Equinox

The Earth At Equinox – September 2012 – I Am At The Very Bottom Of The Photo

Today is the equinox.  It is that time of year when the length of the day and the night are approximately the same, hence the name which comes to us from the Latin aequus (equal) and nox (night).  As mentioned in previous blogs, it is a time when the Sun makes its semi-annual journey across the equator marking the beginning of spring or the onset of fall.  At the South Pole it also is a time of rapid change as the Sun either is setting (March) or rising (September) and activity increases in preparation for the long day or night ahead.  This equinox is special, as it marks the end of a six-month night and the soon arrival of our replacements for the austral summer season.  The stars fade and the wonderful auroras disappear from view, to be replaced by the violet, red, and orange appearing ice crystals as they reflect the glow of the returning Sun.

We can thank a phenomenon known as Rayleigh scattering for both the beautiful blue skies and the red hues of sunrises and sunsets.  Light from the Sun interacts with molecules of oxygen and nitrogen in our atmosphere.  Although this light appears white to us, it contains all the colors of the rainbow.  Colors of light with shorter wavelengths, such as blue, are scattered by the gas molecules in our atmosphere.  This scatter light is what makes our sky appear blue.  Yellow, orange, and red light have progressively longer wavelengths and are less affected as they travel through the atmosphere.  This is why the Sun appears white or yellow when it is directly overhead, then becomes orange and finally reddish as it descends toward the horizon.  The more atmosphere through which the light travels, the more the shorter light wavelengths are scattered until the light that reaches our eyes is composed of mostly colors with the longest wavelengths, such as red.

Sunrise Geometry And Why Sunrises Are Red

 

 

Rayleigh Scattering – Why The Sky Is Blue And Sunsets Are Red

 

At sunset in March a storm arrived that lasted about a week and we only caught of glimpse of the setting Sun.  I was hoping for better weather at sunrise with the opportunity to capture the full array of beautiful colors.  Naturally, we have been enduring whiteout conditions for the last five days with 30 knot winds and blowing snow causing the sky and the horizon to blend into an endless sea of white.

Ceremonial South Pole – 21 SEP 2012 – Photo by Dale Mole’

 

 Despite the stormy weather, the equinox is typically a time of celebration around the world and the South Pole is no exception.  Our galley staff prepared a magnificent dinner with a 1950s theme.  “Amundsen-Scott’s Greasy Spoon”, whose motto is “Best Food, Worst Service On The Ice”, served up quesadillas, “Juicy Loosey Burgers” made with aged beef (all our food this time of year is at least two years old…some much older), and “Banana-Less Splits”, as we haven’t seen fresh bananas for months!  Dinner was accompanied by a showing of the movie “Grease” while we all munched on our food.  A good time was had by all.

Amundsen-Scott Greasy Spoon Menu

 

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