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 May 4
   [2]An artistic illustration of a black hole is shown. The black spot in
        the center is the black hole, while the accretion disk of gas
    surrounding it is shown in orange. Stars and the darkness of space is
    shown near the top in the background. Please see the explanation for
                         more detailed information.

                    Spin up of a Supermassive Black Hole
         Illustration Credit: [3]Robert Hurt, [4]NASA/[5]JPL-Caltech

   Explanation: How fast can a black hole spin? If any object made of
   regular matter spins too fast -- it breaks apart. But a [6]black hole
   might not be able to break apart -- and its maximum spin rate is really
   unknown. Theorists usually model rapidly rotating black holes with the
   [7]Kerr solution to Einstein's [8]General Theory of Relativity, which
   predicts several [9]amazing and [10]unusual things. Perhaps its most
   easily testable prediction, though, is that matter entering a
   [11]maximally rotating black hole should be last seen orbiting at near
   the speed of light, as seen from far away. [12]This prediction was
   tested by NASA's [13]NuSTAR and ESA's [14]XMM satellites by observing
   the supermassive [15]black hole at the center of [16]spiral galaxy NGC
   1365. The near [17]light-speed limit was [18]confirmed by measuring the
   heating and [19]spectral line broadening of nuclear emissions at the
   inner edge of the surrounding [20]accretion disk. [21]Pictured here is
   an artist's illustration depicting an accretion disk of normal
   [22]matter swirling around a black hole, with a [23]jet emanating from
   the top. Since matter randomly falling [24]into the black hol[25]e
   should not spin up a black hole this much, the NuSTAR and XMM
   measurements also validate the existence of the [26]surrounding
   accretion disk.

             Hole New Worlds: [27]It's Black Hole Week at NASA!
                      Tomorrow's picture: planet lines
     __________________________________________________________________

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    Authors & editors: [39]Robert Nemiroff ([40]MTU) & [41]Jerry Bonnell
                                 ([42]UMCP)
          NASA Official: Amber Straughn [43]Specific rights apply.
            [44]NASA Web Privacy, [45]Accessibility, [46]Notices;
                A service of: [47]ASD at [48]NASA / [49]GSFC,
                         [50]NASA Science Activation
                           & [51]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2505/blackholedisk_cfa_1080.jpg
   3. https://www.ipac.caltech.edu/science/staff/hurt
   4. http://www.nasa.gov/
   5. http://www.jpl.nasa.gov/
   6. https://science.nasa.gov/universe/black-holes/
   7. http://en.wikipedia.org/wiki/Kerr_black_hole
   8. http://en.wikipedia.org/wiki/General_relativity
   9. http://en.wikipedia.org/wiki/Penrose_process
  10. http://www.youtube.com/watch?v=T_TU6T4-0LU
  11. http://www.eftaylor.com/pub/SpinNEW.pdf
  12. https://www.jpl.nasa.gov/news/nasas-nustar-helps-solve-riddle-of-black-hole-spin/
  13. https://nustar.caltech.edu/
  14. https://www.esa.int/Science_Exploration/Space_Science/XMM-Newton
  15. https://spaceplace.nasa.gov/black-holes/
  16. https://apod.nasa.gov/apod/ap241113.html
  17. https://apod.nasa.gov/apod/ap111018.html
  18. https://ui.adsabs.harvard.edu/abs/2013Natur.494..449R/abstract
  19. https://physicsopenlab.org/2017/09/07/spectral-lines-broadening/
  20. https://apod.nasa.gov/apod/ap140323.html
  21. https://www.jpl.nasa.gov/images/pia16695-black-holes-monsters-in-space-artists-concept/
  22. http://www.slate.com/blogs/bad_astronomy/2013/02/27/spinning_black_hole_scientists_measure_supermassive_black_hole_rotating.html
  23. https://apod.nasa.gov/apod/ap110828.html
  24. https://apod.nasa.gov/htmltest/rjn_bht.html
  25. http://asterisk.apod.com/viewtopic.php?f=39&t=21666
  26. https://apod.nasa.gov/apod/ap080811.html
  27. https://science.nasa.gov/universe/black-hole-week/
  28. https://apod.nasa.gov/apod/ap250503.html
  29. https://apod.nasa.gov/apod/archivepix.html
  30. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  31. https://apod.nasa.gov/apod/lib/aptree.html
  32. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  33. https://apod.nasa.gov/apod/calendar/allyears.html
  34. https://apod.com/feed.rss
  35. https://apod.nasa.gov/apod/lib/edlinks.html
  36. https://apod.nasa.gov/apod/lib/about_apod.html
  37. https://asterisk.apod.com/discuss_apod.php?date=250504
  38. https://apod.nasa.gov/apod/ap250505.html
  39. http://www.phy.mtu.edu/faculty/Nemiroff.html
  40. http://www.phy.mtu.edu/
  41. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  42. http://www.astro.umd.edu/
  43. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  44. https://www.nasa.gov/about/highlights/HP_Privacy.html
  45. https://www.nasa.gov/general/accessibility/
  46. https://www.nasa.gov/privacy/
  47. https://astrophysics.gsfc.nasa.gov/
  48. https://www.nasa.gov/
  49. https://www.nasa.gov/centers/goddard/
  50. https://science.nasa.gov/learners
  51. http://www.mtu.edu/