At the age of 11, Imam Sadiq (AS) refuted the theory that the sun, moon and the planets rotated around the earth. He said that the sun, during its course round the earth, passes through the 12 constellations in one year and remains in each constellation for 30 days, so why does it then disappear from sight during the night. It should remain visible in each constellation for 30 days.
Ptolemy theory said that the sun has two movements. One of its movements is that it crosses the sign of the zodiac and goes round the earth in one year and the other movement is that it goes round the earth in one night and one day, as a result of which we see it rise in the east and set in the west.
Aristotle was a great thinker and philosopher. His books, Arganan and Physics, are the most precious literary treasures of mankind, but his theory that the earth is stationary and the sun and stars rotate around it, delayed the progress of the science of Astronomy and kept mankind in the darkness of ignorance for 1800 years.
The Imam remarked that those two movements were not compatible. When the sun had to pass through the sign of the zodiac in one year and stay in each constellation for 30 days how could it change its course and go round the earth in 24 hours?
He also announced that the earth rotated around its own axis. The great scholar Poincare who lived in the 20th century made fun of this theory. The rotation of the earth on its own axis could be proved by observation only. When astronauts landed on the surface of the moon, and directed their telescope towards the earth they observed that it was rotating slowly on its axis.
Some people might say that it was only by guesswork that Imam Jaâ€™far as-Sadiq (AS) said that the earth rotates on its own axis. Sometimes it happens that guesswork proves to be correct. But the question arises as to why no one else had guessed that for such a long time. This proves that he knew the laws of astrophysics which enabled him to make that discovery. If he had not known those laws, it would have been impossible for him to discover the rotation of the earth on its axis. This discovery could not have been accidental. One must know the cause to know its effect.
Tragically, for reasons stated above, the real credit of discovery of the movement of the earth round the sun was given to Copernicus who was an astronomer and mathematician, in the 15th Century. The theory of the earth rotation around its own axis went to Galileo who discovered the telescope.