What makes the earth so special in our solar system? Why is life here unique? OUR GOOD green earth sits rather near the far edge of a vast galaxy we call the Milky Way. And our sun is just a small to average star in the Milky Way.
Planet earth is one of nine known to revolve around the sun. Yet the earth is the only planet in our solar system blessed with organic life. Why don't the other planets support living organisms?
More has been learned about our sister planets in the last decade than in the previous two millennia. Our era has been termed "The Golden Age of Astronomy." Ultramodern space technology has permitted this generation to probe our solar system in a way that our forebears never dreamed of. Unmanned spacecraft have actually examined the surfaces of Venus, Mars, Jupiter and Saturn. Men from earth have actually walked on the moon.
Atmospheric physicist Garry Hunt of University College, London, finds that the study of the other planets inevitably turns his thoughts back to our earth. Indeed there is much to be learned about the earth itself from the study of our planetary system.
If only learned men knew the vital significance of the vast amounts of knowledge they are gathering from the heavens. The spiritual implications are enormous. Locked up in this new knowledge is the very reason for man's existence in the universe. But back, now, to the earth.
Man is of the earth, earthy. So let's start with some essential physical knowledge about the planets.
Lessons from Venus Since Venus is the most visible of all the planets to the human eye, we will begin our brief planetary excursion with the "evening star." Venus gets as close as 25 million miles from the earth. Nearer to the sun than the earth, Venus has been called the earth's twin because it is about the same in size and mass. The similarity ends there.
If somehow you could travel to Venus, three things would happen if you dared step outside your spacecraft. Simultaneously you would be poisoned, boiled and squashed. The atmosphere is positively hostile to human life, containing an enormous percentage of carbon dioxide and a fair portion of sulphuric acid. Russian space probes reveal that this planet's surface temperature is in excess of 900°F. It's hard to imagine anything quite that hot.
And what about walking on Venus? American astronauts were able to walk on the surface of the moon with the aid of some highly sophisticated space suits. But so dense is the Venusian atmosphere that walking on Venus would be like trying to take a stroll at the bottom of the deepest part of the ocean.
Contrast the earth's ideal temperature and atmospheric conditions. One could call the earth a peculiar phenomenon in the solar system. Unlike Venus it has far less carbon dioxide and 20 percent life supporting oxygen instead. Venus has no measurable oxygen and consequently no life forms. There are many elements in our atmosphere that fit the exact requirements for living organisms. Venus is acidic and acid is a powerful destroyer of proteins — the very stuff of which life, as we know it, is made. In contrast the mild basicity of the earth is ideally conducive for the existence of life.
What would we do without water? Fortunately the earth has been blessed with a superabundance of water covering about three quarters of its surface. There is almost no water vapor in the atmosphere of Venus. According to Lincoln Barnett, "In the universe as a whole, liquid water of any kind sweet or salt — is an exotic rarity" ("The Miracle of the Sea," Life magazine).
Scientists and astronomers have speculated as to why the Venusian atmosphere is so utterly unlike the earth's. One suggested cause is its lesser distance from the sun. Dr. Michael Hart of the Systems and Applied Sciences Corporation in Maryland made this astute observation. "Were our planet five percent closer to the sun, it would be a pressure cooker like Venus" (The Christian Science Monitor).
But we are neither the victims of an overheated pressure cooker like that of Venus or cold waste like Mars. The earth's orbit is in just the right relationship for the sustenance of physical life.
Venus is too hot; the earth is just right; Mars is too cold.
The Red Planet Mars comes within 35 million miles of the earth, but it is farther away from the sun than we are. Its atmosphere is far too thin to sustain life as we know it even if it contained the correct atmospheric elements, which it doesn't. Like Venus, Mars' atmosphere is made up of far too much carbon dioxide, distinctly forbidding any organic life. Again there is little or no oxygen to breathe. And water is a scarce commodity. The polar caps are composed mainly of dry ice or frozen carbon dioxide. Temperatures at the equator range from +82.4°F in the daytime to -48°F at night.
Life on Mars? The atmospheric conditions are far too hostile. Listen to the assessment of famous French astronomer, Gerard de Vaucouleurs: "Take a desert on earth, shift it to the polar regions, and lift it to stratospheric level — that's what it is like on Mars."
Only the earth satisfies all the complex conditions necessary for physical life in this solar system. The realism of the cosmos demands the conclusion that man's environment was designed and planned for him. If we are at all sensitive to the universe around us, we cannot ignore the fact that organic life is not the result of freak chance spawned from mindless matter. It is the unique creation of a greater intelligence than man's.
The Outer Planets Astronomers divide the nine known planets in our solar system into the inner planets and the outer planets. The earth, Venus, Mars and Mercury constitute the four major planetary bodies closest to our sun — hence the name, the inner planets. (Mercury, though nearest to the sun of all the planets, is omitted from consideration here as an abode for life since its atmosphere is virtually nonexistent.)
There is a giant gap in our solar system between Mars and what are known as the outer planets. The nearest outer planet beyond Mars is Jupiter — a gargantuan space body about 10 times the diameter of the earth. From Jupiter on outward, the gaps get ever wider (see accompanying planetary table). Undiscovered until 1930, Pluto is so small it can hardly be seen in its distant orbit.
Astronauts or cosmonauts would have great difficulty landing on Jupiter since its visible surface is composed entirely of gas. There is no evidence that this giant among planets has any solid surface at all. Interestingly enough Saturn, Uranus and Neptune also have gaseous surfaces and there is serious doubt as to whether these three planets have any solid surface whatsoever. Life as we know it on these outer planetary bodies is beyond the realm of possibility.
Planet number nine is Pluto, even though at the moment and for a number of decades its orbit carries it closer to the sun than Neptune. Nearly the size of our moon, Pluto is so very cold as to negate any possibility of life. There are those who even question its status as a full planet. One noted astronomer dubbed it a "cosmical lightweight."
Astronomers have good reason to believe that a 10th planet exists among the outer planetary bodies. The search continues unabated.
And Now — Back to Earth It is in the human heart to search out the mysteries of the heavens. The wisest man of the ancient world once observed: "It is the glory of God to conceal a thing: but the honour of kings is to search out a matter. The heaven for height, and the earth for depth, and the heart of kings is unsearchable." Many of man's newest astronomical discoveries bring as many questions as answers. Yet man goes on relentlessly pursuing knowledge about the universe. It would be odd if he did not do so.
Centuries later a learned man wrote about certain people "who are ever learning, but are never able to come to a knowledge of the truth." Man seeks the mystery of origins in outer space when the basic answers are right back here on earth.
Today man seeks evidence of intelligent life in outer space, hoping not only for answers to the basic mystery of life, but also for keys to resolving our complex behavioral muddles. Maybe intelligent life from outer space has already visited this planet and brought to earth the answers both to the basic mystery of life and our stubborn human problems. Maybe we've just never used our tools of recognition properly.
One noted author wrote "of the earth visitor who paradoxically came of us, lived with us, and invited us to learn of him — something we have never yet done." You know who this writer was talking about. Jesus of Nazareth — the man from space who visited this earth about 2,000 years ago.
The God — life of another dimension (a spiritual one) — the traveler in outer space — was changed into a tiny spark of life. He then became a babe in his mother's arms. And in due time he grew up to become a man. His disciples wrote down the essence of his message for mankind. He called it the Good News. It's all written down for you in four small books termed the gospel according to Matthew, Mark, Luke and John. You possibly have never taken the trouble to seriously read their contents.
Thirty minutes a day would get you through those four books in less than two weeks. This is reading material well worth your time. Your television can't beat it.
Why is planet earth unique in our solar system? You should know by the time you finish reading the four gospel accounts. If not, you may need to read our attractively printed booklet entitled Why Were You Born? It will give you help in understanding what you've just read.