Speed of Light in the Qur'an

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This article analyzes the apologetic claim that the Qur'an revealed the speed of light more than a thousand years before it was calculated by scientists.

Apologetic Claim

In an article published in Islami City,[1] Dr. Mansour Hassab-Elnaby claims verse 32:5 reveals that light in one day travels a distance equal to 12,000 lunar orbits, and upon calculating that distance we find the exact speed of light.







The average center-to-center distance from the Earth to the Moon is 384,403 km.[2][3]




Light travels at a constant speed of 299,792.458 km. per second

There are 86,400 seconds in one day (60x60x24)



This difference is over twenty times the distance between the Earth and the Sun. So clearly Dr. Hassab-Elnaby is in error. The two numbers do not match.







We are not even considering the orbit of the Earth around the Sun, which inevitably the Moon must also tread. Taking that into account Dr. Hassab-Elnabi's calculations are 36.6 times off.



Which part of this verse talks about light or its speed? This verse clearly has nothing to do with the speed of light. There is no mention of the moon, light or even distance in this verse. These assumptions by Dr. Hassab-Elnany are baseless. All that is being said in this verse is that a day for Allah is 1000 years long. This is allegorical. It is a poetic way of saying Allah is big, everything about him is big, and even his days are big. The same thing is repeated in the verse 22:47.





The length of the day is determined by how fast a planet revolves around its axis and it has nothing to do with the size of its inhabitants. The only possible "science" that can be gleaned from this verse is that the creator of the world lives in a very slow revolving planet.


The following verse is similar in content to verse 32:5, but here it says that the length of the day of Allah is 50,000 years.

Yusuf Ali: The angels and the spirit ascend unto him in a Day the measure whereof is (as) fifty thousand years:


Shakir: To Him ascend the angels and the Spirit in a day the measure of which is fifty thousand years.

If verse 32:5 is not allegorical, then we have a clear contradiction.

Is a day of Allah 1000 years or is it 50,000 years? Does it mean that it takes 50,000 years for angels and spirits to reach Allah? That is slow. How could the angel Gabriel take Muhammad to heaven and back in one night?


The speed of light is constant while the rotation of the Earth, due to a tidal torque between itself and the moon, is slowing down. Therefore, the days of the Earth are becoming longer. Angular momentum in the Earth-Moon system is conserved over time, so as Earth's rotation slows, the moon is boosted to a higher, and slower orbit. To orbit the Earth, the Moon has to travel a little more each time. How can one measure something that is constant with things that are variable?

Note that while both the length of an Earth day and lunar orbit distance are increasing, the ratio between them is not constant, but increases over time (contrary to what one Islamic website claims). This will be easily demonstrated using Kepler's 3rd law of planetary motion, and the fact that when two rotating bodies orbit one another, eventually the smaller body, and then the larger becomes tidally locked facing the other. The moon is already tidally locked with Earth so that the same side always faces us.

First, note that the radius of the lunar orbit is proportional to the distance covered in its orbit (just like the radius and circumference of a circle). So it can be said that the miracle requires that the ratio of Earth's day length to the lunar orbit radius is a constant over time. As per Kepler's 3rd law, there is a relationship between lunar orbital period and its radius (period^2 to radius^3 is a constant for a particular system). Thus as lunar orbital radius increases, the lunar orbital period increases proportionally more. Now if the length of Earth's day only increased in proportion to the increase in lunar orbit radius (as the miracle requires), then the lunar orbital period (which must grow proportionally faster than the radius) would outgrow the length of Earth's day more and more. The length of Earth's day couldn't increase enough to match the lunar orbit period such that the same side of Earth becomes tidally locked facing the moon. Thus the miracle has a requirement that contradicts what we know from physics.


There are nearly 4.5 million thousand years since the Moon is orbiting the Earth. Since each millennium the length of the day and orbit of the Moon change in an increasing ratio, in which one of these 4.5 million millennia the Moon traveled the same distance that the light travels in one day? The claim is wrong, but even if true, only one time out of 4.5 million times the two numbers could match. Then again even a broken watch is right twice every day.

The very notion of measuring the speed of light with the orbit of the Moon and the length of the day is a fallacy, that is because the yardstick is constantly changing. Such an error only reveals Dr. Hassab-Elnaby's lack of understanding of the basic principles of science.


The verse talks about the “affairs of Allah” being sent to Earth and then ascending to him in one day, the length of which is 1000 years. How has Dr. Hassab-Elnaby determined that "affairs" means light? The word used in Arabic is Amr. It means commandment, order, cause, and affair. This is an allusion to Allah’s religion and not to light. Amrullah means the Cause of Allah. A more accurate translation of this verse is, Allah sends his Cause to Earth, which will return to Him, i.e. it will be revoked in one day, the length of which is equal to 1000 years.

This is how Sheikh Ahmad Ahsai (1753–1826), founder of Shi'ite Sheikhieh school and his disciple Seyyed Kazim-i-Rashti (1792–1843) interpreted this verse. They claimed Islam no longer met the needs of the time and since it does not allow reform, it must be abrogated. However, since no one can abrogate the word of Allah but Allah himself, this task rests on the shoulders of the awaited Mahdi, the Promised One of the Shi'ites. Ahsai and Rashti said the end of Islam and the appearance of Mahdi has already been foretold in the Hadith and the Qur'an, and verse 32:5 gives the exact date.

According to these eminent scholars, Amrullah, the cause of Allah, was completed when the last intermediary between Allah and Mankind, Imam Hassan Askari died. Hassan Askari died in the lunar year 260 Hijra. Ahsai believed that since, according to the verse 32:5, one thousand years after the communication between Allah and mankind is interrupted the cause of Allah (Islam) would be revoked يَعْرُجُ إِلَيْهِ , Mahdi should manifest himself in the year 1260 Hijra (1844 AD)


From a religious perspective, one can see that Ahsai and Rashti have given a much more logical interpretation to the Qur'anic verse 32:5 than Dr. Hassab-Elnaby, with his claim that the verse reveals the speed of light.


Verse 32:5 is plagiarized from the Bible. Here are the original Biblical verses:


When the Psalmist says a thousand years for God is like a watch in the night, he means God is timeless. In those days people used sundials to measure the time. It only worked in sunshine. This is a poetic way to say time does not exist for God. This thousand years should be taken allegorically and not literally.

In the New Testament, this was clearly understood, and the message being conveyed is basically "Time is irrelevant for God".

Synodic and Siderial Months


Here is the verse Dr. Mansour Hassab-Elnaby is referring to:




This verse in no way discriminates between synodic and siderial months. Dr. Hassab-Elnaby is engaging in wishful thinking. The verse is also wrong when it claims the moon is a source of light.


Dr. Mansour Hassab-Elnaby is wrong again. Arabs count the synodic months that are 29.5 days and not the siderial months that are 27.3 days. The Qur'an is clear that these thousand years are "of what you count."


As has been shown in section 1, in 1000 lunar years the Moon orbits the Earth 12,967 times and not 12,000 times.


"Affairs traveling permanently through the whole universe at speed of light." When it comes to the Universe, the speed of light is not really that fast. It is a very slow way for Allah to run his affairs. These "cosmic affairs" traveling at the speed of light take one full day to reach the Earth. If a Muslim is in peril, they should forget about asking Allah for help. By the time he sends them his assistance, a day would have passed and that is often too late.

But Muslims should consider themselves lucky because, according to Dr. Hassab-Elnaby, Allah is only one light day away from the Earth. He lives just around the corner of our solar system. Think of other beings that may live hundreds or thousands of light years away, or those who live in galaxies that are millions or billions of light years away from Allah. How can Allah run his affairs in those galaxies when the communication is so slow? For all intent and purposes, as far as those far away galaxies are concerned God does not exist. Just as their light hardly reach us, and when it does it is after millions of years, the "affairs of Allah" can hardly reach them.







See Also

External Links


  1. 1.0 1.1 1.2 1.3 Dr. Mansour Hassab-Elnaby, "A New Astronomical Quranic Method for The Determination Of The Greatest Speed C", Islami City (archived), http://www.islamicity.com/Science/960703A.SHTML. 
  2. Calvin J. Hamilton, "The Moon", Views of the Solar System (archived), http://www.solarviews.com/eng/moon.htm. 
  3. 3.0 3.1 "Moon", Wikipedia, accessed December 19, 2010‎, http://en.wikipedia.org/wiki/Moon.