Our Unique Solar System—How It Got Here
MANY factors combine to make our part of the universe unique. Our solar system is located between two of the Milky Way’s spiral arms in a region that has relatively few stars. Nearly all the stars that we can see at night are so far from us that they remain mere points of light when viewed through the largest telescopes. Is that how it should be?
If our solar system were close to the center of the Milky Way, we would suffer the harmful effects of being among a dense concentration of stars. Earth’s orbit, for example, would likely be perturbed, and that would dramatically affect human life. As it is, the solar system appears to have just the right position in the galaxy to avoid this and other dangers, such as overheating when passing through gas clouds and being exposed to exploding stars and other sources of deadly radiation.
The sun is an ideal type of star for our needs. It is steady burning, long-lived, and neither too large nor too hot. The vast majority of stars in our galaxy are much smaller than our sun and provide neither the right kind of light nor the right amount of heat to sustain life on an earthlike planet. In addition, most stars are gravitationally bound to one or more other stars and revolve around one another. Our sun, by contrast, is independent. It is unlikely that our solar system would remain stable if we had to contend with the gravitational force of two or more suns.
Another factor that makes our solar system unique is the location of the giant outer planets that have almost circular orbits and pose no gravitational threat to the inner terrestrial planets.a Instead, the outer planets fulfill the protective function of absorbing and deflecting dangerous objects. “Asteroids and comets hit us but not excessively so, thanks to the presence of giant gas planets such as Jupiter beyond us,” explain scientists Peter D. Ward and Donald Brownlee in their book Rare Earth—Why Complex Life Is Uncommon in the Universe. Other solar systems with giant planets have been discovered. But most of these giants have orbits that would endanger a smaller earthlike planet.
The Role of the Moon
From ancient times, our moon has filled mankind with wonder. It has inspired poets and musicians. For instance, an ancient Hebrew poet describes the moon as being “firmly established for time indefinite, and as a faithful witness in the skies.”—Psalm 89:37.
One important way in which the moon affects life on earth is that its gravitational pull causes the ebb and flow of the tides. Tidal movements are thought to be fundamental to ocean currents, which, in turn, are vital for our weather patterns.
Another key purpose that our moon serves is that its gravitational force stabilizes earth’s axis with respect to earth’s plane of orbit around the sun. According to the scientific journal Nature, without the moon, the inclination of earth’s axis would wobble over long periods of time from “nearly 0 [degrees] to 85 [degrees].” Imagine if earth’s axis had no tilt! We would miss the delightful change of seasons and suffer from a shortage of rain. The earth’s tilt also prevents temperatures from becoming too extreme for us to survive. “We owe our present climate stability to an exceptional event: the presence of the Moon,” concludes astronomer Jacques Laskar. To fulfill its stabilizing role, our moon is large—relatively larger than the moons of the giant planets.
Yet another function of the earth’s natural satellite, as noted by the writer of the ancient Bible book of Genesis, is that the moon serves as a light by night.—Genesis 1:16.
Chance or Purpose?
How is one to explain the concurrence of multiple factors that make life on earth not only possible but also enjoyable? There appear to be only two alternatives. The first is that all these realities are the casual product of aimless chance. The second is that there is some intelligent purpose behind it.
Thousands of years ago, the Holy Scriptures stated that our universe was conceived and crafted by a Creator—Almighty God. If that is true, it means that the conditions that exist in our solar system are the product, not of chance, but of deliberate design. The Creator left us with a report, so to speak, of the steps he took to make life on earth possible. It might surprise you to know that even though this report is some 3,500 years old, the events in universal history described in it basically correspond to what scientists believe must have taken place. This report is contained in the Bible book of Genesis. Consider what it says.
The Genesis Account of Creation
“In the beginning God created the heavens and the earth.” (Genesis 1:1) The Bible’s opening words refer to the creation of our solar system, including our planet, as well as that of the stars in the billions of galaxies that make up our universe. According to the Bible, at one time the earth’s surface was “formless and waste.” There were no continents and no productive land. But the next words highlight what scientists say is the most important requirement for a life-sustaining planet—an abundance of water. God’s spirit was “moving to and fro over the surface of the waters.”—Genesis 1:2.
For surface water to remain liquid, a planet must be the right distance from its sun. “Mars is too cold, Venus is too hot, Earth is just right,” explains planetary scientist Andrew Ingersoll. Similarly, for the growth of vegetation, there must be sufficient light. And significantly, the Bible account reports that during an early creative period, God caused the sun’s light to penetrate dark clouds of water vapor that enveloped the ocean like a “swaddling band” around a baby.—Job 38:4, 9; Genesis 1:3-5.
In the next verses of Genesis, we read that the Creator produced what the Bible calls “an expanse.” (Genesis 1:6-8) This expanse is filled with gases making up earth’s atmosphere.
The Bible then explains that God changed the formless surface of the earth to make dry land. (Genesis 1:9, 10) He evidently caused earth’s crust to buckle and move. As a result, deep troughs may have been formed and continents pushed out of the ocean.—Psalm 104:6-8.
At some unspecified time in earth’s past, God created microscopic algas in the oceans. Using energy from the sun, these self-reproducing one-celled organisms began to convert carbon dioxide into food while releasing oxygen into the atmosphere. This marvelous process was hastened during a third creative period by the creation of vegetation that eventually covered the land. Thus the amount of oxygen in the atmosphere increased, which would make it possible for man and animals to sustain their lives by breathing.—Genesis 1:11, 12.
To make the land productive, the Creator caused a variety of microorganisms to live in the soil. (Jeremiah 51:15) These tiny creatures break down dead matter, recycling elements that plants use to grow. Special types of soil bacteria capture nitrogen from the air and make this vital element available to plants so that they can grow. Amazingly, an average handful of fertile soil may contain six billion microorganisms!
Genesis 1:14-19 describes the forming of the sun, moon, and stars in a fourth creative period. At first glance, this might seem to contradict the foregoing Scriptural explanation. Bear in mind, however, that Moses, the writer of Genesis, penned the creation account from the viewpoint of an earthly observer, had one been present. Apparently, the sun, moon, and stars became visible through earth’s atmosphere at that time.
The Genesis account assigns the appearance of sea creatures to a fifth creative period and that of terrestrial animals and of man to a sixth.—Genesis 1:20-31.
The Earth Was Made to Be Enjoyed
Does it not seem to you that life on earth, which came about as described in the Genesis account, was made to be enjoyed? Did you ever wake up on a sunny day, breathe in the fresh air, and feel glad to be alive? Perhaps you took a walk in a garden and enjoyed the beauty and scent of the flowers. Or you might have walked in an orchard and picked some delicious fruit. Such delights would be impossible were it not for the following: (1) earth’s abundant water, (2) the correct amount of heat and light from the sun, (3) our atmosphere, with its right mix of gases, and (4) fertile land.
All these features—absent on Mars, Venus, and our other planetary neighbors—are not the product of blind chance. They were fine-tuned to make life on earth pleasurable. As the next article will illustrate, the Bible also says that the Creator designed our beautiful planet to last forever.
a The four inner planets of our solar system—Mercury, Venus, Earth, and Mars—are called terrestrial because they have rocky surfaces. The giant outer planets—Jupiter, Saturn, Uranus, and Neptune—are composed mainly of gas.
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“If I as a geologist were called upon to explain briefly our modern ideas of the origin of the earth and the development of life on it to a simple, pastoral people, such as the tribes to whom the Book of Genesis was addressed, I could hardly do better than follow rather closely much of the language of the first chapter of Genesis.”—Geologist Wallace Pratt.
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JUST RIGHT FOR ASTRONOMY TOO
If the sun were located elsewhere in our galaxy, we would not have such a good view of the stars. “Our Solar System,” explains the book The Privileged Planet, “is located . . . far from dusty, light-polluted regions, permitting an excellent overall view of both nearby stars and the distant universe.”
The moon’s size and distance from the earth, moreover, are just right for the moon to cover the sun during a solar eclipse. These rare, awe-inspiring events permit astronomers to study the sun. Such studies have enabled them to unlock many secrets about how stars shine.
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The moon’s mass is large enough to stabilize the tilt of earth’s axis
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What makes life on earth possible? Its abundant water, correct amount of light and heat, atmosphere, and fertile land
Globe: Based on NASA Photo; wheat: Pictorial Archive (Near Eastern History) Est.