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.

                                2019 August 4
    [2]See Explanation. Clicking on the picture will download the highest
                        resolution version available.

                          Rumors of a Dark Universe
       Image Credit: [3]High-Z Supernova Search Team, [4]HST, [5]NASA

   Explanation: Twenty-one years ago [6]results were [7]first presented
   indicating that most of the energy in our universe is not in stars or
   galaxies but is tied to space itself. In the language of cosmologists,
   a large [8]cosmological constant -- dark energy -- was directly implied
   by new distant [9]supernova observations. Suggestions of a
   [10]cosmological constant were [11]not new -- they have existed since
   the advent of [12]modern relativistic cosmology. Such claims were not
   usually popular with astronomers, though, because dark energy was so
   unlike known [13]universe components, because dark energy's abundance
   appeared limited by other observations, and because less-[14]strange
   cosmologies without a signficant amount of dark energy had previously
   done well in explaining the data. What was exceptional here was the
   seemingly direct and reliable method of the observations and the good
   reputations of the [15]scientists conducting [16]the investigations.
   Over the [17]two decades, independent teams of astronomers have
   continued to accumulate data that appears to [18]confirm the existence
   of [19]dark energy and the unsettling result of a presently
   [20]accelerating universe. In 2011, the team leaders were [21]awarded
   the Nobel Prize in Physics for their work. The [22]featured [23]picture
   of a supernova that occurred in [24]1994 on the outskirts of a
   [25]spiral galaxy was taken by one of these collaborations.

           News: APOD is now available via [26]Facebook in Hindi.
                     Tomorrow's picture: double eclipse
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    Authors & editors: [38]Robert Nemiroff ([39]MTU) & [40]Jerry Bonnell
                                 ([41]UMCP)
          NASA Official: Phillip Newman [42]Specific rights apply.
              [43]NASA Web Privacy Policy and Important Notices
                A service of: [44]ASD at [45]NASA / [46]GSFC
                           & [47]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/1908/SN1994D_Hubble_2608.jpg
   3. https://www.cfa.harvard.edu/supernova//HighZ.html
   4. https://www.stsci.edu/
   5. https://www.nasa.gov/
   6. https://ui.adsabs.harvard.edu/abs/1998AAS...193.3904A/abstract
   7. https://ui.adsabs.harvard.edu/abs/1998AJ....116.1009R/abstract
   8. https://map.gsfc.nasa.gov/universe/uni_accel.html
   9. https://spaceplace.nasa.gov/supernova/en/
  10. https://en.wikipedia.org/wiki/Cosmological_constant
  11. https://link.springer.com/article/10.12942/lrr-2001-1
  12. http://www.astro.ucla.edu/~wright/cosmolog.htm
  13. https://ui.adsabs.harvard.edu/abs/2008AmJPh..76..265N/abstract
  14. https://apod.nasa.gov/apod/ap071021.html
  15. http://cfa-www.harvard.edu/oir/Research/supernova/highz/members.html
  16. http://panisse.lbl.gov/public/
  17. https://apod.nasa.gov/apod/ap980302.html
  18. https://apod.nasa.gov/apod/ap050925.html
  19. http://en.wikipedia.org/wiki/Dark_energy
  20. http://en.wikipedia.org/wiki/Accelerating_universe
  21. http://www.nytimes.com/2011/10/05/science/space/05nobel.html
  22. http://www.cfa.harvard.edu/supernova//highz/figures/pictures.html
  23. https://www.spacetelescope.org/images/opo9919i/
  24. https://ui.adsabs.harvard.edu/abs/1998AGAb...14R.146D/abstract
  25. https://apod.nasa.gov/apod/spiral_galaxies.html
  26. https://www.facebook.com/apodhindi/
  27. https://apod.nasa.gov/apod/ap190803.html
  28. https://apod.nasa.gov/apod/archivepix.html
  29. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  30. https://apod.nasa.gov/apod/lib/aptree.html
  31. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  32. https://apod.nasa.gov/apod/calendar/allyears.html
  33. https://apod.nasa.gov/apod.rss
  34. https://apod.nasa.gov/apod/lib/edlinks.html
  35. https://apod.nasa.gov/apod/lib/about_apod.html
  36. http://asterisk.apod.com/discuss_apod.php?date=190804
  37. https://apod.nasa.gov/apod/ap190805.html
  38. http://www.phy.mtu.edu/faculty/Nemiroff.html
  39. http://www.phy.mtu.edu/
  40. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  41. http://www.astro.umd.edu/
  42. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  43. https://www.nasa.gov/about/highlights/HP_Privacy.html
  44. https://astrophysics.gsfc.nasa.gov/
  45. https://www.nasa.gov/
  46. https://www.nasa.gov/centers/goddard/
  47. http://www.mtu.edu/