Total Eclipse of the Moon
Total Eclipse of the Moon
Evening. 25 May, 2021. Seven more shopping months till Christmas. The sun sets at 5.15 pm. There is a full moon. More than that, it is a "supermoon" —because of the moon's orbit, it is closer to earth than usual and is 12% bigger and brighter than average. And, tonight there is going to be a total lunar eclipse, with the earth's shadow creeping on and off the moon's surface between 8.47 pm and 1.49 am, and completely obscuring the sun for 14 minutes between 11.11 and 11.25 am. My wife and I decide to get up and watch it. Some might say there is not much other night life in Bannockburn.
I love the way the scientists can be so precise about the numbers for something that has not yet happened. Though I wonder if, caught up with what is happening in the night sky, they sometimes forget about the countdown to Christmas and don't get the shopping done. No wonder the Americans managed to land 12 men on the moon. Or did they? Almost 20% of people—unconvinced by unnaturally real photos showing multiple shadows and a flag flying in the absent atmosphere—believe that the whole thing was a hoax. And the astronauts have not been back in almost 50 years since 1972. Certainly, the moon tonight, although it is unusually close and bright, looks an impossibly long way away, almost unreachable.
We set the alarm for 10pm. As promised, there it is—a small shadow beginning to obscure the edge of the moon. The position of the moon in the sky has shifted since sunset. We need to make our way to the dining room to see it from inside our house. So as not to obscure the view, we turn all the lights off. Forgetting to take our phones or torches, we blunder through the house, narrowly avoiding crashing into the furniture. We wonder if this will become a thing. Earlier this year it was people not used to preparing food at home cutting themselves with Smeg knives from New World. Currently the commonest mechanism of injury seems to be old or unfit or unskilled people injuring themselves trying out the cycle trails on e-bikes. We wonder if there will be a new epidemic of lunar eclipse injuries.
The eclipse as it evolves is indeed spectacular. It is literally freezing outside. We don't get a good view through the double-glazed windows. We wrap up with puffer jackets, beanies, and thick socks, over our pyjamas, and brave the temperature outdoors. It is worth it. The unfiltered reflection from the surface of the moon seen outside is more colourful—a diminishing bright yellow surface being steadily invaded by a deep dark red, the "blood moon" we have been told to expect. The moon is too far away to be reached by the cone of complete darkness in the earth's direct shadow and is discoloured instead by the more faint edge of the shadow, or penumbra, from the earth and its atmosphere. For 10 minutes or more the moon is completely red. We wait for the reflected light to appear again on the other side.
As we wait, we contemplate the marvels of the universe. We have internalised the concepts of the nature of the solar system. It seems obvious to us that the earth rotates on its own axis and orbits the sun, that at night time the sun is somewhere beneath us, has been shining past the earth at the full face of the full moon, and that its light is now being temporarily blocked by the shadow of the earth. But this was not always accepted. The basic arrangement was formulated by Aristarchus of Samos more than two centuries before Christ but was rejected by the establishment at the time. The Polish Astronomer Nicolaus Copernicus worked out the details of how the earth and other planets orbit around the sun and the moon orbits around the earth. He realised that his conclusions would be controversial and published his findings in 1543 just before he died. His book was suppressed by the Catholic Church. The Italian Galileo Galilei was imprisoned in 1615 for championing his work.
Not so intuitive is the motion of the planets. We know they all also orbit the sun. Venus we know, from our point of view on Earth, sets in the West as the evening star and rises in the East as the morning star. We can’t see it tonight; we think its bright ball of steady green yellow light has vanished behind the Carrick Range before we get up to look at the eclipse. In a connection with Britain and the Pacific, Venus was indirectly responsible for the exploration of New Zealand in 1769 by Captain James Cook, who had come as far as Tahiti to observe the usually infrequent transit of Venus across the face of the sun, and added on a trip to our shores. On the night of our lunar eclipse, Mars, the other planet often observable at night, with its distinctive red orange glow, has also set.
To my shame, I am unfamiliar with the names and positions of the individual stars. In my childhood, I now realise, I was unable to see them in any detail. I was always short-sighted. It didn't matter in those days, as I spent most of my time reading books, including astronomy books. I remember struggling with outside activities. My father used to take us hunting. One of my memories as a teenager was of Dad pointing out deer down in the creek, or across on another ridge. When he told me exactly where to look, I could see a faint red smudge, but nothing that looked like an animal. I marvelled at his superior powers of perception. I think he thought I was stupid.
When I turned 40, and was still able to see clearly objects in the palm of my hand or in a book, my wife persuaded me to see an optometrist about my distance vision. He quickly diagnosed the problem and prescribed glasses. The world was suddenly a brighter place. Especially at night, when my pupils would have been dilated in the diminished light and I would have been unable to compensate for my refractive errors. I realised why much of the visual material presented to us at medical school, such as histology slides projected onto a screen in a darkened lecture theatre, had made no sense. Now I could see into people's houses at night, if I wanted to, which I don’t. Driving was much easier. I had previously memorised the numbers on the green signs on the motorways displaying how far to the nearest exits, not realising you are supposed to see them at night.
Even with my glasses, the individual constellations of stars remain a mystery to me. Sometimes I can recognise the Big Dipper, or Plough. I struggle to make out the stars of the Southern Cross, and when I lived in the Northern Hemisphere would not have been able to point out the Pole Star. The constellation called Pleiades, or Matariki, recently recognised as important to Māori because its appearance heralds the Māori New Year, and the time for the planting of crops, is not a feature of the night sky with which I am acquainted.
My wife, who grew up in the Western Pacific, is familiar with the stars and their patterns, but does not know the names for them. Unlike the early Polynesians, who journeyed to and from the Eastern Pacific using their detailed knowledge of the stars to help them navigate, including the legendary Tahitian Tupaia who guided Captain James Cook in his travels. My wife and her ancestors are literally more insular, and like me, would not be able to find their way round the ocean at night if they were surrounded by it, as in fact they are.
The nearest star from us, Proxima Centauri, is invisible to the naked eye. The light from it takes us 4.24 years to reach us, travelling at nearly 300,000 kilometres per second. The nearby twin star, Alpha Centauri AB, is visible from earth to those who know where to look for it. Sirius, the brightest star, is 8.6 light years away. At least six of what appear to be individual stars are in fact distant galaxies, each containing billions of stars. Our own galaxy, apart from the stars that are close enough and bright enough to be seen distinctly, is represented by the bright cloud known as the Milky Way. On the edge of the observable universe, the radiation from the Big Bang, which started it all, though not detectable as part of the visible part of the spectrum, is reaching us some 14 billion years later.
The stars have a life of their own, but on an unimaginable time scale. Stars the size of our sun produce energy by fusing hydrogen atoms into helium. Over billions of years, the helium gas expands to produce a red giant, which then burns out and collapses into a white dwarf. Smaller stars do not go through this cycle and remain as red dwarves. Bigger stars expand into super giants, which then collapse, depending on the size of the star, into neutron stars or black holes. In some highly energetic areas, elements of large stars explode into novae or supernovae, which can briefly be the most luminous objects in the night sky. There is speculation that one such event was responsible for the star that is said to have heralded the birth of Jesus.
Back down on earth, people are moving about. As our eyes adjust to the dark, we see lights on at the neighbours places around on the surrounding hills. Car lights from nearby roads flash across our back lawn, then we hear vehicles. Dogs bark, either howling at the strange moon or more likely at the humans who have chosen to come outdoors at such an unusual time. High in the mountains, we notice vehicle lights, possibly people night shooting, taking the chance to eliminate a few rabbits while there is something unusual to see in the night sky.
We stay out in the cold till 11.25. As promised, less spectacular than the darkening edge we saw before, the edge of the moon lightens. Things are returning to normal. We can go back inside, into the warmth. A pale yellow crescent slowly spreads across the lunar surface. The moon is back in the sky. God's in his heaven. All's right with the world.