                        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.

                               2022 August 14

                               4000 Exoplanets
      Video Credit: SYSTEM Sounds (M. Russo, A. Santaguida); Data: NASA
                              Exoplanet Archive

   Explanation: Over 4000 planets are now known to exist outside our Solar
   System. Known as exoplanets, this milestone was passed last month, as
   recorded by NASA's Exoplanet Archive. The featured video highlights
   these exoplanets in sound and light, starting chronologically from the
   first confirmed detection in 1992 and continuing into 2019. The entire
   night sky is first shown compressed with the central band of our Milky
   Way Galaxy making a giant U. Exoplanets detected by slight jiggles in
   their parents-star's colors (radial velocity) appear in pink, while
   those detected by slight dips in their parent star's brightness
   (transit) are shown in purple. Further, those exoplanets imaged
   directly appear in orange, while those detected by gravitationally
   magnifying the light of a background star (microlensing) are shown in
   green. The faster a planet orbits its parent star, the higher the
   accompanying tone played. The retired Kepler satellite has discovered
   about half of these first 4000 exoplanets in just one region of the
   sky, while the TESS mission is on track to find even more, all over the
   sky, orbiting the brightest nearby stars. Finding exoplanets not only
   helps humanity to better understand the potential prevalence of life
   elsewhere in the universe, but also how our Earth and Solar System were
   formed.

                      Tomorrow's picture: wall of stars
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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.

