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 September 17
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                          Solar Cycle 25 Has Begun
                        Image Credit: [3]NASA, [4]SDO

   Explanation: [5]The general trend of monthly sunspot data now confirms
   that the minimum of the approximately 11 year cycle of solar activity
   occurred in December 2019, marking [6]the start of Solar Cycle 25. That
   quiet Sun, at minimum activity, appears on the right of this split
   hemispherical view. In contrast, the left side shows the active Sun at
   the recognized maximum of Solar Cycle 24, captured in April 2014. The
   extreme ultraviolet images from the orbiting [7]Solar Dynamics
   Observatory highlight coronal loops and active regions in the light of
   highly ionized iron atoms. [8]Driving the space weather around our fair
   planet, Solar Cycle 24 was a relatively calm one and predictions are
   that cycle 25 will be calm too. The cycle 25 activity maximum is
   expected in July 2025. Solar Cycle 1, the first solar cycle determined
   from early records of sunspot data, is considered to begin with a
   [9]minimum in February 1755.

                        Tomorrow's picture: 3D Orion
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    Authors & editors: [21]Robert Nemiroff ([22]MTU) & [23]Jerry Bonnell
                                 ([24]UMCP)
          NASA Official: Phillip Newman [25]Specific rights apply.
              [26]NASA Web Privacy Policy and Important Notices
                A service of: [27]ASD at [28]NASA / [29]GSFC
                           & [30]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2009/ig_maxmin.jpg
   3. https://www.nasa.gov/
   4. https://sdo.gsfc.nasa.gov/
   5. https://www.nasa.gov/press-release/solar-cycle-25-is-here-nasa-noaa-scientists-explain-what-that-means/
   6. https://www.weather.gov/news/201509-solar-cycle
   7. https://sdo.gsfc.nasa.gov/data/
   8. https://apod.nasa.gov/apod/ap170914.html
   9. https://en.wikipedia.org/wiki/Solar_cycle_1
  10. https://apod.nasa.gov/apod/ap200916.html
  11. https://apod.nasa.gov/apod/archivepix.html
  12. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  13. https://apod.nasa.gov/apod/lib/aptree.html
  14. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  15. https://apod.nasa.gov/apod/calendar/allyears.html
  16. https://apod.nasa.gov/apod.rss
  17. https://apod.nasa.gov/apod/lib/edlinks.html
  18. https://apod.nasa.gov/apod/lib/about_apod.html
  19. http://asterisk.apod.com/discuss_apod.php?date=200917
  20. https://apod.nasa.gov/apod/ap200918.html
  21. http://www.phy.mtu.edu/faculty/Nemiroff.html
  22. http://www.phy.mtu.edu/
  23. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  24. http://www.astro.umd.edu/
  25. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  26. https://www.nasa.gov/about/highlights/HP_Privacy.html
  27. https://astrophysics.gsfc.nasa.gov/
  28. https://www.nasa.gov/
  29. https://www.nasa.gov/centers/goddard/
  30. http://www.mtu.edu/