Have you ever dreamed of traveling through space? The prospects sound exciting to most people.
Amazingly, we are already traveling through space—but without being aware of it! Our planet can rightly be compared to a giant spacecraft carrying more than 6 billion people and billions more animals and plants. American scientist Buckminster Fuller coined the fitting term "Spaceship Earth" to describe our planet.
We are truly hurtling through space on this giant spacecraft called Earth—at the incredible speed of 66,600 miles per hour! This is far faster than man's speediest aircraft. At the same time, this space vehicle is spinning at 1,000 miles per hour at the equator. Every year we complete an entire circuit around the sun—a journey of more than half a billion miles!
Yet perhaps the most amazing aspect of our voyage is that we don't feel the trip at all. Certainly as we travel in a car at 50 miles per hour, we can sense the velocity and see the scenery go by. But the paradox is, once we get out of the car and sit down, everything on the ground seems at rest—yet we are still traveling at an incredible speed through space.
If we finish our life's journey with an average life span, we will have traveled around the sun some 76 times, and completed a trip of more than 38 billion miles— the equivalent of traveling several times to Pluto and back! All of this happens without us ever feeling the velocity or being aware of the trip itself.
This is just one of the incredible features of our remarkable spaceship.
Our privileged planet
In the last 30 years scientific discoveries have undermined the idea, once popular among some scientists and scholars, that we live on an unexceptional planet. That idea was summarized in the view of astronomer Carl Sagan, who spoke of "the delusion that we have some privileged position in the Universe" (Pale Blue Dot, 1994, p. 7, emphasis added).
We have come quite far from the similar notion posed by philosopher Bertrand Russell that humanity is merely, as he put it, "a curious accident in a backwater" (Religion and Science, 1961, p. 222). As scientific discoveries have accumulated, planet Earth has turned out to be not a backwater region, but instead a very privileged planet.
Astronomer Guillermo Gonzalez and philosopher Jay Richards recently wrote a book about the latest scientific findings that refute Sagan's assertion that we live on an insignificant planet. They aptly titled the book The Privileged Planet.
Instead of a universe once thought to be possibly teeming with life, more and more scientists are now realizing the rare qualities of our terrestrial globe. Cosmologists Peter Ward and Donald Brownlee wrote the 2003 book Rare Earth: Why Complex Life Is Uncommon in the Universe to explain some of our planet's unique features and how difficult it would be to duplicate these conditions on some other planet.
Similarly, the influential science textbook Earth begins its introduction with a section titled "the uniqueness of the planet Earth" (Frank Press and Raymond Siever, 1986, p. 3). So many factors have to be just right to duplicate the feats of our amazing Spaceship Earth that hope is slowly fading of ever finding intelligent life on other planets.
"From the seventeenth to the twentieth century," explain Drs. Gonzalez and Richards, "many expected to find intelligent, even superior life on the Moon, Mars, and other planets in the Solar System . . . Now, at the beginning of the twenty-first century, despite PR blitzes from Martian-life enthusiasts, the search has moved from the planets to a few obscure outlying moons. At the same time, the aspirations have been substantially downgraded" (The Privileged Planet, 2004, p. 253).
What are some of the remarkable features of our Spaceship Earth? Let's explore some of these characteristics so we can appreciate how carefully crafted it is. We can then ask, Could all these precise conditions be only a lucky accident? Hand-in-hand is another crucial question: What is the ultimate purpose of our life's journey through space?
A marvelous "window" to see out into the universe
As every spaceship has a porthole to view the outside, so our atmosphere acts in the same way.
In fact, we have a much better window than an ordinary spacecraft. Our "window" on this Spaceship Earth is not limited to a certain viewing area, but actually covers the entire planet. It is like having a porous crystal 430 miles thick that allows everyone aboard to have a full view of everything outside our planet and yet still blocks out the airless outer space.
Some planets are covered in thick clouds that make it impossible to see out. But our atmosphere enables us to view and discover the universe around us. Our earth is thus an exploration vessel.
The transparent canopy covering the planet also houses a renewable supply of oxygen for human beings and animal life, and carbon dioxide and nitrogen for plants. It also provides the proper air pressure for living things, and the outer edge of this translucent shell is composed of an ozone layer that protects life from harmful ultraviolet rays.
Strange as it may sound, this canopy even comes equipped with a protective force field! It sounds like something out of the TV series Star Trek, but it's true. We have a magnetic field generated by the spinning iron core at the center of our planet that deflects damaging cosmic rays and deadly solar winds. Without these features, life here would not be possible.
Last but not least, this marvelous canopy contains an automatically adjusting "curtain" to shade the terrestrial orb from too much light hitting its surface. This delicate shroud is formed by clouds, which act as moving shades that cover some 60 percent of the earth's surface at any given time.
What's in the cockpit?
What if we enter the cockpit of Spaceship Earth? What do we find?
Incredibly, no pilot is aboard, but instead we find an "autopilot" system governed by carefully adjusted physical laws. Although no one is seen physically aboard our spaceship to manage the system, our planet faithfully obeys the programmed, finely tuned commands of the myriad of physical laws and completes its yearlong journey around the sun, dutifully returning to its starting point only to begin yet another circuit.
What keeps the earth in its orbit? It is mainly the gravitational force of the sun that keeps the planet on its circular path. Truly, as the Bible says about our invisible and omnipotent God, "He hangs the earth on nothing" (Job 26:7). That "nothing" is outer space, and the earth is able to "hang" suspended on nothing through the unseen force of gravity.
In this cockpit, although not seen, are the equivalent of hundreds of elaborate dials, each regulating an aspect of our planet's features. Each dial has been carefully calibrated to permit life to flourish on the planet. You can't see the great Engineer who set up the system, but you can measure the precision of each setting—and every one is just right!
Professor Robin Collins draws this comparison concerning the earth's precise settings: "I like to use the analogy of astronauts landing on Mars and finding an enclosed biosphere, sort of like the domed structure that was built in Arizona a few years ago. At the control panel they find that all the dials for its environment are set just right for life. The oxygen ratio is perfect; the temperature is seventy degrees; the humidity is fifty percent; there's a system for replenishing the air; there are systems for producing food, generating energy, and disposing of wastes.
"Each dial has a huge range of possible settings, and you can see if you were to adjust one or more of them just a little bit, the environment would go out of whack and life would be impossible" (quoted by Lee Strobel, The Case for a Creator, 2004, p. 130).
Everything— everything down to the tiniest details— is "adjusted" just right for us to live comfortably on this planet. We get a glimpse of the marvelous Designer who set up the whole system when the Bible speaks of "the LORD, who created the heavens, who is God, who formed the earth . . . who did not create it in vain, who formed it to be inhabited" (Isaiah 45:18).
Truly, our planet is not some lucky accident since the evidence shows it was carefully designed to be inhabited by mankind and all other forms of life.
The spaceship's engines
What drives this craft and propels it through space? There are "twin engines" aboard, one pushing the planet forward and the other keeping it spinning and fueling its interior heat.
The centripetal force caused by gravity keeps the globe in its orbit. When an object reaches a certain speed and is spun by centripetal forces, it stays in a stable circuit around the center. This is what the earth does when orbiting around the sun. And our planet's distance from the sun, though varying slightly, is perfect for life—not so close to the sun that we would all burn up, nor so far that we would freeze.
The earth travels through space at 66,600 miles an hour as it orbits the sun. That speed perfectly offsets the sun's gravitational pull and keeps the earth's orbit the proper distance from the sun. If the earth's speed were less, it would be gradually pulled toward the sun, eventually scorching and extinguishing life. Mercury, the planet closest to the sun, has a daytime temperature of about 600 degrees Fahrenheit (316 Celsius).
On the other hand, if the earth's speed were greater, it would in time move farther away from the sun to become a frozen wasteland like Pluto, with a temperature of about minus 300 degrees (minus 184 Celsius), also eliminating all life.
The second engine is deep inside the earth itself. There, the fuel is decaying radioactive elements that heat the planet and drive plate tectonics. Geologists Frank Press and Raymond Siever call this "a gigantic but delicately balanced heat engine fueled by radioactivity" (Earth, p. 4).
"Not only does plate tectonics help with the development of continents and mountains, which prevent a water world," adds astronomer Guillermo Gonzalez, "but it also drives the Earth's carbon dioxide–rock cycle. This is critical in regulating the environment through the balancing of greenhouse gases and keeping the temperature of the planet at a livable level . . .
"This radioactive decay also helps drive the convection of the liquid iron surrounding the Earth's core, which results in an amazing phenomenon: the creation of a dynamo that actually generates the planet's magnetic field" (quoted by Strobel, pp. 182-183).
Surely, as Proverbs 3:19 says, "The LORD by wisdom founded the earth, by understanding He established the heavens."
The passenger cabin
What about the passenger cabin of Spaceship Earth? How well designed is it? We find that our planet provides all the comforts a space traveler could desire—abundant and delicious food, plenty of water, gorgeous and entertaining scenery, a comfortable climate, challenging work and plenty of room to have a family.
Our planet is a veritable Noah's ark of animals and plants traveling on its timeless journey through space. It is a self-contained unit with renewable resources that can last, if properly taken care of, for potentially thousands of years into the future.
The atmosphere in the passenger cabin is finely tuned for life. No other planet in our solar system has anything remotely like it. High in the atmosphere, ozone blocks cancer-causing radiation emanating from the sun. The atmosphere also shields us from meteors, burning up the overwhelming majority long before they reach earth. Otherwise they would cause great damage and loss of life.
Our atmosphere contains a mixture of gases in perfect proportions to sustain life. Oxygen makes up 21 percent of our air. Without oxygen, all animate life—including all human life—would die in minutes. But too much oxygen is toxic and makes combustible materials more flammable. If the proportion of oxygen in the air increased to only 24 percent, destructive fires would frequently break out and be much harder to bring under control. Objects around us could literally burst into flame.
Nitrogen, making up 78 percent of earth's atmosphere, dilutes the oxygen and serves a vital function as a fertilizer for plants. Every day around our planet, millions of lightning bolts generated by thunderstorms combine some nitrogen with oxygen, creating compounds that are then washed to the earth by rain, where they can be utilized by plants.
Carbon dioxide makes up much of the rest of our atmosphere. Without it plant life would be impossible. Plants require carbon dioxide, which they take in while giving off oxygen. Animals and human beings are the opposite, breathing in oxygen and exhaling carbon dioxide. Plant life sustains human and animal life and vice versa in a magnificent, precise, self-sustaining cycle.
Another condition that makes Spaceship Earth hospitable for life is its size, which determines its gravity and in turn affects its atmosphere. If the earth were only a little larger, making its gravity slightly stronger, hydrogen, a light gas, would be unable to escape the earth's gravity and would collect in our atmosphere, making it inhospitable to life. Yet, if the earth were only slightly smaller, oxygen—necessary for life—would escape, and water would evaporate. Thus, if our planet were slightly larger or smaller, human life could not have existed here.
But that's not all. Even the thickness of the earth's crust plays a part in regulating our atmosphere. If earth's crust were much thicker, it would hoard oxygen below the surface as oxides. But a thinner crust would leave us susceptible to frequent earthquakes and devastating volcanoes that would permeate our atmosphere with volcanic ash.
How important is the precise balance in our atmosphere? Our neighboring planet Venus suffers from what is thought to be a runaway greenhouse effect in which heat is trapped and cannot escape. NASA planetary scientist John O'Keefe noted that our sterile, lifeless moon "is a friendly place compared to Venus, where, from skies forty kilometers high a rain of concentrated sulfuric acid falls toward a surface that is as hot as boiling lead" (God and the Astronomers, 1992, p. 117).
To keep the temperature comfortable for the passengers, our planet remains in orbit at just the right distance from the sun and is designed with an optimum tilt of 23.5 degrees. As Fred Meldau points out in Why We Believe in Creation Not in Evolution, "If the earth had been tilted as much as 45 degrees instead of what it is, temperate zones would have torrid zone heat in the summer and frigid zone cold in the winter. On the other hand, if the axis of the earth were vertical to the plane of its orbit, January and July would have the same climate and ice would accumulate until much of the continents would be ice-covered six months and flooded the other six months" (1972, pp. 27-28).
Astronomer Hugh Ross points out some of the other ways our planet is perfectly balanced for life: "As biochemists now concede, for life molecules to operate so that organisms can live requires an environment where liquid water is stable. This means that a planet cannot be too close to its star or too far away. In the case of planet Earth, a change in the distance from the sun as small as 2 percent would rid the planet of all life . . .
"The rotation period of a life-supporting planet cannot be changed by more than a few percent. If the planet takes too long to rotate, temperature differences between day and night will be too great. On the other hand, if the planet rotates too rapidly, wind velocities will rise to catastrophic levels. A quiet day on Jupiter (rotation period of ten hours), for example, generates thousand mph winds . . ." (The Creator and the Cosmos, 2001, pp. 135-136).
In contrast to Jupiter's 10-hour rotation, our neighboring planet Venus rotates once every 243 days. If earth's rotation took as long, plant life would be impossible because of the extended darkness and extremes of heat and cold from such long days and nights.
Psalm 104:24 says: "O LORD, how manifold are Your works! In wisdom You have made them all. The earth is full of your possessions."
A protector fleet of spaceships
Not only does our terrestrial vessel have a magnetic force field and renewable resources, but it also has a number of accompanying spacecraft to stabilize and protect it.
The first of these is our moon. It is a veritable workhorse. Not only does it shield our planet from taking some meteor strikes (just look at its surface through a telescope!), but it stabilizes earth's vital tilt. Just as a clock has counterbalancing weights, so the moon acts as a counterbalance to the earth, keeping the planet's tilt carefully adjusted to allow the four seasons of the year. This tilt permits the sun's rays to uniformly heat the globe, much like a rotisserie slowly roasts a chicken.
The moon, along with the sun, also regulates our tides. The earth's tides help circulate the water in the oceans and sweep away waste products from the coasts. "If the moon were half as far away, or twice its present diameter," adds Fred Meldau, "great tides would wreck most of our harbors . . . If the moon were smaller and farther away, it would not have sufficient pull on our tides to cleanse our harbors or adequately rejuvenate (with oxygen) the waters of our oceans" (Why We Believe in Creation Not in Evolution, p. 31).
Also remarkable is the relative size and placement of the moon with respect to the sun. The sun's diameter is 400 times that of the moon, but it is also 400 times farther away—an arrangement that produces perfect solar eclipses when viewed from earth.
This extraordinary phenomenon has revealed crucial scientific facts about the composition of the sun and other stars, as well as providing concrete evidence of Einstein's theory of relativity (again illustrating how our earth is set 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).
Traveling in the right zone
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 Guillermo 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.
Asking some tough questions
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 corner" (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] and anthropocentric [human-centered] design" (Nature's Destiny: 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).