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 July 31 [2]See Explanation. Clicking on the picture will download the highest resolution version available. Supernova 2025rbs in NGC 7331 Image Credit: [3]Ben Godson (University of Warwick) Explanation: A long time ago in a galaxy 50 million light-years away, [4]a star exploded. Light from that [5]supernova was first detected by telescopes on planet Earth on July 14th though, and the extragalactic transient is now known to astronomers as [6]supernova 2025rbs. [7]Presently the brightest supernova in planet Earth's sky, 2025rbs is a Type Ia supernova, likely caused by the thermonuclear detonation of a white dwarf star that accreted material from a companion in a binary star system. [8]Type Ia supernovae are used as standard candles to establish the distance scale of the universe. The host galaxy of 2025rbs is NGC 7331. Itself a bright spiral galaxy in the northern constellation Pegasus, [9]NGC 7331 is often touted as an analog to our own Milky Way. Tomorrow's picture: pixels in space __________________________________________________________________ [10]< | [11]Archive | [12]Submissions | [13]Index | [14]Search | [15]Calendar | [16]RSS | [17]Education | [18]About APOD | [19]Discuss | [20]> __________________________________________________________________ Authors & editors: [21]Robert Nemiroff ([22]MTU) & [23]Jerry Bonnell ([24]UMCP) NASA Official: Amber Straughn [25]Specific rights apply. [26]NASA Web Privacy, [27]Accessibility, [28]Notices; A service of: [29]ASD at [30]NASA / [31]GSFC, [32]NASA Science Activation & [33]Michigan Tech. U. References 1. https://apod.nasa.gov/apod/archivepix.html 2. https://apod.nasa.gov/apod/image/2507/2025rbsAnnotated1024.png 3. https://warwick.ac.uk/fac/sci/physics/research/astro/people/bengodson/ 4. https://science.nasa.gov/resource/type-ia-supernova/ 5. https://goto-observatory.org/bright-supernova-2025rbs-discovered-by-goto/ 6. https://www.wis-tns.org/object/2025rbs 7. https://rochesterastronomy.org/supernova.html 8. https://science.nasa.gov/mission/roman-space-telescope/type-ia-supernovae/ 9. https://apod.nasa.gov/apod/ap220922.html 10. https://apod.nasa.gov/apod/ap250730.html 11. https://apod.nasa.gov/apod/archivepix.html 12. https://apod.nasa.gov/apod/lib/apsubmit2015.html 13. https://apod.nasa.gov/apod/lib/aptree.html 14. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search 15. https://apod.nasa.gov/apod/calendar/allyears.html 16. https://apod.com/feed.rss 17. https://apod.nasa.gov/apod/lib/edlinks.html 18. https://apod.nasa.gov/apod/lib/about_apod.html 19. https://asterisk.apod.com/discuss_apod.php?date=250731 20. https://apod.nasa.gov/apod/ap250801.html 21. http://www.phy.mtu.edu/faculty/Nemiroff.html 22. http://www.phy.mtu.edu/ 23. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html 24. http://www.astro.umd.edu/ 25. https://apod.nasa.gov/apod/lib/about_apod.html#srapply 26. https://www.nasa.gov/about/highlights/HP_Privacy.html 27. https://www.nasa.gov/general/accessibility/ 28. https://www.nasa.gov/privacy/ 29. https://astrophysics.gsfc.nasa.gov/ 30. https://www.nasa.gov/ 31. https://www.nasa.gov/centers/goddard/ 32. https://science.nasa.gov/learners 33. http://www.mtu.edu/