
   features M33's reddish ionized hydrogen clouds or HII regions.
   Sprawling along loose spiral arms that wind toward the core, M33's
   giant HII regions are some of the largest known stellar nurseries,
   sites of the formation of short-lived but very massive stars. Intense
   ultraviolet radiation from the luminous, massive stars ionizes the
   surrounding hydrogen gas and ultimately produces the characteristic red
   glow. In this image, broadband data were combined with narrowband data
   recorded through a filter that transmits the light of the strongest
   visible hydrogen and oxygen emission lines.

                     Tomorrow's picture: pixels in space
     __________________________________________________________________

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

