                        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.

                               2026 August 21

    Time-Lapse of the Star S301 Orbiting the Black Hole in the Center of
                                 the Galaxy
        Image Credit & License: ESO/GRAVITY Collaboration/L. Calçada
             Text: Cecilia Chirenti (NASA GSFC, UMCP, CRESST II)

   Explanation: What does it feel like to zoom around a spinning
   supermassive black hole? The featured video is an animation showing a
   time-lapse of 4 years of observations of the star S301 orbiting
   Sagittarius A*, the 4-million-solar-mass black hole in the center of
   our Galaxy. S301 was discovered in 2023 with the Very Large Telescope
   Interferometer of the European Southern Observatory, located in the
   Atacama Desert in Chile. Astronomers recently found that S301 takes
   approximately 8.7 years to go around the black hole and reaches speeds
   of 25,000 km/s. It comes closer to the black hole than any other stars
   detected before, at a distance similar to that from Saturn to the Sun.
   Because it comes so close to Sagittarius A*, S301 could be used to
   directly measure how fast the black hole spins and test Einstein's
   theory of general relativity. According to the theory, a spinning black
   hole drags the fabric of spacetime around itself, affecting the orbits
   of close-by objects.

                      Tomorrow's picture: 1,706 meteors
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       Authors & editors: Robert Nemiroff (MTU) & Jerry Bonnell (UMCP)
            NASA Official: Amber Straughn Specific rights apply.
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                             & Michigan Tech. U.

