Download Astronomy in the Ancient Near East

Astronomy in the Ancient Near East
Babylonian Astronomy
Robert H. van Gent
Mathematical Institute
Utrecht University
Astronomy, as all other mathematical sciences, was first developed in ancient Mesopotamia.
In many cities, such as Babylon, the heavens were closely observed by astronomer-priests for
signs which were believed to the fate of rulers and their countries.
The development of cuneiform writing
The Development of the Sexagesimal (= 60) System of Numbers
The sexagesimal number system was later also adopted by Hellenistic, Islamic
and European scholars for expressing angular measures and intervals of time
Some examples of sexagesimal numbers – the actual value of the number
has to be inferred from the context of the problem
Old-Babylonian mathematical cuneiform
tablet (YBC 7289) on which the length of
the diagonal (d) of a square with side s =
30 is computed
d = s √2
where √2 is approximated as 1;24,51,10
(≈ 1.41421296…)
resulting in
d = 30 × 1;24,51,10 = 42;25,35
The box (or cylinder) shaped cosmos of ancient Mesopotamia
The cosmos represented as a seven-tiered step pyramid (zikkurat)
The Etemenanki zikkurat of Babylon during the reign of Nebuchadnezzar II (c. 605-562 BCE)
Babylon during the Reign of Nebuchadnezzar II (c. 605-562 BCE)
The Etemenanki zikkurat and associated temple complexes are here seen near the
famous walls of Babylon and the Euphrates River
Remains of the zikkurat of Borsippa
The Babylonian World Map
(London, British Museum, BM 92687)
Representation of the disk of the Earth
with Babylon in the centre of the known
world and encircled by the waters of the
Ocean.
Found in Sippar and probably dating
from the 6th cent. BCE.
Mesopotamian calendars were regulated by the phases of the moon
and each month began at the first sighting of the lunar crescent
shortly after sunset above the western horizon
Neo-Sumerian cylinder seal with Ur-Nammu, the first king of the Third Dynasty of Ur (a city where the
moon god Sin was held in reverence). Approaching from the left are Hashhamer, governor of the city of
Ishkun-Sin, with two female deities (British Museum)
The Babylonian Lunar Calendar
The months in the Babylonian calendar compared with those in our calendar and in
the Hebrew calendar. Lunar months are either 29 or 30 days in length.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Nisannu (BÁRA.ZAG.GAR)
Aiaru (GUD.SI.SÁ)
Simanu (SIG4.GA)
Du'uzi (SHU.NUMUN)
Abu (NE.NE.GAR)
Ululu (KIN.dINNIN)
Teshritu (DU6.KÙ)
Arahsamnu (APIN.DU8.A)
Kislimu (GAN.GAN.È)
Tebetu (AB.BA.È)
Shabatu (ZÍZ.A)
Addaru (SHE.KIN.KUD)
March-April-May
April-May-June
May-June-July
June-July-August
July-August-September
August-September-October
September-October-November
October-November-December
November-December-January
December-January-February
January-February-March
February-March-April
Nisan [7]
Iyar [8]
Sivan [9]
Tammuz [10]
Av [11]
Elul [12]
Tishrei [1]
Marcheshvan [2]
Kislev [3]
Tevet [4]
Shevat [5]
Adar [6]
The Babylonian year started shortly after the vernal equinox. As 12 lunar months are
about 11 days shorter than a solar year (which is based on the astronomical seasons)
an intercalary month was inserted after each 2nd or 3rd year.
After about 500 BCE intercalation was regulated according to a 19-year cycle (later
known as the Metonic cycle) in which a 2nd Addaru [Addaru II] was inserted in the
years 2, 5, 8, 10, 13 and 16, while a 2nd Ululu [Ululu II] was inserted in the 19th year. In
this way the heliacal rising of the bright star Sirius (mulKAK.SI.SÁ) nearly always
occurred in the month of Du'uzi.
Babylonian calendar scheme
on an “astrolabe text” (here
shown with the Hebrew month
names) with the stars which
become visible in each
month.
The numbers refer to the
seasonal variation in the
length of the day and night.
Mesopotamian boundary stones (kudurru’s) from the 2nd
half of the 2nd millennium BCE depict a variety of divine
and astral symbols.
Often depicted are the Sun goddess (Shamash), the Moon
god (Sin), Venus (Ishtar) – always at the top – and the
constellations Scorpion (mulGÍR.TAB), the Archer
(mulPA.BIL.SAG) and the Goatfish (mulSUHUR.MAS)
Tablet from the astronomical cuneiform
compendium MUL.APIN (c. 1000 BCE)
This text discusses the following topics:
• List of constellations and their ordering in the
paths of Enlil, Anu and Ea
• The rising of particular constellations in the
months of the Babylonian calendar
• The constellations in the “Path of the Moon”
• The length of day and night during the year
Originally, the paths of Enlil, Anu and Ea designated the horizon sections in which the
northern, the equatorial and the southern constellations were observed to rise and to set.
Later they were used as divisions of the celestial sphere.
Proto-zodiacal constellations in the “Path of the Moon” according to the MUL.APIN text (c. 1000 BCE).
Many of these were later (c. 5th cent. BCE) used in a zodiac system based on 12 segments of 30° each.
The Babylonian
stellar figures as can
be reconstructed
from various
cuneiform sources.
Based on:
G. White, Babylonian StarLore: An Illustrated Guide
to the Star-Lore and
Constellations of Ancient
Babylonia (London, 2008).
Astrology in Ancient Mesopotamia
I – Astrological predictions from celestial omens
The earliest texts on astrology in Mesopotamia are based on the observation of
celestial phenomena and are known as omen texts. These were typically written
in the form: “when A happens in the sky, then B will happen on Earth”.
The most important collection of omen texts was known as the Enūma Anu Enlil
[“When the gods Anu and Enlil …”].
It contained 68 [or 70] tablets (“books”), each listing about 100 omens, and was
probably compiled at the close of the 2nd millennium BCE.
This collection of omen texts was used until the close of the 1st millennium BCE
by Mesopotamian priest-astronomers (tupsarru) whose task was to observe and
interpret the celestial phenomena.
Astrology in Ancient Mesopotamia
I – Astrological predictions from omens (continued)
Contents of the omen series Enūma Anu Enlil:
•
•
•
•
Tablets
1-22[23] – omens based on the Moon [Sin]
Tablets 23[24]-39[40] – omens based on the Sun [Shamash]
Tablets 40[41]-49[50] – omens based on weather phenomena [Adad]
Tablets 50[51]-68[70] – omens based on the planets and the stars [Ishtar]
The positions of the Moon and the planets were noted with reference to notable stars
or constellations – there is no mention yet of a zodiac or a celestial coordinate
system.
The omens were mostly concerned with the fate of the king, his land and his people.
Some tablets refer to historical events from the Old-Babylonian period (c. 2000 to c.
1500 BCE) and possibly even earlier.
Tablet 63, also known as the “Venus tablet of Ammizaduga”, is of great importance for
dating the reign of Ammizaduga, a descendant of the Old-Babylonian king and
lawgiver Hammurabi.
Astrology in Ancient Mesopotamia
I – Astrological predictions from omens (continued)
The substitute king ritual
When the omens predicted bad news for the king, the priests could advise the king to
appoint a substitute king (shah pukhi) during the period of danger. The king would
then retire into the background while another person would temporarily occupy the
throne.
The substitute king was treated in almost all aspects as the true king but, when the
danger had passed, he would be quietly removed to an uncertain fate.
A.K. Grayson, Assyrian and Babylonian Chronicles (New York, 1975)
Chronicle 20: 31-36
Erra-imitti, the king, installed
Enlil-bani, the gardener,
as substitute king on his throne.
He placed the royal tiara on his head.
Erra-imitti [died] in his palace when he sipped a hot broth.
Enlil-bani, who occupied the throne, did not give it up (and)
so was sovereign.
Erra-imitti and Enlil-bani were kings of Isin who ruled around 1850 BCE.
Omens from Lunar Eclipses
Already in the 8th cent. BCE Assyrian astrologers could
predict the occurrence of lunar eclipses in advance with
reasonable success.
The possible outcome of a lunar eclipse was inferred from
the part of the lunar disk which was darkened and from the
direction of the Earth’s shadow. The divisions of the lunar
disk – Elam, Amurru, Akkad and Subartu – refer to various
geographical regions in Mesopotamia.
The (modern) diagrams describe various lunar eclipses
mentioned on cuneiform tablets from the library of the
Assyrian king Assurbanipal (Nineveh, early 7th cent. BCE).
Astrology in Ancient Mesopotamia
II – The first horoscopes
Horoscopic astrology probably originated in the late 5th cent. BCE. The positions of the
Sun, the Moon and the planets were recorded in ecliptical coordinates based on the
zodiacal coordinate system.
Horoscopes were not only calculated for royal persons and upper-class clients but also
for ordinary people.
About 30+ cuneiform horoscopes are now known.
Horoscope of the Uruk priest-astronomer Anu-Bēlshunu (30 December 249 BCE)
Cuneiform tablet from an astrological compendium, originally containing six illustrated tablets with
explanatory texts, copied by the Uruk priest-astronomer Anu-Bēlshunu (Seleucid Period, c. 200 BCE)
Berlin, Vorderasiatisches Museum, VAT 7847
The astrological properties of the Bull (IN.DUB.AN.NA) with the Moon god (Sin) and the Pleiades
(MUL.MUL) from an astrological compendium, copied by the Uruk priest-astronomer Anu-Bēlshunu
Berlin, Vorderasiatisches Museum, VAT 7851
The astrological properties of the Lion (UR.GU.LA) with Jupiter (dAMAR.UD = Marduk) and the Water
Snake (MUŠ) from an astrological compendium copied by the Uruk priest-astronomer Anu-Bēlshunu
Berlin, Vorderasiatisches Museum, VAT 7847
The astrological properties of the Virgin (AB.SÍN) with Mercury (GU4.UD), the Water Snake (MUŠ) and
the Raven (UGA.MUŠEN), from an astrological compendium copied by the Uruk priest-astronomer
Anu-Bēlshunu
Paris, Musée du Louvre, AO 6448
Astronomical Tablets I
Other tablets (referred to as ACT = Astronomical
Cuneiform Texts) give detailed predictions for the
positions of the Sun, the Moon and the planets with
the dates of their first and last visibility and
predictions of lunar eclipses.
The computations were based on period relations
describing the mean celestial motions and correction terms represented by step or zigzag functions.
Example of a zigzag function as applied in Babylonian astronomical texts
Babylonian Period Relations
The following list gives the periods used by Babylonian astronomers for predicting (approximate)
positions of the celestial bodies over long periods of time.
Babylonian ‘Goal Year’ texts (‘almanacs’)
•
•
•
•
•
•
•
Saturn:
Jupiter (short):
Jupiter (long):
Mars (short):
Mars (long):
Venus:
Mercury:
57 synodic periods [2 sidereal periods] = 59 solar years
65 synodic periods [6 sidereal periods] = 71 solar years
76 synodic periods [7 sidereal periods] = 83 solar years
22 synodic periods [25 sidereal periods] = 47 solar years
37 synodic periods [42 sidereal periods] = 79 solar years
5 synodic periods [13 sidereal periods] = 8 solar years
145 synodic periods [191 sidereal periods] = 46 solar years
Babylonian ACT texts
•
•
•
•
•
Saturn :
Jupiter:
Mars:
Venus:
Mercury:
256 synodic periods
[9 sidereal periods] = 265 solar years
391 synodic periods [36 sidereal periods] = 427 solar years
133 synodic periods [151 sidereal periods] = 284 solar years
720 synodic periods [1871 sidereal periods] = 1151 solar years
217 to 848 solar years for the first or last visibility
Babylonian astronomers knew that after 18 years and 11 days [= 223 lunations = 242 draconic
months] eclipses of the Sun and the Moon tend to repeat in a regular pattern. This period is now
commonly known as the “Saros Period”.
The Length of the Month and the Year
According to Late-Babylonian cuneiform texts the average length of a
lunation [= lunar month = synodic period] was equal to:
Psyn (Moon) = 29;31,50,8,20d = 29d 12h 44m 31/3s
The value of the solar year [= sidereal year] was determined as:
Pyear (Sun) = (235/19) × Psyn (Moon) = 365d 5h 55m 25.4s
The modern values are:
Psyn (Moon) = 29d 12h 44m 2.877s
Ptrop (Sun) = 365d 5h 48m 45.187s
Psid (Sun)
= 365d 6h 9m 9.54s
The Babylonian value for Psyn (Moon) was later adopted by Hellenistic
astronomers as Hipparchus of Nicaea (c. 150 BCE) and Claudius Ptolemy (c.
150 CE) and is still used today for computing the modern Jewish calendar.
Astronomical Tablets II
The computation schemes of several ACT tablets are so
well known that damaged tablets can often be restored
with a high level of confidence, even if only a few small
fragments are preserved.
In the following example a small fragment (ACT 20) can be
shown to have been part of a much larger tablet listing the
new and full moons for the year 167 of the Seleucid Era [=
145/144 BCE].
The Astronomical Diaries
From about 750 BCE onwards Babylonian
priest-astronomers kept detailed records
of astronomical and other ominous
phenomena, the level of the Euphrates
River and the price of important
commodities such as grain and oil.
These records were afterwards gathered
into monthly and yearly registers. This
practice was probably continued until the
begin of the Christian Era.
Especially from the last few centuries
BCE many of these ‘dairies’ have been
recovered.
The last known cuneiform text with
astronomical content dates from 75 CE.
The Conquests of Alexander the Great (356 – 323 BCE)
In the last few centuries BCE a substantial part of the astronomical and astrological
knowledge of the Mesopotamians was assimilated into the Hellenistic world due to
translations from into Greek
The Death of Alexander the Great Predicted?
According to several classical historical sources, the
death of Alexander the Great (356-323 BCE) in Babylon
was predicted in advance by local astrologers who
appear to have (unsuccessfully) performed a substitute
king ritual.
The exact date of the death of Alexander the Great, 11
June 323 BCE, is recorded on a fragmentary cuneiform
tablet in the British Museum (from the collection of
“Astronomical Diaries”) which soberly mentions “the
King died”.
See further: Diodorus of Sicily, Library of History XVII 116.1-4;
Plutarch of Chaironeia, Life of Alexander 73-74; Lucius Flavius
Arrianus, The Campaigns of Alexander VII 24.1-3.
Babylonian Astrology and
Hellenistic Astrology
In addition to the use of a zodiac in 12
equal sections of 30° and the sexagesimal number system, the following
Babylonian astrological concepts were
also adopted by Hellenistic astrologers:
1) The hypsomata (“exaltations”) of the
planets – these were already mentioned
in Assyrian texts around 700 BCE as the
ašar nisirti or bīt nisirti (“secret place”)
of a planet.
2) The dodecatemoria (“micro-zodiac”)
in which each sign of the zodiac is
divided into 12 equal sectors of 2½°.
3) The doctrine of the triplicities in
which the signs of the zodiac which are
120° distant are astrologically linked
with each other.
4) The use of the ‘terms’ in which parts of the
zodiacal signs are linked to individual planets.
5) The use of the ‘sidereal zodiac’ in which the
positions of the celestial bodies are measured
with respect to the fixed stars.
The Three Kings mosaic in the Basilica di Sant’Apollinare Nuovo (Ravenna, early 6th cent.)