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.

                                2022 April 3
   [2]The featured image depicts the cosmic microwave background radiation
   as seen by the NASA's COBE mission over four years ending in 1993. The
      hot and cold dipole pattern is indiciative of the Sun moving with
    respect to this microwave light, but the cause of the motion remains
        mostly unknown. Please see the explanation for more detailed
                                information.

                  CMB Dipole: Speeding Through the Universe
          Image Credit: [3]DMR, [4]COBE, [5]NASA, Four-Year Sky Map

   Explanation: Our [6]Earth is not at rest. The Earth moves around the
   [7]Sun. The Sun orbits the center of the [8]Milky Way Galaxy. The Milky
   Way Galaxy orbits in the [9]Local Group of Galaxies. The Local Group
   falls toward the [10]Virgo Cluster of Galaxies. But these speeds are
   less than the speed that all of these [11]objects together move
   relative to the [12]cosmic microwave background radiation (CMBR). In
   the [13]featured all-sky map from the [14]COBE satellite in 1993,
   microwave light in the Earth's direction of motion appears
   [15]blueshifted and hence hotter, while [16]microwave light on the
   opposite side of the sky is [17]redshifted and colder. The [18]map
   indicates that the [19]Local Group moves at about 600 kilometers per
   second relative to this [20]primordial radiation. This [21]high speed
   was initially unexpected and its magnitude is still unexplained.
   [22]Why are we moving so fast? [23]What is out there?

                     Tomorrow's picture: auroral vortex
     __________________________________________________________________

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    Authors & editors: [35]Robert Nemiroff ([36]MTU) & [37]Jerry Bonnell
                                 ([38]UMCP)
          NASA Official: Phillip Newman [39]Specific rights apply.
              [40]NASA Web Privacy Policy and Important Notices
                A service of: [41]ASD at [42]NASA / [43]GSFC
                           & [44]Michigan Tech. U.

References

   1. https://apod.nasa.gov/apod/archivepix.html
   2. https://apod.nasa.gov/apod/image/2204/CmbDipole_cobe_960.jpg
   3. https://lambda.gsfc.nasa.gov/product/cobe/dmr_overview.html
   4. https://lambda.gsfc.nasa.gov/product/cobe/
   5. https://www.nasa.gov/
   6. https://apod.nasa.gov/apod/ap070325.html
   7. https://apod.nasa.gov/apod/ap070624.html
   8. https://solarsystem.nasa.gov/resources/285/the-milky-way-galaxy/
   9. http://www.atlasoftheuniverse.com/localgr.html
  10. https://apod.nasa.gov/apod/ap110422.html
  11. https://apod.nasa.gov/apod/ap190806.html
  12. https://www.astro.ubc.ca/people/scott/faq_basic.html
  13. https://lambda.gsfc.nasa.gov/product/cobe/dmr_image.cfm
  14. https://en.wikipedia.org/wiki/Cosmic_Background_Explorer
  15. https://astro.ucla.edu/~wright/doppler.htm
  16. https://science.nasa.gov/ems/06_microwaves
  17. https://en.wikipedia.org/wiki/Redshift
  18. https://map.gsfc.nasa.gov/
  19. https://en.wikipedia.org/wiki/Local_Group
  20. http://www.youtube.com/watch?v=S4QWnBJvVq4
  21. https://www.rover.com/blog/wp-content/uploads/2019/07/51nbKlz5ssL.jpg
  22. https://en.wikipedia.org/wiki/Cosmic_microwave_background
  23. https://apod.nasa.gov/apod/ap000104.html
  24. https://apod.nasa.gov/apod/ap220402.html
  25. https://apod.nasa.gov/apod/archivepix.html
  26. https://apod.nasa.gov/apod/lib/apsubmit2015.html
  27. https://apod.nasa.gov/apod/lib/aptree.html
  28. https://antwrp.gsfc.nasa.gov/cgi-bin/apod/apod_search
  29. https://apod.nasa.gov/apod/calendar/allyears.html
  30. https://apod.nasa.gov/apod.rss
  31. https://apod.nasa.gov/apod/lib/edlinks.html
  32. https://apod.nasa.gov/apod/lib/about_apod.html
  33. http://asterisk.apod.com/discuss_apod.php?date=220403
  34. https://apod.nasa.gov/apod/ap220404.html
  35. http://www.phy.mtu.edu/faculty/Nemiroff.html
  36. http://www.phy.mtu.edu/
  37. https://antwrp.gsfc.nasa.gov/htmltest/jbonnell/www/bonnell.html
  38. http://www.astro.umd.edu/
  39. https://apod.nasa.gov/apod/lib/about_apod.html#srapply
  40. https://www.nasa.gov/about/highlights/HP_Privacy.html
  41. https://astrophysics.gsfc.nasa.gov/
  42. https://www.nasa.gov/
  43. https://www.nasa.gov/centers/goddard/
  44. http://www.mtu.edu/