June 26 1964 - Astronomy Old and New

Astronomy is a fast-developing science; it has altered more in the past hundred years than it did in the previous thousand. But despite the modern emphasis upon vast telescopes, refined photographic techniques and space probes, it is always worth while to pause for a moment and look back at some of the ideas current in past ages. This was what we did for the July 1964 programme, in which I was joined by Henry Brinton. Following it, I had some amusing letters.

There is one point that should be made. During the programme, I ex­pressed serious doubts about Professor Hawkins' theory that Stonehenge is an ancient computer. My viewpoint was that people who possessed enough knowledge to build anything of the sort would not need to do so; they could manage excellently by calculations, without going to the trouble of constructing a huge monument. Since then, the evidence seems to indicate that Professor Hawkins was right and that I was wrong, so that I hereby retract my scepticism even though I have not altered the article as it appeared in 1964.

Astronomy is the oldest science in the world. The earliest men must have looked up at the heavens and wondered at what they saw there; it was not until later that the pseudo-science of astrology arrived upon the scene to confuse men's minds and hold up progress.

Observational records of celestial phenomena go back for thousands of years. For instance, the ancient Chinese observed eclipses of the Sun and Moon, although they did not know why an eclipse occurs and they would have found it impossible to believe that the Earth is a planet moving round the Sun. At the time of a solar eclipse, the Chinese believed the Sun to be in danger of being eaten by a dragon, so that they used to bang pots and pans and make as much noise as possible in order to scare the dragon away.

Solar eclipses, caused when the Moon passes between the Earth and the Sun, are indeed highly spectacular. When the Moon passes into the Earth's shadow, at a lunar eclipse, the usual result is to make the Moon turn a dim and somewhat coppery colour. The only light reaching the lunar surface during the total phase of the eclipse has been refracted through the Earth's atmosphere, and it is obvious that the state of the atmosphere will affect the look of the eclipsed Moon. Quantities of volcanic dust in the upper air will produce a 'dark' eclipse, such as seen in 1816, following the Tamboro eruption of the previous year; the eclipses following the eruptions from Krakatoa (1883), Katmai (1912), and Mount Agung, on Bali in the East Indies (December 1963), were also very dark.

There is strong evidence that a lunar eclipse was recorded by the Chinese as long ago as 1136 b.c. The Greeks, however, were the first to raise astronomy to the level of a true science, because they did their best to interpret their observations; by using the so-called Saros Period, they were able to predict eclipses with fair accuracy. Thales of Miletus, the earliest of the great Greek philosophers, knew that any solar or lunar eclipse will be followed by a similar eclipse 18 years 10J days later; the relationship is only approximate, but for lunar eclipses, in particular, it works quite well. By 450 b.c. another Greek, Anaxagoras of Clazomenaj, was able to explain the cause of an eclipse of the Moon, and to state that because the Earth's shadow was curved, the Earth itself must be spherical.

Recently, Professor Gerald Hawkins, of Harvard, has suggested that the early Britons, too, were able to predict eclipses. Accord­ing to Hawkins, Stonehenge is nothing more than a primitive computer, the outer circle of fifty-six pits being used as a form of protractor. For instance, eclipses are likely to occur when, to an observer standing in the centre of the monument, the mid-winter Moon rises over the large block known as the Heel Stone.

This fascinating that it may be regarded as a form of observatory as well as a lemple. Midsummer ceremonies are always associated with it, and it is also popularly linked with the ancient Druids. In point of fact, the monument existed long before the Druids were active in England, and there is no evidence that the Druids ever used it, while there is a great deal of indirect evidence that they did not. The same applies to the other stone circles found all over Britain - at Roll right in Oxfordshire, for instance, and Callanish on the Island of Lewis. G. Henderson considers that they could be used as 'star markers' to check the march of the seasons, and this is certainly possible, since the observations themselves would be very simple and straightforward.*

Undoubtedly the old star-gazers were skilled at what may be termed positional astronomy; Egyptian observations, for instance, were very precise, and the later Greeks drew up remarkably good star catalogues. Subsequently, however, some strange theories were put forward. One of the most curious relates to the Egyptian pyramids, with special reference to the Great Pyramid of Khufu. Here again there is no doubt about the astronomical alignment. This is related to the north celestial pole, now marked by Polaris to within one degree, but in Egyptian times situated near the much fainter star Thuban in Draco; the slow shift is due to the phenomenon of precession, or change in direction of the Earth's axis.

The great pyramid

In 1859 John Taylor, an eccentric London publisher, issued a book called The Great Pyramid.: Why was it Built? And Who Built it? Taylor never visited the pyramid, but he believed that he had found various mathematical truths in its measurements which showed him that the Egyptian priests knew most, if not all, of the secrets of the universe, but had prudently decided to keep these truths to themselves. Taylor was, therefore, the founder of the cult of pyramidology, but his speculations would soon have been forgotten but for the fact that he found a strong supporter in Charles Piazzi Smyth, Astronomer Royal for Scotland. Smyth's theory may or may not be correct, but in any case Stonehenge has certainly an astronomical significance, so subsequent book, Our Inheritance in the Great Pyramid, is a classic of crank science.

Smyth began by taking Taylor's discovery that if you divide the height of the monument into twice the side of a base, you obtain a fairly close approximation to the value of pi (the ratio of diameter to circumference of a circle). The square of the height, moreover, is equal to the area of one face of the pyramid. On these and other similar grounds Smyth claimed that the Egyptians were able to 'square the circle'. By juggling with the length of the diagonals, he also considered that he had proved that the pyramid builders had worked out an exact figure for the preces­sion of the equinoxes - the movement of the celestial Pole which revolves once in about 26,000 years. From this Smyth went on by ingenious but rather arbitrary calculations to derive the unit of measure which the builders used. This he believed to be a little more than two feet, and he associated the unit with the cubit of the Bible. He then divided the cubit into twenty-five 'pyramid inches', which were very slightly different from the English inch. Smyth attributed the discrepancy to carelessness on the part of later artisans. This, of course, proved that the pyramid inch was sacred, and in 1879, in Boston, U.S.A., a movement was started for outlawing the 'atheist' metric system. The movement actually had the moral support of President James Garfield.

The possibilities are endless. For instance, the number of pyramid inches in the height of the pyramid, multiplied by a thousand million, yields 91,840,000 miles, which was close enough to the Earth's distance from the Sun (rather less than 93 million miles, on the average) to make Smyth sure that he had found another sacred relationship. But it was in connection with the pyramid's internal passageways that Smyth rose to his greatest heights. When these passages are measured in pyramid inches, counting one inch to the year, and the symbolism is properly interpreted, then - said Smyth - the principal dates in the Earth's past and future are plainly indicated. These include the creation of the world in 4004 b.c., the birth of Christ and of course the end of the world, which has been predicted so often in so many different ways.

When many measures are available, a dextrous mathemati­cian - as Smyth was - can make a judicious selection to prove almost anything. It was a great pity that Smyth himself, who made many valuable contributions to astronomy, should have become a convert to eccentricity of this sort; it damaged his reputation, and also led to a positive craze for pyramidology which lingers on even today. It is perfectly harmless, but it can hardly be re­garded as scientific. Sir Flinders Petrie, the great archaeologist, once caught a fervent pyramidologist filing down a projecting stone to make it conform with his theories.

One feels that the builders of the pyramids were rather more logical than some of the nineteenth-century theorists. Yet the Egyptians made little effort to interpret their astronomical ob­servations; this was left to the Greeks, who made amazing pro­gress in all fields of physical science. Had they realized that the Earth moves round the Sun, instead of lying at rest in the centre of the universe, astronomy would have developed quickly. A few of the Greek philosophers (Aristarchus, for example) did take this vital step, but met with little support, and the reality of the Earth's movement round the Sun was not properly demonstrated until about 400 years ago.

On the other hand, the Greeks knew that the Earth is a globe. The form of the shadow on the eclipsed Moon was only one of their many proofs. For instance, ships disappear below the horizon when sailing out to sea, which would be impossible on a flat Earth. And Aristotle, in about 350 b.c., pointed out that the stars appear to alter in height above the horizon according to the observer's position on Earth; Canopus, a brilliant southern star, can be seen from Egypt, but never from Greece. This is easy to explain on the assumption that the Earth is a globe, but cannot be accounted for by supposing the Earth to be flat. Moreover, yet another Greek scientist, Eratosthenes, measured the circum­ference of the globe with remarkable accuracy. The value which he obtained was much better than that used by Christopher Columbus on his pioneer voyage so many centuries later.

It is rather surprising, then, to find that even in the modern age there are still some people who doubt the spherical form of the Earth. The International Flat Earth Society flourished up to a year or two ago, and issued pamphlets as well as holding meetings. Their 'proofs' were fascinating, though hardly con­vincing. They pointed out, for instance, that a time-exposure of the night sky will produce a photograph showing star trails, which are hard, sharp lines. Astronomers attribute this to the rotation of the globe. The Flat Earthers, however, considered that the sharpness of the trails showed the world to be stationary - otherwise the trails would have been blurred. And in the town of Zion, Illinois, on the shores of Lake Michigan, may be found the remnants of a religious sect known as the Christian Apostolic Church, founded in 1895 and ruled for thirty years by Wilbur Glenn Voliva, who regarded the Earth as flat, with the North Pole in the centre and the South Pole distributed round the circumference. Voliva held that a huge wall of ice and snow prevented ships from sailing off the edge and tumbling into Hades. He added, as an aside, that the Sun was a mere 32 miles across, and not more than 3,000 miles away.

Other theories have been put forward. In 1818, an American officer, Captain John Cleves Symmes, claimed that the Earth was made up of five concentric spheres, with openings several thousand miles in diameter at the poles; sea flowed through both polar openings, and plant and animal life abounded on the con­cave interior as well as on the convex surface of the next sphere. Later, he petitioned Congress to finance a trip to the North Pole in order to check his theory. Congress did not agree, though it must be recorded that on the second petition Symmes found twenty-five supporters.

Perhaps the strangest theorists of all are those who maintain that the Earth is the inside of a hollow globe, with the Sun in the middle of the structure and Australia above our heads, and then he obtained was much better than that used by Christopher Columbus on his pioneer voyage so many centuries later.

It is rather surprising, then, to find that even in the modern age there are still some people who doubt the spherical form of the Earth. The International Flat Earth Society flourished up to a year or two ago, and issued pamphlets as well as holding meetings. Their 'proofs' were fascinating, though hardly con­vincing. They pointed out, for instance, that a time-exposure of the night sky will produce a photograph showing star trails, which are hard, sharp lines. Astronomers attribute this to the rotation of the globe. The Flat Earthers, however, considered that the sharpness of the trails showed the world to be stationary - otherwise the trails would have been blurred. And in the town of Zion, Illinois, on the shores of Lake Michigan, may be found the remnants of a religious sect known as the Christian Apostolic Church, founded in 1895 and ruled for thirty years by Wilbur Glenn Voliva, who regarded the Earth as flat, with the North Pole in the centre and the South Pole distributed round the circumference. Voliva held that a huge wall of ice and snow prevented ships from sailing off the edge and tumbling into Hades. He added, as an aside, that the Sun was a mere 32 miles across, and not more than 3,000 miles away.

Other theories have been put forward. In 1818, an American officer, Captain John Cleves Symmes, claimed that the Earth was made up of five concentric spheres, with openings several thousand miles in diameter at the poles; sea flowed through both polar openings, and plant and animal life abounded on the con­cave interior as well as on the convex surface of the next sphere. Later, he petitioned Congress to finance a trip to the North Pole in order to check his theory. Congress did not agree, though it must be recorded that on the second petition Symmes found twenty-five supporters.

Perhaps the strangest theorists of all are those who maintain that the Earth is the inside of a hollow globe, with the Sun in the middle of the structure and Australia above our heads, and the Earth itself extending infinitely in all directions. This is still the view of a German society, and in 1933, at Magdeburg, a rocket was sent up to test the hypothesis, the idea being that if the ascent were vertical the rocket would inevitably crash-land in the Antipodes. The first rocket rose to a height of six feet and ex­ploded ; the second vehicle was launched horizontally instead of vertically, and after that the experimenters ran out of money.

There are many other eccentric theories which would have seemed strange even to our ancestors. Dr Velikovsky, Russian- born but now resident in the U.S.A., has published some large books in which he claims that the planet Venus is an ancient comet (!) which once stopped the Earth's rotation for a while, causing the Red Sea to divide precisely at the time when the Children of Israel wanted to cross it. The universal ice theory of Hans Horbiger, who regarded the Milky Way as being composed of ice blocks which periodically hit the Sun and produced sun- spots, became so popular in Nazi Germany that the Propaganda Ministry actually had to issue a statement that it was possible to be a good National Socialist without believing in Horbiger's doctrines. The cult spread to Britain, mainly through the writings of H. S. Bellamy, and still exists. Finally, there is astrology, which retains a considerable following even though it has long since been shown to be as baseless as pyramidology or universal ice.

Most of these strange ideas are innocuous enough, and they have their amusing side - yet their continued existence shows that we cannot afford to laugh at the understandable mistakes made by theorists of long ago. Moreover, there is every prospect that the astronomers of, say, a.d. 3000 will look back at us in the same light as we ourselves regard the early star-gazers who be­lieved the Earth to be the centre of all things.