Astronomy Picture of the Day

                         Astronomy Picture of the Day

    Discover the cosmos! [1] Each day a different image or photograph of our
 fascinating universe is featured, along with a brief explanation written by a
                           professional astronomer.

                                2019 April 11
                                      [2]
                  First Horizon-Scale Image of a Black Hole
          Image Credit: Event Horizon Telescope [3] Collaboration [4]

Explanation: What does a black hole look like? To find out, radio telescopes
[5]  from around the Earth [6]  coordinated observations of black holes [7]
with the largest known event horizon [8] s on the sky. Alone, black holes are
just black [9] , but these monster attractors are known to be surrounded by
glowing gas. The first image was released yesterday and resolved [10]  the
area around the black hole [11]  at the center of galaxy M87 [12] on a scale
below that expected for its event horizon [13] . Pictured [14] , the dark
central region is not the event horizon, but rather the black hole's shadow
[15]  -- the central region of emitting gas darkened by the central black
hole's gravity. The size and shape of the shadow is determined by bright gas
near the event horizon [16] , by strong gravitational lensing deflections [17]
, and by the black hole's spin. In resolving this black hole's shadow [18] ,
the Event Horizon Telescope [19]  (ETH) bolstered evidence that Einstein's
gravity [20]  works even in extreme regions [21] , and gave clear evidence
that M87 [22] has a central spinning black hole of about 6 billion solar
masses. The EHT [23]  is not done -- future observations will be geared toward
even higher resolution [24] , better tracking of variability, and exploring
the immediate vicinity of the (link)black hole in the center [25]  of our
Milky Way Galaxy [26] .

                        Tomorrow's picture: open space

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    Authors & editors: Robert Nemiroff [38] (MTU [39] ) & Jerry Bonnell [40]
                                  (UMCP [41] )
          NASA Official:  Phillip Newman Specific rights apply [42] .
              NASA Web Privacy Policy and Important Notices [43]
              A service of: ASD [44]  at NASA [45]  / GSFC [46]
                           & Michigan Tech. U. [47]
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Site notes:
  [1] archivepix.html
  [2] image/1904/M87bh_EHT_2629.jpg
  [3] https://eventhorizontelescope.org/
  [4] https://eventhorizontelescope.org/organizatio...
  [5] https://en.wikipedia.org/wiki/Radio_telescope
  [6]
https://iopscience-event-horizon.s3.amazonaws...
focus_figure_2_resized.jpg
  [7] https://science.nasa.gov/astrophysics/focus-a...
  [8] https://en.wikipedia.org/wiki/Event_horizon#E...
  [9] https://en.wikipedia.org/wiki/Black
  [10]
https://www.eso.org/public/usa/outreach/first...
  [11] https://www.nsf.gov/news/special_reports/blac...
  [12] ap100520.html
  [13]
https://www.forbes.com/sites/startswithabang/...
black-holes-are-real-and-spectacular-and-so-are-their-event-horizons/
  [14] https://iopscience.iop.org/journal/2041-8205/...
  [15] https://www.esa.int/gsp/ACT/projects/blackhol...
  [16] https://www.youtube.com/watch?v=t-O-Qdh7VvQ
  [17] https://apod.nasa.gov/htmltest/rjn_bht.html
  [18] https://iopscience.iop.org/article/10.3847/20...
  [19] https://eventhorizontelescope.org/about
  [20] https://en.wikipedia.org/wiki/General_relativ...
  [21] https://youtu.be/bciCbN8lc08
  [22] http://chandra.si.edu/photo/2019/black_hole/
  [23] https://eventhorizontelescope.org/
  [24]
https://previews.123rf.com/images/aleksandrrr...
aleksandrrr160600010/60185350-gray-kitten-and-microscope.jpg
  [25] ap180729.html
  [26] https://solarsystem.nasa.gov/resources/285/th...
  [27] ap190410.html
  [28] archivepix.html
  [29] lib/apsubmit2015.html
  [30] lib/aptree.html
  [31] https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apo...
  [32] calendar/allyears.html
  [33] /apod.rss
  [34] lib/edlinks.html
  [35] lib/about_apod.html
  [36] http://asterisk.apod.com/discuss_apod.php?dat...
  [37] ap190412.html
  [38] http://www.phy.mtu.edu/faculty/Nemiroff.html
  [39] http://www.phy.mtu.edu/
  [40] https://antwrp.gsfc.nasa.gov/htmltest/jbonnel...
  [41] http://www.astro.umd.edu/
  [42] lib/about_apod.html#srapply
  [43] https://www.nasa.gov/about/highlights/HP_Priv...
  [44] https://astrophysics.gsfc.nasa.gov/
  [45] https://www.nasa.gov/
  [46] https://www.nasa.gov/centers/goddard/
  [47] http://www.mtu.edu/

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