                        Astronomy Picture of the Day

    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
   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: Aurore Simonnet (SSU/EdEon), LVK, URI; LIGO
                                Collaboration

   Explanation: It was the strongest gravitational wave signal yet
   measured -- what did it show? GW250114 was detected by both arms of the
   Laser Interferometer Gravitational-wave Observatory (LIGO) in
   Washington and Louisiana USA earlier this year. Analysis showed that
   the event was created when two black holes, each of mass around 33
   times the mass of the Sun, coalesced into one larger 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
   black holes, as well as initial ringing of the final black hole, was
   deduced with exceptional accuracy. Furthermore, it was confirmed better
   than before, as previously predicted, that the total event horizon area
   of the combined black hole was greater than those of the merging black
   holes. Featured, an artist's illustration depicts an imaginative and
   conceptual view from near one of the black holes before collision.

                       Tomorrow's picture: open space
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Amber Straughn Specific rights apply.
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                           NASA Science Activation
                             & Michigan Tech. U.

