The Night Sky

Aug 2012

Wiping the Windscreen of the Universe

You will have noticed the night sky; that dark vault of void speckled with pinpoints and twinkles, an occasional meteor, the part-time moon and the Milky Way. You may even – perhaps without knowing it – have made out some of the more exotic features, such as the clusters and nebulae where stars are born or the barely-discernible, tiny scuffed smudges of distant galaxies. Unless you are an astronomer, a boffin or a dedicated sky-watcher of some other kind, the chances are that when you last looked, you were having a crafty smoke out the back door or were letting the dog out in the garden in order to do something we needn’t go into here. Or you might have been taking a break on a long journey at a motorway service area or walking a wobbly line back from the pub when you came over all astrally-minded; but, either way, you were looking at a tiny excerpt of the most astonishing thing that has ever happened, the universe.

For all of that, we don’t spend a lot of time looking at it once we are away from our back door or safely back home from our excursions. In fact, I would go as far as to suggest that we fear the consequences of doing so. If you see someone out and about showing more than a passing interest in the stars, when all around there are more immediate pleasures and pressing concerns to occupy them, you might be inclined to feel that they were either drunk or, worse, a poet. Hang a pair of binoculars around their neck and place them in the vicinity of housing and you even have a ready-made, cardboard cut-out of a pervert, such is our culture’s fear of anyone caught not doing what everyone else is doing.

If you have seen someone fitting this description, you may well have bumped into me or, at least, someone like me – an enthusiast who believes that a clear night sky is one of the most amazing sights in nature, an exquisite jewel box, an endlessly fascinating panorama. The American essayist Ralph Waldo Emerson once wrote that if ‘the stars should appear but one night in a thousand years, how man would marvel and stare’, hinting at the apathy that comes with our passing familiarity with the night sky. Yet our outlook on the universe is far from universal; there is something rather extraordinary and unusual about our view of the stars in that it was an unlikely consequence of a rare event, a benefaction from the universe to our forebears, one which came in the form of an accidental gift from an ancient hero.

Twinkle, Twinkle, Bang.

A roaming group of hunters, the direct ancestors of modern humans, gaze at a new star, a piercing pinpoint of bright, white light that shines in the late afternoon sky. As evening draws in, the light reveals its source; the dazzling glint of a sword, the blade of another hunter who has emerged from the night – the constellation of Orion. A full moon rises and its shadows compete with those of the new star; except that the star is only new to Homo heidelbergensis and its glare, which outshines an entire galaxy for months on end, is the last that anyone will see of it for around 340,000 years.

Our ancestors have witnessed not a new star, but the death of an old one; a spectacular supernova at relatively close quarters, the swan song of a sun that was at least eight times as large as our own and an explosion so large that its remains are still hurtling across the sky at 15,000 miles an hour. Today, we know the remnants of this star as Geminga.

It’s well named. In 1972, Italian astrophysicists discovered a powerful source of radiation coming from an apparently empty patch of sky in the constellation of Gemini. Geminga, it turns out, is not only a handy contraction of “Gemini gamma radiation source”, but is also pronounced exactly the same as a word in the Milanese dialect that means “it isn’t there”. It was there, however, it just took twenty years of observations through the most powerful telescopes on earth to see what’s left of it; a rapidly spinning, super-dense radioactive ballbearing just 12 kilometres in diameter which emits a faint glow a million times dimmer than even the least enthusiastic star that can be seen by the naked eye.

It’s ironic that Geminga is only barely visible, because the manner of its disintegration blew away a local patch of gas and dust that normally fills the space between the stars – the interstellar medium – and left us an exceptionally bright night sky as a consequence. Scientists call this hole in the cosmic cobwebs that normally obscure our view the ‘Local Bubble’ and its effect on our outlook is surely staggering. To see why, you only need to imagine the night sky without its canopy of stars. In the 1950s, science fiction authors Robert Silverberg and Randall Garrett invented a planet that was permanently sheathed in clouds – Nidor – where the human-like occupants had no concept of a universe beyond the clouds. Perhaps because of the lack of any external stimulation, Silverberg and Garrett painted Nidorian culture and technology stuck in an agrarian phase not unlike early Renaissance Europe.

Similarly, in Douglas Adams’ Life, the Universe and Everything, the planet of Krikkit exists in a dust cloud, blissfully unaware of the existence of the rest of the universe. Having built a spaceship that could take them outside of the dust cloud and thereby witnessing the wonder and magnificence of the universe before them, they casually declare war against all of it. Although these are only works of speculative fiction, the mind can only boggle at how different our civilisation might have turned out without such a rich and opulent night sky, a backdrop that has, perhaps, given all of our dealings on Earth something of a sense of perspective.

Without the Local Bubble, which is less like a bubble and more like an open cylinder, there would simply not be as many stars to see in the sky and, consequently, it would be far less exciting because of it. Even the stars that would be visible would appear much redder and dimmer, for the same reasons that a hot, dry day in high summer produces aesthetically appealing sunsets - we’re looking at the sun through a thick layer of dust. And it’s not just a clearer view of our galaxy, where the majority of objects we see in the night sky reside, but also other galaxies – as luck would have it, the Local Bubble is oriented at right angles to the disk of the Milky Way, offering us a window of clear space to observe the rest of the Universe through.

But even now, when Geminga has done its cosmic housekeeping, set the default setting for the brightness of the stars and long hurtled away from the scene, the constellation from which it was borne – Orion – is still captivating. Gazing up on a moonless winter’s night, Orion draws the eye and dominates the midwinter sky as he strides across the heavens with the kind of chutzpah we demand from a Greek hero. It isn’t one of those fiddly zodiac signs that look nothing like their designation, either; it’s a constellation, along with the Big Dipper or Plough, that does exactly what it says in the star catalogue. You want a big saucepan in the sky? No problem. How about a large man with a club, wearing a belt and dagger? Here’s Orion.

Like the Plough, Orion is a constellation that a lot of us know from a very early age. Perhaps these easy-to-identify groupings of stars call on our innate ability to recognize patterns in a jumble of visual data. That intuitive sense that once alerted us to the presence of partially obscured man-eating tigers in the undergrowth is still alive, and now that there is less call for that kind of thing in the suburbs of Godalming and Splott, it assists us instead, in the solution of sky-based dot-to-dot puzzles. Many of those patterns are purely an outcome of our position in space; the stars themselves can be at wildly different distances from us and the constellations would look very different from another part of the galaxy. Most of the stars of Orion, however, are moving through space together in a loose association and the constellation’s shape is, by and large, not merely an accident of our line of sight. Either way, as a shape in the sky, Orion is so ingrained in our consciousness, it would be difficult to combine its stars into any other shape and that, it appears, is how it has been with almost every cosmologically-aware culture since the Babylonian star catalogues of the Bronze Age, in which Orion is the Loyal Shepherd of Heaven. The Babylonians inherited the constellation from the Sumerians who saw their own hero – Gilgamesh – in the pattern of stars. The Bible, too, mentions the same configuration of stars (naming Orion as ‘Kesil’) three times, while the ancient Egyptians called him the Soul of Osiris. He appears in Homer’s Odyssey and Iliad as both a legendary hunter and as a constellation; in short, wherever you look in history, Orion is there in some form or another.

For those reasons alone it would be a terrible shame if one of its number – like Geminga before it – went bang tonight. That is, it would be a shame were it not for the spectacular surprise that the star that marks the left shoulder of Orion, Betelgeuse (there are various pronunciations, but most people opt for beetlejuice) appears to be preparing for us.

Betelgeuse is a red supergiant - not only one of the brightest, but also one of the biggest stars in the sky - a relatively cool, low density sun, around twenty times the mass and over one and a half billion times the volume of our own but little more than half as hot. Red supergiants have brief, glorious lives; Betelgeuse is under nine million years old and will be lucky to last another million before it goes, in the words of one astrophysicist, ‘ker-blooey’. By way of comparison, our dependable, gracefully-aging sun is five billion years old and will be around for a long while yet. Betelgeuse’s life span, however, is so short that while it first shined on a relatively modern world - albeit one that predates the earliest species of humans, even Heidelbergensis – its disintegration will be witnessed by man, possibly tonight, maybe in a 1,000 years or more but certainly, in terms of deep time, very soon (just as long as man doesn’t go ‘ker-blooey’ first).

The Moon Marketing Board

Image: NASA

In the early hours of July 21, 1969, Neil Armstrong spoke the most famous eleven words in history when he became the first man to set foot on the moon. “That’s one small step for [a] man, one giant leap for mankind” was a succinct summary of Apollo 11’s extraordinary feat and, according to Armstrong, the result of four days of spaceflight and a few hours in the Lunar Module. The achievement those words marked was the culmination of thousands of years of observation and decades of hard science, not to mention countless centuries of artistic speculation through poetry, song, science fiction and fantasy. It’s hard to view the lunar landing as anything less than the apex of human achievement, the crowning glory of an ancient fascination, a preoccupation so primal it lies at the base of human consciousness. In those terms, the first giant leap for mankind was, in a sense, not walking on the moon, but noticing it in the first place.

It isn’t hard for us to notice, of course. In the modern world, the moon is ubiquitous, even when it isn’t in the sky. It looms out at us from advertising hoardings, is sung and spoken of with great affection in every language on earth, has cameo appearances in films and on television and its progress and daily movements are endlessly followed – as if the moon was a star – by daily newspaper columns around the world. It makes its way, several times a day, into every nook and crevice of our life; it is almost as if the unseen hand of the Moon Marketing Board is at work to fill our lives with lunacy.

Maybe that’s why we all feel that we have a passing familiarity with the moon and its appearance, in the same way that we say hello to newsreaders we spot in the wild from time to time, even though they haven’t the faintest idea who we are. As with our brief moment of familiarity with a journalist from the telly, there’s much we don’t see behind the public face of the moon. I’ve no idea how much Krishnan Guru-Murthy is hiding from us, but with the moon it’s around 41% and the reason for the observational deficit is tidal locking. It’s well known that the moon causes the tides on earth, by dragging a bulge of sea water around in its gravitational wake, but the earth also has a tidal effect on the moon. Because there are no oceans to pull, the earth tugs only at the moon’s crust and that tidal pull has locked the moon’s rotation to its orbit around the earth. As a consequence, the moon always presents the same face – the near side – to us and we see precious little of the far side. The limited views we have of the edges of the far side are caused by eccentricities in the moon’s orbit and axis which, with a sprinkling of parallax, add up to an apparent wobble that astronomers call libration; over time, an observer on earth sees around 59% of the moon’s surface.

The two sides of the moon are as different in appearance as the opposite faces of a chocolate Hob-Nob. The side that we see, with its pattern of blotches suggestive of the man in the moon, a rabbit, a dragon, somebody carrying sticks or whatever else your cultural conditioning dictates, differs wildly from the b-side – an evenly pock-marked disc that looks like a cartoon planet from a children’s television programme. There are no large dark blotches on the far side and science awaits a fully convincing explanation why that may be.

On the near side, the blotches were once thought to be expanses of water and were consequently named as maria, the plural of mare, the Latin for sea, by early astronomers, while the areas of the moon that appear brighter are the highlands or terrae, from the Latin for earth. Seventeenth century science was so convinced that the blotches were sea, they graded them by size and labelled them accordingly as bays, lakes and, the largest, an ocean. There’s a whole nautical almanac of names for things on the moon and hardly a drop of water in any of them. We now know that the maria are not oceans, but basalt plains formed from the flood lavas of ancient volcanic eruptions. The volcanic activity that formed the maria may have been a long time ago – around 3 billion years – but it is still more recent than the formation of the lunar highlands. The face of the moon, like those of humans, can be aged by appearance; in the case of the moon, the more craters a surface has, the older it is, but how old is the moon?

The moon is almost as old as the earth or the earth is almost as old as the moon, depending on your perspective and where you think the story begins. For stories about the moon, we can eschew the traditional ‘once upon a time’ and start the story in the solar nebula – the spinning protoplanetary disc of dust, gas and rock from which planets begin to coalesce. The first moments of a planet formed in a swirling cloud of dust, rocks, asteroids and planetesimals, is as precarious as it sounds and, indeed, the earth was perhaps only as young as 23 million years old – a mere moment in geological time – when it is believed that it was hit by a planet the size of Mars. That hypothetical planet – named Theia by scientists – came off worse in the impact. Smashed into countless pieces, it lost most of its iron core to the earth but then formed an orbiting ring of dust and rock which gradually reassembled what remained of itself from millions of fragments and began to orbit the earth as the moon. And they all lived happily ever after, but please see footnote 1 for further clarification on this.

The next time you catch yourself idly gazing at the moon, do consider the possibility that the moment isn’t in the least bit romantic or wistful and that you are neither nostalgic, plaintive or forlorn. Depending on your emotional peccadilloes, you might find a long, cold stare at the moon, while not being in possession of a poorly-expressed yearning for something or other, rather difficult – all of which brings us to the question of why that might be so. Why might a large rock in the sky inspire longing and a reflective mood (The moon is not really that reflective at all. It may be 100,000 times as bright as the brightest night-time star, but its surface is approximately as reflective as asphalt. If you put a car park in space, it would shine as much light back as the moon.)? The answer, of course, lies in the layers of meaning we have imbued the moon with over the thousands of years we have been looking at it.

As our closest neighbour in space and the most obvious thing in the night sky, it’s perhaps not much of a surprise that the moon has loomed large in our lives for millennia. Indeed, our fascination with our constant companion has blessed the moon with more-or-less equal billing to the sun in mythology, in folklore and nature worship – a cooler, reflective, evening analogue to Sol, a yin to the yang of the sun.

It’s an enduring theme, recycled in one form or another across many cultures. Classical Greek mythology had a number of pairings of god and goddess to represent the sun and moon. Brother and sister Apollo and Artemis were god and goddess of, respectively, the sun and moon, as were Phoebus and Phoebe, Helios and Selene and their later Roman counterparts. The Aztecs and Mayans had similar, though largely unpronounceable, arrangements while there are an equal number of moon gods with associated sun goddesses – even though the dominance of Mediterranean myth in Western culture rather blinds us to the fact. There’s a modern pantheon also; the neopagan and wiccan traditions now practised quietly in groves and on windy hill tops are reconstructed interpretations of what their advocates imagine to be the indigenous ancient religion of Britain and northern Europe. Their principal deities are the Horned God, who is venerated in many forms including the sun and the Triple Goddess, whose aspects include the moon and who I once spent a merry evening in the company of in a Westcountry field.

That’s Witchcraft

It isn’t even closing time and witchcraft is already afoot in the field next door, though nobody at the Red Lion in Avebury seems in the least bit surprised. This alone speaks volumes about the average English village but even the most unsystematic inspection of Avebury reveals that it is nothing of the sort. It isn’t just an odd place; at the centre of an enormous stone circle – fourteen times the size of Stonehenge – and arranged around the inner perimeter of a precipitous bank and ditch six storeys high and five thousand years-old, the village transcends ‘odd’ altogether on its way to ‘truly astounding’. The great 17th century antiquary, John Aubrey put it best when he noted that Avebury ‘doth as much exceed in greatness the so renowned Stonehenge, as a cathedral doth a parish church’.

The henge at Avebury was originally arranged as one large circle of stones which, in turn, contained two smaller rings known as the Sun and the Moon Circles, hinting – if not screaming – at astronomical alignments. The eighteenth century antiquarian William Stukeley, who cheerfully bent the facts into spurious theories about Avebury’s purpose, was the first to designate the inner rings in this way and the description stuck, along with his attribution of the ring to the work of Druids.

Even though only a fraction of the 600 or so stones that were planted around the site remain, there are still enough to line up and point to anywhere you fancy in the sky, so Avebury’s well-developed fringe of pseudo-archaeologists have plenty to inspire Stukeley-esque conjecture. Joining the dots is easy here, but there are solar alignments and, ironically, one of the most convincing of those is at the Cove – the centre of Stukeley’s ‘Moon Circle’ – and the location of tonight’s witchcraft.

Leaving the pub in my own slightly eccentric orbit, I notice the bob and swing of hand-held lanterns on the far side of a dark field punctuated with sarsen monoliths. Despite tonight’s full moon rising over the clutch of thatched cottages at Avebury’s centre, there seems precious little light about and I stumble over a short wall, up and down kerbs, over a stile and across rough ground, cursing the darkness with every step. Perhaps I’m not really cut out for the dark arts of witchcraft, but what I am really here for is the full moon and to get a sense of how it may have been important to our ancestors, so I have come to pay my respects at an Ogam Observance, a neopagan ceremony that marks the exact moment of the moon’s zenith. Tonight, that moment turns out to be at three in the morning and, though I am willing, my hotel is a mile up the dark road north, on which motorists observe only the reckless pursuit of Swindon; a hazardous how-do-you-do for the hapless moonlit pedestrian, so it was with some relief that I discovered Gordon Rimes, a 61-year old Wiccan priest and – as it turns out – a day job as a balloon artist of some standing, who told me that there was more than one ceremony on the bill tonight. Some Wiccans are having an ‘Energy Raising Circle’ as the moon waxes towards its peak and Gordon has invited me to come along.

Neopaganism seems to come in almost as many flavours as there are people who follow it, but there are a few things that every one agrees on and the moon is one of them. It’s a reconstructed faith but there’s a heavy presumption that it broadly follows ancient beliefs and those ancient beliefs are assumed to have recognised the Sun and Moon as celestial powers.

There’s some evidence for the assumption; the Abri Blanchard bone fragment, between 12 and 20,000 years old and engraved and cut with notches, was recovered from a cave in the Dordogne region of France and then gathered dust in the bowels of a French museum for nearly fifty years. It was uncovered by amateur archaeologist Alexander Marshack, who had been commissioned by NASA to mark the Apollo missions by researching what the moon has meant to various cultures throughout history. Marshack believed that the notches cut into the palm-sized fragment of reindeer bone in a series of twists and spirals represented a stone-age attempt to count the phases of the moon over a two lunar month period. This extreme claim has never been proven and his theory has as many detractors as supporters, but nearby, roughly contemporary, cave paintings at Lascaux are also marked in a way that suggests some early astronomical observations. It’s not a huge leap to acknowledge that when Avebury was in use during the Neolithic and Bronze Age, 10,000 years or so later, the moon was being used all over the world to mark time.

I stumble across the field and find Gordon in a long green robe and a fake fur jerkin laying out lanterns at the cardinal points of a small imaginary circle. A larger, wilder flame flickers in the centre and on the eastern side, two lanterns form a metaphorical doorway through which all exit and enter. I am invited to either remain on the periphery and watch, or join the circle and participate. I decide to join in.

Drawing an imaginary gateway on the side of the circle, Gordon invites me in. Immediately, the four elements are beckoned to come and join us in the moonlight. We all join hands in the circle. We walk, gather pace, then run clockwise around the circle. The others begin to sing but I don’t know any of the words and have lost the tingle by the time we come to a halt.

After a moment of reflection, off we go again, wheeling around hand in hand, singing, invocations flung out into the night like bats lobbed from a fast car on a roundabout. The vortex grows wilder still, hands are released and we fizz around like unstable electrons. The circle is briefly chaotic and Gordon acquires a puckish effervescence in his eyes.

I’m not really given to singing and dancing in public – not even in a dark field with a limited audience, so I’m grateful as things settle down a bit and offerings are made, but even here there are surprises. When we met earlier, Gordon confessed that he doesn’t always play it by the book and some Wiccans probably take issue with his interpretations of pagan rituals.

His choice of offerings – traditionally cake and ale – could raise a pagan eyebrow or two. On the one hand, we drink mead from a chalice – which seems old-school-spiritual enough, even though Gordon boasts that he bought it in Morrisons for £3.74, but for ‘cake’, we pass around a bowl of ready salted crisps.

At almost midnight our hosts wind things up by scattering the remnants of crisps to the four elements and thanking them in turn – air, fire, earth and water – each to a chorus of ‘hail and farewell’. Final words are spoken – ‘merry meet and merry part and merry meet again’ – and we go our separate ways, a little lighter, under the watchful gaze of the still waxing moon.