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 November 8 [2]See Explanation. Clicking on the picture will download the highest resolution version available. Martian Moon Phobos from Mars Express Image Credit: [3]G. Neukum ([4]FU Berlin) et al., [5]Mars Express, [6]DLR, [7]ESA; Acknowledgement: Peter Masek Explanation: Why is Phobos so dark? [8]Phobos, the largest and innermost of two Martian moons, is the darkest moon in the entire [9]Solar System. Its unusual orbit and color indicate that it may be a captured [10]asteroid composed of a mixture of ice and dark rock. The [11]featured picture of Phobos near the limb of [12]Mars was captured in 2010 by the robot spacecraft [13]Mars Express currently orbiting Mars. [14]Phobos is a heavily cratered and [15]barren moon, with its [16]largest crater located on the far side. From images like this, [17]Phobos has been determined to be covered by perhaps a meter of [18]loose dust. Phobos [19]orbits so close to Mars that from some places it would appear to rise and set twice a day, but from other places it would not be visible at all. [20]Phobos' orbit around Mars is continually decaying -- it will likely [21]break up with pieces crashing to the Martian surface in about 50 million years. Tomorrow's picture: in green company __________________________________________________________________ [22]< | [23]Archive | [24]Submissions | [25]Index | [26]Search | [27]Calendar | [28]RSS | [29]Education | [30]About APOD | [31]Discuss | [32]> __________________________________________________________________ Authors & editors: [33]Robert Nemiroff ([34]MTU) & [35]Jerry Bonnell ([36]UMCP) NASA Official: Phillip Newman [37]Specific rights apply. [38]NASA Web Privacy Policy and Important Notices A service of: [39]ASD at [40]NASA / [41]GSFC & [42]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2011/phoboslimb_marsexpress_2592.jpg 3. http://www.esa.int/esaSC/SEMGQOXLDMD_people_0_iv.html 4. https://www.fu-berlin.de/ 5. https://www.esa.int/Science_Exploration/Space_Science/Mars_Express 6. https://www.dlr.de/pf 7. https://www.esa.int/ 8. https://en.wikipedia.org/wiki/Phobos_(moon) 9. https://solarsystem.nasa.gov/planets/overview/ 10. https://solarsystem.nasa.gov/asteroids-comets-and-meteors/asteroids/overview/ 11. http://www.unmannedspaceflight.com/index.php?showtopic=480&st=195&p=167059&#entry167059 12. https://solarsystem.nasa.gov/planets/mars/overview/ 13. http://www.esa.int/SPECIALS/Mars_Express/SEMFU55V9ED_0.html 14. https://apod.nasa.gov/apod/ap080414.html 15. https://apod.nasa.gov/apod/ap031109.html 16. https://apod.nasa.gov/apod/ap080410.html 17. https://apod.nasa.gov/apod/ap061203.html 18. https://apod.nasa.gov/apod/ap980914.html 19. http://www.youtube.com/watch?v=7rxqZcO-0uI 20. https://apod.nasa.gov/apod/ap990313.html 21. https://ui.adsabs.harvard.edu/abs/2008AGUFM.P51C1423H/abstract 22. https://apod.nasa.gov/apod/ap201107.html 23. https://apod.nasa.gov/apod/archivepix.html 24. https://apod.nasa.gov/apod/lib/apsubmit2015.html 25. https://apod.nasa.gov/apod/lib/aptree.html 26. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 27. https://apod.nasa.gov/apod/calendar/allyears.html 28. https://apod.nasa.gov/apod.rss 29. https://apod.nasa.gov/apod/lib/edlinks.html 30. https://apod.nasa.gov/apod/lib/about_apod.html 31. http://asterisk.apod.com/discuss_apod.php?date=201108 32. https://apod.nasa.gov/apod/ap201109.html 33. http://www.phy.mtu.edu/faculty/Nemiroff.html 34. http://www.phy.mtu.edu/ 35. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 36. http://www.astro.umd.edu/ 37. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 38. https://www.nasa.gov/about/highlights/HP_Privacy.html 39. https://astrophysics.gsfc.nasa.gov/ 40. https://www.nasa.gov/ 41. https://www.nasa.gov/centers/goddard/ 42. http://www.mtu.edu/