                        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 January 18

                    Northern Lights from the Stratosphere
                    Image Credit & Copyright: Ralf Rohner

   Explanation: Northern lights shine in this night skyview from planet
   Earth's stratosphere, captured on January 15. The single, 5 second
   exposure was made with a hand-held camera on board an aircraft above
   Winnipeg, Canada. During the exposure, terrestrial lights below leave
   colorful trails along the direction of motion of the speeding aircraft.
   Above the more distant horizon, energetic particles accelerated along
   Earth's magnetic field at the planet's polar regions excite atomic
   oxygen to create the shimmering display of Aurora Borealis. The
   aurora's characteristic greenish hue is generated at altitudes of
   100-300 kilometers and red at even higher altitudes and lower
   atmospheric densities. The luminous glow of faint stars along the plane
   of our Milky Way galaxy arcs through the night, while the Andromeda
   galaxy extends this northern skyview to extragalactic space. A diffuse
   hint of Andromeda, the closest large spiral to the Milky Way, can just
   be seen to the upper left.

            Tomorrow's picture: shortest day in the Solar System
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Ryan Smallcomb Specific rights apply.
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