Astronomy? Nothing to do with me

By Bob Mizon

One of the more frustrating aspects of being amateur astronomers, even when we are not being confused with astrologers (my postman asked me if I did readings the other day), is the frequent assumption by many non-astronomers that we are a race apart from normal beings (whatever they might be). To some, our particular craft or science, whatever you like to call it, is an alien and irrelevant body of knowledge pursued in the dead of night while others sleep, and we are seen as eccentrics, as curiosities who know a lot about things that don't really impinge on everyday life. Surely all that stuff up there has little in common with what goes on down here.

Perhaps it's time to set the record straight. Astronomy is the science of everything. Just about every atom in every material object around us was made inside a star. We have all no doubt heard that the various elements that make up our own bodies and are vital to their functioning can be reduced to a large puddle of water, an assortment of nails, match-heads, sticks of chalk and the like. But few of us ask ourselves where they came from in the first place. We, like the things around us, and the planet we stand on, are made of star-stuff.

The calcium in our bones, the iron that colours our blood, the nitrogen in our DNA, the various elements that facilitate the electrical activity in our brains and the intricate interplay of our organs, all were cooked up, built from lesser atoms, in the interiors of old, collapsing stars billions of years ago; many of those stars are now white dwarfs, invisible to the largest telescopes, swept into the distant reaches of our giant Milky Way galaxy by its majestic 200-million-year rotation.

Further back still, at the very beginning of time, all the hydrogen that now makes up most of the Universe - and, as a component of water, a large proportion of the bodies of living creatures - was formed in the Big Bang, the stupendous explosion which kick-started the cosmos as we know it today. The faint background hiss that is the echo of this event of 20 billion years ago is still detected by sensitive radio telescopes.

Whatever is left of our long-departed bodies in, on or around this planet when it finally ceases to exist, vaporised by the dying, swelling Sun in a few billion years from now, will be redistributed into the clouds of dust and gas which swirl within our Galaxy. Indeed, most of our atoms may already have been recycled through planetary systems more than once, and some may even have been part of other living organisms on distant planets in the dim past.

So the stars in the sky are certainly part of our lives in a very wide and real sense. Though they remain a symbol of remoteness, they are massively relevant to our being. In what other ways does the cosmos outside the Earth intrude into our everyday existence?

The Sun, our neighbourhood star, keeps us alive every second of the day and night, and powers our every action and thought, by growing our food. It warms and circulates Earth's air so that we do not freeze to death at night, and provides our motive power as we use the sunshine energy stored millions of years ago in the fossil fuels we burn.

Other stars, having created the basic elements from which our planet and its biomass are made, have also forged atoms heavier than those of iron, for example gold and uranium. These are made in the immense "cookers" of supernova explosions, when giant stars explode at the end of their lives. Because these events are rare, the heavy elements they add to the cosmos are rare, and are therefore expensive and sought after. It is an interesting fact that all the gold in the world, mined and unmined, would form a cube about 17 metres on a side. So, the relative abundances and values of the commodities around us are determined by their stellar origins.

The Moon has not only, over millions of years, allowed life to function at night, but may well have been instrumental in bringing life out of the sea, and onto the land. Creatures evolved to live on the land via an amphibian stage, and the tides caused by the Moon provided a wet-dry-wet area where they could survive in this mode. If the Earth had had no Moon, would we all be clever fish? Our only natural satellite, especially when full, does seem to have an effect upon certain susceptible people (hence "lunacy"), although the causes are little understood. Many creatures regulate their behaviour, especially in breeding and egg-laying, according to the full Moon, and the human menstrual cycle's mimicking of the Moon's cycle may be no coincidence.

Perhaps the most important contribution of the far universe to our evolution is the fact that genetic mutations, which drive natural selection, are incessantly being triggered by the impacts on living cells of high-energy cosmic rays. These originate in supernova explosions, so it is an ironic fact that the progress of life on Earth is driven partly by the deaths of distant, supermassive stars.

On a more mundane note, our clocks and calendars are set by the motions of heavenly bodies. A day is one rotation of the Earth, and the position of the Sun sets the time: when the Sun is at its highest over your time zone, it is midday. Months are "moonths", time periods based on the changing phases of the Moon. Why are there 24 hours in a day, and 60 seconds in a minute? The ancient Babylonians had a base-12 counting system, and divided the sky, time and angular surfaces accordingly - hence the twelve houses of the Zodiac. Why are there seven days in a week? They are the days of the seven naked-eye bodies (gods and goddesses) which move around in the sky against the starry background: Sun (Sunday), Moon (Monday), Mercury (French: mercredi), Venus (French: vendredi), Mars (French: mardi), Jupiter (French: jeudi) and Saturn (Saturday). When is Easter Sunday? It's the first Sunday after the first full Moon following the vernal equinox (the moment in spring when the Sun crosses the equator of the sky in its apparent annual journey through the stars).

Last, but by no means least, is the part the starry night sky has played in human culture, science and religion. Our faculty of wonder was stimulated during the dark nights of millions of years by the apparently unknowable vault of stars above, and the human love of research may stem from our aching need to understand such natural wonders which long ago seemed beyond our reach. Astronomy, developed from astrology, was already 2 000 years old when physics and mathematics flowered; in its modern form, it embraces most other scientific disciplines, and overflows into philosophy and theology. The apparently unchanging cosmos was long ago compared with the corruptible and ever-changing Earth below, and appropriate conclusions were drawn about the perfection of the Gods and the fallibility of humankind.

There is of course one overwhelming reason why many people feel cut off from the rest of the universe, and why a generation is growing up assuming that the Earth is all that exists: a dangerous vanity. One of the saddest manifestations of the damage which human technical progress can do to the environment, and indirectly to the human spirit, is the slow eradication of the visibility of the night sky to modern people because of light pollution. Lighting schemes in urban areas, and unregulated lights in rural areas, throw light into the night sky and take away the stars. The current and completely unproven belief that very bright lights deter criminals, and the lack of any regulation or law about light spill and intensity, mean that most people nowadays see little of the rest of the Universe.

Michael Crichton, author of Jurassic Park and many other works of fiction and non-fiction, wrote in his autobiographical work Travels*: The natural world, our traditional source of direct insights, is rapidly disappearing. Modern city-dwellers cannot even see the stars at night. This humbling reminder of Man's place in the scheme of things, which human beings once saw every twenty-four hours, is denied them. It's no wonder that people lose their bearings, that they lose track of who they really are, and what their lives are really about.

* Michael Crichton, Travels (Pan/Macmillan, 1988. ISBN 0-330-30126-8)

Bob Mizon is coordinator of the British Astronomical Association's Campaign for Dark Skies