‘The sun, centre and sire of light,
The keystone of the world-built arch of heaven.’‘Philip James Bailey, Festus (1813)
Winter sunsets have a propensity for magnificence. Certainly here in the Western Cape, the early days of June have seen a sharing on social media of pictures of spectacular, red-tinged sunsets around the Peninsula; some of the sun settling in a blood-red bath over the Atlantic horizon, others of the rays silhouetting our mountain tops like a rampant wildfire. At Waterfront Charters we are blessed by being out on the waters every evening, our range of vessels hosting guests who marvel at the beauty. It’s not only the sunset itself, it’s the effect on the surrounding scenery: seeing Cape Town encircled by her mountainous arms bathed in the westerly light is enough to get poets scribbling celebratory sonnets while the rest of us just sip our chilled sundowners and sigh with pleasure.
We have written about our star – that Sun – and sunsets before, and some of the amazing facts that sum up its magnificence; it’s certainly worthwhile revisiting this celestial body and exploring the strange, the fanciful and the serendipity of its existence. We use the word serendipity with deliberation here; most of us who have an interest in the Earth, the cosmos and the universe will be aware of the ‘Goldilocks Principle’ that is ascribed to Earth’s relationship with our sun. Named – rather obviously, of course – for the Goldilocks of Three Bears fame, the Goldilocks Principle when applied to astrobiology refers to the habitable zone around a star. As famed theoretical physicist and cosmologist Stephen Hawking put it, “like Goldilocks, the development of intelligent life requires that planetary temperatures be ‘just right’.” Earth, it would appear, is exactly like Goldilocks’ porridge: not too hot nor too cold to develop and sustain life.
But that Goldilocks Principle extends way beyond Earth’s relationship with Sol. For life to be sustainable, the sun that hosts, warms and energises a planet needs to be in a ‘Goldilocks Zone’ itself. Our Sun’s celestial location in the galaxy is just as important to our longevity as a species as our Earth’s position in the solar system. Our galaxy – one of countless billions – is an island in space that is around 100 000 light-years in diameter, and comprises around about 100 billion stars. You can count them if you don’t believe us. We are not in the crowded centre of this melee of stars; we are lurking in one of the Milky Way’s outer spiral arms, known as the Orion–Cygnus Arm or Local Spur. Our sun ambles around the galaxy, much like Earth does around the sun, at one orbit or galactic year every 240 million earth years. Whilst this means very long waits for New Year’s Day on a galactic plane, it does mean that we here on Earth are much safer than we would be if we were closer to that monstrous Black Hole that lurks like Charybdis at the centre of our galaxy.
For evolution to work there needs to be long term stability, not only here on the planet, but in the solar system we inhabit. Our spiral arm is safe from the gravitational instabilities of the ‘crowded’ centre and the far larger concentration supernovae that erupt. (A supernova burst can momentarily exceed the combined radiation of the sum of all the stars in a galaxy. You don’t want to be close to that; there isn’t a factor eight billon sunscreen.) Those gravitational tugs are also present deeper into the spiral arms of the galaxy, but fortunately our speed of orbit keeps us from passing through the arms, which would have the disconcerting habit of sending many more comets and extra-terrestrial objects into our orbit, with potentially catastrophic results. Ask any surviving dinosaur. Oh, hang on…
So we are safe. Sort of. Those sunsets we marvel at are caused by the atomic fusion of hydrogen into helium, a very prolonged nuclear reaction that burns four million tons of hydrogen every second. So, since you started reading this sentence, around 16 million tons of H, atomic number 1, have kept us alive, and are now morosely scudding around, demoted to atomic number 2 as He. At this phenomenal rate of conflagration our sun has a limited lifespan, with a mere five billion years or so left. It will then run out hydrogen, expand into a cooler red-giant (we are back in Goldilocks-type mythology) and gobble up the nearest planets. If mankind has not emigrated to another galaxy by then, well, no more spectacular sunsets for humans to photograph.
But you still have a lot of time, trust us, to book a Waterfront Charters Champagne Sunset Cruise. You can choose between our luxurious catamaran cruises, with complimentary chilled sparkling wine to toast the burning hydrogen, or take a more classic sailing adventure on our schooner Esperance, making use of the fully-stocked onboard cash bar to quench your thirst. Either way, you’ll get to see a fantastic Cape sunset, and we have no doubt you’ll record the memory for posterity, both mentally and photographically.