﻿ 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 July 18 [2]The picture shows the Andromeda Galaxy, M31, as seen by NASA's GALEX spacecraft in ultraviolet light. Please see the explanation for more detailed information. The Andromeda Galaxy in Ultraviolet Image Credit: [3]NASA, [4]JPL-Caltech, [5]GALEX Explanation: What does the Andromeda galaxy look like in ultraviolet light? Young blue stars circling the galactic center dominate. A mere 2.5 million light-years away, the [6]Andromeda Galaxy, also known as M31, really is just next door as large galaxies go. [7]Spanning about 230,000 light-years, it took 11 different image fields from NASA's [8]Galaxy Evolution Explorer (GALEX) satellite telescope to produce this gorgeous portrait of the [9]spiral galaxy in [10]ultraviolet light in 2003. While its spiral arms stand out in [11]visible light images, Andromeda's arms look more like [12]rings in ultraviolet. The rings are sites of intense [13]star formation and have been interpreted as evidence that Andromeda collided with its smaller neighboring [14]elliptical galaxy M32 more than 200 million years ago. The [15]Andromeda galaxy and our own comparable [16]Milky Way galaxy are the most massive members of the [17]Local Group of galaxies and are [18]projected to collide in several billion years -- perhaps around the time that our Sun's [19]atmosphere will expand to [20]engulf the Earth. Tomorrow's picture: the galaxy above __________________________________________________________________ [21]< | [22]Archive | [23]Submissions | [24]Index | [25]Search | [26]Calendar | [27]RSS | [28]Education | [29]About APOD | [30]Discuss | [31]> __________________________________________________________________ Authors & editors: [32]Robert Nemiroff ([33]MTU) & [34]Jerry Bonnell ([35]UMCP) NASA Official: Phillip Newman [36]Specific rights apply. [37]NASA Web Privacy Policy and Important Notices A service of: [38]ASD at [39]NASA / [40]GSFC & [41]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2107/M31_Galex_6000.jpg 3. https://www.nasa.gov/ 4. https://www.jpl.nasa.gov/ 5. http://www.galex.caltech.edu/ 6. https://en.wikipedia.org/wiki/Andromeda_Galaxy 7. https://apod.nasa.gov/apod/ap200925.html 8. https://www.nasa.gov/mission_pages/galex/galex20120516.html 9. https://en.wikipedia.org/wiki/Spiral_galaxy 10. https://science.nasa.gov/ems/10_ultravioletwaves 11. https://apod.nasa.gov/apod/ap181217.html 12. https://svs.gsfc.nasa.gov/10485 13. https://kids.frontiersin.org/articles/10.3389/frym.2019.00092 14. https://www.nasa.gov/feature/goddard/2017/messier-32 15. https://apod.nasa.gov/apod/ap200426.html 16. https://solarsystem.nasa.gov/resources/285/the-milky-way-galaxy/ 17. http://www.atlasoftheuniverse.com/localgr.html 18. https://ui.adsabs.harvard.edu/abs/2008MNRAS.386..461C/abstract 19. https://en.wikipedia.org/wiki/Future_of_Earth 20. https://photobest1.com/wp-content/uploads/2018/11/Funny-Cats-wallpaper-backgrounds-images-09.jpg 21. https://apod.nasa.gov/apod/ap210717.html 22. https://apod.nasa.gov/apod/archivepix.html 23. https://apod.nasa.gov/apod/lib/apsubmit2015.html 24. https://apod.nasa.gov/apod/lib/aptree.html 25. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 26. https://apod.nasa.gov/apod/calendar/allyears.html 27. https://apod.nasa.gov/apod.rss 28. https://apod.nasa.gov/apod/lib/edlinks.html 29. https://apod.nasa.gov/apod/lib/about_apod.html 30. http://asterisk.apod.com/discuss_apod.php?date=210718 31. https://apod.nasa.gov/apod/ap210719.html 32. http://www.phy.mtu.edu/faculty/Nemiroff.html 33. http://www.phy.mtu.edu/ 34. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 35. http://www.astro.umd.edu/ 36. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 37. https://www.nasa.gov/about/highlights/HP_Privacy.html 38. https://astrophysics.gsfc.nasa.gov/ 39. https://www.nasa.gov/ 40. https://www.nasa.gov/centers/goddard/ 41. http://www.mtu.edu/