So many of our planet's forms of life are dependent on an environment In which liquid water Is stable. This means that the earth must not be too close or too far from the sun. Astronomers estimate that If the distance from the earth to the sun changed by as little as 2 percent, all life would be extinguished as water either froze or evaporated.
Another factor making life on earth possible Is an unusual characteristic of water when It freezes Into Ice. Water Is such a common substance that most of us do not stop to consider that the balance of life depends on Its simple physical properties.
Water Is one of the few substances that expands when frozen. Most substances when frozen become denser and sink when placed In a container of the same substance In liquid form. But this Isn't the case with Ice In water. Since water expands by one tenth Its volume when frozen, frozen water has the unusual characteristic of floating on top of liquid water.
When rivers and lakes freeze In the winter, they freeze at the surface, with the Ice forming an Insulating barrier that prevents the denser a Water's unique characteristics are crucial for life on earth. If our planet were only a little closer to or further from the sun, earth's water would be either evaporated away or frozen as ice.
water underneath from freezing and thereby preserving aquatic life during very cold weather. If Ice acted like almost all other compounds, It would sink, and rivers and lakes would freeze from the bottom up. All bodies of water would eventually become solid bodies of Ice, eliminating most life as we know It.
up to allow us to make scientific discoveries about the universe).
Yet the moon is only the first of Spaceship Earth's protector fleet. The two gas giants, Jupiter and Saturn with their strong gravitational pulls, also help shield the planet by functioning as giant vacuum cleaners, sweeping the solar system of dangerous comets and asteroids. Astronomers witnessed a stark example of such protection in 1994 when Jupiter took a hit as the Shoemaker-Levy 9 comet broke apart due to Jupiter's gravitational pull and smashed into its atmosphere.
Dr. Hugh Ross describes how these planets play a vital role in preserving life on earth: "Late in 1993, planetary scientists George Wetherell, of the Carnegie Institution of Washington, D.C., made an exciting discovery about our solar system. In observing computer simulations of our solar system, he found that without a Jupiter-sized planet positioned just where it is, Earth would be struck about a thousand times more frequently than it is already by comets and comet debris. In other words, without Jupiter, impacts such as the one that is thought to have wiped out the dinosaurs would be common.
"Here is how the protection system works. Jupiter is two and a half times more massive than all the other planets combined. Because of its huge mass, thus huge gravity, and its location between the earth and the cloud of comets surrounding the solar system, Jupiter either draws comets (by gravity) to collide with itself, as it did in July 1994, or, more commonly, it deflects comets (again by gravity) right out of the solar system. In Wetherell's words, if it were not for Jupiter, 'we wouldn't be around to study the origin of the solar system.'
"Neither would we be around if it were not for the very high regularity in the orbits of both Jupiter and Saturn. Also in July 1994, French astrophysicist Jacques Laskar determined that if the outer planets were less [orbitally] regular, then the inner planets' motions would be chaotic, and Earth would suffer orbital changes so extreme as to disrupt its climatic stability. In other words, Earth's climate would be unsuitable for life ... Thus even the characteristics of Jupiter and Saturn's orbits must fit within certain narrowly defined ranges for life on Earth to be possible..." (The Creator and the Cosmos, pp. 137-138).
As the book The Privileged Planet notes: "The existence of a well-placed moon, of circular planetary orbits... of the outlying gas giants to sweep the Solar System of sterilizing comets ... all these and more are profoundly important for the existence of complex life on our planet" (p. 256).
Our planet's plant and animal life doesn't simply exist; it is a source of great beauty and enjoyment to us.
Our Amazing Spaceship Earth 31
Our Amazing Spaceship Earth 31
Not only is Spaceship Earth just the right distance from the sun to have a temperate climate, but its solar system is in an excellent neighborhood of stars. It lies between two spiral arms of the Milky Way galaxy, far away from the dangerous galactic core or the spiral arms, and is in what astronomers call a "safe zone."
"Certainly, our type of galaxy optimizes habitability," explains Guillenno Gonzalez, "because it provides safe zones. And Earth happens to be located in a safe zone, which is why life has been able to flourish here...
"Places with active star formation are very dangerous, because that's where you have supernovae exploding at a fairly high rate. In our galaxy, those dangerous places are primarily in the spiral arms, where there are also hazardous giant molecular clouds. Fortunately, though, we happen to be situated safely between the [Milky Way's] Sagittarius and Perseus spiral arms" (quoted by Strobel, p. 169).
This clear zone is a good vantage point for viewing our own galaxy and the rest of the universe—once again demonstrating the way our exploratory spaceship is set up for cosmic discovery.
We can learn a great deal from examining the universe with telescopes or viewing life through a microscope, but even with the best scientific instruments we will never find the ultimate purpose of why we are traveling through space or what the meaning of our existence is.
All we can infer from the precise natural laws and the fine-tuned features of our planet is that the earth was optimally designed for life and for scientific understanding. Even a skeptical astrophysicist such as Stephen Hawking admits as much on the matter of life. "Wheeler agrees with Hawking and Carter," writes John Boslough, "that our own universe is uniquely fine-tuned to produce life, even if in just one small, lost comer" (Stephen Hawking's Universe, 1985, p. 125).
After surveying the astronomical and biological evidence, biochemist Michael Denton comes to this conclusion: "Four centuries after the scientific revolution science has provided no significant evidence that any alternative life is possible ... Scientific exploration has found no token of another life, no shred of evidence for something other than ourselves or of our type of life as it exists on earth.
"On the contrary, science has revealed a universe stamped in every corner, riven in every tiny detail, with an overwhelmingly and all-pervasive biocentric [life-centered] andanthropocentric [human-centered] design" (Nature'sDestiny: How the Laws of Biology Reveal Purpose in the Universe, 1998, p. 380).
So here we are, traveling on this spaceship called Earth, and everything we see around us is carefully designed and calibrated to sustain our existence. No wonder the Genesis creation account concludes with this summary of God's handiwork: "Then God saw everything that He had made, and indeed it was very good" (Genesis 1:31).
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