Astronomy

The brightness of the sun, which lights up the world, the brightness of the moon and of fire — these are my glory.
— Bhagavad Gita, 15:12, in the translation of Eknath Easwaran, Arkana Books, 1985.

Howbeit, we cannot choose but confess, that the true reason and knowledge of agriculture, dependeth principally upon the observation of the order in heavenly bodies
— Pliny the Elder (CE 23 – 79), The Natural History, translated by Philemon Holland (1552 – 1637)

Yet we have but to make a few lines on a chart
And the distance of the furthest stars
In the sky can be measured.
— The Sixth Dalai Lama, (1682 – 1705).

The Pythagoreans say, that the moon appears to us terraneous, by reason it is inhabited as our earth is, and in it there are animals of a larger size and plants of a rarer beauty than our globe affords; that the animals in their virtue and energy are fifteen degrees superior to ours; that they emit nothing excrementitious; and that the days are fifteen times longer.
— Plutarch (45 – 120), Sentiments Concerning Nature, Book II, Chapter XXX

Why should I feel lonely? Is not our planet in the Milky Way?
— Henry David Thoreau (1817 – 1862), Walden.

It is necessary that the genuine astronomer should not, like Hesiod and others such as Hesiod, confine himself to a knowledge of the risings and settings of the constellations: he ought to be likewise acquainted with the circuits of the seven planets, and of the eighth celestial sphere.
— Plato (c. 427 – 347 BCE).

Thirdly, the natural motion of the earth as a whole, like that of its parts, is towards the centre of the universe: that is the reason why it is now lying at the centre. It might be asked, since the centre of both is the same point, in which capacity the natural motion of heavy bodies, or parts of the earth, is directed towards it; whether as centre of the universe or of the earth. But it must be towards the centre of the universe that they move, seeing that light bodies like fire, whose motion is contrary to that of the heavy, move to the extremity of the region which surrounds the centre. It so happens that the earth and the universe have the same centre, for the heavy bodies do move also towards the centre of the earth, yet only incidentally, because it has its centre at the centre of the universe. As evidence that they move also towards the centre of the earth, we see that weights moving towards the earth do not move in parallel lines but always at the same angles to it [normal to the surface]: therefore they are moving towards the same centre, namely that of the earth. It is now clear that the earth must be at the centre and immobile …

From these conclusions it is clear that the earth does not move …
— Aristotle (384 – 322 BCE)

It is possible to see that the sun, moon and stars do not rise and set at the same time for every observer, but always rise earlier in the east and later in the west. Eclipses, especially those of the moon, are not always recorded at the same time after noon, being at a later hour in the east than in the west. And as this difference in times is proportional to the distances between places, we can see that the surface of the earth is spherical.
— Claudius Ptolemy (c. 75 – c. 150 CE), Almagest, written about 150 CE.

It is possible to see that the sun, moon and stars do not rise and set at the same time for every observer, but always rise earlier in the east and later in the west. Eclipses, especially those of the moon, are not always recorded at the same time after noon, being at a later hour in the east than in the west. And as this difference in times is proportional to the distances between places, we can see that the surface of the earth is spherical.
— Claudius Ptolemy (c. 100 – c. 178) and the shape of the planet.

The Meditations of Marcus Aurelius begin by acknowledging his indebtedness to his grandfather, father, adopted father, various teachers, and the gods … He owes it to the gods … that when he took to philosophy he did not waste time on history, syllogism or astronomy.
— Bertrand Russell (1872 – 1970) A History of Western Philosophy, chapter XXVIII, 271.

[On the eleventh November 1572, after sunset] when according to my habit, I was looking at the stars in a clear sky, I noticed that a new and unusual star, brighter than all the other stars, was shining almost directly above me. Since I had, almost from boyhood, known all of the stars of the heavens perfectly (it is not difficult to learn), I knew that there had never been a star in this place in the sky, not even a faint one … This so astonished me that I wondered if I could trust my eyes. But other people, when shown the place, could see the star too, so I had no further doubts …

It is hard to calculate the distances of the stars from us, because they are so far away. It is best and most surely done by measuring the [diurnal] parallax, if a star has one. If we view a star at the horizon and overhead, and see some difference in its position, then it must be at a distance not too different from the Earth’s size. We then calculate the size of the orbit from the measure of parallax and the Earth’s radius …

I tried to measure the parallax by comparing the star with Schedir of Cassiopeia … and in each case found the same result of 7 degrees and 55 minutes. I repeated this with other fixed stars, and still obtained no differences … It follows that the new star is at a distance so great that the Earth’s size is nothing by comparison …
— Tycho Brahe (1546 – 1601) and a nova.

May I not be seen to have lived in vain
— Tycho Brahe (1546 – 1601), long-time astronomer on the island of Ven. He actually died in Prague, not in Ven.

These earthly godfathers of Heaven’s lights,
That give a name to every fixed star,
Have no more profit of their shining nights
Than those that walk and wot not what they are.
— William Shakespeare (1564 – 1616), Love’s Labour’s Lost, I, i, 88-91.

Two stars keep not their motion in one sphere
— William Shakespeare, King Henry IV, Part 1, V, iv, 65

Fool:    The reason why the seven stars are no more than seven is a pretty reason.
Lear:    Because they are not eight?
Fool:    Yes, indeed; thou wouldst make a good fool.
— William Shakespeare, King Lear, I, v.

When beggars die, there are no comets seen;
The heavens themselves blaze forth the death of princes.
— William Shakespeare (1564-1616), Julius Caesar, II, ii, 30-31

On the 7th day of January in the present year, 1610, the first hour of the following night, as I was viewing the constellations of the heavens through a telescope, the planet Jupiter presented itself to my view, and … I noticed that three little stars, small but very bright, were near the planet, and although I believed them to belong to the number of the fixed stars, yet they made me somewhat wonder, because they seemed to be arranged exactly in a straight line, parallel to the ecliptic, and to be brighter than the rest of the stars.
— Galileo Galilei (1564 – 1642), The Sidereal Messenger.

The mathematical professor at Padua hath discovered four new planets rolling about the sphere of Jupiter, besides many other unknown fixed stars [and] that the moon is not spherical but endowed with many prominences [he shall either be] exceeding famous or exceeding ridiculous.
— Sir Henry Wotton (1568-1639), English ambassador to Venice, letter to England, 1610, in Reliquiae Wottoniae, quoted by Jacob Bronowski (1908 – 1974) in The Ascent of Man.

Alas … Galileo, your devoted friend and servant, has been for a month totally and incurably blind; so that this heaven, this earth, this universe, which by my remarkable observations and clear demonstrations I have enlarged a hundred, nay a thousand fold beyond the limits universally accepted by learned men of all previous ages, are now shrivelled up for me into such a narrow compass as is filled by my own bodily sensations.
— Galileo Galilei (1564-1642), writing in about 1638.

That is what they would appear to be to anyone who saw them from Jupiter. For they are dark in themselves, and receive their light from the sun; that is obvious from their being eclipsed when they enter into the cone of Jupiter’s shadow. And since only that hemisphere of theirs is illuminated which faces the sun, they always look entirely illuminated to us who are outside their orbit and closer to the sun, but to anyone on Jupiter they would look completely lighted only when they were at the highest points of their circles. In the lowest part that is, when between Jupiter and the sun they would appear horned from Jupiter. In a word, they would make for Jovians the same changes of shape that the moon makes for us terrestrials.
— Galileo Galilei (1564 – 1642), The Sidereal Messenger.

O dark, dark, dark, amid the blaze of noon,
Irrecoverably dark, total eclipse,
Without all hope of day!
— John Milton, (1608-1674), Samson Agonistes, lines 80 – 82
(Milton visited Galileo after Galileo lost his sight.)

Propositions to be forbidden: that the sun is immovable at the centre of the heaven; that the earth is not at the centre of the heaven, and is not immovable, but moves by a double motion.
— Codex 1181, Proceedings Against Galileo Galilei, February 1616.

Eppur si muove. [But it does move.]
— Galileo Galilei (1564 – 1642) (attributed to Galileo after he was required to recant.)

They have likewise discovered two lesser stars, or satellites, which revolve about Mars, whereof the innermost is distant from the centre of the primary planet exactly three of his diameters, and the outermost five; the former revolves in the space of ten hours, and the latter in twenty-one and a half; so that the squares of their periodical times are very near in the same proportion with the cubes of their distance from the centre of Mars, which evidently shows them to be governed by the same law of gravitation that influences the other heavenly bodies.
— Jonathan Swift (1667 – 1745), ‘A Voyage to Laputa’ in Gulliver’s Travels.

The question of whether Mars had a satellite or not, although at times occurring to me, I did not seriously consider until the spring of 1877. At that time several things had happened that brought this question prominently before me. Perhaps the principal of these was the discovery, in December 1876, of a white spot on the ball of Saturn, which gave me the means of determining the time of rotation of that planet, and taught me how untrustworthy may be the statements of the textbooks; this had made me ready to doubt the phrase one reads so often, “Mars has no Moon”. Again, the favourable opposition of Mars in 1877 naturally attracted my attention …

At first my attention was directed to faint objects at some distance from Mars; but all these proving to be fixed stars, I began to examine the region close to the planet, and within the glare of light that surrounded it. This was done by keeping the planet just outside the field of view, and turning the eyepiece so as to pass completely around the planet. While making this examination on the night of August 11, I found a faint object on the following side of the planet, but had barely time to secure an observation of its position when fog from the Potomac River stopped the work. Cloudy weather intervened for several days.

The search resumed on August 15. On August 16 the object was found again on the following side of the planet, and the observation of that night showed that it was moving with the planet. On August 17, while waiting and watching for the outer satellite, the inner one was discovered. The observations made on the seventeenth and eighteenth put beyond doubt the character of these objects, and their discovery was publicly announced … For several days the inner moon was a puzzle. It would appear on different sides of the planet on the same night, and at first I thought there were two or three different moons, since it seemed very improbable to me, at that time, that a satellite should revolve around its primary in less time than that in which the primary rotates.
— Asaph Hall (1829 – 1907), Monthly Notices of the Royal Astronomical Society, Vol 38, 1877-78.

I have had a great divertion this year by the spots that have apeard in the sun, but that which has been most satisfactory to me was the spot I observed in November, as being the most aposite one for determining the position of the sun exis, it haveing continued longer than any this year except that in January, though a small one, and happening at a time of the year when the earth was in or near the solar equinox, the suns revolution and position of the exis were more easly to be determined, which I finde exactly enough agreeable to what you computed from your observations of the sun spots in the former year, viz that the sun revolves to a fixed star in 25 1/2 days on an axis inclined to the plane of the Ecliptic 82 or 83 degrees …
— Stephen Gray (1666? – 1736), Letter to John Flamsteed, 27 December, 1704, quoted by Clark and Murdin, New Scientist, 24 May, 1979, 652.

The phenomena of nature, especially those that fall under the inspection of the astronomer, are to be viewed, not only with the usual attention to facts as they occur, but with the eye of reason and experience. In this we are however not allowed to depart from plain appearances; though their origin and signification should be indicated by the most characterising features. Thus, when we see, on the surface of the moon, a great number of elevations, from half a mile to a mile and a half in height, we are strictly entitled to call them mountains; but, when we attend to their peculiar shape, in which many of them resemble the craters of our volcanoes, and thence argue that they owe their origin to the same cause which has modelled many of these, we may be said to see by analogy, or with the eye of reason. Now in this latter case, though it may be convenient, in speaking of the phenomena, to use expressions that can only be justified by reasoning upon the facts themselves, it will certainly be the safest way not to neglect a full description of them, that it may appear to others how far we have been authorised to use the mental eye. This being premised, I may safely proceed to give my observations …
— Sir (Frederick) William Herschel (1738 – 1822), Report read by Herschel before the Royal Society, April 1787.

Almost all its conclusions stand in open and striking contradiction with those of superficial and vulgar observation, and with what appears to every one, until he has understood and weighed the proofs to the contrary, the most positive of his senses. Thus, the earth on which he stands, and which has served for ages as the unshaken foundation of the firmest structures, either of art or nature, is divested by the astronomer of its attribute of fixity, and conceived by him as turning swiftly on its centre, and at the same time moving through space with great rapidity.
— Sir John Herschel (1792 – 1871), Outlines of Astronomy, 1849.

CAROLINE, sister of William, was trained by him as a singer in the Bath days and had considerable success in Handel’s oratorios under her brother’s conductorship. (The method of training adopted was for her to sing the violin parts of concertos with a gag in her mouth.) It was with great reluctance that she dropped music to be trained as an assistant astronomer, yet she made discoveries — eight minor planets, one of them named after her.
— Percy A. Scholes, The Oxford Companion to Music, 9th edition, 1955, 470.

All that is needed to make these dark bodies visible is a luminous region behind them. This is supplied in one way by the rich stellar regions of the Milky Way. An excellent example of how such a thing may be possible is shown by a phenomenon that presented itself to me one beautiful, transparent, moonless night in the summer of 1913, while I was photographing the southern Milky Way with the Bruce telescope. I was struck with the presence of a group of tiny cumulous clouds scattered over the rich star clouds of Sagittarius. They were remarkable for their smallness and definite outlines some not being larger than the moon. Against the bright background they appeared as conspicuous and black as drops of ink. They were in every way like the black spots shown on the photographs of the Milky Way, some of which I was at that moment photographing. The phenomenon was impressive and full of suggestions. One could not resist the impression that many of the black spots in the Milky Way are due to a cause similar to that of the small, black clouds mentioned above that is, to more or less opaque masses between us and the Milky Way. I have never before seen this peculiarity so strongly marked from clouds at night, because the clouds have always been too large to produce the effect.
— Edward Emerson Barnard (1857 – 1923).

Of Human Bondage
— W. Somerset Maugham, novel title.

Of Herman Bondiage
— Subtitle to Duncan Bain’s Herschel Bars and Other Sweet Astronomers, Saccharistella Press, 1985.

When fishes flew and forests walked
And figs grew upon thorn,
Some moment when the moon was blood
Then surely I was born;
— G. K. Chesterton (1874 – 1936), The Donkey

The Milky Way, our galaxy (a word derived from the Greek gala, meaning milk), has great depth. Its distances are most conveniently measured in terms of travelling times at the speed of light.
— Bart J. Bok, ‘The Milky Way’, Scientific American Reader (1953), 13.

We are no other than a magic row
Of Magic Shadow-shapes that come and go
Round with the Sun-illumin’d Lantern held
In Midnight by the Master of the Show …
— Edward Fitzgerald (1809-1883), The Rubaiyat of Omar Khayyam

If anything as whacky as this has planets going round it, then surely ordinary stars stand a much better chance these days.
— Heather Couper, British astronomer, 1991, on a pulsar with possible planets.

Sir Francis Stuart had heard Mr Hariot say that he had seen nine Cometes, and had predicted Seaven of them, but did not tell them how. ‘Tis very strange: excogitent Astronomi.
— John Aubrey, of Thomas Hariot (1560 – 1621), Aubrey’s Brief Lives, Penguin Books, 281.

Of all the comets in the sky,
There’s none like comet Halley:
We see it with the naked eye
And periodically.
— Anon

Jan Oort of the Netherlands has calculated that the total mass of this interstellar dust and gas is as great as all the material in the stars themselves, including all possible planet systems.
— Fred L. Whipple (1906 – 2004), ‘The Dust Cloud Hypothesis’, Scientific American Reader (1953), 36.

Ye country comets, that portend
No war, nor prince’s funeral,
Shining unto no higher end
Than to presage the grasses’ fall.
— Andrew Marvell (1621-1678), The Mower to the Glow-worms

In the first place, a blazing star or comet appeared for several months before the plague, as there did the year after another, a little before the fire. The old women and the phlegmatic hypochondriac part of the other sex, whom I could almost call old women too, remarked (especially afterward, though not till those judgments were over) that those two comets passed directly over the city, and that so very near the houses that it was plain they imported something peculiar to the city alone; that the comet before the pestilence was of a faint, dull, languid colour, and its motion was very heavy, solemn and slow; but that the comet before the fire was bright and sparkling, or, as others said, flaming, and its motion swift and furious …
— Daniel Defoe (1660 – 1731) A Journal of the Plague Year, 1722, Everyman edition pp. 21-22.

If the Lord Almighty had consulted me before embarking upon Creation, I should have recommended something simpler.
— Attributed to King Alfonso X of Castile (Spain) (1221-1284), on having the Ptolemaic system explained to him.

I agree. But I wonder what it would have looked like if the sun had been circling the earth.
— Ludwig Wittgenstein (1889-1951), on being told how foolish the ancients were for accepting the Ptolemaic system.

My own suspicion is that the universe is not only queerer than we suppose, but queerer than we can suppose.
— J. B. S. Haldane (1892 – 1964)

The most incomprehensible thing about the world is that it is comprehensible.
— Albert Einstein (1879 – 1955)

In the middle of all sits the Sun enthroned. In this most beautiful temple, could we place this luminary in any better position from which he can illuminate the whole at once?
— Nicolaus Copernicus (1473-1543)

Now what was it that gave Hubble the notion that the galaxies are running away from one another and that the universe is expanding? His basic discovery was made with that indispensable tool of the astronomer, the spectrograph…
— George Gamow (1904-1968), Galaxies in Flight, Scientific American Reader (1953), 7.

While engaged in a research carried out by Bunsen and myself in common on the spectra of colored flames, by which it became possible to recognize the qualitative composition of complicated mixtures from the appearance of their spectra in the flame of the blow pipe, I made some observations which give an unexpected explanation of the origin of the Fraunhofer lines and allow us to draw conclusions from them about the composition of the sun’s atmosphere and perhaps also that of the brighter fixed stars.

Fraunhofer noticed that in the spectrum of a candle flame two bright lines occur which coincide with the two dark lines D of the solar spectrum. We obtain the same bright lines in greater intensity from a flame in which common salt is introduced. I arranged a solar spectrum and allowed the sun’s rays, before they fell on the slit, to pass through a flame heavily charged with salt. When the sunlight was sufficiently weakened, there appeared in place of the two dark D lines, two bright lines; if its intensity, however, exceeded a certain limit the two dark D lines showed much more plainly than when the flame charged with salt was not present…

I conclude from these observations that a colored flame in whose spectrum bright sharp lines appear so weakens rays of the color of these lines, if they pass through it, that dark lines appear in place of the bright ones, whenever a source of light of sufficient intensity, in whose spectrum these lines are otherwise absent, is brought behind the flame.

— Gustav Kirchhoff (1824 – 1887), 1859.

Twinkle, twinkle little star,
I don’t wonder what you are,
For by spectroscopic ken
I know that you are hydrogen.
— Anon

… the situation regarding QSO’s at the present time is rather similar to that existing about fifty years ago when the first redshifts of the spiral nebulae had been measured. At that time their extragalactic nature had not been established, and astronomers attempted to interpret the redshifts in terms of galactic objects streaming in preferred directions (similar to the concept of star streaming with which they were familiar). It took more than a decade before their extragalactic nature was firmly established.
— Margaret Burbidge and Geoffrey Burbidge, Quasi-stellar Objects, Freeman, 1967.

We may begin by accepting Sir Arthur Eddington’s admission that, although astronomers had long preferred to regard space as empty, there was no real reason to believe that this was the case. It was merely a matter of convenience in that the present appearance and probable histories of stars could be most easily classified on the supposition that there was no appreciable ‘atmosphere’ between them.
— A. W. Haslett, Unsolved Problems of Science, London 1937.

When an astronomer speaks of a class A star, he refers to white stars like Sirius or Vega, in whose spectra we see a very strong series of dark lines caused by hydrogen in the atmosphere. For blue-white stars like Rigel, we use the letter B. The gas, helium, so precious and so scarce here on earth, is very abundant in the atmosphere of these stars. The letter G is used for our own Sun and other yellow stars; and for red stars like Betelgeuse, we use the letter M. between A and G are the F stars; between G and M, the K stars. Other letters designate several rarer varieties. After a large number of stars had been classified, it was found that the letters B, A, F, G, K, M, stand for six divisions, including a great majority of the stars. B must go before A in the astronomer’s alphabet, because when it was too late to reverse the letters, the B stars were found to precede the A stars in life-history. Thus we have the so-called B A F classification, which is easy to remember, said an Irish astronomer, because B A F stands for baffling.
— Annie Jump Cannon (1863 – 1941), ‘Classifying the Stars’ in Harlow Shapley and Cecilia H. Payne (eds), The Universe of Stars, Harvard College Observatory Press, 1929, quoted in Ferris (ed) The World Treasury of Physics, Astronomy and Mathematics, 272-273.

Investigations into the nature of the stars must necessarily be largely based on the average characteristics of groups of stars selected in various ways — as by brightness, proper motion and the like … of all the principles of division, that which separates the stars according to their spectral types has revealed the most remarkable differences, and those which most stimulate attempts at a theoretical explanation …

Thanks to the possibility of obtaining with the objective prism photographs of the spectra of hundreds of stars on a single photographic plate, the number of stars the spectra of which have been observed and classified now exceeds one hundred thousand, and probably as many more are within the reach of existing instruments …

The spectra of the stars show remarkably few radical differences in type. More than 99 per cent. of them fall into one or other of the six great groups which, during the classic work of the Harvard College Observatory, were recognised as of fundamental importance, and received designations, by the process of “survival of the fittest,” the rather arbitrary series of letters B, A, F, G, K, and M. That there should be so few types is noteworthy; but much more remarkable is the fact that they form a continuous series, a fact recognised in the familiar decimal classification, in which B5, for example, denotes a spectrum half-way between the typical examples of B and A. This series is not merely continuous; it is linear.
— Henry Norris Russell (1877 – 1957), Nature, 1914.

In the year 1929 the Mount Wilson astronomer Edwin Hubble made a very remarkable discovery. He found that the giant accumulations of stars known as galaxies, which are scattered in great multitudes through the vast expanses of the universe as far as the best telescopes can see, seem to be running away from one another at fabulously high speeds. From this observed fact originated the famous theory of the expanding universe. Although the theory is still not finally proved, it seeded a whole generation of fruitful study, not only in astronomy, but also in geology, physics and chemistry. It gave us a new start for investigating the age of the universe and the creation of the stuff of which it is made.

— George Gamow (1904 – 1968), ‘Galaxies in Flight’, Scientific American, July 1948. 

You will find an index to this blog at the foot of this link. Please be patient: I am pedalling as fast as I can.