Subj : Daily APOD Report To : All From : Ben Ritchey Date : Thu Nov 08 2018 08:09:30 Astronomy Picture of the Day Astronomy Picture of the Day Discover the cosmos! [1] Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. 2018 November 8 [2] Mars in the Loop Image Credit & Copyright [3] : Tunc Tezel [4] (TWAN [5] ) Explanation: This composite of images spaced some 5 to 9 days apart, from late April (bottom right) through November 5 (top left), traces the retrograde motion of ruddy-colored Mars [6] through planet Earth's night sky [7] . To connect the dots and dates in this 2018 Mars retrograde loop, just slide your cursor over the picture (and check out this animation [8] ). But Mars didn't actually reverse the direction of its orbit. Instead, the apparent backwards motion with respect to the background stars is a reflection of the motion of the Earth itself. Retrograde motion can be seen [9] each time Earth overtakes and laps planets orbiting farther from the Sun, the Earth moving more rapidly through its own relatively close-in orbit. On July 27, Mars was near its favorable 2018 parihelic opposition, when Mars was closest to the Sun in its orbit while also opposite the Sun [10] in Earth's sky. For that date, the frame used in this composite was taken during the total lunar eclipse [11] . Tomorrow's picture: lookout ------------------------------------------------------------------------------- < [12] | Archive [13] | Submissions [14] | Index [15] | Search [16] | Calendar [17] | RSS [18] | Education [19] | About APOD [20] | Discuss [21] | > [22] ------------------------------------------------------------------------------- Authors & editors: Robert Nemiroff [23] (MTU [24] ) & Jerry Bonnell [25] (UMCP [26] ) NASA Official: Phillip Newman Specific rights apply [27] . NASA Web Privacy Policy and Important Notices [28] A service of: ASD [29] at NASA [30] / GSFC [31] & Michigan Tech. U. [32] ---------- Site notes: [1] archivepix.html [2] image/1811/Ma2018_tezelN.jpg [3] lib/about_apod.html#srapply [4] http://www.twanight.org/tezel [5] http://www.twanight.org/ [6] https://mars.nasa.gov/ [7] http://www.twanight.org/Mars [8] https://vimeo.com/298439756 [9] http://projects.astro.illinois.edu/data/Retrograde/ [10] ap180727.html [11] ap180802.html [12] ap181107.html [13] archivepix.html [14] lib/apsubmit2015.html [15] lib/aptree.html [16] https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search [17] calendar/allyears.html [18] /apod.rss [19] lib/edlinks.html [20] lib/about_apod.html [21] http://asterisk.apod.com/discuss_apod.php?date=181108 [22] ap181109.html [23] http://www.phy.mtu.edu/faculty/Nemiroff.html [24] http://www.phy.mtu.edu/ [25] https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html [26] http://www.astro.umd.edu/ [27] lib/about_apod.html#srapply [28] https://www.nasa.gov/about/highlights/HP_Privacy.html [29] https://astrophysics.gsfc.nasa.gov/ [30] https://www.nasa.gov/ [31] https://www.nasa.gov/centers/goddard/ [32] http://www.mtu.edu/ --- Mystic BBS v1.12 A39 (Windows/32) * Origin: FIDONet - The Positronium Repository (1:393/68) .