                  APOD: 2018 May 8 - The Observable Universe

                         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.

                                  2018 May 8
                                      [2]
                           The Observable Universe
 Illustration Credit & Licence [3] : Wikipedia [4] , Pablo Carlos Budassi [5]

Explanation: How far can you see? Everything you can see, and everything you
could possibly see, right now, assuming your eyes could detect all types of
radiations around you -- is the observable universe [6] . In visible light,
the farthest we can see comes from the cosmic microwave background [7] , a
time 13.8 billion years ago [8] when the universe was opaque like thick fog.
Some neutrinos [9]  and gravitational waves [10] that surround us come from
even farther out, but humanity does not yet have the technology to detect
them. The featured image [11]  illustrates the observable universe on an
increasingly compact scale [12] , with the Earth [13]  and Sun [14] at the
center surrounded by our Solar System [15] , nearby stars [16] , nearby
galaxies [17] , distant galaxies [18] , filaments of early matter [19] , and
the cosmic microwave background [20] . Cosmologists typically assume that our
observable universe [21]  is just the nearby part of a greater entity known as
"the universe" where the same physics applies. However, there are several
lines of popular but speculative reasoning that assert [22]  that even our
universe is part of a greater multiverse [23]  where either different physical
constants occur, different [24]  physical laws apply, higher dimensions [25]
operate, or slightly different-by-chance versions [26] of our standard
universe exist.

                    Tomorrow's picture: outer space X [27]

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    Authors & editors: Robert Nemiroff [39] (MTU [40] ) & Jerry Bonnell [41]
                                  (UMCP [42] )
          NASA Official:  Phillip Newman Specific rights apply [43] .
              NASA Web Privacy Policy and Important Notices [44]
              A service of: ASD [45]  at NASA [46]  / GSFC [47]
                           & Michigan Tech. U. [48]
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Site notes:
  [1] archivepix.html
  [2] image/1805/ObsUni_WikipediaPablo_2100.jpg
  [3] https://creativecommons.org/licenses/by-sa/3.0/
  [4]
https://en.wikipedia.org/wiki/Observable_universe#/media/
File:Observable_universe_logarithmic_illustration.png
  [5] https://commons.wikimedia.org/wiki/User:Unmismoobjetivo
  [6] https://en.wikipedia.org/wiki/Observable_universe
  [7] https://wmap.gsfc.nasa.gov/universe/bb_tests_cmb.html
  [8] https://en.wikipedia.org/wiki/Age_of_the_universe
  [9] https://icecube.wisc.edu/info/neutrinos
  [10] https://www.ligo.caltech.edu/page/what-are-gw
  [11]
https://en.wikipedia.org/wiki/Observable_universe#/media/
File:Observable_universe_logarithmic_illustration.png
  [12] https://en.wikipedia.org/wiki/Logarithmic_scale
  [13] https://solarsystem.nasa.gov/planets/earth/overview/
  [14] https://solarsystem.nasa.gov/solar-system/sun/overview/
  [15] https://solarsystem.nasa.gov/solar-system/our-solar-system/in-depth/
  [16] http://www.atlasoftheuniverse.com/12lys.html
  [17] ap110614.html
  [18] ap180305.html
  [19] ap140512.html
  [20] ap130325.html
  [21]
https://science.nasa.gov/astrophysics/big-questions/
How-do-matter-energy-space-and-time-behave-under-the-extraordinarily-diverse-
conditions-of-the-cosmos
  [22] http://asterisk.apod.com/viewtopic.php?f=39&t=21958
  [23] https://en.wikipedia.org/wiki/Multiverse
  [24]
https://medium.com/starts-with-a-bang/
ask-ethan-96-is-the-multiverse-science-ecceb24fa2af
  [25]
http://www.pbs.org/wgbh/nova/blogs/physics/2014/04/
how-many-dimensions-does-the-universe-really-have/
  [26] ap170401.html
  [27] ap180509.html
  [28] ap180507.html
  [29] archivepix.html
  [30] lib/apsubmit2015.html
  [31] lib/aptree.html
  [32] https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  [33] calendar/allyears.html
  [34] /apod.rss
  [35] lib/edlinks.html
  [36] lib/about_apod.html
  [37] http://asterisk.apod.com/discuss_apod.php?date=180508
  [38] ap180509.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] lib/about_apod.html#srapply
  [44] https://www.nasa.gov/about/highlights/HP_Privacy.html
  [45] https://astrophysics.gsfc.nasa.gov/
  [46] https://www.nasa.gov/
  [47] https://www.nasa.gov/centers/goddard/
  [48] http://www.mtu.edu/
