Prehistoric astronomical activity is represented by a Stonehenge-like megalithic
circle and "Observatory" at Rujm-el-Hiri, near Yonathan in the Golan, the
Westernmost sector of the historical Bashan plateau dating from the IIIrd
Star worship is mentioned in the Old Testament as being common among the
Canaanites, but the Bashan inhabitants who built that Golan megalithic
circle antedate the Canaanites. Very little is known about them and the
presumably religous role of their edifice.
To the IIIth Century B.C. Israelitis, they appeared as the work of giants
(Refa'im, also Anakim, Emim, Zuzim), and this is probably the source of
the legends about races of giants that had lived in Eretz-Israel prior
to the Israelite conquest — including the characterization "a remnant of
the giants" for Og, King of Bashan, in Deuteronomy and Joshua. Indeed,
the Rujm-el-Hiri circle is just one among many megalithic remains in the
Bashan, probably at the origin in Greece and England (the "Giant's Dance"
ASTRONOMY IN THE MISHNA
The Israelitis' abstract monotheism and their centering of intellectual
creativity on ethical issues were detrimental to a natural development
of observational science, as did happen in Sumeria or Greece. However,
the requirements of agriculture induced a cycle of holidays that were incorporated
in time into Judaism and were given Ethnical or National religious significance.
There thus developed a need for an understanding of the recurrence of seasons
and for a synchronized calendar fitted to Solar, Lunar and Sidereal time
. Several of the Mishnaic scholars were versed in Astronomy, such as the
"Tannaim" Yehoshua ben Zakkai, the Patriarch Gamliel II and in particular
Yehoshua (=Joshua) ben Hananiah.
In the tractate Horayoth, dealing with errors of Justice, the following
anecdote is related:
"Rabbi Gamliel and Rabbi Yehoshua went together on a voyage at sea. Rabbi
Gamliel carried a supply of bread, Rabbi Yehoshua carried a similar amount
of bread and in addition a reserve of flour. At sea, they used up the entire
supply of bread and had to utilize Rabbi Yehoshua's flour reserve. Rabbi
Gamliel then asked Rabbi Yehoshua - "Did you know that this trip would
last longer than usual, when you decided to carry this flour reserve?"
Rabbi Yehoshua answered - "There is a star that appears every 70 years
and induces navigational errors. I thought it might appear and cause us
to go astray." Rabbi Gamliel then exclaimed "You are so knowledgeable and
you nevertheless have to travel to make a living?" Rabbi Yehoshua then
answered bitterly - "How come you are so surprised? Don't you know that
two of your own students Rabbi Eliezer Hisma and Rabbi Yehohanan ben Gudgada
who are so smart that they can tell you how many drops there are in the
ocean, have neither bread to eat nor clothes to wear?"
This observation is generally interpreted as relating to Halley's Comet,
with a period aproximating 76 years. Observing a comet's periodicity, with
such a long period, requires records covering many centuries; it is possible
that the Mishnaic scholars did inherit such records from the Great Knesset
scholars (before 300 BC) who received them during the Babylonian exile
(586-537 BC) from the "Chaldeans" (i.e. from Sumer, Akad etc. going back
to the IIIrd Millenium BC). Indeed, the Hebrew agricultural names of the
months were replaced by Sumerian and Akadian names after the Babylonian
However, there is perhaps a difficulty with the dates: Rabbi Yehoshua was
born in 35 AD and died in 117 AD. Rabbi Gamliel died in 115 AD. The only
appearance of Halley's Comet in the interval 55-155 (when Yehoshua was
older than 20), is in 66 AD.
Rabbi Gamliel was younger then Rabbi Yehoshua and it has been argued that
if he was 20-25 years old, it is doubtful whether he could have had students
at the time. Still, this is not a strong argument, as Rabbi Gamliel II
was also the hereditary Patriarch, and may have had students attached to
him formally from the moment he was appointed head of the Sanhedrin.
Philippe Veron has, however, come up recently with a different identification
of Rabbi Yehoshua's star, and argues that this was the variable Mira Ceti.
Mar Samuel, who became around 220 AD the Dean of the Talmudic Academy of
Nehardea in Babylonia, was an astronomer who could calculate and adjust
the calendar with great precision, intercalating an extra month or reassigning
the length of a month.
The prescriptions for the calendar adjustments were written down in a special
Baraita. They include the 19 years synchronization cycle to this very day
in the Jewish Calendar.
SPAIN AND PROVENCE
Science spreads by convection. When Khushru Anushirvan, Sassanid Emperor
of Persia, signed a ten year truce with Justinian of Byzance, he ensured
the continuity of science by requesting that the teachers of the recently
abolished Academy of Athens be transferred to Persia. In his fanaticism,
Justinian was then trying hard to put an end to Judaism at the same time
eradicating Neo-Platonicism and what was left of Greek science. The Neo-Platonicists
settled in Mesopotamia under Persian rule, and their school was already
flourishing when Persia was conquered by Islam. Mathematics and Astronomy
thrived (e.g. Omar Khayyam, whose Rubayat was just a hobby, his professional
creativity having yielded methods for solving factorizable cubic equations
etc.) and spread all over the new Mohammedon Empire.
The Jews were active participants, and the first Arabic-languate treatise
on the Astrolabe was written by the Jew Joel, known as Masha-Allah of Basra
(Iraq) around the year 800. This is the treatise that was translated into
English by Geoffrey Chaucer ("The Treatise on the Astrolabe") around 1380,
from a prior Latin translation. Masha-Allah also wrote a book on Lunar
and Solar Eclipses, that was later translated into Hebrew by Abraham Ibn
Ezra ("Sefer be kadrut ha levana ve ha shemesh")
Sind ben Ali, a heretic Jew, was the main contributor (~830) to the astronomical
tables of the Caliph Maimum. The scene now shifts to Spain, where Abraham
bar Hiyya Hanasi ("The Prince") of Barcelona (d. 1336) improved on these
tables, using calculations performed by the Arab astronomer Al-Battani
(d. 929). Abraham bar Hiyya was a prominent mathematician and astronomer,
and wrote famous textboks in both fields. He introduced Europe to (Arab)
trigonometry in his "Treatise on Mensuration and Calculations". The Hebrew
was translated by Plast of Tivoli into Latin in 1145 and his book served
as main source material for that later work of Leonardo Fibonacci of Pisa.
In Astronomy, his book "The Shape of the Earth" is based upon the Ptolemaic
system, contains a roughly correct estimate of the distance to the Moon
(but the wrong distance to the Sun). The principles for Calender intercalation
make up yet another book.
His student, Abraham Ibn Ezra (1089-1164), poet, philosopher, Biblical
commentator and Astronomer, spent the last part of this life travelling
in Italy and France, ending up in Eretz-Israel. He continued the publication
of tables, mostly on the movement of the planets. The "Toledo Tables" were
compiled by 12 Jewish astronomers led by the Cordovan Arab astronomer Ibn
Arzarkali ("Azarchel"). The Latin version (translated by John of
Brescia and Jacob Ibn Tibbon) was further improved in 1272 by a group of
astronomers led by Isaac Ibn Said, and is known as the "Alphonsine Tables".
Rabbi Moshe ben Maimon's (=Maimonides) main contribution to Astronomy
in his complete rejection of Astrology (1194). He is is unique, throughout
the Centuries, in making this clear-cut. Remember that Kepler was still
drawing horoscopes! Perhaps this should justify a visit to Maimonides'
tomb in Tiberias.
Rabbi Levi ben Gershom ( = Gersonides, also Maestre Leo de Bagnols,
Maestre Leo Hebraeus; 1288-1344), was one of the greatest of Medieval astronomers.
He lived in Provence, mostly at Orange. As a mathematician, he re-discovered
the law of sines and published a sine table, correct to the 5th decimal.
As an astronomer (he wrote 136 "chapters"!), he is the first to have relied
on his own observations (in his studies of eclipses) rather than on Ptolemy's.
He invented "Jacob's staff", a navigational instrument which was widely
used for 3 centuries, and was the first person kown to have used a Camera
Obscura for his observations.
Rabbi Levi is also the first scientist to derive more realistice estimates
of the distance to the fixed stars. Ptolemy's estimate was of the order
of 10-5 light years ( a million times smaller than the distance to the
nearest star), whereas Rabbi Levi reached a figure of about 105 light years,
10 times our present estimate for the distance to an average star in the
Galaxy. Gersonides was also one of the greatest Medieval philosophers and
published Commentaries to the Bible.
The Zohar, a compilation of Jewish mystic writings drawn in Spain in the
XIIIth Century anticipates Copernicus by stating that "the whole earth
spins in a circle like a ball; the one part is up when the other part is
down; the one part is light when the other is dark; it is day in the one
part and night in the other".
Jewish astronomers played a key role in the theoretical preparation of
the great voyages of discovery in the XVth Century. Judah Cresques, forced
to adopt Christianity in the massacres of 1391, later became the Director
of the Prince Henry of Portugal's ("The Navigator") Nautical Academy of
Sagres. Abraham Zacuto ("Zacut", 1452-1515) worked first at Salamanca but
moved to Portugal after the expulsion from Spain.
As Court Astronomer to Kings John II and Manuel I, he prepared the voyage
of Vasco da Gama (1496) and supplied instumentation (include his newly
perfected copper astrolabe), improved tables, charts, intruction and briefs.
He developed the first copper astrolabe. His very precise predictions of
eclipses were used by Columbus to threaten the natives at a dangerous moment.
Like all Jews, Zacut had to flee Portugal in 1497 and went to Tunis. He
died in Eretz-Israel.