• NOAA
    1 of 10

    At 7:20 a.m. ET on March 20, 2013, Earth was at its equinox. At 7:45 a.m. ET, the GOES-13 satellite captured this full disk image of Earth. Twice a year the relative angle of Earth is perpendicular to the Sun, causing equal incoming solar energy to the Northern and Southern hemispheres - as well as equal day and nighttime.

    (Note: the Sun in this image is artificially created, though the GOES spacecraft does have sensors continually monitoring the Sun for solar activity.)

  • Cmdr_Hadfield/Twitter
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    This photo of Jeddah, Saudi Arabia, was tweeted by astronaut Chris Hadfield from the International Space Station on March 19. He wrote, "Jeddah, Saudi Arabia. 3 million people on the Red Sea. You can see the road that leads to Mecca. pic.twitter.com/MQyWMhJxsY"

  • AP Photo/The St. Paul Pioneer Press, Ben Garvin
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    Patrick Wenzel sprays thick layers of snow and ice off the seats of Target Field in Minneapolis, Minn., on Tuesday, March 19. Crews used high-pressure heated water to clean snow and ice from the seats of the baseball field in preparation for the Minnesota Twins' April 1 opening day game.  

  • Cmdr_Hadfield/Twitter
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    This photo of the Cayman Islands was tweeted by astronaut Chris Hadfield from the International Space Station on March 19. He wrote, "Airport, beach, coral, sunshine. A little bit of Cayman paradise. pic.twitter.com/RzB2R6YMAH"

  • AP Photo/Frank Augstein
    5 of 10

    A stroller walks his dog while snow falls on the first day of spring in Duisburg, Germany, Wednesday, March 20.

  • AstroMarshburn/Twitter
    6 of 10

    This image of a storm over the North Pacific Ocean was tweeted by astronaut Thomas H. Marshburn from the International Space Station on March 19. He wrote, "Storm brewing over the North Pacific, sweeping up the cloud cover pic.twitter.com/AEtxSWG38Z"

  • Cmdr_Hadfield/Twitter
    7 of 10

    This photo of Paris was tweeted by astronaut Chris Hadfield from the International Space Station on March 19. He wrote, "Paris sous le soleil. Les ombres de l'Arc de Triomphe et la Tour Eiffel sont a peine visible. pic.twitter.com/oxryiH0Xrd"

  • AP Photo/Ali Hamed Haghdoust
    8 of 10

    Afghans shop at an open air market a day before the celebration of the Persian New Year Nowruz in Kabul, Afghanistan, Wednesday, March 20. Nowruz marks the first day of spring and the beginning of the year on the Iranian calendar. 

  • Cmdr_Hadfield/Twitter
    9 of 10

    This photo of storm clouds over Africa was tweeted by astronaut Chris Hadfield from the International Space Station on March 19. He wrote, "Tonight's Finale: Storm clouds standing tall in the atmosphere over Africa. pic.twitter.com/Hx81FoTseP"

  • Cmdr_Hadfield/Twitter
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    Next: Today's 10 Must-See Photos: 3-19-2013

    This photo of Homs, Syria, was tweeted by astronaut Chris Hadfield from the International Space Station on March 20. He wrote, "Homs, Syria. Currently enveloped in fighting - an uncertain future layered upon a storied past. pic.twitter.com/zYaRJEuBi3"