Quelltext der Seite History of Astronomy Forbes 1909 01 Primitive Astronomy and Astrology

{{Werk
|Titel=History of Astronomy
|Autor=Forbes-George
|Copyright=Siehe eLib Lizenzen
|Auflage=1
|Erscheinungsjahr=1909
|Sprache=English
|Verlag=
|Typ=Monographie
|Fachgebiete=103 Physik Astronomie,211 Andere Technische Wissenschaften,601 Geschichte Archäologie
|Tags=Wissenschaftsgeschichte, Astronomie, Physik, Raumfahrt, Teleskop
|Originalsprache=English
|Kurzbeschreibung=Geschichte der Astronomie bis 1909.
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HISTORY OF ASTRONOMY

:BY
:GEORGE FORBES,
:M.A., F.R.S., M. INST. C. E.,
:(FORMERLY PROFESSOR OF NATURAL PHILOSOPHY, ANDERSON'S COLLEGE, GLASGOW)

:AUTHOR OF &quot;THE TRANSIT OF VENUS,&quot; RENDU'S &quot;THEORY OF THE :GLACIERS OF SAVOY,&quot; ETC., ETC.

:1909


:BOOK I.  THE GEOMETRICAL PERIOD



==1. PRIMITIVE ASTRONOMY AND ASTROLOGY.==


The growth of intelligence in the human race has its counterpart in
that of the individual, especially in the earliest stages.
Intellectual activity and the development of reasoning powers are in
both cases based upon the accumulation of experiences, and on the
comparison, classification, arrangement, and nomenclature of these
experiences. During the infancy of each the succession of events can
be watched, but there can be no _à priori_ anticipations.
Experience alone, in both cases, leads to the idea of cause and effect
as a principle that seems to dominate our present universe, as a rule
for predicting the course of events, and as a guide to the choice of a
course of action. This idea of cause and effect is the most potent
factor in developing the history of the human race, as of the
individual.

In no realm of nature is the principle of cause and effect more
conspicuous than in astronomy; and we fall into the habit of thinking
of its laws as not only being unchangeable in our universe, but
necessary to the conception of any universe that might have been
substituted in its place. The first inhabitants of the world were
compelled to accommodate their acts to the daily and annual
alternations of light and darkness and of heat and cold, as much as to
the irregular changes of weather, attacks of disease, and the fortune
of war.  They soon came to regard the influence of the sun, in
connection with light and heat, as a cause. This led to a search for
other signs in the heavens. If the appearance of a comet was sometimes
noted simultaneously with the death of a great ruler, or an eclipse
with a scourge of plague, these might well be looked upon as causes in
the same sense that the veering or backing of the wind is regarded as
a cause of fine or foul weather.

For these reasons we find that the earnest men of all ages have
recorded the occurrence of comets, eclipses, new stars, meteor
showers, and remarkable conjunctions of the planets, as well as
plagues and famines, floods and droughts, wars and the deaths of great
rulers. Sometimes they thought they could trace connections which
might lead them to say that a comet presaged famine, or an eclipse
war.

Even if these men were sometimes led to evolve laws of cause and
effect which now seem to us absurd, let us be tolerant, and gratefully
acknowledge that these astrologers, when they suggested such &quot;working
hypotheses,&quot; were laying the foundations of observation and deduction.

If the ancient Chaldæans gave to the planetary conjunctions an
influence over terrestrial events, let us remember that in our own
time people have searched for connection between terrestrial
conditions and periods of unusual prevalence of sun spots; while De la
Rue, Loewy, and Balfour Stewart[1] thought they found a connection
between sun-spot displays and the planetary positions. Thus we find
scientific men, even in our own time, responsible for the belief that
storms in the Indian Ocean, the fertility of German vines, famines in
India, and high or low Nile-floods in Egypt follow the planetary
positions.

And, again, the desire to foretell the weather is so laudable that we
cannot blame the ancient Greeks for announcing the influence of the
moon with as much confidence as it is affirmed in Lord Wolseley's
_Soldier's Pocket Book_.

Even if the scientific spirit of observation and deduction (astronomy)
has sometimes led to erroneous systems for predicting terrestrial
events (astrology), we owe to the old astronomer and astrologer alike
the deepest gratitude for their diligence in recording astronomical
events. For, out of the scanty records which have survived the
destructive acts of fire and flood, of monarchs and mobs, we have
found much that has helped to a fuller knowledge of the heavenly
motions than was possible without these records.

So Hipparchus, about 150 B.C., and Ptolemy a little later, were able
to use the observations of Chaldæan astrologers, as well as those of
Alexandrian astronomers, and to make some discoveries which have
helped the progress of astronomy in all ages.  So, also, Mr. Cowell[2]
has examined the marks made on the baked bricks used by the Chaldæans
for recording the eclipses of 1062 B.C. and 762 B.C.; and has thereby
been enabled, in the last few years, to correct the lunar tables of
Hansen, and to find a more accurate value for the secular acceleration
of the moon's longitude and the node of her orbit than any that could
be obtained from modern observations made with instruments of the
highest precision.

So again, Mr. Hind [3] was enabled to trace back the period during
which Halley's comet has been a member of the solar system, and to
identify it in the Chinese observations of comets as far back as 12
B.C. Cowell and Cromellin extended the date to 240 B.C. In the same
way the comet 1861.i. has been traced back in the Chinese records to
617 A.D. [4]

The theoretical views founded on Newton's great law of universal
gravitation led to the conclusion that the inclination of the earth's
equator to the plane of her orbit (the obliquity of the ecliptic) has
been diminishing slowly since prehistoric times; and this fact has
been confirmed by Egyptian and Chinese observations on the length of
the shadow of a vertical pillar, made thousands of years before the
Christian era, in summer and winter.

There are other reasons why we must be tolerant of the crude notions
of the ancients. The historian, wishing to give credit wherever it may
be due, is met by two difficulties. Firstly, only a few records of
very ancient astronomy are extant, and the authenticity of many of
these is open to doubt. Secondly, it is very difficult to divest
ourselves of present knowledge, and to appreciate the originality of
thought required to make the first beginnings.

With regard to the first point, we are generally dependent upon
histories written long after the events.  The astronomy of Egyptians,
Babylonians, and Assyrians is known to us mainly through the Greek
historians, and for information about the Chinese we rely upon the
researches of travellers and missionaries in comparatively recent
times. The testimony of the Greek writers has fortunately been
confirmed, and we now have in addition a mass of facts translated from
the original sculptures, papyri, and inscribed bricks, dating back
thousands of years.

In attempting to appraise the efforts of the beginners we must
remember that it was natural to look upon the earth (as all the first
astronomers did) as a circular plane, surrounded and bounded by the
heaven, which was a solid vault, or hemisphere, with its concavity
turned downwards. The stars seemed to be fixed on this vault; the
moon, and later the planets, were seen to crawl over it. It was a
great step to look on the vault as a hollow sphere carrying the sun
too. It must have been difficult to believe that at midday the stars
are shining as brightly in the blue sky as they do at night. It must
have been difficult to explain how the sun, having set in the west,
could get back to rise in the east without being seen _if_ it was
always the same sun. It was a great step to suppose the earth to be
spherical, and to ascribe the diurnal motions to its rotation.
Probably the greatest step ever made in astronomical theory was the
placing of the sun, moon, and planets at different distances from the
earth instead of having them stuck on the vault of heaven. It was a
transition from &quot;flatland&quot; to a space of three dimensions.

Great progress was made when systematic observations began, such as
following the motion of the moon and planets among the stars, and the
inferred motion of the sun among the stars, by observing their
_heliacal risings_--i.e., the times of year when a star
would first be seen to rise at sunrise, and when it could last be seen
to rise at sunset. The grouping of the stars into constellations and
recording their places was a useful observation. The theoretical
prediction of eclipses of the sun and moon, and of the motions of the
planets among the stars, became later the highest goal in astronomy.

To not one of the above important steps in the progress of astronomy
can we assign the author with certainty. Probably many of them were
independently taken by Chinese, Indian, Persian, Tartar, Egyptian,
Babylonian, Assyrian, Phoenician, and Greek astronomers.  And we have
not a particle of information about the discoveries, which may have
been great, by other peoples--by the Druids, the Mexicans, and the
Peruvians, for example.

We do know this, that all nations required to have a calendar. The
solar year, the lunar month, and the day were the units, and it is
owing to their incommensurability that we find so many calendars
proposed and in use at different times. The only object to be attained
by comparing the chronologies of ancient races is to fix the actual
dates of observations recorded, and this is not a part of a history of
astronomy.

In conclusion, let us bear in mind the limited point of view of the
ancients when we try to estimate their merit. Let us remember that the
first astronomy was of two dimensions; the second astronomy was of
three dimensions, but still purely geometrical. Since Kepler's day we
have had a dynamical astronomy.


===FOOTNOTES:===

[1] Trans. R. S. E., xxiii. 1864, p. 499, _On Sun Spots_, etc., by
B. Stewart. Also Trans. R. S. 1860-70. Also Prof. Ernest Brown, in
_R. A. S. Monthly Notices_, 1900.

[2] _R. A. S. Monthly Notices_, Sup.; 1905.

[Illustration: CHALDÆAN BAKED BRICK OR TABLET, _Obverse and reverse
sides_, Containing record of solar eclipse, 1062 B.C., used lately by
Cowell for rendering the lunar theory more accurate than was possible
by finest modern observations. (British Museum collection,
No. 35908.)]

[3] _R. A. S. Monthly Notices_, vol. x., p. 65.

[4] R. S. E. Proc., vol. x., 1880.


*[[History of Astronomy Forbes 1909 02 Ancient Astronomy - Chinese and Chaldaens|2. ANCIENT ASTRONOMY--CHINESE AND CHALDÆANS]]


==Contents==

:[[History_of_Astronomy_Forbes_1909|PREFACE]]

:BOOK I. THE GEOMETRICAL PERIOD

*[[History of Astronomy Forbes 1909 01 Primitive Astronomy and Astrology|1. PRIMITIVE ASTRONOMY AND ASTROLOGY]]

*[[History of Astronomy Forbes 1909 02 Ancient Astronomy - Chinese and Chaldaens|2. ANCIENT ASTRONOMY--CHINESE AND CHALDÆANS]]

*[[History of Astronomy Forbes 1909 03 Ancient Greek Astronomy|3. ANCIENT GREEK ASTRONOMY]]

*[[History of Astronomy Forbes 1909 04 Reign of Epicycles - Ptolemy to Copernicus|4. THE REIGN OF EPICYCLES--FROM PTOLEMY TO COPERNICUS]]


:BOOK II. THE DYNAMICAL PERIOD

*[[History of Astronomy Forbes 1909 05 Discovery of the true solar system - Brahae to Kepler|5. DISCOVERY OF THE TRUE SOLAR SYSTEM--TYCHO BRAHE--KEPLER]]

*[[History of Astronomy Forbes 1909 06 Galileo and the telescope - Notions of gravity by Horrocks|6. GALILEO AND THE TELESCOPE--NOTIONS OF GRAVITY BY HORROCKS, ETC.]]

*[[History of Astronomy Forbes 1909 07 Newton Law of Universal Gravitation|7. SIR ISAAC NEWTON--LAW OF UNIVERSAL GRAVITATION]]

*[[History of Astronomy Forbes 1909 08 Newton successors Halley Euler Lagrange Laplace|8. NEWTON'S SUCCESSORS--HALLEY, EULER, LAGRANGE, LAPLACE, ETC.]]

*[[History of Astronomy Forbes 1909 09 Discovery of new planets Herschel Piazzi Adams Le Verrier|9. DISCOVERY OF NEW PLANETS--HERSCHEL, PIAZZI, ADAMS, AND LE VERRIER]]


:BOOK III. OBSERVATION

*[[History of Astronomy Forbes 1909 10 Instruments of precision - size of the solar system|10. INSTRUMENTS OF PRECISION--SIZE OF THE SOLAR SYSTEM]]

*[[History of Astronomy Forbes 1909 11 History of the telescope spectroscope|11. HISTORY OF THE TELESCOPE--SPECTROSCOPE]]

:BOOK IV. THE PHYSICAL PERIOD

*[[History of Astronomy Forbes 1909 12 The Sun|12. THE SUN]]

*[[History of Astronomy Forbes 1909 13 The Moon and Planets|13. THE MOON AND PLANETS]]

*[[History of Astronomy Forbes 1909 14 Comets and Meteors|14. COMETS AND METEORS]]

*[[History of Astronomy Forbes 1909 15 Stars and Nebulae|15. THE STARS AND NEBULÆ]]

*[[History of Astronomy Forbes 1909 16 Index|INDEX]]





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