Last sunset! (22 October 2022)


Scott Base's latitude officially make the transition to 24-hour sunlight today. We're familiar, of course, with our NZ summer days enjoying a lot more sunlight than in the depth of winter. As one heads further south towards Antarctica (and equivalently, northward into the Arctic) this difference between summer and winter daylight hours becomes more and more pronounced.
Eventually one crosses the imaginary line beyond which there is at least one day of 24-hour sunlight in summer, and one night of 24-hr darkness in winter, known as the 'Antarctic Circle' (or 'Arctic Circle' in the north). This is possible because the angle of the Earth's axis, relative to our plane of orbit around the sun, means that locations near the poles do not fall into the Earth's shadow within a >24-hr period in summer. Equivalently, they do not emerge from the Earth's shadow within a >24-hr period in winter.

Scott Base is so far south (latitude 77.85 S) that it gets ~4 months of continuous daylight in summer, ~4 months of continuous darkness in winter, and ~2 months of transition either side of each. At the extreme, the South Pole gets one 6-month long period of sunlight in 'summer', and 6 months of darkness over 'winter' with the sun circling around the horizon at the vernal (northern spring) and autumnal (northern fall) equinoxes.

Consequently, when viewed from Scott Base last night's sunset was the last time that the sun will dip below the horizon until late February. This means we have been treated to some gorgeous late evening light, turning the surface of the snow lovely shades of pink and orange, and generating long shadows across the flat white surface.

I've had a wee go at capturing the moment with some timelapse photography. Thankfully, I had three chances left by the time we arrived at camp… the first two failed because batteries run down fast in the cold. But on the third try I finally got the USB powerbank to keep charging the camera battery all night, with the aid of a couple of chemical handwarmers.

(I'll update this post with a photo of the last sunset next time I'm back at base)

Sent from Iridium Mail & Web.



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