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The Earth: Flat or Spherical?
The Earth: Flat or Spherical?
Insights from Early Astronomy
A number of Muslims believes that the Qur'an talks about the earth as being
spherical [actually 'eggshaped'] and not flat
as supposedly everybody in Muhammad's life time believed. This is claimed
as another "scientific miracle" confirming the divine origin of the Qur'an.
Also that the moon does not shine by its own light but only reflects the
light is hailed as a "miraculous" insight. As it turns out, the answers
to these two questions are related.
If really all people in Muhammad's time had believed that the earth
was flat, this might indeed have been an astonishing factoid about the
Qur'an. Some Muslim speakers claim the sphericity has not been known until
Columbus sailed to America or Magellan sailed around the earth.
But it is not true. The spherical shape of the earth has been known since
about 900 years before the Qur'an. The property that the moon only reflects
light and doesn't shine by itself is only mentioned in passing since this
is a completely obvious fact for anybody who has watched the moon for a
while and sees the different phases. The only explanation that some parts
of moon don't shine most of the time, is that it only reflects and we
see only the part that is currently reached by the light of the sun.
In the following I am quoting from George O. Abell, Exploration of the
Universe, 4th edition, New York: Holt, Rinehart and Winston, pages 16
and 18.
... Pythagoras (who died ca. 497 B.C.) also believed that the earth,
moon, and other heavenly bodies were spherical. It is doubtful that
he had a sound reason for this belief, but it may have stemmed from the
realization that the moon shines only by reflected sunlight, and
that the moon's sphericity is indicated bv the curved shape of the
terminator, the demarcation line between its illuminated and dark
portions. If he had so reasoned that the moon is round, the sphericity
of the earth might have seemed to follow by analogy.
Another member of the Pythagorean school was Philolaus, who lived in
the following century. He may have been the first person to introduce
the concept that the earth is in motion. Apparently he held that it is
too base to occupy the center of the universe; he assigned a central
fire to that position. About the fire revolved the earth and other
planets...
Philolaus regarded the celestial sphere as motionless and its apparent
rotation as the result of the revolution and rotation of the earth. He
proposed that the sun, the moon, and the planets moved in their
respective spheres outside the orbit of the earth. It was an imaginative
concept based entirely on fancy and cannot be regarded as a forerunner
of the heliocentric theory. Nevertheless, the concept of a moving earth
had been introduced, although in a completely erroneous manner. It was
a bold idea that may have had some influence on later Greek thought.
Other Greek philosophers of the sixth to fourth centuries B.C. who are
said to have believed in a moving earth are Hicetas, Heracleides, and
Ecphantus...
So, far from being an unknown thought, this was an opinion held by a
considerable number of the Greek astronomers. But even if those were
speculations, Aristotle definitely has given a sound reasoning for
his theories, over 900 years before the Qur'an. And Aristotle is not
some obscure writer, but his works have been read in all centers of
higher learning in antiquity.
Another important topic discussed by Aristotle (384-322 B.C.) was the
shape of the earth. He cited two convincing arguments for the earth's
sphericity. First is the fact that during a lunar eclipse, as the moon
enters or emerges from the earth's shadow, the shape of the shadow
seen on the moon is always round. Only a spherical object always
produces a round shadow. If the earth were a disk, for example, there
would be some occasions when the sunlight would be striking the disk
edge on, and the shadow on the moon would be a line.
As a second argument, Aristotle explained that northbound travelers
observe the stars near the north celestial pole to be higher in the
sky than is observed at home, and different stars pass throulh the
zenith. Conversely, when one travels to more southern latitudes the
stars near the north celestial pole are seen lower in the sky, and
some stars that are never above the horizon at home are seen to rise
and move across the southern sky. The only possible explanation is
that the travelers' horizons had tipped to the north or south,
respectively, which indicates that they must have moved over a
curved surface of the earth....he also advanced a theoretical
argument that material falling to a center would take on a spherical
shape - an idea consistent with the gravitational theory of Newton
two millennia later.
Some might argue that even if some scholars knew that the earth
was a sphere the general public would still have believed that
the earth is flat and in particular the illiterate Muhammad would
not have had access to the learning of the scholars.
This is effectively rebutted by the existence of many ancient
coins which show the earth as globe. Muhammad was a merchant
and he might not have read the books of astronomers but he has
handled money as nearly everybody would have at many times
of his life and even more than today people would be interested
to know what was printed on the coins they are using. Through
these coins, the knowledge of the earth as globe has certainly
spread widely even to the common people of this time.
Qur'an and Science
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