The universe, at the instant of the Big Bang 13.7 billion years ago, was an 'infinitely small dot' containing its total (and constant) energy. At that point — just before space-time came into existence — some of the energy within our energy-only 'dot universe', for some unknown reason, began to convert into matter, creating at the same time the energy-matter-space-time framework we perceive as our universe...

The Magnificent Dot.

After a lot of conjecture and speculation and theorizing, pretty much all working astronomers believe in this so-called Big Bang picture, in which the universe started out really small at some time roughly 15 billion years ago. It exploded. All of this stuff came out of it. But the thing that's so hard for us to picture is, the explosion of something that started the size of a dot, all the matter and all the energy, but in addition, all the space was in there. And when the thing exploded, not only did all this matter and energy come out of this explosion, but all the space came out of it too. So we were in there. And the concept of what was outside the dot before the dot exploded, it turns out is a non-concept because all the space was inside there too. Imponderable stuff. And so the subject of cosmology, the origin of the universe, and all that kind of stuff is a kind of mixture of science and philosphy, a very interesting subject and very hard to come to grips with.

-- Frank Bash - Director, McDonald Observatory

A Theologian's Nightmare by Bertrand Russell

The eminent theologian Dr. Thaddeus dreamt that he died and pursued his course toward heaven. His studies had prepared him and he had no difficulty in finding the way. He knocked at the door of heaven, and was met with a closer scrutiny than he expected. "I ask admission," he said, "because I was a good man and devoted my life to the glory of God." "Man?" said the janitor, "What is that? And how could such a funny creature as you do anything to promote the glory of God?" Dr. Thaddeus was astonished. "You surely cannot be ignorant of man. You must be aware that man is the supreme work of the Creator." "As to that," said the janitor, "I am sorry to hurt your feelings, but what you're saying is news to me. I doubt if anybody up here has ever heard of this thing you call 'man.' However, since you seem distressed, you shall have a chance of consulting our librarian."

The librarian, a globular being with a thousand eyes and one mouth, bent some of his eyes upon Dr. Thaddeus. "What is this?" he asked the janitor. "This," replied the janitor, "says that it is a member of a species called 'man,' which lives in a place called 'Earth.' It has some odd notion that the Creator takes a special interest in this place and this species. I thought perhaps you could enlighten it." "Well," said the librarian kindly to the theologian, "perhaps you can tall me where this place is that you call 'Earth.'" "Oh," said the theologian, "it's part of the Solar System." "And what is the Solar System?" asked the librarian. "Oh," said the theologian, somewhat disconcerted, "my province was Sacred Knowledge, but the question that you are asking belongs to profane knowledge. However, I have learnt enough from my astronomical friends to be able to tell you that the Solar System is part of the Milky Way." "And what is the Milky Way?" asked the librarian. "Oh, the Milky Way is one of the Galaxies, of which, I am told, there are some hundred million." "Well, well," said the librarian, "you could hardly expect me to remember one out of so many. But I do remember to have heard the word galaxy' before. In fact, I believe that one of our sub-librarians specializes in galaxies. Let us send for him and see whether he can help."

After no very long time, the galactic sub-librarian made his appearance. In shape, he was a dodecahedron. It was clear that at one time his surface had been bright, but the dust of the shelves had rendered him dim and opaque. The librarian explained to him that Dr. Thaddeus, in endeavoring to account for his origin, had mentioned galaxies, and it was hoped that information could be obtained from the galactic section of the library. "Well," said the sub-librarian, "I suppose it might become possible in time, but as there are a hundred million galaxies, and each has a volume to itself, it takes some time to find any particular volume. Which is it that this odd molecule desires?" "It is the one called 'The Milky Way,'" Dr. Thaddeus falteringly replied. "All right," said the sub- librarian, "I will find it if I can."

Some three weeks later, he returned, explaining that the extraordinarily efficient card index in the galactic section of the library had enabled him to locate the galaxy as number QX 321,762. "We have employed," he said, "all the five thousand clerks in the galactic section on this search. Perhaps you would like to see the clerk who is specially concerned with the galaxy in question?" The clerk was sent for and turned out to be an octahedron with an eye in each face and a mouth in one of them. He was surprised and dazed to find himself in such a glittering region, away from the shadowy limbo of his shelves. Pulling himself together, he asked, rather shyly, "What is it you wish to know about my galaxy?" Dr. Thaddeus spoke up: "What I want is to know about the Solar System, a collection of heavenly bodies revolving about one of the stars in your galaxy. The star about which they revolve is called 'the Sun.'" "Humph," said the librarian of the Milky Way, "it was hard enough to hit upon the right galaxy, but to hit upon the right star in the galaxy is far more difficult. I know that there are about three hundred billion stars in the galaxy, but I have no knowledge, myself, that would distinguish one of them from another. I believe, however, that at one time a list of the whole three hundred billion was demanded by the Administration and that it is still stored in the basement. If you think it worth while, I will engage special labor from the Other Place to search for this particular star."

It was agreed that, since the question had arisen and since Dr. Thaddeus was evidently suffering some distress, this might be the wisest course.

Several years later, a very weary and dispirited tetrahedron presented himself before the galactic sub-librarian. "I have," he said, "at last discovered the particular star concerning which inquiries have been made, but I am quite at a loss to imagine why it has aroused any special interest. It closely resembles a great many other stars in the same galaxy. It is of average size and temperature, and is surrounded by very much smaller bodies called 'planets.' After minute investigation, I discovered that some, at least, of these planets have parasites, and I think that this thing which has been making inquiries must be one of them."

At this point, Dr. Thaddeus burst out in a passionate and indignant lament: "Why, oh why, did the Creator conceal from us poor inhabitants of Earth that it was not we who prompted Him to create the Heavens? Throughout my long life, I have served Him diligently, believing that He would notice my service and reward me with Eternal Bliss. And now, it seems that He was not even aware that I existed. You tell me that I am an infinitesimal animalcule on a tiny body revolving round an insignificant member of a collection of three hundred billion stars, which is only one of many millions of such collections. I cannot bear it, and can no longer adore my Creator." "Very well," said the janitor, "then you can go to the Other Place."

Here the theologian awoke. "The power of Satan over our sleeping imagination is terrifying," he muttered.


Aristarchus and Greek Astronomy

Aristarchus of Samos, who lived approximately from 310 to 230 B.C., and was thus about twenty-five years older than Archimedes, is the most interesting of all ancient astronomers, because he advanced the complete Copernican hypothesis, that all the planets, including the earth, revolve in circles round the sun, and that the earth rotates on its axis once in twenty-four hours. It is a little disappointing to find that the only extant work of Aristarchus, On the Sizes and Distances of the Sun and the Moon, adheres to the geocentric view. It is true that, for the problems with which this book deals, it makes no difference which theory is adopted, and he may therefore have thought it unwise to burden his calculations with an unnecessary opposition to the general opinion of astronomers; or he may have only arrived at the Copernican hypothesis after writing this book. Sir Thomas Heath, in his work on Aristarchus, which contains the text of this book with a translation, inclines to the latter view. The evidence that Aristarchus suggested the Copernican view is, in any case, quite conclusive.

The first and best evidence is that of Archimedes, who, as we have seen, was a younger contemporary of Aristarchus. Writing to Gelon, King of Syracuse, he says that Aristarchus brought out "a book consisting of certain hypotheses," and continues: "His hypotheses are that the fixed stars and the sun remain unmoved, that the earth revolves about the sun in the circumference of a circle, the sun lying in the middle of the orbit." There is a passage in Plutarch saying that Cleanthes "thought it was the duty of the Greeks to indict Aristarchus of Samos on the charge of impiety for putting in motion the Hearth of the Universe (i.e. the earth), this being the effect of his attempt to save the phenomena by supposing the heaven to remain at rest and the earth to revolve in an oblique circle, while it rotates, at the same time, about its own axis." Cleanthes was a contemporary of Aristarchus, and died about 232 B.C. In another passage, Plutarch says that Aristarchus advanced this view only as a hypothesis, but that his successor Seleucus maintained it as a definite opinion. (Seleucus flourished about 150 B.C.). Atius and Sextus Empiricus also assert that Aristarchus advanced the heliocentric hypothesis, but do not say that it was set forth by him only as a hypothesis. Even if he did so, it seems not unlikely that he, like Galileo two thousand years later, was influenced by the fear of offending religious prejudices, a fear which the attitude of Cleanthes (mentioned above) shows to have been well grounded.

The Copernican hypothesis, after being advanced, whether positively or tentatively, by Aristarchus, was definitely adopted by Seleucus, but by no other ancient astronomer. This general rejection was mainly due to Hipparchus, who flourished from 161 to 126 B.C. He is described by Heath as "the greatest astronomer of antiquity." He was the first to write systematically on trigonometry; he discovered the precession of the equinoxes; he estimated the length of the lunar month with an error of less than one second; he improved Aristarchus's estimates of the sizes and distances of the sun and moon; he made a catalogue of eight hundred and fifty fixed stars, giving their latitude and longitude. As against the heliocentric hypothesis of Aristarchus, he adopted and improved the theory of epicycles which had been invented by Apollonius, who flourished about 220 B.C.; it was a development of this theory that came to be known, later, as the Ptolemaic system, after the astronomer Ptolemy, who flourished in the middle of the second century A.D. Copernicus came to know something, though not much, of the almost forgotten hypothesis of Aristarchus, and was encouraged by finding ancient authority for his innovation. Otherwise, the effect of this hypothesis on subsequent astronomy was practically nil.

Ancient astronomers, in estimating the sizes of the earth, moon, and sun, and the distances of the moon and sun, used methods which were theoretically valid, but they were hampered by the lack of instruments of precision. Many of their results, in view of this lack, were surprisingly good. Eratosthenes estimated the earth's diameter at 7850 miles, which is only about fifty miles short of the truth. Ptolemy estimated the mean distance of the moon at 29 ½ times the earth's diameter; the correct figure is about 30.7. None of them got anywhere near the size and distance of the sun, which all underestimated. Their estimates, in terms of the earth's diameter, were:

Aristarchus, 180;

Hipparchus, 1245;

Posidonius, 6545.

The correct figure is 11,726. It will be seen that these estimates continually improved (that of Ptolemy, however, showed a retrogression); that of Posidonius is about half the correct figure. On the whole, their picture of the solar system was not so very far from the truth.

Greek astronomy was geometrical, not dynamic. The ancients thought of the motions of the heavenly bodies as uniform and circular, or compounded of circular motions. They had not the conception of force. There were spheres which moved as a whole, and on which the various heavenly bodies were fixed. With Newton and gravitation a new point of view, less geometrical, was introduced. It is curious to observe that there is a reversion to the geometrical point of view in Einstein's General Theory of Relativity, from which the conception of force, in the Newtonian sense, has been banished.

The problem for the astronomer is this: given the apparent motions of the heavenly bodies on the celestial sphere, to introduce, by hypothesis, a third co-ordinate, depth, in such a way as to make the description of the phenomena as simple as possible. The merit of the Copernican hypothesis is not truth, but simplicity; in view of the relativity of motion, no question of truth is involved. The Greeks, in their search for hypotheses which would "save the phenomena," were in effect, though not altogether in intention, tackling the problem in the scientifically correct way. A comparison with their predecessors, and with their successors until Copernicus, must convince every student of their truly astonishing genius.

The History of Western Philosophy, Bertrand Russell, Chapter 24

The Science and Cosmology of Empedocles

The mixture of philosopher, prophet, man of science, and charlatan... was exemplified very completely in Empedocles, who flourished about 440 B.C., and was thus a younger contemporary of Parmenides... He was a citizen of Acragas, on the south coast of Sicily; he was a democratic politician, who at the same time claimed to be a god. In most Greek cities, and especially in those of Sicily, there was a constant conflict between democracy and tyranny; the leaders of whichever party was at the moment defeated were executed or exiled. Those who were exiled seldom scrupled to enter into negotiations with the enemies of Greece—Persia in the East, Carthage in the West. Empedocles, in due course, was banished, but he appears, after his banishment, to have preferred the career of a sage to that of an intriguing refugee. It seems probable that in youth he was more or less Orphic; that before his exile he combined politics and science; and that it was only in later life, as an exile, that he became a prophet.

Legend had much to say about Empedocles. He was supposed to have worked miracles, or what seemed such, sometimes by magic, sometimes by means of his scientific knowledge. He could control the winds, we are told; he restored to life a woman who had seemed dead for thirty days; finally, it is said, he died by leaping into the crater of Etna to prove that he was a god. In the words of the poet:

Great Empedocles, that ardent soul Leapt into Etna, and was roasted whole.

...His most important contribution to science was his discovery of air as a separate substance. This he proved by the observation that when a bucket or any similar vessel is put upside down into water, the water does not enter into the bucket. He says:

"When a girl, playing with a water-clock of shining brass, puts the orifice of the pipe upon her comely hand, and dips the waterclock into the yielding mass of silvery water, the stream does not then flow into the vessel, but the bulk of the air inside, pressing upon the close-packed perforations, keeps it out till she uncovers the compressed stream; but then air escapes and an equal volume of water runs in."

This passage occurs in an explanation of respiration.

He also discovered at least one example of centrifugal force: that if a cup of water is whirled round at the end of a string, the water does not come out.

He knew that there is sex in plants, and he had a theory (somewhat fantastic, it must be admitted) of evolution and the survival of the fittest. Originally, "countless tribes of mortal creatures were scattered abroad endowed with all manner of forms, a wonder to behold." There were heads without necks, arms without shoulders, eyes without foreheads, solitary limbs seeking for union. These things joined together as each might chance; there were shambling creatures with countless hands, creatures with faces and breasts looking in different directions, creatures with the bodies of oxen and the faces of men, and others with the faces of oxen and the bodies of men. There were hermaphrodites combining the natures of men and women, but sterile. In the end, only certain forms survived.

As regards astronomy: he knew that the moon shines by reflected light, and thought that this is also true of the sun; he said that light takes time to travel, but so little time that we cannot observe it; he knew that solar eclipses are caused by the interposition of the moon, a fact which he seems to have learnt from Anaxagoras.

He was the founder of the Italian school of medicine, and the medical school which sprang from him influenced both Plato and Aristotle. According to Burnet, it affected the whole tendency of scientific and philosophical thinking.

All this shows the scientific vigour of his time, which was not equalled in the later ages of Greece.

I come now to his cosmology. It was he... who established earth, air, fire, and water as the four elements (though the word "element" was not used by him). Each of these was everlasting, but they could be mixed in different proportions, and thus produce the changing complex substances that we find in the world. They were combined by Love and separated by Strife. Love and Strife were, for Empedocles, primitive substances on a level with earth, air, fire, and water. There were periods when Love was in the ascendant, and others when Strife was the stronger. There had been a golden age when Love was completely victorious. In that age, men worshipped only the Cyprian Aphrodite. The changes in the world are not governed by any purpose, but only by Chance and Necessity. There is a cycle: when the elements have been thoroughly mixed by Love, Strife gradually sorts them out again; when Strife has separated them, Love gradually reunites them. Thus every compound substance is temporary; only the elements, together with Love and Strife, are everlasting.

...Empedocles held that the material world is a sphere; that in the Golden Age Strife was outside and Love inside; then, gradually, Strife entered and Love was expelled, until, at the worst, Strife will be wholly within and Love wholly without the sphere. Then—though for what reason is not clear—an opposite movement begins, until the Golden Age returns, but not for ever. The whole cycle is then repeated. One might have supposed that either extreme could be stable, but that is not the view of Empedocles. He wished to explain motion while taking account of the arguments of Parmenides, and he had no wish to arrive, at any stage, at an unchanging universe.

The History of Western Philosophy, Bertrand Russell, Chapter 6