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.

                              2019 November 30
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                        Star Trails for a Red Planet
                Image Credit & [3]Copyright: [4]Dengyi Huang

   Explanation: [5]Does Mars have a north star? In long exposures of
   [6]Earth's night sky, star trails make concentric arcs around the north
   celestial pole, the direction of our fair planet's [7]axis of rotation.
   [8]Bright star Polaris is presently the Earth's North Star, close on
   the sky to Earth's north celestial pole. But long exposures on [9]Mars
   show star trails too, concentric arcs about a celestial pole determined
   by Mars' axis of rotation. Tilted like planet Earth's, the martian axis
   of rotation points in a different direction in space though. [10]It
   points to a place on the sky between stars in Cygnus and Cepheus with
   no bright star comparable to Earth's north star Polaris nearby. So even
   though this ruddy, weathered landscape is [11]remarkably reminiscent of
   terrain in images from the [12]martian surface, the view must be from
   planet Earth, with north star Polaris near the center of concentric
   star trails. The landforms in the foreground are found in Qinghai
   Province in [13]northwestern China.

                     Tomorrow's picture: blue starburst
     __________________________________________________________________

      [14]< | [15]Archive | [16]Submissions | [17]Index | [18]Search |
   [19]Calendar | [20]RSS | [21]Education | [22]About APOD | [23]Discuss |
                                    [24]>
     __________________________________________________________________

    Authors & editors: [25]Robert Nemiroff ([26]MTU) & [27]Jerry Bonnell
                                 ([28]UMCP)
          NASA Official: Phillip Newman [29]Specific rights apply.
              [30]NASA Web Privacy Policy and Important Notices
                A service of: [31]ASD at [32]NASA / [33]GSFC
                           & [34]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/1911/StarTrailsOnRedPlanet2048.jpg
   3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
   4. mailto: huang dengyi [at] 126 [dot] com
   5. https://earthsky.org/astronomy-essentials/mars-north-south-star
   6. https://apod.nasa.gov/apod/ap131023.html
   7. https://apod.nasa.gov/apod/ap070519.html
   8. https://apod.nasa.gov/apod/ap110514.html
   9. https://www.jpl.nasa.gov/spaceimages/details.php?id=PIA03615
  10. https://en.wikipedia.org/wiki/Astronomy_on_Mars#Celestial_poles_and_ecliptic
  11. https://en.wikipedia.org/wiki/Yardangs_on_Mars
  12. https://phys.org/news/2019-04-small-china-mars-base-teens.html
  13. https://en.wikipedia.org/wiki/Dunhuang_Yardang_National_Geopark
  14. https://apod.nasa.gov/apod/ap191129.html
  15. https://apod.nasa.gov/apod/archivepix.html
  16. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  17. https://apod.nasa.gov/apod/lib/aptree.html
  18. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  19. https://apod.nasa.gov/apod/calendar/allyears.html
  20. https://apod.nasa.gov/apod.rss
  21. https://apod.nasa.gov/apod/lib/edlinks.html
  22. https://apod.nasa.gov/apod/lib/about_apod.html
  23. http://asterisk.apod.com/discuss_apod.php?date=191130
  24. https://apod.nasa.gov/apod/ap191201.html
  25. http://www.phy.mtu.edu/faculty/Nemiroff.html
  26. http://www.phy.mtu.edu/
  27. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  28. http://www.astro.umd.edu/
  29. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  30. https://www.nasa.gov/about/highlights/HP_Privacy.html
  31. https://astrophysics.gsfc.nasa.gov/
  32. https://www.nasa.gov/
  33. https://www.nasa.gov/centers/goddard/
  34. http://www.mtu.edu/