Uh-oh, it looks like your Internet Explorer is out of date.

For a better shopping experience, please upgrade now.

Greek Astronomy

Greek Astronomy

by Sir Thomas L. Heath

See All Formats & Editions

Astronomy as a science began with the Ionian philosophers, with whom Greek philosophy and mathematics also began. While the Egyptians and Babylonians had accomplished much of astronomical worth, it remained for the unrivalled speculative genius of the Greeks, in particular, their mathematical genius, to lay the foundations of the true science of astronomy. In this


Astronomy as a science began with the Ionian philosophers, with whom Greek philosophy and mathematics also began. While the Egyptians and Babylonians had accomplished much of astronomical worth, it remained for the unrivalled speculative genius of the Greeks, in particular, their mathematical genius, to lay the foundations of the true science of astronomy. In this classic study, a noted scholar discusses in lucid detail the specific advances made by the Greeks, many of whose ideas anticipated the discoveries of modern astronomy.
Pythagoras, born at Samos about 572 B.C., was probably the first to hold that the earth is spherical in shape, while his later followers anticipated Copernicus with the then-startling hypothesis that the earth was not the center of the universe but a planet like the others. Heraclides of Pontus (c. 388–315 B.C.), a pupil of Plato, declared that the apparent daily rotation of the heavenly bodies is due, not to a rotation of the heavenly sphere about an axis through the center of the earth, but to the rotation of the earth itself around its own axis. Secondly, Heraclides discovered that Venus and Mercury revolve around the sun like satellites. Perhaps the greatest astronomer of antiquity was Hipparchus, who flourished between 161 and 126 B.C. He compiled a catalog of fixed stars to the number 850 or more, made great improvements in the instruments used for astronomical observations, and discovered the precession of the equinoxes, among other accomplishments. The astronomy of Hipparchus takes its definitive form in the Syntaxis (commonly called the Almagest) of Ptolemy, written about A.D. 150, which held the field until the time of Copernicus.
The extraordinary achievements of these and many more Greek theorists are given full coverage in this erudite account, which blends exceptional clarity with a readable style to produce a work that is not only indispensable for astronomers and historians of science but easily accessible to science-minded lay readers.

Product Details

Dover Publications
Publication date:
Dover Books on Astronomy
Sold by:
Barnes & Noble
Sales rank:
File size:
1 MB

Related Subjects

Read an Excerpt

Greek Astronomy

By Thomas L. Heath

Dover Publications, Inc.

Copyright © 1991 Dover Publications, Inc.
All rights reserved.
ISBN: 978-0-486-14388-0



I KNOW that I am mortal and the creature of a day; but when I search out the massed wheeling circles of the stars, my feet no longer touch the earth, but, side by side with Zeus himself, I take my fill of ambrosia, the food of the gods.




PLATO, Theaetetus, 174 A.

A CASE in point is that of Thales, who, when he was star-gazing and looking upward, fell into a well, and was rallied (so it is said) by a clever and pretty maidservant from Thrace because he was eager to know what went on in the heaven, but did not notice what was in front of him, nay, at his very feet.


When, in the sixth year, they [the Lydians and the Medes] encountered one another, it so fell out that, after they had joined battle, the day suddenly turned into night. Now that this transformation of day (into night) would occur was foretold to the Ionians by Thales of Miletus, who fixed as the limit of time this very year in which the change actually took place.


Eudemus observes in his History of Astronomy that Thales predicted the eclipse of the sun which took place at the time when the Medes and the Lydians engaged in battle, the King of the Medes being Cyaxares, the father of Astyages, and the King of the Lydians being Alyattes, the son of Croesus; and the time was about the fiftieth Olympiad [580—577 B.C.]. (But cf. Pliny, N. H., c. 12, § 53: "Among the Greeks Thales was the first of all men to investigate (the cause of eclipses), in the fourth year of the forty-eighth Olympiad [585/4 B.C.], he having predicted an eclipse of the sun which took place in the reign of Alyattes in the year 170 A.U.C.")


Eudemus relates in his Astronomies ... that Thales was the first to discover the eclipse of the sun, and the fact that the sun's period with respect to the solstices is not always the same.


Thales was the first to discover the length of the interval from solstice to solstice.

ARISTOTLE, Metaph. A. 3, 983 b 20—2.

Thales, the originator of this kind of philosophical inquiry [i.e. the search for one material cause of all things], says that water is the first principle (this is why he also declared that the earth rests on water).


Thales laid it down that the first principle of all things is water, and that the universe is animate and full of gods. They say too that he discovered the seasons of the year, and divided the year into 365 days.


It is said that the Egyptians were the first of all men to discover the year, to which they gave twelve parts

(months) making up the (four) seasons. And herein the Egyptians reckon, as it seems to me, more sensibly than the Greeks, in so far as the Greeks put in an intercalary month every third year to keep the seasons right, whereas the Egyptians reckon their twelve months at thirty days each and add in every year five days outside the number (of twelve times thirty).


Callimachus knows him (Thales) to be the discoverer of the "Little Bear," for he says in his lambi that "he was said to have marked (lit. 'measured') the stars of the Wain, by which the Phoenicians sail."



SIMPLICIUS, in Phys. Aristotelis, p. 24, 13, Diels.

ANAXIMANDER of Miletus, who was a fellow-citizen and friend of Thales, said that the first principle (i.e. material cause) and element of existing things is the Infinite, and he was the first to introduce this name for the first principle. He maintains that it is neither water nor any other of the so-called elements, but another sort of substance which is infinite, and from which all the heavens and the worlds in them are produced; and into that from which existent things arise they pass away once more, "as is ordained; for they must pay the penalty and make reparation to one another for the injustice they have committed, according to the sequence of time," as he says in these somewhat poetical terms.


Anaximander said that the Infinite contains the whole cause of the generation and destruction of the All; it is from the Infinite that the heavens are separated off, and generally all the worlds, which are infinite in number. He declared that destruction and, long before that, generation have been going on from infinitely distant ages, all the worlds recurring in cycles.

HIPPOLYTUS, Refutation of all Heresies, I, 6.

He says that this [the Infinite] is eternal and ageless and embraces all the worlds. And he implies the existence of time in that the three stages of coming into being, existence, and passing-away are distinguished.... And besides the Infinite he says there is eternal motion, in the course of which it happens that the heavens come into being.

HERMIAS, Irrisio, 10.

Anaximander says eternal motion is a principle older than the moist, and it is by this eternal motion that some things are generated and others destroyed.

AËTIUS, De placitis, I, 3, 3.

He says that the first principle (or material cause) is infinite, in order that the process of coming into being which is set up may not suffer any check.

SIMPLICIUS, on De caelo, p. 615, 13, Heiberg.

Anaximander was the first to assume the Infinite as first principle, in order that he might have it available for his new births without stint.

SIMPLICIUS, in Phys. p. 1121, 5.

Those who assumed that the worlds are infinite in number, as did Anaximander, Leucippus, Democritus, and, in later days, Epicurus, assumed that they also came into being and passed away, ad infinitum, there being always some worlds coming into being and others passing away; and they maintained that motion is eternal: for without motion there is no coming into being or passing away.


Anaximander says that that which is capable of begetting the hot and the cold out of the eternal was separated off during the coming into being of our world, and from this there was produced a sort of sphere of flame which grew round the air about the earth as the bark round a tree; then this sphere was torn off and became enclosed in certain circles or rings, and thus were formed the sun, the moon, and the stars.

HIPPOLYTUS, Refut. I, 6, 4, 5.

The stars are produced as a circle of fire, separated off from the fire in the universe and enclosed by air. They have as vents certain pipe-shaped passages at which the stars are seen; hence, when the vents are stopped up, eclipses take place. The moon appears sometimes as waxing, sometimes as waning, to an extent corresponding to the closing or opening of the passages.

AËTIUS, II, 13, 7.

The stars are compressed portions of air, in the shape of wheels filled with fire, and they emit flames at some point from small openings.

HIPPOLYTUS, loc. cit.

The earth is poised aloft, supported by nothing, and remains where it is because of its equidistance from all other things. Its form is rounded, circular, like a stone pillar; of its plane surfaces one is that on which we stand, the other is opposite.


The earth, he says, is cylinder-shaped and its depth is such as to have a ratio of one-third to its breadth.

HIPPOLYTUS, Refut. I, 6, 5.

The circle of the sun is twenty-seven times as large of the moon .

AËTIUS, II, 20, 21, 24, 25, 29, 15.

(20, 1) The sun is a circle twenty-eight times the size of the earth; it is like a chariot-wheel, the rim of which is hollow and full of fire, and lets the fire shine out at a certain point in it through an opening like the nozzle of a pair of bellows: such is the sun.

(21, 1) The sun is equal to the earth, and the circle from which the sun gets its vent and by which it is borne round is twenty-seven times the size of the earth.

(24, 2) The eclipses of the sun occur through the orifice by which the fire finds vent being shut up.

(25, 1) The moon is a circle nineteen times as large as the earth; it is like a chariot-wheel, the rim of which is hollow and full of fire, like the circle of the sun, and it is placed obliquely, as that of the sun also is; it has one vent like the nozzle of a pair of bellows; its eclipses depend on the turnings of the wheel.

(29, 1) The moon is eclipsed when the orifice in the rim of the wheel is stopped up.

(I5, 6) The sun is placed highest of all, after it the moon, and under them the fixed stars and the planets.

EUSEBIUS, Praeparatio evangelica, X, 14, 11.

Anaximander was the first to construct gnomons (sundials) for the purpose of distinguishing the turnings-back of the sun (solstices), times, seasons, and the equinoxes. (But cf. Herodotus, II, 109: "The Greeks learnt from the Babylonians the use of the polos and the gnomon, and also the twelve parts of the day.")


He was the first to make a drawing of the contour of the (inhabited) earth and the sea.


Anaximander of Miletus, a pupil of Thales, was the first who ventured to make a drawing of the inhabited earth on a tablet, and after him Hecataeus of Miletus, a much-travelled man, corrected it so that it became an object of general admiration.

HIPPOLYTUS, Refut. I, 6, 6.

(Anaximander held) that living creatures arose evaporated by the sun. Man was in the beginning like another living creature, namely a fish.

AËTIUS, V, 19, 4.

Anaximander said that the first living creatures came into existence in the moist element, and had prickly coverings, but, as they advanced in age, they moved to the drier part; and, when the covering peeled off, they survived in their changed state for a short time.

PLUTARCH, Symp. VIII, 8,4.

The descendants of Hellen of old sacrifice to the ancestral Poseidon, thinking, like the Syrians, that man was born of the moist substance; hence they venerate the fish as being of like race and like nurture with man, a doctrine which is more reasonable than that of Anaximander; for the latter declares, not that fishes and men lived in the same conditions, but that men were at first born inside fishes, and were reared like sharks, after which, when they became capable of fending for themselves, they left the water and took to land.

PSEUDO-PLUTARCH, Stromat. fr. 2.

Anaximander says that at the beginning man was born from other species of animals; this he inferred from the fact that, while other animals quickly manage to find food for themselves, man alone needs long nursing. If he had been what he is now, he could not possibly have survived.



SIMPLICIUS, in Phys. p. 24, 26.

ANAXIMENES of Miletus, son of Eurystratus, who had been an associate of Anaximander, said, like him, that the underlying substance was one and infinite. He did not, however, say it was indeterminate, like Anaximander, but determinate; for he said it was Air. It differs in different substances in virtue of its rarefaction and condensation.

HIPPOLYTUS, Refut. I, 7.

From it (i.e. Air), he said, the things that are, and have been, and shall be, the gods and things divine, took their rise, while other things came from its offspring. And the form of the air is as follows. Where it is most even, it is invisible to our sight; but cold and heat, moisture and motion, make it visible. It is always in motion; for, if it were not, it would not change so much as it does. When it is dilated so as to be rarer, it becomes fire; while winds, on the other hand, are condensed Air. Cloud is formed from Air by felting; and this, still further condensed, becomes water. Water, condensed still more, turns to earth; and when condensed as much as it can be, to stones.

AËTIUS, I, 3, 4.

"Just as," he said, "our soul, being air, holds us together, so do breath and air encompass the whole world."


Anaximenes says that, as the air was felted, the earth first came into being. It is very broad and is accordingly supported by the air.

HIPPOLYTUS, loc. cit.

In the same way, the sun and the moon and the other heavenly bodies, which are of a fiery nature, are supported by the air because of their breadth. The heavenly bodies were produced from the earth by moisture rising from it. When this is rarefied, fire comes into being, and the stars are composed of the fire thus raised aloft. There were also bodies of earthy substance in the region of the stars, revolving along with them. And he says that the heavenly bodies do not move under the earth, as others suppose, but round it, as a cap turns round our head. The sun is hidden from sight, not because it goes under the earth, but because it is concealed by the higher parts of the earth, and because its distance from us becomes greater. The stars give no heat because of the greatness of their distance.

AËTIUS, II, 14, 16, 20, 22, 23, 25; III, 10.

(II, 14, 3) The stars [are fixed like nails in the crystalline vault of the heavens, but some say they] are fiery leaves, like paintings.

(16, 6) They do not go under the earth, but turn round it.

(20, 2) The sun is fiery.

(22, 1) It is broad like a leaf.

(23, I) The. heavenly bodies turn back in their courses owing to the resistance of compressed air.

(25, 2) The moon is of fire.

(III, 10, 3) The earth was like a table in shape.





FURTHER we are told that Pythagoras was the first to call the heaven the universe, and the earth round (i.e. spherical), though according to Theophrastus it was Parmenides, and according to Zeno it was Hesiod.

Ib., IX, 23.

And he (Parmenides) is thought to have been the first to see that the Evening Star and the Morning Star are one and the same, as Favorinus says in the fifth book of his Memorabilia; but others say it was Pythagoras. (Cf. VIII, 14: "It was he (Pythagoras) who first declared that the Evening and Morning Stars are the same, as Parmenides maintains.")

THEON OF SMYRNA, p. 150, 12-18.

The impression of variation in the movement of the planets is produced by the fact that they appear to us to be carried through the signs of the zodiac in certain circles of their own, being fastened in spheres of their own and moved by their motion, as Pythagoras was the first to observe, a certain varied and irregular motion being thus grafted, as a qualification, upon their simply and uniformly ordered motion in one and the same sense (i.e. that of the daily rotation from east to west).

AËTIUS, I, 21, I.

Pythagoras held that time is the sphere of the enveloping (heaven).

ARISTOTLE, Phys. Δ 10, 218 a 33.

Some (of the Pythagoreans) say that time is the motion of the whole (the universe), others that it is the sphere itself.

Ib., Δ 6, 213 b 22-4.

The Pythagoreans also held that void exists, and that the void enters the heaven itself from the infinite breath (outside it), as if the heaven inhaled even the void.



AËTIUS, II, 16, 2-3.

ALCMAEON and the mathematicians hold that the planets have a motion from west to east, in a direction opposite to that of the fixed stars.



ARISTOTLE, Metaph. A 5, 986 b 21-4.

XENOPHANES was the first of these philosophers to maintain the doctrine of the One, though he made no clear statement on the subject ... but, referring to the whole Heaven, he states that the One is God.

Fragments, II, 13-29 (tr. JOHN BURNET).

Homer and Hesiod have ascribed to the gods all things that are a shame and a disgrace among mortals, stealings and adulteries and deceivings of one another.

But mortals deem that the gods are begotten as they are, and have clothes like theirs, and voice and form.

Yes, and if oxen and horses or lions had hands, and could paint with their hands, and produce works of art as men do, horses would paint the forms of the gods like horses, and oxen like oxen, and make their bodies in the image of their several kinds.

The Ethiopians make their gods black and snub-nosed; the Thracians say theirs have blue eyes and red hair.

The gods have not revealed all things to men from the beginning, but by seeking they find in time what is better.

One god, the greatest among gods and men, neither in form like unto mortals nor in thought.

He sees all over, thinks all over, and hears all over.

But without toil he swayeth all things by the thought of his mind.

And he abideth ever in the selfsame place, moving not at all; nor doth it befit him to go about now hither, now thither.

All things come from the earth, and in earth all things end.

The limit of the earth above is seen at our feet in contact with the air; below it reaches down without a limit.

All things are earth and water that come into being and grow.


Excerpted from Greek Astronomy by Thomas L. Heath. Copyright © 1991 Dover Publications, Inc.. Excerpted by permission of Dover Publications, Inc..
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
Excerpts are provided by Dial-A-Book Inc. solely for the personal use of visitors to this web site.

Customer Reviews

Average Review:

Post to your social network


Most Helpful Customer Reviews

See all customer reviews