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 September 24
      [2]Artwork depicts a colorful version of two black holes nearing
    collision from between the black holes. Swirling gas is depicted with
     wavey lined depicting gravitational waves ringing and an artificial
    grid depicting spacetime shown distorting. Please see the explanation
                       for more detailed information.

                   GW250114: Rotating Black Holes Collide
    Illustration Credit: [3]Aurore Simonnet ([4]SSU/[5]EdEon), LVK, URI;
                            [6]LIGO Collaboration

   Explanation: It was the strongest gravitational wave signal yet
   measured -- what did it show? [7]GW250114 was detected by both arms of
   the [8]Laser Interferometer Gravitational-wave Observatory (LIGO) in
   [9]Washington and [10]Louisiana [11]USA earlier this year. Analysis
   showed that the event was created when two [12]black holes, each of
   mass around 33 times the mass of the [13]Sun, coalesced into one larger
   [14]black hole with a mass of around 63 solar masses. Even though the
   event happened about a billion light years away, the signal was so
   strong that the spin of all [15]black holes, as well as initial
   [16]ringing of the final black hole, was deduced with [17]exceptional
   accuracy. Furthermore, it was confirmed better than before, as
   [18]previously predicted, that the total [19]event horizon area of the
   combined black hole was greater than those of the [20]merging black
   holes. Featured, an [21]artist's illustration depicts an imaginative
   and conceptual view from near one of the [22]black holes before
   collision.

                       Tomorrow's picture: open space
     __________________________________________________________________

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    Authors & editors: [34]Robert Nemiroff ([35]MTU) & [36]Jerry Bonnell
                                 ([37]UMCP)
          NASA Official: Amber Straughn [38]Specific rights apply.
            [39]NASA Web Privacy, [40]Accessibility, [41]Notices;
                A service of: [42]ASD at [43]NASA / [44]GSFC,
                         [45]NASA Science Activation
                           & [46]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2509/ArtGw250114_Simonnet_2400.jpg
   3. https://auroresimonnet.com/about-me/
   4. https://phys-astro.sonoma.edu/
   5. https://edeon.sonoma.edu/
   6. https://www.ligo.caltech.edu/page/ligo-scientific-collaboration
   7. https://en.wikipedia.org/wiki/GW250114
   8. https://www.ligo.caltech.edu/
   9. https://en.wikipedia.org/wiki/Washington_(state)
  10. https://en.wikipedia.org/wiki/Louisiana
  11. https://www.cia.gov/the-world-factbook/countries/united-states/
  12. https://spaceplace.nasa.gov/black-holes/
  13. https://science.nasa.gov/sun/
  14. https://science.nasa.gov/universe/black-holes/
  15. https://apod.nasa.gov/apod/ap191001.html
  16. https://www.caltech.edu/about/news/first-overtones-heard-ringing-black-hole
  17. https://i.pinimg.com/736x/ea/de/1f/eade1feca67faed06570cf5495621746.jpg
  18. https://en.wikipedia.org/wiki/Black_hole_thermodynamics#Second_law_2
  19. https://science.nasa.gov/universe/black-holes/anatomy/
  20. https://apod.nasa.gov/apod/ap190414.html
  21. https://www.ligo.caltech.edu/WA/image/ligo20250910a
  22. https://apod.nasa.gov/htmltest/rjn_bht.html
  23. https://apod.nasa.gov/apod/ap250923.html
  24. https://apod.nasa.gov/apod/archivepix.html
  25. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  26. https://apod.nasa.gov/apod/lib/aptree.html
  27. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  28. https://apod.nasa.gov/apod/calendar/allyears.html
  29. https://apod.com/feed.rss
  30. https://apod.nasa.gov/apod/lib/edlinks.html
  31. https://apod.nasa.gov/apod/lib/about_apod.html
  32. https://asterisk.apod.com/discuss_apod.php?date=250924
  33. https://apod.nasa.gov/apod/ap250925.html
  34. http://www.phy.mtu.edu/faculty/Nemiroff.html
  35. http://www.phy.mtu.edu/
  36. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  37. http://www.astro.umd.edu/
  38. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  39. https://www.nasa.gov/about/highlights/HP_Privacy.html
  40. https://www.nasa.gov/general/accessibility/
  41. https://www.nasa.gov/privacy/
  42. https://astrophysics.gsfc.nasa.gov/
  43. https://www.nasa.gov/
  44. https://www.nasa.gov/centers/goddard/
  45. https://science.nasa.gov/learners
  46. http://www.mtu.edu/