Archive 2657

Stonehenge and the terror in the sky

Stonehenge was built to predict meteor showers, argues space researcher Duncan Steel

When, in the 1960s, Stonehenge was interpreted as an eclipse predictor by astronomers Gerald Hawkins and Sir Fred Hoyle, and by amateur enthusiast C.A. `Peter’ Newham, an outcry issued from the archaeological community.

I can see why: the astronomical theories rode roughshod over the evidence on and under the ground. For example, they required that the four Station Stones were part of the original development, whereas these are clearly of a later phase. Archaeologists therefore had reason to be irked because the evidence of their science was being overlooked.

Nevertheless it is clear that a significant fraction of their agitation was provoked by what might be termed discipline-protection: resentment that outsiders should dare to dabble in their bailiwick.

Possibly astronomy played no part in the design and usage of megalithic monuments, although I think not. If astronomical matters were involved, then it behoves us all to work together to try to find the real reason for the huge effort which went into the many henge developments of the era.

I have some expertise in the field of small solar system bodies (meteors, asteroids and comets), and an interest in Stonehenge not only astronomical, but also personal: presently I live in Australia, but I was born in north-east Somerset, not so far from Stonehenge.

I believe that Hoyle, Newham and Hawkins were on the right lines, but that their ideas of tracking the moon and the sun apply only to the later phases of the developments (broadly Stonehenge II and III, after about 2500BC). Their interpretation was that Stonehenge was used to foresee when eclipses were to occur for ritual purposes. Actually I see the significance of charting the sun and the moon, and predicting eclipses, as being more closely tied up with refining a calendar rather than an end in itself. However, that is not my subject here.

My own interpretation of Stonehenge has more to do with meteor showers. What I am suggesting is that the very earliest developments at Stonehenge – the Cursus and Stonehenge I, dating from 3500-2800BC – were used to predict when meteor showers were to occur, those showers being of interest in themselves, as opposed to mere tools to determine the year.

Why would meteor showers – the debris trails from comets – be important to these people? When the sun was formed 4.5 billion years ago, it was about 30 per cent fainter than it is now. Five billion years hence it is expected to be twice as bright as now. Elsewhere in the cosmos processes generally alter on similarly long timescales: if you watched the Andromeda galaxy for a million years it would not change much.

This is not the case for comets and meteors. Comet Hale-Bopp has made its fleeting visit, not to be back for two millennia. Some other bright comet may soon flash into view. The meteor shower emanating from Gemini, which occurs each year around 13 December, was not observed before the 19th century, because at that stage its orbit did not intersect with that of the Earth. Today the Earth experiences about ten annual showers. Meteor showers, however, come and go over epochs of centuries or millennia. That is, on brief timescales, comparable to those of discrete civilizations.

There is no reason to believe that what people saw 5,000 years ago is what we see now. The stars, the planets, the moon and the sun would all look much the same as today, but not the comets and meteors. And those are the phenomena which often worry people most. In 1833, for example, there was a mighty meteor storm seen over the eastern parts of North America. Many hid under their beds whilst others fell to their knees, interpreting it as the sign of the Second Coming and the Apocalypse.

These meteors, the Leonids, are due back on 17 November this year. They have been seen every 33 years since AD902, often literally scaring people to death.

But there is no reason to suspect that the Leonid shower is the most extreme form of meteoric shower which occurs. Astronomers see comets break asunder all the time, spewing out great quantities of debris, whereas the parent of the Leonids (comet Tempel-Tuttle) is quite well-behaved.

There is a principle in natural science which we should consider, that of catastrophism. The fundamental tenet of catastrophism is that infrequent major events dominate the effects of plentiful smaller events. For example, the dearth of great trees in England’s green and pleasant land compared to 20 years back is the result of a few discrete episodes – two hurricanes and Dutch elm disease – rather than a large number of smaller storms and minor arboreal afflictions.

This is the main thing which Charles Darwin got wrong. Influenced by his geologist friend Charles Lyell, Darwin saw biological evolution as slow and gradual. In recent decades evidence has accumulated to sugest that this notion is incorrect: it is unusual major events which dominate, not the minor, gradual alterations. Darwin still holds us back in this way, natural scientists tacitly preferring a gradualistic explanation rather than a catastrophic one. But when you see a river valley, understand that most often it has been spasmodic floods which have shaped it, not the plodding flow which is evident for 99 per cent of the time.

Similarly when I see an extraordinary phenomenon like Stonehenge, I seek an extraordinary explanation. It is simply not the case that such an explanation is unlikely. With various colleagues I have developed a theory that the current interglacial period (the Holocene) is warmer than the long-term norm as a result of a heightened influx of cometary dust. There is much evidence for this, including lunar rocks returned by the Apollo astronauts which indicate that the flux of dust near Earth has been much elevated over the past ten millennia.

The source of this dust we believe is a broken-up giant comet, which has spawned a huge complex of material in the inner solar system including numerous asteroids, meteoroid streams, and one comet, Encke, which is now active (that is, it is liberating sufficient water vapour to produce a bright cloud about itself).

Every so often the swivelling of the orbit of the main stream of debris will bring it around to intersect Earth’s orbit, and then you can expect fireworks. Our tracking of the orbit indicates that great meteor storms will then occur every few years in epochs lasting for a few centuries. There will be pairs of these epochs separated by 300-500 years, followed by a gap of about 2,500-3,000 years before the next pair occurs. These timings fall out from the celestial mechanics, involving some quite complicated calculations.

In this scenario I can account for many aspects of the early developments at Stonehenge, such as the orientations (the approaching stream of material would appear in the sky near where the sun rises at the summer solstice around 3200-3000BC, but closer to due east half a millennium earlier) and the dates (the Cursus in the centuries after 3500BC, Stonehenge I following a few centuries later).

I am happy to play the devil’s advocate, and make further suggestions which many will find outrageous. If we are to progress, we need to consider all possibilities.

Take the numerous long barrows associated with Neolithic sites like Stonehenge. Question: what do they look like from the modern world? Answer: air-raid shelters. Thus, hypothesis for debate: they were air-raid shelters.

What I mean is, imagine that every so often the sky lit up with myriad shooting stars, many large enough to cause percussions shaking the ground (this does happen). You would be able to see the comet-related trail of material approaching in the sky. The long barrows were shelters in which to cower, safe from the terrifying spectacle outside, just as some modern humans hide their heads under the pillow during a lightning storm. If that were your need, what else could you build on Salisbury Plain, given the local materials?

The era of these meteor storms would have been temporary, lasting only through to about 2800BC. Thereafter the interest in the sky was transferred to charting the sun and the moon. The long barrows obtained a revised usage as burial sites, and other barrow forms were developed disconnected from the original purpose.

But eventually the meteor showers came back, with another set of intersections with the Earth starting around 500 BC. Are there any similar `air-raid shelters’ dating from that time? Well, yes. The Iron Age fogous (elaborate souterrains with built-up walls capped with flat slab roofs) of southern Britain, and in particular western Cornwall, have long been a mystery. The purpose usually ascribed to them – food storage – hardly warrants the extreme care with which they were constructed, compared to other dwellings of the period.

Taking this further, how do you react when a low-flying aircraft shakes your windows? By shaking your fist at the sky? Would not the Iron Age Britons have done the same thing, metaphorically-speaking? If the gods had come back again and again to wreak havoc, one tactic (good for the morale if nothing else) would have been some fist-shaking, trying to scare off the celestial apparition.

It seems that some of the great White Horses cut in chalk hillsides date from this era, and might be interpreted as a hostile gesture towards the sky. Let me hypothesize that when the Cerne Abbas Giant is properly dated, we will find that it originated in the last half millennium BC. The message it was designed to convey to the unwelcome visitors from above seems unmistakable.

Dr Duncan Steel published his ideas about Stonehenge in more detail in Natural Catastrophes During Bronze Age Civilizations (BAR 728, 1998). He is the author of Rogue Asteroids and Doomsday Comets (Wiley, 1995), and two books to be published later this year: Eclipse (Headline) on the history and astronomy of eclipses, and Marking Time (Wiley) on the calendar.