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. 2023 April 15 [2]See Explanation. Clicking on the picture will download the highest resolution version available. When Z is for Mars Image Credit & [3]Copyright: [4]Tunc Tezel ([5]TWAN) Explanation: [6]A composite of images captured about a week apart from mid August 2022 through late March 2023, this series traces the [7]retrograde motion of ruddy-colored Mars. Progressing from lower right to upper left Mars makes a [8]Z-shaped path as it wanders past the Pleiades and Hyades star clusters, through the constellation Taurus in planet Earth's night sky. Seen about every two years, Mars doesn't actually reverse the direction of its orbit to trace out the Z-shape though. Instead, the apparent backwards or retrograde motion with respect to the background stars is a reflection of the orbital motion of Earth itself. Retrograde motion can be seen each time Earth overtakes and laps planets orbiting farther from the Sun, the Earth moving more rapidly through its own relatively close-in orbit. High in northern hemisphere skies the [9]Red Planet was opposite the Sun and at its closest and brightest on December 8, near the center of the frame. [10]Seen close to Mars, a popular visitor to the inner Solar System, comet ZTF (C/2022 E3), was also captured on two dates, February 10 and February 16. Tomorrow's picture: winging it __________________________________________________________________ [11]< | [12]Archive | [13]Submissions | [14]Index | [15]Search | [16]Calendar | [17]RSS | [18]Education | [19]About APOD | [20]Discuss | [21]> __________________________________________________________________ Authors & editors: [22]Robert Nemiroff ([23]MTU) & [24]Jerry Bonnell ([25]UMCP) NASA Official: Phillip Newman [26]Specific rights apply. [27]NASA Web Privacy Policy and Important Notices A service of: [28]ASD at [29]NASA / [30]GSFC, [31]NASA Science Activation & [32]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2304/Ma2022-3.jpg 3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 4. http://www.twanight.org/tezel 5. http://www.twanight.org/ 6. https://apod.nasa.gov/apod/image/2304/Ma2022-3La.jpg 7. https://mars.nasa.gov/all-about-mars/night-sky/retrograde/ 8. https://vimeo.com/813818095 9. https://apod.nasa.gov/apod/ap221215.html 10. https://apod.nasa.gov/apod/ap230213.html 11. https://apod.nasa.gov/apod/ap230414.html 12. https://apod.nasa.gov/apod/archivepix.html 13. https://apod.nasa.gov/apod/lib/apsubmit2015.html 14. https://apod.nasa.gov/apod/lib/aptree.html 15. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 16. https://apod.nasa.gov/apod/calendar/allyears.html 17. https://apod.nasa.gov/apod.rss 18. https://apod.nasa.gov/apod/lib/edlinks.html 19. https://apod.nasa.gov/apod/lib/about_apod.html 20. http://asterisk.apod.com/discuss_apod.php?date=230415 21. https://apod.nasa.gov/apod/ap230416.html 22. http://www.phy.mtu.edu/faculty/Nemiroff.html 23. http://www.phy.mtu.edu/ 24. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 25. http://www.astro.umd.edu/ 26. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 27. https://www.nasa.gov/about/highlights/HP_Privacy.html 28. https://astrophysics.gsfc.nasa.gov/ 29. https://www.nasa.gov/ 30. https://www.nasa.gov/centers/goddard/ 31. https://science.nasa.gov/learners 32. http://www.mtu.edu/