¿ 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. 2021 May 12 [2]Rainbow airglow over the Azores. See Explanation. Moving the cursor over the image will bring up an annotated version. Clicking on the image will bring up the highest resolution version available. A Meteor and the Gegenschein Image Credit: [3]J.C. Casado, [4]StarryEarth, [5]EELabs, [6]TWAN Explanation: Is the night sky darkest in the direction opposite the Sun? No. In fact, a rarely discernable faint glow known as [7]the gegenschein (German for "counter glow") can be seen 180 degrees around from the Sun in an extremely [8]dark sky. The gegenschein is sunlight back-scattered off small interplanetary [9]dust particles. These dust particles are millimeter sized splinters from [10]asteroids and orbit in the [11]ecliptic plane of the planets. [12]Pictured here from last March is one of the more spectacular pictures of [13]the gegenschein yet taken. The deep exposure of an extremely dark sky over [14]Teide Observatory in [15]Spain's [16]Canary Islands shows [17]the gegenschein as part of extended [18]zodiacal light. Notable background objects include a [19]bright meteor (on the left), the [20]Big Dipper (top right), and [21]Polaris (far right). The meteor nearly points [22]toward Mount Teide, Spain's highest mountain, while the [23]Pyramid solar laboratory is visible on the right. During the day, a phenomenon like [24]the gegenschein called [25]the glory can be seen in reflecting air or clouds opposite the [26]Sun from an airplane. Tomorrow's picture: open space __________________________________________________________________ [27]< | [28]Archive | [29]Submissions | [30]Index | [31]Search | [32]Calendar | [33]RSS | [34]Education | [35]About APOD | [36]Discuss | [37]> __________________________________________________________________ Authors & editors: [38]Robert Nemiroff ([39]MTU) & [40]Jerry Bonnell ([41]UMCP) NASA Official: Phillip Newman [42]Specific rights apply. [43]NASA Web Privacy Policy and Important Notices A service of: [44]ASD at [45]NASA / [46]GSFC & [47]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2105/GegenscheinBolide_Casado_2500.jpg 3. http://twanight.org/profile/juan-carlos-casado/ 4. https://www.flickr.com/photos/starryearth/albums/ 5. https://www.eelabs.eu/ 6. https://twanight.org/about/ 7. http://en.wikipedia.org/wiki/Gegenschein 8. https://www.darksky.org/ 9. https://apod.nasa.gov/apod/ap010813.html 10. https://apod.nasa.gov/apod/ap980712.html 11. https://apod.nasa.gov/apod/ap151126.html 12. https://www.instagram.com/p/COfkiYNpzdP/ 13. http://www.as.wvu.edu/~jel/skywatch/skw9810h.html 14. https://en.wikipedia.org/wiki/Teide_Observatory 15. https://en.wikipedia.org/wiki/Spain 16. https://en.wikipedia.org/wiki/Canary_Islands 17. http://io9.com/5662511/gegenschein-the-glowing-circle-in-the-sky 18. https://apod.nasa.gov/apod/ap210311.html 19. https://solarsystem.nasa.gov/asteroids-comets-and-meteors/meteors-and-meteorites/overview/ 20. https://www.adlerplanetarium.org/blog/discover-big-dipper/ 21. https://starchild.gsfc.nasa.gov/docs/StarChild/questions/question64.html 22. https://youtu.be/Vx0jimhalAU 23. https://3dwarehouse.sketchup.com/model/a25ba51c87e33afc465ebc912c8fdaee/Laboratorio-Solar 24. https://ui.adsabs.harvard.edu/abs/1997MNRAS.288.1022J/abstract 25. https://apod.nasa.gov/apod/ap161222.html 26. https://solarsystem.nasa.gov/solar-system/sun/overview/ 27. https://apod.nasa.gov/apod/ap210511.html 28. https://apod.nasa.gov/apod/archivepix.html 29. https://apod.nasa.gov/apod/lib/apsubmit2015.html 30. https://apod.nasa.gov/apod/lib/aptree.html 31. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 32. https://apod.nasa.gov/apod/calendar/allyears.html 33. https://apod.nasa.gov/apod.rss 34. https://apod.nasa.gov/apod/lib/edlinks.html 35. https://apod.nasa.gov/apod/lib/about_apod.html 36. http://asterisk.apod.com/discuss_apod.php?date=210512 37. https://apod.nasa.gov/apod/ap210513.html 38. http://www.phy.mtu.edu/faculty/Nemiroff.html 39. http://www.phy.mtu.edu/ 40. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 41. http://www.astro.umd.edu/ 42. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 43. https://www.nasa.gov/about/highlights/HP_Privacy.html 44. https://astrophysics.gsfc.nasa.gov/ 45. https://www.nasa.gov/ 46. https://www.nasa.gov/centers/goddard/ 47. http://www.mtu.edu/