Our Marvelous Roof the Sky
ONE of the most beautiful, ever-changing sights on earth is the sky. Its scope and grandeur simply stagger the imagination. The whole earth is enveloped with the skyâs endless majestic and colorful panorama. In the east a golden glow announces the dawn, while a crimson western sky bids the day adieu. There are moments when the sky may be adorned in a royal canopy of blue, or dismal gray or in resplendent white. White billowy, cotton-like clouds called âcumulusâ proclaim a fine spring day; gay featherlike clouds called âcirrusâ tell that summer is here, and a sporty fall mantle of clouds that appear like lambâs wool betokens the nearness of winter.
At night the skyâs beauty is even more magnificent when bedecked in starry splendor. The breathless glory of the night is enhanced when the aurora weaves a delicate tapestry of color high overhead. Each garment assumes an infinite variety of shapes, all dazzling masterpieces of beauty, all creations of perfect art. Little wonder that worshipers of Jehovah referred to the beauties of our marvelous âroofâ as âthe wonderful works of the One perfect in knowledge,â âthe wonderful works of God.â Job 37:14, 16.
Almost daily across the skyâs broad highway parade clouds of every size and description. Fluffy clouds, billowy clouds, fleecy clouds these are like glorious floats that silently glide by. There are white pillar clouds surrounded by straggling cloudlets, like children about their parents. There are wavy clouds and rolling clouds, the shapes and forms of which are worthy of the finest sculptor. There are huge clouds that look something like a mammoth cauliflower or an enormous white anvil.
The cumulonimbus, also called thunderheads, are massive. They are composed of billions of ice crystals. These formations can rise to 50,000 feet or more in height. A single formation can contain as much as 300,000 tons of water! An estimated 44,000 thunderstorms lash the earthâs surface every day, some 1,800 of them in action at any given moment! They are majestic in their awesomeness and from them can burst forth creationâs regal spectacle the rainbow. God speaks of it as âmy rainbow,â obviously one of His wonderful works. Gen. 9:11-16.
Often the sky foretells the weather. In the western hemisphere when scattered cumulus clouds dot the sky, when the barometer remains steady or rises, and when the wind blows gently, fair weather will probably continue. The long curling clouds known as âmaresâ tailsâ are generally a sign that foul weather, in the form of snow or heavy rain, will probably arrive within twenty-four hours. Also when dull-gray altostratus clouds darken the whole sky and the barometer drops, rain or snow will probably continue to fall. The Bible, at Matthew 16:2, 3, gives meaning to the fiery sky often seen at sunset: âWhen evening falls you are accustomed to say, âIt will be fair weather, for the sky is fire-redâ; and at morning, âIt will be wintry, rainy weather today, for the sky is fire-red, but gloomy-looking.ââ A red sunrise presages the opposite of a red sunset.
Why the Sky Is Blue
What is this wonderful work of God we call âthe blue skyâ? Blue is not the color of air, as was believed by some in the nineteenth century. Nor is the blue due to light emitted by the atmosphere itself, for then it would appear blue at night. Were the air completely transparent or nonexistent, the sky would necessarily be as black as space, a fact confirmed by astronauts who journeyed above the atmosphere. âUp there, itâs a black-and-white world. There is no color,â said American astronaut Jim Lovell. But more recently spacemen returning from the surface of the moon have described the lunar surface as a nondescript gray.
Since the sky is not black to us on earth, the cause, then, must lie in the behavior of sunlight when it comes in contact with the substance of the atmosphere.
The color of the sky results from the air within less than one hundred miles of the earth. This belt of atmosphere is made up primarily of five gases, namely, nitrogen, oxygen, argon, water vapor (a compound of hydrogen and oxygen) and carbon dioxide. Besides these gases there are others that are rare, but in smaller amounts, such as helium, xenon, neon; and a few poisonous gases, such as methane, ammonia, carbon monoxide, nitrous oxide. Up to the realm of the highest familiar clouds the sky also holds quantities of foreign matter, such as pollen, dust, bacteria, soot, spores, volcanic ash, salt particles from the seas and dust from outer space.
When the sunâs radiation, which consists of electromagnetic waves of many different wavelengths, passes through the atmosphere, the longer wavelengths plow through the atmosphere quite easily and reach our earth. We may feel them as heat. But the shorter ones are scattered in all directions by the air molecules and other particles in the atmosphere. The blue light is bounced about again and again as it comes earthward from the sun. In other words, the blue sky is a gauzy glowing fabric spun of blue light and air. It is, moreover, only about twelve miles high; beyond this the sky darkens to violet. Above twenty miles the sky becomes black and the stars emerge.
Why the Other Colors?
Though generally blue, the sky may be red, orange, green, in fact, almost any color. It all depends on how light waves enter the atmosphere and what they encounter on their way down.
In the lower atmosphere are concentrated clouds, dust and all kinds of particle material. These being larger than air molecules, they scatter the longer wavelengths of light. When the sun is near the horizon its rays enter the atmosphere at a slant, passing through much more of the particle-laden air. All wavelengths are scattered, and only the longest red rays penetrate at all. So we have the ruddy hues at dawn and sunset. The more dust or cloud particles in the air, the deeper is the color. The less dust, the bluer the sky, because the long light waves come right through to the earth without being deflected, while the short blue light waves we see are the ones being bounced about by air molecules in the sky. Therefore, on a clear, relatively dust-free day, our marvelous âroofâ is blue.
Other Sights in the Sky
When, after a few days of bright winter weather, high clouds, feathery and fragile, give to the sky a milky-white opalescence, bright rings, called halos, appear encircling the sun or moon. Halos of the moon are necessarily much fainter, and their colors are nearly imperceptible. In many parts of the world halos are visible, on the average, as often as once each four days. Even some of the brighter stars show coronas as thin, fleecy clouds glide slowly past. These halos may show several distinct concentric circles of color, each bluish on the inside, then passing through a yellowish white to a reddish brown on the outside. Sometimes they resemble circle rainbows in the sky. This phenomenon is caused by light waves being reflected off regularly shaped ice crystals floating high in the air.
The regular rainbow we see in the sky, which arouses awe and excitement, is formed by light playing on waterdrops as they fall. Each raindrop acts as a tiny prism, breaking down the sunâs white rays of mixed light into their component spectral colors. Occasionally droplets of mist can cause a rainbow, but generally it is the larger raindrops.
No two persons see the same rainbow. Each individual sees the rainbow from his particular point of view, because a rainbow is only light coming from a certain direction. Since the drops reflecting the light are falling, this means that we see a new rainbow formed by every new set of raindrops. What a magnificent gift from God the rainbow!
Sometimes a second rainbow may appear in the sky, lying outside the first and shining rather more faintly. Have you noticed, the colors in this rainbow are in the reverse order, with blue on the outside and red on the inside? This is because the light rays have undergone one more reflection on the internal surfaces of the raindrops and are reversed in much the same way as left becomes right and right becomes left in a mirror. But this extra reflection causes a reduction in intensity of the light, which is why the second rainbow is always dimmer.
The Aurora
Neither a rainbow nor a cloud formation, except perhaps a glorious sunset or sunrise, can compare with the aurora in the sky, that is, the northern or southern lights. No written description or photographs can convey the true magnificence of these ever-changing, luminous displays, often in vivid colors. Sometimes they are so bright that one can read by their light.
Generally the aurora flickers, suggesting a blazing fire just over the hill. Often the glow kindles into brilliance, assuming the shape of a huge arc, or it may take the form of bundles of rays like those of sunlight shining through holes in a cloud. These shafts of light may be pale white, emerald green, violet or rose red. At times the aurora may appear to hang in folds like a huge curtain or drapery of a stage. It may shimmer like the folds of a great screen hanging from the sky that is stirred by a silent wind. Or it may burst into feverish activity. Yellow becomes tinged with red and green as rays leap upward, subside, then dart ahead again.
There is nothing with which one can compare the delicate beauty and coloring of the aurora caused by clouds of electrically charged particles coming from the sun and entering the earthâs magnetic field. These particles collide with molecules of air, causing them to vibrate and give off the red, white, blue and green lights of their awesome displays. The aurora another of Godâs marvelous gifts to man.
The Lightning Miracle
An estimated 9,000,000 lightning bolts strike the ground daily. About half the time, what people see in the sky as a single lightning flash is actually composed of up to ten successive strokes streaking along the same path as the first. There may be as many as forty pulses in a second, which is about how long the lightningâs path stays open. The heat in the path rises so abruptly that the surrounding air breaks the sound barrier in moving away. The result is thunder. The sky at such a time is alive with fire and sound.
There are various kinds of lightning. Heat lightning occurs on the horizon and is considered to be the reflection of strokes too far away to be directly seen or heard. Sheet lightning takes place inside clouds, blanketing them with a widespread flickering light. Ribbon lightning occurs when a strong wind blows the conductive channel of a multiple stroke to one side. The successive strokes rage upward a few feet apart, appearing like ribbons of light.
But what good is accomplished by all this fire filling the sky? It is now known that lightning helps greatly to fertilize the soil. Eighty percent of the atmosphere or sky is nitrogen, an essential food for plants. About 22,000,000 tons of this nutriment float over each square mile of the earth. But as it exists in the atmosphere nitrogen is unusable by plants. Before plants can take life from it, it must undergo a series of chemical changes, very much as food in our digestive system must undergo changes. Lightning in the sky touches off the series of changes. Air particles are made white-hot by lightning, for it can heat a two- to ten-inch channel of air hotter than the sunâs surface. Under this intense heat, the nitrogen combines with the oxygen in the air to form nitrogen oxides that are soluble in water. The rain dissolves the oxides and carries them down to earth as dilute nitric acid. Reaching the earth, the nitric acid reacts with the minerals of the earth, there to become nitrates on which plants can feed. Since plants can feed and live, man and animals can feed on plants and live!
What a marvelous gift lightning is from God to man! It does more than light the sky. Meteorologists estimate that lightning bombards the earth at a rate of more than one hundred times a second, transforming the upper air into fertilizer for plants!
God has given us, not only a practical sky, but a marvelous âroofâ filled with awe-inspiring, ever-changing beauties and wonder, a sky that moves faithful men to praise Jehovah the Doer of all these wonderful things. Ps. 136:4.
Â
Did you find this article useful? For more useful tips, hints, points to ponder and keep in mind, do please browse for more information at our websites. http://www.marvelsofcreation.com and http://www.adsflick.com
Find More Sky Articles
