Astronomy Picture of the Day

   [1]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 January 9
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                           Perihelion to Aphelion
         Image Credit & [3]Copyright: [4]Ian Griffin (Otago Museum)

   Explanation: [5]Perihelion for 2020, the point in Earth's elliptical
   orbit when it is closest to the Sun, occurred on January 5th. The
   distance from the Sun doesn't determine the seasons, though. Those are
   governed by [6]the tilt of Earth's axis of rotation, so January is
   still winter in the north and summer in southern hemisphere. But it
   does mean that on January 5 the Sun was at its largest apparent size.
   This composite neatly compares two pictures of the Sun, both taken from
   planet Earth with the same telescope and camera. The left half was
   captured on the date of the 2020 perihelion. The right was recorded
   only a week before the July 4 date of the 2019 aphelion, the farthest
   point in Earth's orbit. Otherwise difficult to notice, the change in
   the Sun's apparent diameter between perihelion and aphelion amounts to
   a little over 3 percent. The 2020 perihelion and the preceding 2019
   aphelion correspond to the closest and farthest [7]perihelion and
   aphelion of the 21st century.

                   Tomorrow's picture: clouds like pearls
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   > Authors & editors: [19]Robert Nemiroff ([20]MTU) & [21]Jerry Bonnell
                                 ([22]UMCP)
          NASA Official: Phillip Newman [23]Specific rights apply.
              [24]NASA Web Privacy Policy and Important Notices
                A service of: [25]ASD at [26]NASA / [27]GSFC
                           & [28]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2001/peri-api-sun.jpg
   3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
   4. https://twitter.com/iangriffin
   5. https://earthsky.org/tonight/earth-comes-closest-to-sun-every-year-in-early-january
   6. https://solarsystem.nasa.gov/planets/earth/in-depth/#orbit_and_rotation_otp
   7. http://astropixels.com/ephemeris/perap2001.html
   8. https://apod.nasa.gov/apod/ap200108.html
   9. https://apod.nasa.gov/apod/archivepix.html
  10. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  11. https://apod.nasa.gov/apod/lib/aptree.html
  12. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  13. https://apod.nasa.gov/apod/calendar/allyears.html
  14. https://apod.nasa.gov/apod.rss
  15. https://apod.nasa.gov/apod/lib/edlinks.html
  16. https://apod.nasa.gov/apod/lib/about_apod.html
  17. http://asterisk.apod.com/discuss_apod.php?date=200109
  18. https://apod.nasa.gov/apod/ap200110.html
  19. http://www.phy.mtu.edu/faculty/Nemiroff.html
  20. http://www.phy.mtu.edu/
  21. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  22. http://www.astro.umd.edu/
  23. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  24. https://www.nasa.gov/about/highlights/HP_Privacy.html
  25. https://astrophysics.gsfc.nasa.gov/
  26. https://www.nasa.gov/
  27. https://www.nasa.gov/centers/goddard/
  28. http://www.mtu.edu/