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. 2025 June 19 [2]See Explanation. Clicking on the picture will download the highest resolution version available. NGC 3521: Galaxy in a Bubble Image Credit & [3]Copyright: [4]Vikas Chander Explanation: [5]Gorgeous spiral galaxy NGC 3521 is a mere 35 million light-years away, toward the northern [6]springtime constellation Leo. Relatively bright in planet Earth's sky, NGC 3521 is easily visible in small telescopes but often overlooked by amateur imagers in favor of other Leo spiral galaxies, like [7]M66 and M65. It's hard to overlook in this colorful cosmic portrait though. Spanning some 50,000 light-years the galaxy sports [8]characteristic patchy, irregular spiral arms laced with dust, pink star forming regions, [9]and clusters of young, blue stars. The deep image also finds NGC 3521 embedded in fainter, gigantic, bubble-like shells. The shells are likely tidal debris, streams of stars torn from satellite galaxies that have [10]undergone mergers with NGC 3521 in the distant past. Tomorrow's picture: lunistice __________________________________________________________________ [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: Amber Straughn [26]Specific rights apply. [27]NASA Web Privacy, [28]Accessibility, [29]Notices; A service of: [30]ASD at [31]NASA / [32]GSFC, [33]NASA Science Activation & [34]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2506/NGC3521-2048.jpg 3. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 4. https://www.instagram.com/vikaschanderastrophotography/ 5. https://www.nasa.gov/image-feature/goddard/hubble-shears-a-woolly-galaxy 6. https://earthsky.org/favorite-star-patterns/spring-triangle-regulus-arcturus-spica/ 7. https://apod.nasa.gov/apod/ap210320.html 8. https://arxiv.org/abs/1803.03653 9. https://arxiv.org/abs/1312.2399 10. http://www.cosmotography.com/images/galaxy_formation_and_evolution.html 11. https://apod.nasa.gov/apod/ap250618.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.com/feed.rss 18. https://apod.nasa.gov/apod/lib/edlinks.html 19. https://apod.nasa.gov/apod/lib/about_apod.html 20. https://asterisk.apod.com/discuss_apod.php?date=250619 21. https://apod.nasa.gov/apod/ap250620.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://www.nasa.gov/general/accessibility/ 29. https://www.nasa.gov/privacy/ 30. https://astrophysics.gsfc.nasa.gov/ 31. https://www.nasa.gov/ 32. https://www.nasa.gov/centers/goddard/ 33. https://science.nasa.gov/learners 34. http://www.mtu.edu/