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The Design in Light
 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.
Ian Campbell, British Physicist 65
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
THE DIFFERENT WAVELENGTHS OF ELECTROMAGNETIC RADIATION
The stars and other sources of light in the universe do not all give
out the same kind of radiation. Instead, they radiate energy with
a broad range of wavelengths. Gamma rays, which have the shortest
wavelengths, are just 1/1025 the length of the longest radio waves.
Strangely enough, nearly all of the radiation emitted by the sun falls
into a single band that is also 1/1025 of the whole spectrum. The
reason, is that the only kinds of radiation that are necessary and
fit for life fall in this narrow band. |
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. Let's make a few comparisons.
For example, in 4 billion years (the estimated age of the earth) there
are about 1017 seconds. If you wanted to count from 1 to 1025
and did so at the rate of one number a second nonstop, day and night,
it would take you 100 million times longer than the age of the earth!
If we were to build a pile of 1025 playing cards, we would
end up with a stack stretching halfway across the observable universe.
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".66
Let us now examine this "staggering design of light" more closely.
From Ultraviolet to Infrared
We said that there was a range of 1:1025 in the sizes of the
longest and shortest electromagnetic wavelengths. We also said that the
amount of energy that was carried depended upon the wavelength: shorter
wavelengths pack more energy than longer ones. Another difference has
to do with how radiation at different wavelengths interacts with matter.
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."67
That the sun should radiate light so exactly right for life is indeed
an extraordinary example of design.
Nearly all of the sun's radiation is restricted to a narrow band
of wavelengths ranging from 0.3 to 1.50 microns. This band encompasses
near ultraviolet, visible, and infrared light.
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Is the rest of the light the sun radiates good for anything?
When we look at this part of the light we see that
a large part of solar radiation falling outside the range of visible light
is in the section of the spectrum called "near infrared". This begins
where visible light ends and again occupies a very small part of the total
spectrum-less than 1/1025.68
Is infrared light good for anything? Yes, but this time it's no use to
look around because you can't see it with the naked eye. However you can
easily feel it: the warmth you feel on your face when you look up on a
bright sunny summer or spring day is caused by infrared radiation coming
from the sun.
The sun's infrared radiation is what carries the thermal energy that
keeps Earth warm. It too is as essential for life as visible light is.
And the fascinating thing is that our sun was apparently created just
to serve for these two purposes, because these two kinds of light make
up the greatest part of sunlight.
And the third part of sunlight? Is that of any benefit?
You can bet on it. This is "near ultraviolet light"
and it makes up the smallest fraction of sunlight. Like all ultraviolet
light, it is highly energized and it can cause damage to living cells.
The sun's ultraviolet light however is the "least harmful" kind since
it is closest to visible light. Although overexposure to solar ultraviolet
light has been shown to cause cancer and cellular mutations, it has one
vital benefit: the ultraviolet light concentrated in such a miniscule
band 69 is needed for the
synthesis of vitamin D in humans and other vertebrates. (Vitamin D is
necessary for the formation and nourishment of bone: without it, bones
become soft or malformed, a disease called rickets that occurs in people
deprived of sunlight for great lengths of time.)
In other words, all the radiation emitted by the sun is essential to
life: none of it is wasted. The amazing thing is that all this radiation
is limited to a 1/1025 interval of the whole electromagnetic
spectrum yet it is sufficient to keep us warm, see, and allow all the
chemical reactions necessary for life to take place.
Even if all the other conditions necessary for life and mentioned elsewhere
in this book existed, if the light radiated by the sun fell into any other
part of the electromagnetic spectrum, there could be no life on Earth.
It is certainly impossible to explain the fulfillment of this condition
having a probability of 1 in 1025 with a logic of coincidence.
And if all this were not enough, light does something else: it keeps
us fed, too!
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.
But photosynthesis is important for another reason. The reaction has
two products: in addition to glucose, it also releases six molecules of
oxygen. What's happening here is that plants are continuously cleaning
up an atmosphere that is constantly being "polluted" by air-breathing
creatures-human beings and animals, whose energy is derived from combustion
in oxygen, a reaction that produces carbon dioxide. If plants didn't release
oxygen, the oxygen-breathers would eventually use up all the free oxygen
in the atmosphere and that would be the end of them. Instead, the oxygen
in the atmosphere is constantly being replenished by plants.
For hundreds of millions of years, plants have been busy doing something
no laboratory has ever been able to duplicate: Using sunlight, the
produce food. A crucial condition for this extraordinary transformation
however is that the light that the plants receive must be precisely
right for photosynthesis to take place. |
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.
The interesting thing is what a carefully-designed process photosynthesis
is. When we study it, we can't help but observe that there is a perfect
balance between plant photosynthesis and the energy consumption of oxygen-breathers.
Plants supply glucose and oxygen. Oxygen-breathers burn the glucose in
the oxygen in their cells to get energy and they release carbon dioxide
and water (in effect, they're reversing the photosynthesis reaction) that
the plants use to make more glucose and oxygen. And so it goes on, a continuous
cycle that is called the "carbon cycle" and it is powered by the energy
of the sun.
In order to see how perfectly-created this cycle truly is, let us focus
our attention on just one of its elements for the moment: the sunlight.
In the first part of this chapter we looked at sunlight and found that
its radiation components were specially tailored to allow life on Earth.
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 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.
A good analogy is that of a television set. In order for
the set to receive a given channel it must be tuned to that channel; tune
it differently and the reception will not occur. It is the same with photosynthesis,
the Sun functioning as the transmitter in the analogy and the chlorophyll
molecule as the receiving TV set. If the molecule and the Sun are not
tuned to each other-tuned in the sense of colour- photosynthesis will
not occur. As it turns out, the sun's color is just right.70
 
THE FITNESS OF SUNLIGHT AND CHLOROPHYLL
Plants are able to perform photosynthesis because the chlorophyll
molecules in their cells are sensitive to sunlight. But chlorophyll
is only able to use a very limited range of light wavelengths and
those are the wavelengths that the sun radiates the most. What is
even more interesting is that this interval corresponds to just
1/1025 of the whole electromagnetic spectrum.
In the two graphs above, the extraordinary fitness between sunlight
and chlorophyll can be seen. In the upper chart is the distribution
of the light emitted by the sun. In the lower one is the light under
which photosynthesis will work. The fact that these two curves are
almost identical is an indication of how perfectly designed visible
light is. <
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In the last chapter we drew attention to the error inherent in the idea
of the adaptability of life. Some evolutionists hold that "if conditions
had been different, life would have evolved to be perfectly in harmony
with them as well". Thinking superficially about photosynthesis and plants,
one could come to a similar conclusion: "If sunlight were different, plants
would have just evolved according to that." But this is in fact impossible.
Although he's an evolutionist himself, George Greenstein admits this:
One might think that a certain adaptation
has been at work here: the adaptation of plant life to the properties
of sunlight. After all, if the Sun were a different temperature could
not some other molecule, tuned to absorb light of a different colour,
take the place of chlorophyll? Remarkably enough the answer is no, for
within broad limits all molecules absorb light of similar colours. The
absorption of light is accomplished by the excitation of electrons in
molecules to higher energy states, and the same no matter what molecule
you are discussing. Furthermore, light is composed of photons, packets
of energy and photons of the wrong energy simply can not be absorbed…
As things stand in reality, there is a good fit between the physics of
stars and that of molecules. Failing this fit, however, life would have
been impossible.71
What Greenstein is saying briefly is this: No plant can only perform
photosynthesis except within a very narrow range of light wavelengths.
And that range corresponds exactly to the light given out by the sun.
The harmony between stellar and molecular physics that Greenstein refers
to is a harmony too extraordinary ever to be explained by chance. There
was only one chance in 1025 of the sun's providing just the
right kind of light necessary for us and that there should be molecules
in our world that are capable of using that light. This perfect harmony
is unquestionably proof of intentional, deliberate design.
In other words, there is a single Creator, the Ruler of starlight and
of the molecules of plants Who has created all these things in harmony
with one other, exactly as is revealed in the Qur'an:
He is Allah- the Creator, the Maker, the Giver
of Form. To Him belong the Most Beautiful Names. Everything in the heavens
and earth glorifies Him. He is the Almighty, the All Wise. (Surat al-Hashr:
24)
The Light of Your Eyes
We have seen how the light coming to us from the sun consists of just
three narrow bands of the electromagnetic spectrum:
1) Infrared light, whose wavelengths are longer than visible light and
which keeps Earth warm.
2) A small amount of ultraviolet light, whose wavelengths are shorter
than visible light and which is necessary for the synthesis of vitamin
D among other things.
3) Visible light, which makes vision possible and supports plant photosynthesis.
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.
To explain why this should be so, we first need to understand how vision
takes place. It begins with particles of light called "photons" passing
through the pupil of eye and falling onto the surface of the retina located
at the back of the eye. The retina contains cells that are light-sensitive.
They are so sensitive that each can recognize when even a single photon
strikes it. The photon's energy activates a complex molecule called "rhodopsine",
large quantities of which are contained in these cells. The rhodopsine
in turn activates other cells and those activate still others in turn.72
Eventually an electrical current is generated and this is carried to the
brain by the optic nerves.
The first requirement for this system to work is that the retina cell
must be able to recognize when a photon strikes it. For that to happen,
the photon must carry an exact amount of energy: if it is too much or
too less, it won't activate the formation of rhodopsine. Changing the
size of the eye makes no difference: the crucial thing is the harmony
between the size of the cell and the wavelengths of the photons coming
in.
The only rays of light that are suitable for biological vision have
wavelengths that fall within the range of what is called "visible
light". A large part of the energy that is emitted by the sun falls
in that range. |
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. Denton
tells us why:
UV, X-ray, and gamma rays are too energetic
and are highly destructive, while infrared and radio waves are too weak
to be detected because they impart so little energy interacting with matter...
And so it would appear that for several different reasons, the visual
region of the electromagnetic spectrum is the one region supremely fit
for biological vision and particularly for the high-resolution vertebrate
camera eye of a design and dimension very close to that of the human eye.73
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.
The Right Star, the Right Planet, and the Right
Distance
In "The Blue Planet" we compared our world with the other planets of
the solar system and found that the range of temperatures necessary for
life exists only on Earth. The biggest reason for this is that the earth
is just the right distance from the sun: the outer planets like Mars,
Jupiter, or Pluto are too cold while the inner planets Venus and Mercury
are too hot.
Those who refuse to admit that there is intentional design in the distance
between Earth and Sun suggest something like the following:
"The universe is full of stars, some of them much bigger
than the sun and some of them much smaller. These could very well have
planetary systems of their own. If a star is bigger than the sun, then
the ideal planet for life would be located at a much greater distance
than the earth is from the sun. For example, a planet in an orbit around
a red giant at the distance of Pluto could have a temperate climate like
our world has. Such a planet would be just as fit for life as our earth
is."
The claim is invalid in one very important respect for it ignores the
fact that stars of different masses radiate different types of energy.
The factors that determine the wavelengths of the energy that a star
radiates are its mass and its surface temperature (the latter of which
is directly related to mass). For example, the sun radiates near ultraviolet,
visible, and near infrared light because its surface temperature is around
6,000°C. If the sun's mass were a bit bigger, its surface temperature
would be higher; but in that case, the energy levels of the sun's radiation
would also be higher and the sun would be radiating much more destructive
ultraviolet rays than it does.
This tells us that any star that is to radiate light that will support
life absolutely must have a mass close to that of our sun. But if there
are to be life-supporting planets orbiting around such stars, those planets
must be located at distances not substantially different from that between
the earth and the sun.
In other words, no planet revolving around a red giant, a blue giant,
or any other star whose mass was substantially different from the sun's
could harbor life. The only source of energy capable of supporting life
is a star like our sun. The only planetary distance that is suitable for
life is the distance between the earth and the sun.
There is another way of expressing this truth: The sun and the earth
were each created to be just as they needed to be. And indeed, in the
Qur'an it is revealed that Allah created everything according to precise
calculation:
It is He Who splits the sky at dawn, and appoints
the night as a time of stillness and the sun and moon as a means of reckoning.
That is what the Almighty, the All-Knowing has ordained. (Surat al-Anam:
96)
The Harmony of Light and Atmosphere
Since the beginning of this chapter we have been talking about the radiation
given out by the sun and how it was specially designed to support life.
There is yet another crucially important factor that we have not yet touched
upon: In order for this radiation to reach the earth's surface, it has
to pass through the atmosphere.
 Our
sun has a surface temperature of about 6,000°C. If this temperature
were even slightly more or less, the resulting sunlight would be incapable
of supporting life. |
Sunlight certainly couldn't do us any good if the atmosphere didn't let
it through. But it does; in fact, our atmosphere is specially designed
to be transparent to this beneficial radiation.
The really interesting thing is not so much that the atmosphere allows
beneficial sunlight to pass but that sunlight is the only radiation that
it allows through. The atmosphere lets in the visible and near infrared
light that is necessary for life but it blocks other forms of radiation
that are deadly. This makes the atmosphere an important filter against
the cosmic radiation that reaches the earth from the sun and from other
sources. Denton has this to say about the matter:
Atmospheric gases themselves absorb
electromagnetic radiation immediately on either side of the visible and
near infrared... The only region of the spectrum allowed to pass through
the atmosphere over the entire range of electromagnetic radiation from
radio to gamma rays is the exceedingly narrow band including the visible
and near infrared. Virtually no gamma, X, ultraviolet, far infrared, and
microwave radiation reaches the surface of the earth.74
It is impossible to ignore the artfulness of this design. The sun sends
only 1/1025 of the whole range of electromagnetic radiation
that could be sent, that happens to be the range that is good only for
us, and that is the radiation that the atmosphere lets through! At this
point it's also worth pointing out that nearly all of the near ultraviolet
that the sun radiates gets trapped by the atmosphere's ozone layer.
 Although
it blocks all other forms of radiation, water allows visible light
to penetrate into its depth for many meters. Thanks to this, sea plants
are able to perform photosynthesis. If water did not have this property,
the ecological balance necessary for life on our planet could not
have come into being. |
Another point that makes this even more interesting is that, like air,
water also has an extremely particular sort of transparency: the only
radiation capable of spreading through water is the range of visible light.
Even near infrared radiation, which penetrates the atmosphere (and thus
provides heat) penetrates only a few millimeters into water. Because of
this, only a few millimeters of the surface of the world's oceans are
heated by radiation from the sun. That heat is conveyed in stages to lower
levels and as a result of this, below a particular depth, the temperature
of the seawater is quite similar all over the world. This of course creates
an environment quite suitable for life.
Another interesting point concerning water is that the different colors
of visible light are able to travel different distances in it. Below eighteen
meters, for example, red light cannot penetrate while yellow can reach
depths of up to a hundred meters. Blue and green on the other hand descend
to 240 meters. This is an extremely important design because the light
that is particularly crucial for photosynthesis is the blue and green
portion of the spectrum. Since water allows these colors to penetrate
more deeply than the others, photosynthesizing plants can live up to 240
meters beneath the surface.
These are all facts of the utmost importance. No matter what physical
law related to light we examine, we discover that everything has been
exactly arranged so that life can exist. Commenting on this situation,
Encyclopedia Britannica admits how extraordinary it all is:
Considering the importance of visible
sunlight for all aspects of terrestrial life, one can not help being awed
by the dramatically narrow window in the atmosphere absorption and in
the absorption spectrum of water. 75
Conclusion
Materialist philosophy and Darwinism, which takes materialism as its
source, both claim that human life appeared in the universe by chance
and that it is an "accident" with no purpose whatsoever. The knowledge
that is being gained through advances in science however is showing that,
in every detail of the universe, there is a design and a plan whose intention
is human life. It is such a design that, even such a component as light,
which we might never have thought about before, is so clearly "just right"
that one can't help but be amazed.
To try and explain such careful design as "accidental" is irrational.
The fact that all the sun's radiation is constricted to a narrow band
just 1/1025 of the total electromagnetic spectrum, the fact that the light
necessary for life falls precisely within that narrow band, the fact that
the atmosphere blocks all other wavelengths of radiation and admits just
these, the fact that water also blocks all other forms of deadly radiation
and permits the passage only of visible light: Can these really all be
coincidences? Such extraordinary fine-tuning as this can be explained
not by chance but only by conscious design. This in turn shows us that
the whole universe and all the details of that universe-including the
light of the sun that enables us to see and keeps us warm-have been specially
created and arranged for us to live.
The conclusion reached by science is a truth that has been taught to
mankind in the Qur'an for fourteen centuries. Science shows that sunlight
has been created for us, in other words, that it has been made to be "at
our service". In the Qur'an we are told that "The
sun and moon both run with precision." (Surat ar-Rahman: 5) Elsewhere
it is stated:
Allah 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
Allah's blessings, you could never count them. Man is indeed wrongdoing,
ungrateful. (Surah Ibrahim: 32-34)
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