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byPaul Lunde - with Zayn Bilkadi[Precise observation and an ability to find new
mathematical solutions to old problems were the two main strengths
of Muslim scientists in the Middle Ages. Celestial mapping sprang
from a religious concern: the need to establish correct
coordinates of cities so that Muslims could determine the
direction of Ka'bah - the qibla - towards which all Muslims face
themselves in prayer five times a day. This need led to
significant developments in Trigonometry, a field fundamental to
terrestrial mapping and to the computation of planetary orbits.
The medieval qibla tables were often accurate to within one or two
minutes.Muslim scientists were the first to express doubts
about many of the details of the Ptolemaic system. Al-Battani
(ninth century) showed, contrary to Ptolemy, annular eclipses were
possible, and that the angular diameter of the sun was subject to
variation. He also developed a theory of the conditions of
visibility of the new moon. The greatest Muslim physicist Ibn
al-Haytham (Alhazen) argued that the Milky Way was quite far from
the earth no matter what Aristotle said, and estimated the height
of the earth's atmosphere at about 32 miles, very close to 31
miles as we know today. Arabs also excelled at making astronomical
instruments - particularly astrolabes which were used for
navigational purposes and for determining the positions of
stars.]To
scientists in Islam's Golden Age - whose bold thoughts laid the
groundwork for today's exploration of space - the satellite might
have been astonishing; but the Prince's photographic assignment and
his other assignments would not have been totally unfamiliar. They
too were knowledgeable about optics and astronomy and they were
experts in ephemerides - tables showing the positions of celestial
bodies on given dates.Lunar
observation, for example, was, and is, important to Muslims; for
religious purposes they follow a lunar calendar [twelve months] and
the new moon marks the beginning and end of [Islamic months] the
fast of Ramadan and determines the date of the pilgrimage to Makkah
(Mecca) - the Hajj - two of the five religious duties incumbent upon
all Muslims.Celestial
mapping also sprang from a religious concern: the need to establish
correct coordinates of cities so that Muslims could determine the
direction of Makkah [Ka'bah] - the
qibla - towards which all Muslims [face] prostrate themselves in
prayer five times a day. And though observation of the new moon and
determination of the qibla may seem prosaic subjects today, it was
by pondering just such everyday phenomena that advances in science
were made.The
mathematical determination of the qibla, for example, was one of the
most advanced problems in spherical astronomy faced by medieval
astronomers and mathematicians and the trigonometric solution
eventually found was of great sophistication. Trigonometry itself,
largely an Arab development, is fundamental to the computation of
planetary orbits as well as to terrestrial mapping, and consequently
medieval qibla tables often attained great accuracy. That of
al-Khalili, who wrote in Syria in the 14th century, gives the
coordinates of a large number of towns in degrees and minutes and is
generally accurate to within one or two
minutes.It could be
argued, in fact, that precise observation and an ability to find new
mathematical solutions to old problems were the two main strengths
of Muslim scientists in the Middle Ages. And though they, like their
European counterparts, never fully escaped the tyranny of Aristotle
and Ptolemy - whose models of terrestrial geography and of the
heavens dominated men's minds until the Renaissance and were not
finally demolished until the publication of Newton's Principia in
1687.Muslim
scientists were the first to express doubts about many of the
details of the Ptolemaic system. Indeed, it was the growing
awareness of the divide between Ptolemy's theoretical model of the
universe and observed reality that culminated in the discoveries of
Nicolaus Copernicus, Tycho Brahe and Johannes Kepler during the l5th
to l7th centuries, and some of those doubts had been transmitted to
European scientists from Spain in 12th- and 13th-century
translations of Arabic scientific works.Al-Battani,
called by his European translators Albategni[us], is a case in
point. He wrote in the ninth century on a wide number of scientific
topics and some of his observations struck at cherished Ptolemaic
dogmas. He showed, for example that, contrary to Ptolemy, annular
eclipses - in which a ring of light encircles the eclipsed portion -
were possible, and that the angular diameter of the sun was subject
to variation. He showed - again contrary to Ptolemy - that the solar
apogee was subject to the precession of the equinoxes; he corrected
a number of planetary orbits; he determined the true and mean orbit
of the sun. Interestingly in the light of Prince Sultan's
observation of the new moon, al-Battani also developed a theory of
the conditions of visibility of the new
moon.Other Muslim
astronomers also came up with data that conflicted with Ptolemy, one
of them perhaps the greatest Muslim physicist of them all: Ibn
al-Haytham, called Alhazen in the
medieval West. Al-Haytham argued that the Milky Way was quite far
from the earth no matter what Aristotle said, and estimated the
height of the earth's atmosphere at 52,000 paces - a pace being
roughly one meter, or three feet. Al-Haytham worked that out from
his observation that the astronomic twilight begins when the
negative height of the sun reaches 19 degrees. Since the atmosphere
is about 50 kilometers up (31 miles) and 52,000 paces is roughly 52
kilometers (32 miles), Ibn al-Haytham was very close
indeed.In the
pre-telescope age, observational astronomy was, of course, carried
out with the naked eye. Muslim scientists, however, perfected
observatories in a number of places; those at Maragha and Samarkand
are the most famous. At these observatories, astronomers gathered to
refine Ptolemy's coordinates for the stars and, eventually, to
revise Ptolemy's catalog of stars. This catalog which gave the
positions of 1,022 stars, classified, as they are today, by
magnitude, or brightness, was heavily revised, notably by the
l0th-century astronomer Abd al-Rahman
al-Sufi [Azophi], whose Book of the fixed Stars is the
earliest illustrated astronomical manuscript known; the copy in the
Bodleian Library, the work of the author's son, is dated 1009 and
the author expressly states that he traced the drawings from a
celestial globe.There is an
even earlier representation of the heavens in an Umayyad hunting
lodge built about A.D. 715 in Jordan. It is called Qasr al-'Amra and
in the dome of the bath house in the lodge are fragments of a fresco
showing some 400 stars and parts of 37 constellations, drawn on a
stereographic projection - which implies a familiarity even at that
early date, with Ptolemy's Planispheriurn.Arabs also
excelled at making astronomical instruments - particularly
astrolabes which were used for navigational purposes, for
determining the positions of stars and for solving problems in
spherical astronomy. There were three sorts of astrolabes:
planispheric, linear and spherical. These were used at the
observatories of Maragha and Samarkand, and were substantially the
same as the instruments used [later] by European astronomers until
the invention of the telescope.The
observatory at Maragha was founded by the famous mathematician Nasir
al-Din al-Tusi in 1259, one year after the fall of Baghdad to the
Mongols. Because the Mongol invasions into the lands of Islam had
opened a land route to China, Muslim astronomers were eventually
able to work together with their Chinese
counterparts.The main
theoretical work done at the observatory had to do with simplifying
the Ptolemaic model and bringing it into line with the Aristotelian
model, which postulated uniform circular orbits for the planets.
Although they were often misguided, they made very important
contributions; Ibn al-Shatir [early 14th century], for example, came
up with models of the movement of the moon and of Mercury that are
strikingly similar to those of Copernicus.The
observatory of Ulugh Beg at Samarkand,
built between 1420 and 1437, was used to re-compute the positions of
the stars in Ptolemy's catalog, and there is little doubt
that the organization of this observatory and the instruments
employed there influenced Tycho Brahe's famous observatories at
Uraniborg and Stjerneborg.Another
observatory thought to have influenced Tycho Brahe was that proposed
and built in Istanbul in the 16th century. In 1571 in Istanbul, Taqi
al-Din Mohammed ibn Ma'ruf, a former judge from Egypt and author of
several books on astronomy was appointed head-astronomer of the
Ottoman Empire and immediately proposed construction of an
observatory. He wanted to begin the urgent task of updating the old
astronomical tables describing the motion of the planets, the sun
and the moon. His request was well received by the Grand Vizier and
patron of sciences, Sokullu Muhammad, but between 1571 and 1574 the
Ottomans had to fight no less that three costly wars against the
three major powers of Europe, Venice, Spain and Portugal, so it was
not until mid-1577 that the project was
completed.Taqi
al-Din's observatory consisted of two magnificent buildings, perched
high on a hill overlooking the European section of Istanbul and
offering an unobstructed view of the night sky. Much like a modern
institution, the main building was reserved for the library and the
living quarters of the technical staff, while the smaller building
housed an impressive collection of instruments built by Taqi al-Din
himself - including a giant armillary sphere and a mechanical clock
for measuring the position and speed of the planets; aware that
Europe was beginning to move ahead in astronomy he was determined to
restore the Islamic world's once uncontested
supremacy.A few months
later, unfortunately, on a cold November night - the first night of
the holy month of Ramadan - a comet with an enormous tail
unexpectedly edged into sight and set off a controversy that would
put an end to his dream - and the observatory. Twisting and
twirling, the comet grew brighter and steadier by the day for 40
days, and soon became a fireball soaring in the heavens like the sun
and terrifying observers on earth.One such
observer was the Sultan Murad III, whose own father Sultan Selim,
had died shortly after another comet had appeared. About to open a
campaign in the Caucasus aginst Persia and its allies, Murad
demanded a prognostication on the comet and Taqi al-Din, working day
and night without food and rest, did so...Unfortunately for Taqi
al-Din, his predictions didn't quite turn out right. Though two
Persian armies were defeated in the war, the Ottomans experienced
certain reverses, a devastating plague broke out in some parts of
the empire and several important persons died, and within a short
period of time the Ottoman court began to quarrel about the
observatory. One faction, headed by the Grand Vizier Sokullu favored
continued support of the institution, and the other led by Sokullu's
political rival, said that prying into the secrets of the future
was...a waste of funds.For a short
period Sokullu prevailed and Taqi al-Din plunged into astronomy at a
feverish pace for two years. But then Sokullu was killed and in 1580
a wrecking squad from the Marine Ordnance Division appeared on the
premises, and its commander, citing the misfortunes that had
befallen the Ottomans since the apparition of the comet, gave orders
to level the buildings.Another
subject allied to astronomy that deeply interested Muslim scientists
- and to which they made important contributions -was optics. Thus
Newton's Optics, published in 1704, had a long history of
experimentation behind it. Classical theories of vision held that
sight was the result of rays emanated from the eyes, rather than the
reflection of light from the object viewed. It was Ibn al-Haytham
who broke with this classical theory and developed a theory with
mathematical proof, in accord with the facts. His work with the
camera obscura and discovery of the mathematical principles behind
the phenomenon of the rainbow were important steps in the
development of optical instruments - though an explanation of the
colors of the rainbow had to wait for
Newton.Other Muslim
scientists also made important contributions to this subject,
including the famous al-Biruni. One
of the scientists connected with the Maragha observatory
Kamal al-Din al-Farisi, wrote an important commentary on Ibn al-
Haytham's work on optics, in which he gives the results of a
fascinating series of experiments with the camera
obscura.Men like
these would have been fascinated at the idea of photographing the
earth from outer space, and with the theories that make such
achievement possible - theories that are in some cases based on
observations they themselves originated. It is thus peculiarly
fitting that an Arab Muslim should take part in a scientific mission
in the heavens that so interested and perplexed the scientists of
the Middle Ages to whom we all owe so much.
