By Helen Balfour, Assistant Curator
Boreal summer for our on-island team always makes me reflect on our past austral summers. Cool evenings spent walking between King Edward Point and Grytviken. Watching Antarctic fur seal pups learning to swim in the shallow end, before they venture on to learning for their deep end tests. Dusky chats with other islanders long after the expedition ships have left the bay. But mostly, I remember the intensity of those indescribable South Georgia sunsets.
What is it that makes South Georgia’s famous fiery displays so special? Is it the sheer scale of the snow-capped mountains silhouetted against the reds and oranges and pinks of the sky? Is it the exclusiveness of the show? Or is it purely scientific?
Credit: Helen Balfour
According to meteorologists, the process of light scattering creates the beautiful colours that we see at dawn and dusk. To make sense of this phenomenon, you need to know a little bit about the spectrum of colours.
During the day, the sky appears blue. Blue and violet are the colours that have the shortest wavelength, in contrast to red, which has the longest wavelength. As these wavelengths pass into the atmosphere, they are scattered through different molecules. This means that as the sun moves across the sky during the day, the light passes through varying thicknesses of the atmosphere. At sunrise and sunset, the Sun is lower, so its light must get through a thicker layer of atmosphere. The blue light is therefore distributed further, and we are more clearly able to see the longer wavelengths of reds, oranges and yellows of sunset.
Credit: Helen Balfour
Researchers at the University of Newcastle have written about the effect of air quality on sunsets. Pollution and cloud cover can of course have an impact on the skies a sunset. In South Georgia, as long as the clouds are higher, we have a beautiful view of the sky owing to the lack of pollution.
Humidity can also affect the beauty of sunsets as the moisture in the air can scatter light, even red wavelengths. Places with low humidity, like South Georgia, can expect to see better sunsets that appear less ‘washed-out’ as there are fewer droplets in the air. Leading to a crisp sunset in the sky.
Credit: Paula O’Sullivan
While science can explain the incredible colours, few words can genuinely describe the beauty of South Georgia at sunset. On this very special island, witnessing such a spectacular view by yourself, or with only a few others, does imbue a sense of wonder in the land around you. It is truly a sight I feel lucky to have seen.