                        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.

                              2024 September 13

            Aurora Australis and the International Space Station
                    Image Credit: NASA, ISS Expedition 71

   Explanation: This snapshot from the International Space Station was
   taken on August 11 while orbiting about 430 kilometers above the Indian
   Ocean, Southern Hemisphere, planet Earth. The spectacular view looks
   south and east, down toward the planet's horizon and through red and
   green curtains of aurora australis. The auroral glow is caused by
   emission from excited oxygen atoms in the extremely rarefied upper
   atmosphere still present at the level of the orbiting outpost. Green
   emission from atomic oxygen dominates this scene at altitudes of 100 to
   250 kilometers, while red emission from atomic oxygen can extend as
   high as 500 kilometers altitude. Beyond the glow of these southern
   lights, this view from low Earth orbit reveals the starry sky from a
   southern hemisphere perspective. Stars in Orion's belt and the Orion
   Nebula are near the Earth's limb just left of center. Sirius, alpha
   star of Canis Major and brightest star in planet Earth's night is above
   center along the right edge of the southern orbital skyscape.

              Looking Up: International Observe the Moon Night
                 Tomorrow's picture: If the Moon could smile
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Phillip Newman Specific rights apply.
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                      A service of: ASD at NASA / GSFC,
                           NASA Science Activation
                             & Michigan Tech. U.

