For a long time European philosophers and scientists believed that the earth stood still in the centre of the universe and every other body including the sun moved around it. In the West, this geocentric concept of the universe was prevalent right from the time of Ptolemy in the second century B.C. In 1512, Nicholas Copernicus put forward his Heliocentric Theory of
Planetary Motion, which asserted that the sun is motionless at the centre of the solar system with the planets revolving around it.
In 1609, the German scientist Yohannus Keppler published the ‘Astronomia Nova’. In this he
concluded that not only do the planets move in elliptical orbits around the sun, they also rotate upon their axes at irregular speeds. With this knowledge it became possible for European scientists to explain correctly many of the mechanisms of the solar system, including the sequence of night and day.
After these discoveries, it was thought that the Sun was stationary and did not rotate about its axis like the Earth. I remember having studied this fallacy from Geography books during my school days.
Consider the following Qur’anic verse:
“It is He Who created the Night and the Day, and the sun and the moon: All (the celestial bodies) swim along, each in its rounded course.”
[Al-Qur’an 21:33]
The Arabic word used in the above verse is yasbahoon . This word is derived from the word
sabaha. It carries with it the idea of motion that comes from any moving body. If you use this word for a person on the ground, it would not mean that he is rolling but would imply that he is walking or running. If you use this word for a person in water, it would not mean that he is floating but would imply that he is swimming.
Similarly, if you use the word yasbah for a celestial body such as the sun, it would not only mean that it is flying through space but would also mean that it is rotating as it goes through space. Most school textbooks have now incorporated the fact that the sun rotates about its axis. The rotation of the sun about its own axis can be proved with the help of an
equipment that projects the image of the sun on the top of a table, so that one can examine the image of the sun without being blinded. It is noticed that the sun has spots which complete a circular motion once every 25 days i.e. the sun takes approximately 25 days to rotate round its axis.
The sun travels through space at roughly 240 km per second, and takes about 200 million years to complete one revolution around the centre of our Milky Way Galaxy.
“It is not permitted to the Sun to catch up the Moon, nor can the Night outstrip the Day:
Each (just) swims along in (its own) orbit (according to Law).”
[Al-Qur’an 36:40]
This verse mentions an essential fact discovered only recently by modern astronomy, i.e. the
existence of the individual orbits of the Sun and the Moon, and their journey through space with their own motion.
The ‘fixed place’ towards which the sun travels, carrying with it the solar system, has been located preirsely by modern astronomy. It has been given a name, the Solar Apex. The solar system is indeed moving in space towards a point situated in the constellation of Hercules (alpha Lyrae) whose exact location is now firmly established.
The moon rotates around its axis in the same duration that it takes to revolve around the earth. It takes approximately 291⁄2 days to complete one
rotation.