The Living Planet

PLANET Earth hosts a prodigious amount and variety of living organisms​—perhaps many millions of species. Much of this life, which thrives in the soil, the air, and the water, is too small for the naked eye to see. For example, just one gram (0.04 ounces) of soil has been found to host 10,000 species of bacteria, not to mention the total number of microbes! Some species have been found up to two miles [3 km] underground!

The atmosphere too is packed with life​—and this does not mean just birds, bats, and insects. Depending on the time of year, it is also filled with pollen and other spores, as well as seeds and​—in certain areas—​thousands of different kinds of microbes. “This puts the diversity of microbes in the air on par with the diversity of microbes in the soil,” says Scientific American magazine.

Meanwhile, the oceans remain largely a mystery because in order to study the watery deep, scientists often have to use costly technology. Even coral reefs, which are relatively accessible and are well-surveyed, may host millions of yet unknown species.

What we do know, though, is that planet Earth hosts so much life that as a result, life actually changes chemical properties of the planet, particularly its biosphere​—the part of the earth where life exists. In the oceans, for example, the calcium carbonate in shells and coral helps to stabilize the chemistry of the water “much the same as an antacid works in the stomach,” says a report by the U.S. National Oceanic and Atmospheric Administration. Plants and phytoplankton​—single-celled algae found near the surface of lakes and oceans—​help to regulate carbon dioxide and oxygen levels in water and air. And in the soil, bacteria and fungi work as decomposers, providing inorganic nutrients for plants. Yes, earth has rightly been called the living planet.

Yet, terrestrial life could not exist were it not for some extremely fine tuning in a number of areas, some of which were not fully grasped until the 20th century. That fine-tuning includes the following:

1. Earth’s location in the Milky Way galaxy and the solar system, as well as the planet’s orbit, tilt, rotational speed, and moon

2. A magnetic field and atmosphere that serve as a dual shield

3. An abundance of water

4. Natural cycles that replenish and cleanse the biosphere

As you consider these topics in the articles that follow, ask yourself: ‘Are earth’s features a product of blind chance or of intelligent design? If the latter, what was the Creator’s purpose in forming the earth?’ The final article of this series will discuss that question.

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“WE CANNOT ALLOW A DIVINE FOOT IN THE DOOR”

Despite the evidence that the natural world seems too well designed to be a mindless accident, many scientists refuse to believe in a Creator. It is not that science somehow compels atheists to “accept a material explanation” of the world, says evolutionist Richard C. Lewontin. Rather, he says, it is their “prior commitment . . . to materialism,” their determination to create “a set of concepts that produce material explanations.” “That materialism,” he adds, speaking for scientists in general, “is absolute, for we cannot allow a Divine Foot in the door.”

Is such dogmatism wise, especially if the evidence overwhelmingly points to a Creator? What do you think?​—Romans 1:20.

Earth’s Perfect “Address”

OUR address often includes our country, city, and street. By way of comparison, let’s call the Milky Way galaxy earth’s “country,” the solar system​—that is, the sun and its planets—​earth’s “city,” and earth’s orbit within the solar system earth’s “street.” Thanks to advances in astronomy and physics, scientists have gained deep insights into the merits of our tiny spot in the universe.

To begin with, our “city,” our solar system, is in a part of the Milky Way that many scientists call the galactic habitable zone. This zone is about 28,000 light years from the center of the galaxy and contains just the right concentrations of the chemical elements needed to support life. Farther out, those elements are too scarce; farther in, the neighborhood is too dangerous because of the greater abundance of potentially lethal radiation and other factors. “We live in prime real estate,” says Scientific American magazine.

The Ideal “Street”

No less “prime” is earth’s “street,” or orbit within our solar system “city.” About 93 million miles from the sun, this orbit is in what scientists call the circumstellar habitable zone, where life neither freezes nor fries. Moreover, earth’s path is almost circular, keeping us roughly the same distance from the sun year-round.

The sun, meanwhile, is the perfect “powerhouse.” It is stable, it is the ideal size, and it emits just the right amount of energy. For good reason, it has been called “a very special star.”

The Perfect Neighbor

If you had to choose a “next-door neighbor” for the earth, you could not improve on the moon. Its diameter measures just over a quarter of the earth’s. Thus, when compared with other moons in our solar system, our moon is unusually large in relation to its host planet. This, however, is no coincidence.

For one thing, the moon is the principal cause of ocean tides, which play a vital role in the planet’s ecology. The moon also contributes to earth’s stable spin axis. Without its tailor-made moon, our planet would wobble like a spinning top, perhaps even tipping right over and turning on its side, as it were! The resulting climatic, tidal, and other changes would be catastrophic.

Earth’s Perfect Tilt and Spin

Earth’s tilt of 23.5 degrees causes the annual cycle of seasons, moderates temperatures, and enables a wide range of climate zones. “Our planet’s tilt axis seems to be ‘just right,’” says the book Rare Earth​—Why Complex Life Is Uncommon in the Universe.

Also just right is the length of day and night, a result of earth’s spin. If the rotation period were substantially longer, the side of the earth facing the sun would bake while the other froze. Conversely, if days were shorter, perhaps just a few hours long, earth’s rapid spin would cause relentless gale-force winds and other harmful effects.

Yes, everything about our planet​—from its “address” to its rate of spin to its lunar neighbor—​gives evidence of thoughtful design by a wise Creator.a Says physicist and evolutionist Paul Davies: “Even atheistic scientists will wax lyrical about the scale, the majesty, the harmony, the elegance, the sheer ingenuity of the universe.”

Could such ingenuity be a product of chance, or does it reflect purposeful design? Think about that question as you read the next short article, which discusses two amazing shields that protect life on earth from threats originating in space.

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ARE YOU GOING FASTER THAN A BULLET?

By the time you finish reading this box, you will have traveled thousands of miles​—and without any bumps! Consider the following.

The earth is 25,000 miles [40,000 km] in circumference and rotates once every 24 hours. Thus, points at or near the equator move at about 1,000 miles [1,600 km] an hour. (The poles, of course, just spin on the spot.)

The earth itself orbits the sun at 18.5 miles [30 km] a second, while the solar system as a whole travels around the hub of the Milky Way at an astonishing 155 miles [249 km] a second. Bullets, by comparison, travel at less than a mile a second.

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Milky Way: NASA/​JPL/​Caltech

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Earth: Based on NASA/​Visible Earth imagery

Earth’s Dynamic Shields

SPACE is a dangerous place filled with lethal radiation and meteoroids. Yet, our blue planet seems to fly through this galactic “shooting gallery” with relative impunity. Why? Because earth is protected by amazing armor​—a powerful magnetic field and a custom-made atmosphere.

Earth’s magnetic field originates deep inside the planet and stretches far into space, where it forms an invisible shield called the magnetosphere (shown at right). This shield protects us from the full force of cosmic radiation and from dangers emanating from the sun. The latter include the solar wind, which is a steady stream of energetic particles; solar flares, which release in minutes as much energy as billions of hydrogen bombs; and coronal mass ejections (CMEs), which blast billions of tons of matter from the sun’s corona into space. Both solar flares and CMEs trigger intense auroras (shown lower right), colorful displays of light visible in the upper atmosphere near earth’s magnetic poles.

Earth’s atmosphere provides additional protection. An outer layer of the atmosphere, the stratosphere, contains a form of oxygen called ozone, which absorbs up to 99 percent of incoming ultraviolet (UV) radiation. Thus, the ozone layer helps to protect many forms of life, including humans and plankton, from dangerous radiation. Interestingly, the amount of stratospheric ozone is not fixed but is directly proportional to the intensity of UV radiation, making the ozone layer a dynamic, efficient shield.

The atmosphere also protects us from a daily barrage of millions of meteoroids, ranging in size from tiny particles to boulders. Fortunately, by far the majority of these burn up in the atmosphere, becoming bright flashes of light called meteors.

Earth’s shields do not block radiation that is essential to life, such as heat and visible light. The atmosphere even helps to distribute the heat around the globe, and at night the atmosphere acts as a blanket, slowing the escape of heat.

Earth’s atmosphere and magnetic field truly are marvels of design that are still not fully understood. The same could be said of another terrestrial phenomenon​—earth’s abundance of water in its liquid form.

The Liquid of Life

WATER is an enigma. It is both simple and complex. Each molecule comprises just three atoms​—two of hydrogen and one of oxygen. Yet, scientists still do not fully understand how water molecules work. What we all know, though, is that water is essential to life, making up about 80 percent by weight of all living things. Consider just five attributes of this amazing substance.

1. Water can store a lot of heat without a substantial rise in temperature, thus helping to moderate climate.

2. Water expands when it freezes, causing ice to float and form an insulating layer. If, like other substances, water became more dense as it froze, the lakes, the rivers, and the seas would solidify from the bottom up, entombing everything in ice!

3. Water is highly transparent, enabling light-dependent organisms to survive at considerable depths.

4. Water molecules produce surface tension, creating an elastic “skin.” This tension enables insects to scamper about on a pond, causes water to form into droplets, and contributes to the capillary effect, which helps water to hydrate the tallest plants.

5. Water is the most efficient solvent known. It is able to carry in solution oxygen, carbon dioxide, salts, minerals, and many other vital substances.

Essential to Earth’s “Air Conditioner”

Oceans cover about 70 percent of the earth, giving them a major role in climate control. Indeed, oceans and atmosphere are practically one, constantly exchanging heat, water, gases, and momentum in the form of wind and waves. They also work together carrying solar heat away from the Tropics toward the poles, thus moderating global temperatures. In fact, for most organisms to survive, temperatures must stay within the range that allows water to remain a liquid. “It appears that Earth got it just right,” says the book Rare Earth​—Why Complex Life Is Uncommon in the Universe.

Of course, the earth is an effect, not a cause. But was the cause chance, or was the cause a wise and loving Creator? The Bible says the latter. (Acts 14:15-17) In the following article, we shall see how the Bible’s view is supported by additional evidence​—amazing cycles that keep our planet clean and healthy.

Cycles for Life

IF A city’s supply of fresh air and water were cut and its sewers blocked, disease and death would soon follow. Yet, our planet is a closed system​—clean air and water are not shipped in from outer space, nor is waste matter rocketed out! So how does earth’s biosphere remain healthy and habitable? The answer: natural cycles, such as the water, carbon, oxygen, and nitrogen cycles, here explained and shown simplified.

The water (hydrologic) cycle involves three stages. 1. Solar power lifts water into the atmosphere by evaporation. 2. Condensation of this purified water produces clouds. 3. Clouds, in turn, form rain, hail, sleet, or snow, which fall to the ground, closing the loop. How much water is thus recycled annually? According to estimates, enough to cover the entire surface of the planet to a depth of more than three feet [100 centimeters].

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The carbon and oxygen cycles involve two key processes​—photosynthesis and respiration.a Photosynthesis uses sunlight, carbon dioxide, and water to produce carbohydrates and oxygen. Respiration, which occurs in animals and humans, combines carbohydrates and oxygen to produce energy, carbon dioxide, and water. Thus, the output of one cycle is the input of the other, and it all happens cleanly, efficiently, and quietly.

Oxygen

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Carbon dioxide

The nitrogen cycle is essential to the production of amino acids, proteins, and other organic molecules. A. The cycle begins when lightning and bacteria convert atmospheric nitrogen into compounds that can be absorbed by plants. B. Plants, in turn, incorporate these compounds into organic molecules. Animals that eat plants thus also acquire nitrogen. C. When plants and animals die, another family of bacteria break down the nitrogen compounds, releasing nitrogen back into the soil and the atmosphere.

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Perfect Recycling!

Consider: Humans, with all their technology, create countless tons of unrecyclable toxic waste annually. Yet, the earth recycles all its wastes perfectly, using ingenious chemical engineering. “Chance processes alone almost certainly could never have duplicated” such environmental harmony, says religion and science writer M. A. Corey.

Giving credit where it is due, the Bible says: “How many your works are, O Jehovah! All of them in wisdom you have made.” (Psalm 104:24) That wisdom has been manifest in a special way toward humankind.

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