Abstract:
The greatest speed C, denoting the velocity of light in vacuum, is hinted at in two glorious Quranic verses relating this fundamental universal contant C with the motion of the Earth-Moon system. A new relativistic interpretation of this Quranic relation gives C=299792.5 km/s in an extremely marvellous agreement with the accepted international value. This astonishing result emphasises the unity of the physical world, the validity of the special theory of relativity and the authenticity of the Glorious Quran for unbelievers.

Introduction:
The velocity of light C in vacuum belongs to a small group of the fundamental constants; however, it occupies an outstanding position even within this group. First of all, it is encountered in very different branches of physics. It will come as no exaggeration if one says the story of the determination of the velocity of light is a concise history of physics. And this story has not come to an end yet.
From the ancient Greeks down to the Middle ages, the speed of light was believed to be infinite. Aristotle believed that light propagates instantly!. In the eleventh century, an Arabic scientist Alhassan suggests that light travels at a finite speed. Galileo (1600) tried this speed but he Eailed saying that light is extraordinarily rapid(l). Roemer (1676) was the first measuring C using the eclipses of the Jovian satellite Io. He obtained an inaccurate value of C (215000 km/s) because the diameter of the earth's orbit was not known exactly.

Froome's value was considered to be the most accurate for a long period until 1983 when the modulated laser radiation interferometers were applied for the determination of C with great precision.

According to the US National Bureau of Standards(3): C = 299792.4574 + 0.0011 km/

and according to the British National Physical Laboratory C = 299792.4590 + 0.0008 km/s

A basically new definition of the metre wasaccepted in October 1983 at the 17th General Conference on Measures and Weights(3):

"The metre is the length of the path travelled by light in vacuum during a time interval of
1/299792458 of a second".

The Fixation of the value of C after the formation of the new definition of the meter does not mean yet the end of the story of this fundamental constant C. There are numerous other questions dealing with the realtion between this multifarious, enigmatic constant C and the theory of Relativity.

Recalling the second postulate of the special theory of relativity declared by Albert Einstein (1905):

"The velocity C of light in vacuum is the same in all inertial frames of reference in all directions and depend neither on the velocity of the source nor on the velocity of the observer".

Pauli(4) (1958) said that the data on binarystars allowed us to consider this postulate of the constancy of the velocity of light to be almost certainly correct.

According to Einstein's general theory of relativity (1917), the law of the constancy of the velocity C of light in vacuum can not claim any unlimited validity because the curvature of rays of light can only take place when the velocity of propagation of light varies with position!. Einstein(4) himself solved this contradiction between special and general relativity declaring in his paper written (1917):

"The results of the special relativity hold only so long as we are able to disregard the influence of gravitational fields on the phenomena".

This validity condition of the second postulate of special relativity is considered in the present work because the constancy of the velocity C needs absolute space (vacuum). To attain vacuum in the Einstein's sense of this word. it is not: sufficient just to eleminate from a volume of space every atom, molecule and particle, it is necessary also to get rid of the gravitational field. Therefore we have screened out the effect of the solar gravitational field on the geocentric orbital motion of the moon, which is considered here, according to the applied Quranic equation; as a standard measure reference for evaluating the greatest cosmic speed described in the Holy Quranic verses.

Lunar Orbital Motion described in Quran:
Fourteen centuries ago, the QURAN(5), i.e. .the Holy Book of Islamic Religion, was directed from GOD to all humanity through Prophet Mohammad, who lived in the Arabian Peninsula.

The ARAB people use the lunar system in their calculation of time. The Quran addressed them in the only language they could understand without upsetting their habits. GOD (in Arabic ALLAH: the ONE and Only GOD, the CREATOR) says in the Quran:

"GOD is the ONE who made the sun a shining glory and the moon a light and for her ordained mansions, so that you might know the number of years and the reckoning" (10:5)

The lunar year is twelve months, the month is defined recently as the time of one revolution of the moon in its orbit around the earth. God hints at such orbit in the Quran:

"GOD is the ONE who created the night, the day, the sun, and the moon. Each one is travelling in an orbit with its own motion" (21:33).

Here an essential scientific fact is clearly stated, namely, the existence of the earth's, sun'so and moon's orbits; besides, a reference is made to the travelling of these celestial bodies in space with their own motion! A new concept had therefore been established in the Quran, hundreds of years before it was discovered by modern science(6-7)

Today the concept of the lunar year is widely spread and, as we know, the moon is our nearest neighbour in space, and a companion to our planet. It is often said that the earth and moon form a twin-planet. As the moon orbits around the earth, the change in the relative positions of the moon, earth and sun cause the moon to show its phases(8-9). The time between consecutive new moons is 29.53 days and is called the synodic month. During this time, however, the earth, and consequently the moon's orbit, have travelled some way around the sun, so the position of the moon against the background of stars is different. 'l;he time for the moon to return to the same position in the sky as viewed from earth is called the sidereal month (27.32 days) which represents the actual real net time of one revolution in the moon's orbit. This orbit is almost circular having an average radius r=384264 km.

Fig. 1 describes the moon's motion during a lunar month. Position A1 shows a new moon. Position B (about 2 weeks later than A1) illustrates the following full moon. Position A2 the moon has orbited the earth once (with respect to an apparently fixed star). Thus one sidereal period (27.32 days) has elapsed since position A1. The next new moon does not occur until position A3 where the moon has once again lined up with the sun. Thus one lunar synodic period (29.53 days) has elapsed since position A1.

Referring to the Quranic verse (10:5), we notice that it discriminates between the apparent synodic period for knowing the number of years and the real sidereal period for reckoning in scientific calculations. These two systems of measuring time are now given in the text books of Astronomy as indicated(l،) in table 2:

Table (2) Lunar month and terrestrial:day

The aim of this work is to determine the value of the greatest speed mentioned in the following relativistic Quranic verses. In these verses the sideral system should be used for both the lunar month and the terrestrial day as accurate measured periods (with respect to a distant apparently fixed star).

A New Relation in the Earth-Moon System:
The length of the moons' orbit L and the time t of one terrestrial day are correlated in a marvellous Quranic verse which describes a universal constant velocity of a certain cosmic affair as follows:

"GOD rules the cosmic affair from the heavens to the earth. Then this affair travels, to Him (i.e. through the whole universe) in one day, where the measure is one thousand years of your reckoning"(32:5)

the Quranic expression "of your reckoning" leaves no doubt as to our understanding of the year as the lunar year.

The verse begins with a reference to a certain "cosmic affair" which GOD creates and commands. This affair travels, permanently through the whole universe between the heavens and the Earth, so speedily that it crosses in ONE DAY a maximum distance in space equivalent to that which the moon passes during ONE THOUSAND LUNAR YEAR (i.e. during 12000 Sidereal months). The question which pause.; itself now is: what could this cosmic affair be? and what is its greatest velocity as expressed in this Quranic equation?.

To answer this question. The above Quranic verse has been understood** in terms of the following equation:

Distance crossed in vacuum by the universal cosmic affair in Osle sidereal day = length of 12000 revolutions of the moon around the earth.

.:. Ct = 12000 L .

where:

C is the velocity of the cosmic affair,

t is the time interval of one terrestrial sidereal day kefined as the time of one rotation of the earth. about its axis (relative to the stars). i.e. 23 hr, 56 min, 4.0906 sec = 86164.0906sec. )

L is the inertial distance which the moon covers in c-o revolution around the earth during one sidereal month i.e. L is the net length of the moon's orbit due to its own geocentric motion, without the interference of its spiral motion causec by the earth's revolution around the sun, i.e. _ is the lunar orbit length excluding the effec- of the solar gravitational field on the measured value.

Let V is the measured average orbital velocity of the moon deduced from the average radius R of the lunar geocentric orbit tas measured from an orbiting earth during its heliocentric motion)

.:. V=2 Pi *R/T....................................................(2)

substituting R = 384264 km and T = the siderial lunar month = 655.71986 hr

.:. V= (2X3.l4l6x384264 )/ 655.71986= 3682.07 km/hr

This value is given in all text books of astronomy and is accepted by NASA.

Let @ (Fig. 1) is the angle travelled by the earth moon system around the sun during one sidereal month of period 27.321661 days. We can calculate @ if we take into consideration the period (365.25636 days)of one heliocentric revolution (1 year) of the earth-moon system (Fig.l).

@ = 27.321661*360/365.25636= 26,92848

Thus @ is a characteristic constant of this system depending on uniformperiods of the month and the year.

Since the presence of the sun changes the geometrical properties of space and time , we must screen out its gravitational effect on the earth moon system according to the validity condition of the second postulate of special relativity, i.e. we must only consider the lunar geocentric motion without the heliocentric motion of the earth-moon system. Thus a velocity component VO=V cosO representing the net orbital velocity of the moon as shown in fig. (1) is introduced for calculating the net length L of the lunar orbit assuming a stationary earth.

.:. L = V cos @ T ......................... (3)

From equation (1) and (3) we get a new Quranic relation for the earth moon system:

Ct= 12000 V cos @T.......................................(4)

.:. C =12000 V cos @ T/t..................................(5)

substituting the sidereal values of the periods t and T from table (2), the NASA value of the measured orbital lunar velocity V = 3682.07 km/hr., and the calculated yalue of cos@ = cos 26.92848 = 0.89157, we get the velocity of the cosmic affair from eq. 5 as expressed in the Holy Quran.

C=12000 x 3682.07 x 0.89157 x 655.71986/86164.0906

.:. C = 299792.5 km/s

Referring to table (1) and the international value of C = 299792.458 km/s we find an extremely marvellous agreement. Thus we conclude that the cosmic affair, mentioned in the previous Quranic verse, is identical to LIGHT and all similar cosmic affairs travelling in vacuum with this maximum speed such as: all types of electro magnetic waves propagating between the heavens and the earth, the expected Gravitational waves spreading all over the universe, and all particles travelling in this cosmic greatest spead such as neutrinos.

It is very interesting to mention here the second Quranic verse that hints at the same relativistic Quranic equation in the earth-moon system: God Most High said:

"A day in the sight of thy Lord is like a thousand years of your reckoning" (22:47)

Thus both relativistic Quranic equations emphasise the obtained value of the greatest speed C and show that C is a permanent absolute constant. Actually there have been no scientific evidence that the value of C can change in time as yet. The constancy principle of special relativity is confirmed in the present work, which correlates also the speed of light C in vacuum with the celestial mechanics of the earth-moon system. Referring to equation (4) and substituting the velocity V from eq. (2), we find that the average radius of the moon.

R = [C/12000x2 Pi Cos@]*t......................................(6)

.:. "The average radius R of the lunar orbit is directly proportional to the period of one terrestrial sidereal day t.".

This new law deduced in the present work is important so far as it confirms the law of conservation of momentum in the Earth-Moon system. Moreover it implies the influence of the tidal effect and the gravitational change factor on the this system.

According to Dirac's cosmology, the universal gravitational constant G must be variable in time! i.e., it decreases with the age Tv of the universe according to Diracs equation:

G=[e^4/(m*e^2pC^3)]*1/T......................................(7)

where e the electronic charge, m and p are the masses of the the electron and proton respectively. Also according to Newtons law, the gravitational changes affect the radius R of the lunar orbit as indicated in the following equation(ll)

R=[h^2/m^2*M]*1/G................................................(8)

where h is the angular momentum of the moon about the earth, m and M are the masses of the moon and earth respectively. Since h,m and M remain unchanged with time, the radius R is inversely proportional to G. Correlating the last three equations, further studies in Cosmology may be prompted and facilitated.

Conclusion:
It is both important and interesting to find a new astronomical relationZ between the radius of the lunar orbit R and the time t of one terrestrial day deduced according to a new relativistic interpretation of a cosmic Quranic verse alluding to the greatest universal speed identical to the velocity C of light in vacuum.

It is so awesome to find unity in the complex of phenomena, that at first sight appear to have nothing in common. This work proves the universality and constancy of the fundamental constant C as the Greatest Cosmic Speed and reveals the Glorious Quran as a Holy Book worth studying with meticulous analysis since its author is the CREATOR of the Universe.

References:
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4) Theory of Relativity, Pauli, W. Pergmann Press, Oxford, 1958.

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6) The Glorious Quran and Modern Science, Mansour, Hassab, El-Naby, General Egyptian Book Organization BoulacCairo (1990).

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