The Design in Light

The Sun emits light at such a finely designed frequency that it is at the ideal level for life. This astonishing design in life belongs to Almighty God, Who enfolds all things with His knowledge.

The sun is probably the one thing we see most often throughout our lives. Whenever we raise our sight to the sky during the day, we can see its dazzling light. If someone were to come up and ask "What good is the sun? we would probably reply without even a thought that the sun gives us light and heat. That answer, although a bit superficial, would be correct.

But does the sun just "happen" to radiate light and heat for us? Is it accidental and unplanned? Or is the sun specially designed for us? Could this great ball of fire in the sky be a gigantic "lamp" that was created so as to meet our exact needs?

Recent research indicates that the answer to the last two questions is "yes". "Yes" because in sunlight there is a design that inspires amazement.

The Right Wavelength

Both light and heat are different manifestations of electromagnetic radiation. In all its manifestations, electromagnetic radiation moves through space in waves similar to those created when a stone is thrown into a lake. And just as the ripples created by the stone may have different heights and the distances between them may vary, electromagnetic radiation also has different wavelengths. The analogy shouldn't be taken too far however because there are huge differences in the wavelengths of electromagnetic radiation. Some are several kilometers long while others are shorter than a billionth of a centimeter and the other wavelengths are to be found in a smooth, unbroken spectrum everywhere in between. To make things easier, scientists divide this spectrum up according to wavelength and they assign different names to different parts of it.

The radiation with the shortest wavelength (one-trillionth of a centimeter) for example is called "gamma rays": these rays pack tremendous amounts of energy. The longest wavelengths are called "radio waves": they can be several kilometers long but carry very little energy. (One result of this is that radio waves are quite harmless to us while exposure to gamma rays can be fatal.)

Light is a form of electromagnetic radiation that lies between these two extremes. The first thing to be noticed about the electromagnetic spectrum is how broad it is: the longest wavelength is 10²⁵ times the size of the shortest one. Written out in full, 10²⁵ looks like this: 10,000,000,000,000,000,000,000,000 A number that big is pretty meaningless by itself.

This is the vast spectrum over which the different wavelengths of the universe's electromagnetic energy extend. Now the curious thing about this is that the electromagnetic energy radiated by our sun is restricted to a very, very narrow section of this spectrum. 70% of the sun's radiation has wavelengths between 0.3 and 1.50 microns and within that narrow band there are three types of light: visible light, near-infrared light, and ultraviolet light.

Three kinds of light might seem quite enough but all three combined make up an almost insignificant section of the total spectrum. Remember our 10²⁵ playing cards extending halfway across the universe? Compared with the total, the width of the band of light radiated by the sun corresponds to just one of those cards!

Why should sunlight be limited to such a narrow range?

The answer to that question is crucial because the only radiation that is capable of supporting life on earth is the kind that has wavelengths falling within this narrow range.

In Energy and the Atmosphere, the British physicist Ian Campbell addresses this question and says "That the radiation from the sun (and from many sequence stars) should be concentrated into a minuscule band of the electromagnetic spectrum which provides precisely the radiation required to maintain life on earth is very remarkable." According to Campbell, this situation is "staggering".

Let us now examine this "staggering design of light" more closely.

From Ultraviolet to Infrared

The shortest forms of radiation are called (in increasing order of wavelength) "gamma rays", "X-rays", and "ultraviolet light". They have the ability to split atoms because they are so highly energized. All three can cause molecules-especially organic molecules-to break up. In effect, they tear matter apart at the atomic or molecular level.

Radiation with wavelengths longer than visible light begins at infrared and extends up to radio waves. Its impact upon matter is less serious because the energy it conveys is not as great.

The "impact upon matter" that we spoke of has to do with chemical reactions. A significant number of chemical reactions can take place only if energy is added to the reaction. The energy required to start a chemical reaction is called its "energy threshold". If the energy is less than this threshold, the reaction will never start and if it is more, it is of no good: in either case, the energy will have been wasted.

In the whole electromagnetic spectrum, there is just one little band that has the energy to cross this threshold exactly. Its wavelengths range between 0.70 microns and 0.40 microns and if you'd like to see it, you can: just raise your head and look around-it's called "visible light". This radiation causes chemical reactions to take place in your eyes and that is why you are able to see.

The radiation known as "visible light" makes up 41% of sunlight even though it occupies less than 1/10²⁵ of the whole electromagnetic spectrum. In his famous article "Life and Light", which appeared in Scientific American, the renowned physicist George Wald considered this matter and wrote "the radiation that is useful in prompting orderly chemical reactions comprises the great bulk of that of our sun." That the sun should radiate light so exactly right for life is indeed an extraordinary example of design.

Photosynthesis and Light

Photosynthesis is a chemical process whose name almost everyone who's ever gone to school will be familiar with. Most people however fail to realize how vitally important this process is for life on Earth or what a mystery its workings are.

First let's brush off our high-school chemistry and take a look at the formula for the photosynthesis reaction:

6H₂O + 6CO₂ + Sunlight = C₆H₁₂O6 + 6O₂

Glucose

Translated into words this means: Water and carbon dioxide and sunlight produces glucose and oxygen.

To be more exact what is happening in this chemical reaction is that six molecules of water (H₂O) combine with six molecules of carbon dioxide (CO₂) in a reaction that is energized by sunlight. When the reaction is complete, the result is a single molecule of glucose ( C₆H₁₂O6), a simple sugar that is a fundamental element of nutrition-, and six molecules of gaseous oxygen (O₂). The source of all nutriments on our planet, glucose contains a great deal of energy.

Simple though this reaction may look, it is in fact incredibly complex. There is only one place where it occurs: in plants. The plants of this world produce the basic food for all living things. Every other living thing is ultimately nourished in one way or another by glucose. Herbivorous animals eat the plants themselves and carnivorous animals eat plants and/or other animals. Human beings are no exception: our energy is derived from the food we eat and comes from the same source. Every apple, potato, chocolate, or steak or anything else you eat is supplying you with energy that came from the sun.

If you pay close attention to the above formula you will see that in addition to glucose, photosynthesis also releases six oxygen molecules. Plants thus clean the atmosphere that is constantly "polluted" by human beings and animals.

Without photosynthesis, plant life could not exist; and without plant life, there would be no animal or human life. This marvelous chemical reaction, which has never been duplicated in any laboratory, is taking place deep in the grass you step on and in trees you may not even notice. It once occurred in the vegetables on your dinner plate. It is one of the fundamental processes of life.

Could sunlight also be deliberately tailored for photosynthesis as well? Or are plants flexible enough so that they can perform the reaction no matter which kind of light reaches them?

The answer to this question, of course, is that sunlight is specially designed for photosynthesis.

The American astronomer George Greenstein discusses this in The Symbiotic Universe:

Chlorophyll is the molecule that accomplishes photosynthesis... The mechanism of photosynthesis is initiated by the absorption of sunlight by a chlorophyll molecule. But in order for this to occur, the light must be of the right color. Light of the wrong color won't do the trick...."

The Light of Your Eyes

The existence of a range of "visible light" is as important for the support of biological vision as it is for photosynthesis. The reason is that it is impossible for a biological eye to see any band of the spectrum outside that of visible light and a very small section of near infrared.

Designing an organic eye that could see other ranges of the electromagnetic spectrum turns out to be impossible in a world dominated by carbon-based life. In Nature's Destiny, Michael Denton explains this subject in detail and confirms that an organic eye can only see within the range of visible light. While other models of eyes that could, in theory, be designed, none of them would be able to see different ranges of the spectrum.

Pausing to think about everything that has been said so far, we come to this conclusion: The sun radiates energy within a narrow band (a band so narrow that it corresponds to just 1/10²⁵ of the whole electromagnetic spectrum) that has been carefully chosen. So finely adjusted is this band that it keeps the world warm, supports the biological functions of complex life-forms, enables photosynthesis, and allows the creatures of this world to see.

These facts are among the signs of creation that show the flawlessness and perfection in God's creation. God calls our attention to the entities He has created in the Qur'an:

God is He Who created the heavens and the Earth and sends down water from the sky and by it brings forth fruits as provision for you. ...He has made the sun and moon subservient to you holding steady to their courses, and He has made the night and day subservient to you. He has given you everything you have asked Him for. If you tried to number God's blessings, you could never count them. Man is indeed wrongdoing, ungrateful. (Qur'an, 14:32-34)

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