Our Precious Atmosphere
ON May 4, 1961, Malcolm Ross and Vic Prather were carried aloft to an altitude of 21.5 miles [34.6 km]. At the time, setting a new record did not mean much to Ross. What impressed him was the view as he carefully raised a blind and looked out of the gondola for the first time.
“The scene as we topped 100,000 feet [30,500 m],” he recalls, “was utterly magnificent.” Ross was amazed by the colors that mark different layers of the atmosphere. First, there is the “bright and whitish-blue” of the troposphere, which extends about ten miles [16 km] above the earth. Then the deep blue stratosphere gets darker and darker until finally there is the blackness of space. “In silent awe we contemplated the supernal loveliness of the atmosphere,” Ross wrote in National Geographic.
Indeed, our lovely atmosphere is worth contemplating.
Our atmosphere is, in effect, an ocean of air that encircles the earth to a height of about 50 miles [80 km]. It weighs more than 5 quadrillion [5,000,000,000,000,000] tons and presses down on our heads with a force of 14.7 pounds per square inch [1.03 kg per sq cm or 101 kilopascals or 1,013 millibars] at sea level. Without that air pressure, we could not survive, since it prevents our body fluids from vaporizing. The upper atmosphere lacks sufficient air pressure to sustain human life. For that reason Ross and Prather had to wear pressurized space suits. “Without artificial pressure,” explained Ross, “our blood would boil, our blood vessels and organs rupture.”
Of course, we also need this ocean of air to keep breathing. Most of us, however, take it for granted because we cannot see it. A religious man of ancient times said appreciatively: “[God] gives to all persons life and breath and all things.”—Acts 17:24, 25.
Without our atmosphere, there would be no medium to hold aloft dust around which drops of water form. So there would be no rain. If it were not for our atmosphere, we would be scorched by the sun’s direct rays, and we would freeze at night. Thankfully, the atmosphere acts like a blanket, trapping some of the sun’s heat so that nights are not too cold.
Furthermore, the atmosphere provides protection from incoming meteors that would harm earth’s inhabitants. “Solid bodies from space,” explains Herbert Riehl in his book Introduction to the Atmosphere, “arrive at the outer limit of the atmosphere with an estimated total mass of several thousand tons per day.” However, most meteors disintegrate in the atmosphere before reaching the earth’s surface.
The atmosphere adds to our enjoyment of life. It gives us our lovely blue skies, puffy white clouds, refreshing rain, and gorgeous sunrises and sunsets. Moreover, without the atmosphere we could not hear the voices of those we love, nor could we listen to our favorite music. Why? Because sound waves need a substance through which to travel. Air is a perfect conveyer of sound, whereas no sound is heard in outer space.
A Marvelous Mixture
In ancient times men viewed the atmosphere as a single substance. Then, in the late 18th century, scientists discovered that it is composed mainly of the two complementary gases, nitrogen and oxygen. About 78 percent of the atmosphere is nitrogen and 21 percent oxygen; the remaining 1 percent is composed of such gases as argon, water vapor, carbon dioxide, neon, helium, krypton, hydrogen, xenon, and ozone.
Oxygen, of course, is the life-sustaining gas that our bodies absorb through breathing. The level of oxygen in our atmosphere is perfect for life on earth. If it were to drop significantly, we would become drowsy and eventually lose consciousness. If its concentrations were to increase too much, it is said that even damp twigs and the grass of the forest would ignite.
Nitrogen is the perfect diluent of oxygen, yet it plays more than a passive role in sustaining life. All organisms must have it to live. Plants obtain nitrogen from the atmosphere with the aid of lightning and a special class of bacteria. We, in turn, obtain nitrogen from the food we eat.
That our atmosphere maintains the correct ratio of oxygen and nitrogen is a marvel. Nitrogen is returned to the atmosphere, thanks to the valuable work of microorganisms. What about oxygen? Vast quantities are used up in fires and through the breathing of humans and animals. Yet the atmosphere maintains its level of 21 percent oxygen. How? Through photosynthesis—a chemical process in green leaves and algae—which releases over one billion tons of oxygen into the atmosphere every day.
Photosynthesis cannot take place without carbon dioxide—a trace gas that makes up only 0.03 percent of the atmosphere. With the aid of light, plants depend on carbon dioxide to grow and produce fruits, nuts, grains, and vegetables. Carbon dioxide also reflects heat back toward the earth to keep our planet warm. But if the level of carbon dioxide were to increase through the combustion of too much wood, coal, gas, and oil, the temperature on earth would eventually become so hot that life would cease. On the other hand, if carbon dioxide were to decrease too much, photosynthesis would cease, and we would starve.
Ozone is another trace gas upon which life on earth depends. Ozone in the upper part of the atmosphere called the stratosphere absorbs ultraviolet rays from the sun. Thus we on earth are shielded from these harmful ultraviolet rays.
Indeed, the more we get to know about the atmosphere, the more reason there is to marvel. Its composition of nitrogen, oxygen, and other trace gases is just right. The size of the earth is also just right to maintain the balance. If the earth were smaller and weighed less, its gravitation would be too weak, and much of our precious atmosphere would escape into space.
“On the other hand,” states the science textbook Environment of Life, “if the earth were slightly more massive than it is, the increased gravitational force would cause larger quantities of gases to be retained. . . . The delicate balance between the gases of the atmosphere would be upset.”
Sadly, however, the “delicate balance” is being upset by man’s modern life-style. How serious is the situation, and what hope is there that our precious atmosphere will be saved from ruin?
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When Sunsets Look Better
The atmosphere reflects the sun’s rays in such a way that it gives the sky a pleasing blue appearance. As the sun drops toward the horizon, its rays have to pass through much more atmosphere. This produces a variety of vivid colors that city dwellers may never see.
Sunsets over industrial cities are usually dull and lack colors other than shades of red. If the region is heavily polluted, observes the journal New Scientist, “the Sun appears as a dull red disc that may fade away even before it reaches the horizon.”
“In an exceptionally clear, unpolluted atmosphere,” the above journal explains, “the colours of sunset are especially vivid. The Sun is bright yellow and the adjacent sky is shades of orange and yellow. As the Sun disappears below the horizon, the colours change gradually from orange to blue. Low-lying clouds continue to reflect the light of the Sun, even after it has vanished.”
Just imagine the variety of beautiful sunsets that will be enjoyed in a pollution-free world!—Revelation 21:3-5.