Galaxies and planetary systems
In the previous topic entitled “The Birth of the Universe”, the Quranic account was presented. After describing the beginning state as a singularity, a verse was quoted which describes the early universe as hot, hazy and gaseous. Gravity would shape the gaseous material into “multiple cosmic systems”. What are these systems? According to the Quran they are planetary and galactic structures.
Planetary system (solar system)
A planetary system is made of a whole community of worlds. A typical solar system (typical means similar to ours) would consist of the following bodies:
This body is centrally placed and is by far the largest member around which all the other bodies rotate. Our sun (an average star) makes up more than 99 percent of the total mass of the solar system. This confers upon it the bulk of the gravitational influence and for this reason it is responsible for maintaining the orbits of its other members.
These are significantly large celestial bodies which follow elliptical pathways around its parent star. Planets do not generate their own light, but are visible due to reflected star light.
These revolve around their parent planets. Our moon is unique in the sense that it is about one fifth of the Earth’s size whereas all the other satellite members are much smaller compared to their parent planets.
Asteroids are chunks of rock and iron in orbit around the sun. In our solar system they are described as cosmic rubble since they are made of unused material that has remained after the formation of our solar system four and a half billion years ago. The Earth has been the site of many asteroid impacts in the distant past. Fortunately large asteroid impacts have become a rare occurrence.
Just like asteroids comets are left over debris from the time the solar system formed. Because they are so far from the sun, their bodies take the shape of frozen lumps of ice, gas and organic material. Large-period comets (the most common type), derive their name from their very large orbits which may take millions of years to complete. The less common short-period comets, like Haley’s Comet, which visits our cosmic neighbourhood every 86 years, possess a head and a tail.
Meteors and meteorites
These are mainly chipped-off fragments from asteroids which bombard the Earth on a daily basis. They rarely pose any threat since most are reduced to ashes by heat generated by friction on entering the atmosphere. The resulting fireworks in the sky are termed a meteor. However, when they are much larger, they may escape total incineration and crash into the earth as meteorites.
The Quran and the solar systems
Let’s look as to how the Quran describes the layout of the solar system. Once again I must emphasize that the amazing scientific truths expressed in the Quran should be traceable to the original documents of earlier revelations. Remember the message given to Muhammad in the form of the Quran is essentially the same as that of the earlier original Books. As stated in the article, The Birth of the Universe, verses not quoted will have a footnote that can be checked at the end of the article.
Since the sun is a star, the Quranic description of the sun applies to stars as well. The Quran describes stars as bodies that generate their own light (10-5)1. They move in orbits of their own (36-38)2. There are different sizes of stars and the large ones in particular exert powerful gravitational forces (15-16)3. Stars have a life cycle- the various phases they pass through are referred to in the following verses: Red-giant phase (75-94, 55-375 and 81-66), white dwarf (81-1)7, supernovae (86-1, 2, 38 and 53-499) and black holes (15-163). These verses are discussed under the article, “The life cycle of stars”.
In 37-6 a key Arabic word (kawakib) means the Earth; it is also a title applied to the planet Venus and hence may be applicable to planets in general. Since planets share certain features, a description of the Earth may also have a bearing on the other planets. Verse 79-3010 describes the Earth as oval-shaped while 7-54 states: “(God) makes the night cover the day each pursuing each other in rapid succession”. If darkness follows light in a repetitive cycle on a spherical body (and assuming illumination by the sun as we understand it) as suggested by these two verses, it follows logically that such a body must be rotating and therefore all the other planets. In 24-3511 the same Arabic word kawakib (translated as planets) appears which is compared to glittering pearls. Comparing planets to glittering pearls is appropriate since planets, like pearls, are more or less spherically- shaped and like pearls, shine as a result of reflected light borrowed from the sun. Planets also move in elliptical orbits according to 21-3312.
Comets in the Quran are referred to as “…..Heavenly bodies that recede, continue to run their courses, go into hiding before returning” (81-15). Thus comets pursue an orbital path and go “into hiding” before returning to their departure point. The phrase” go into hiding” is a hint at their very large orbits. They spend long periods of time away before returning after their “hibernation”. In another verses (114-1) the Arabic word khunnas which describes a comet in 81-15 above, is applied to a person who steps forward to whisper into the ear of another and steps back again. What is characteristic about this motion is that the head or face of the whisperer remains in the direction of the person being whispered to while his back continues to point in the opposite direction. Similarly, when a comet approaches the sun, some of the ice evaporates and the comet grows a tail which is attached to its head. Speeding towards the sun its head faces the sun while its tail (back) projects in the opposite direction. As it is flung around the sun and recedes from it, its face continues to point towards the sun and its tail (back) away from it, just like the whispering motion described.
Reference to asteroids is made in the following verse: “We could cause the Earth to swallow them (disbelievers), or cause fragments of a celestial body to fall down upon them” (34-9). This is a familiar theme in the Quran; it uses a natural phenomenon to convey a religious principle, the threat of divine retribution. Meteorites (including comets and asteroids) are hinted at in 22-65: “It is (His gravitational laws) that hold the celestial bodies (in their orbits) so that they may not fall upon the Earth other than with His leave”. The verse alludes to the possibility of space objects striking the Earth, a fact disclosed hundreds of years after the Quran appeared. My insertion (bracketed words) may be explained as follows. It is permissible in fact sensible to interpret where appropriate God as God’s laws. The Arabic word Rabb describes one of the key titles of God, the Law Giver. In the Quran God is at the centre of existence and He interacts with the natural world through His laws. The term Sunnah-Allah in the Quran signifies His Ways or His divine laws. This line of reasoning is supported by verse 31-2013 which states that the entire creation is subject to His laws. The other bracketed phrase (in their orbits) is derived from 21-3312 which points to the motion of celestial bodies in their individual orbits. My insertion of gravity is deduced from 77-2514 and 55-5 quoted in the next section. The latter two verses will; be discussed in the article dealing with gravity.
Such is the composition of the solar system: the planets, moons, asteroids, comets and meteorites revolving around a centrally placed sun: “Indeed, We have created multiple orbits above you” (23-17), and as stated before, they move in accordance with precise mathematical laws: “The sun and the moon (and all other celestial bodies) follow pathways (exactly) computed” (55-5).
Alien solar systems
Our solar system is not unique. So far, more than two thousand solar systems have been discovered. Their multiplicity is addressed in two verses: ”Do you not see how God has created multiple solar systems (consisting of) several layers one above the other, (and created them) in stages and has placed in every one of them a moon that reflects light and a sun that generates light” (71-15). The many Earth-like worlds is addressed in 65-13: ”God is He who created multiple cosmic systems and of the Earth a similar number”. These two verses will be discussed in the article extra-terrestrial existence.
Contemplate the following verse: ‘’Consider the planets, stars and groups of stars that set, rise and set (again). They move along with steady motion, drifting silently and smoothly, unperturbed through space, yet outstrip each other swiftly in speed” (79-1,2,3). The first part of the verse refers to the apparent rising and setting of astronomical bodies, an illusionary motion created by the rotation of the Earth. What follows is a reference to real motion of planets, stars and groups of stars. Groups of stars may be interpreted as galaxies as shown below. Note that the description of the motion of celestial bodies as silent and smooth is based on Einstein’s equivalence principle. For instance, we on Earth do not sense its motion although it is hurtling through space at a 100 000km per hour. This concept will be dealt with under a future article, celestial motion. Groups of stars are a major component of a galaxy. Although the constituent stars of a galaxy “cluster”, they are separated by enormous distances as pointed out in 55-7, meaning that such systems must stretch across vast regions of space like galaxies do: “He raised the celestial bodies to great heights and set up the balance”. The sun like other stars moves in an orbit of its own (36-38) quoted above. Since 79-1,2,3 above refers to aggregate of stars and since every star moves in its own orbit, we may infer that such collection of stars rotate around a centre which in essence is a galaxy. Note also from the same verse that stars have different and enormous velocities. The stars that are close to the centre of the galaxy where gravity is concentrated generally move faster than their distant counterparts. The importance of gravity in maintaining the structure of the cosmos (which must include galaxies) are mentioned in 77-2514, 55-7 (quoted above) and 13-215 which will be addressed under the subject of gravity. In 19-65 reference is made to the presence of material (like gas and dust) between stars and galaxies: “It is God that created the heavens and the Earth and all that is between them”. Heaven, a translation from the Arabic word sama includes all the celestial bodies. The above verses describe the key feature of a galaxy. Summarizing, the layout of the universe is a network of stars, galaxies and planetary systems, and includes gas, dust, dark matter etc. as indicated by the phrase “all that is between them” in 19-6516.