“The Earth is the Lord’s, and all it contains, The world, and those who dwell in it” (Psalm 24:1). It’s not the largest planet, nor the brightest. It is one planet among billions, perhaps even billions of billions. But the Earth is uniquely designed for life (Isaiah 45:18). This makes it quite different from any other known world. And while it may not be the center of the physical universe, the Earth is certainly central to God’s plan of redemption.
Discovery
It seems strange to discuss the discovery of the planet Earth. After all, people have lived on its surface since the sixth day of creation. But people have not always known that Earth is a planet. From our everyday experiences, it is not obvious that Earth is the same kind of object as those five “wandering stars” that people have watched since antiquity. Throughout most of recorded history, most people believed that the Earth was a stationary object at the center of the universe. The heavens were thought to be very different from Earth. They were considered to be the unreachable realm of the gods, while the Earth was the lowest order of creation.
But the Lord delights in defying our expectations. He has ways of showing us that hasty generalizations from our extremely limited experiences often lead to wrong understandings of reality. The field of astronomy is full of examples. Who in antiquity could have imagined that we live on a massive sphere that encircles the sun at 67,000 miles per hour? Who would have guessed that from the cloud tops of Venus or from the surface of Mars, the Earth would appear as a tiny bright star, just like the other planets? Did Adam understand any of this? Did Noah or Moses?
Educated people have known since the 500s B.C. that the Earth was spherical. Biblical verses such as Job 26:10 suggest that believers knew about the roundness of Earth since 2000 B.C. But the first record we have of someone claiming that the Earth orbits the sun goes back to the Greek mathematician Aristarchus in the early 200s B.C. He used geometry to demonstrate that the sun was bigger than the Earth – contrary to previous thinking. Aristarchus then correctly supposed that it made more sense for the little sphere to orbit the big one than the reverse. But few people, if any, were persuaded by his claims. It would take the advancement of Christianity to allow science to triumph over preconceptions.
When we think biblically, we recognize that God is Lord of both heaven and Earth (Acts 17:24). Both are under His sovereign control, and neither are divine (Deuteronomy 4:19). God upholds the cosmos in the same consist way that He upholds activity on Earth, for they are equally His, and hence obey the same laws (Job 38:33; Jeremiah 33:25). Contrary to what is often claimed, biblical thinking made possible the scientific discovery that the Earth is a planet that orbits the sun. And great Christian astronomers such as Johannes Kepler were instrumental in this scientific revolution. Thanks to the advancement of Christianity in Europe by the 1600s, science began to advance rapidly due to the common expectation that God upholds His creation – both heaven and Earth – in a consistent and rational way. Today we have pictures of Earth taken from space. We even have pictures of Earth taken from the surface of Mars. And indeed, the Earth is a planet that orbits the sun.
Similarities and Differences
As a planet, the Earth has much in common with the other worlds of the solar system. But since it was uniquely designed by God to be inhabited, it also has important differences. Let’s consider some of the more significant similarities and differences.
Like Mercury, Venus, and Mars, Earth is a terrestrial planet – meaning it has a solid surface and consists mainly of rock. In fact, Earth is the protype of terrestrial planets since the term terrestrial means “Earthlike.” Like the other terrestrial planets, Earth is relatively small – a mere 7900 miles in diameter. This seems large with respect to our everyday experiences. But the Jovian (“Jupiter-like”) planets in our solar system are much larger. Earth is, however, the largest of the terrestrial planets in our solar system – just 5% larger than Venus.
Earth has an atmosphere that is far more substantial than the atmosphere of Mars, or the virtually non-existent atmosphere of Mercury. On the other hand, Earth’s atmosphere is less than 2% the mass of the atmosphere of Venus. The composition of Earth’s atmosphere is rather unusual. It is about 80% nitrogen, which is common, but the remaining 20% is primarily oxygen. No other known planet or moon has abundant oxygen in its atmosphere. From a biblical perspective, this makes sense because humans and animals need oxygen to breathe.
Being the third planet in distance from the sun, the Earth has a cooler surface temperature than that of Venus or the (average) temperature of Mercury. And it is warmer than Mars. Its unique position, being neither too close nor too far from the sun leads to a very significant difference between Earth and the other planets: liquid water.
Liquid water can only exist in a fairly narrow temperature range, and with significant atmospheric pressure. Earth has the right kind of atmosphere and orbits at the right distance from the sun for water to exist in a liquid state. Water is essential for life, and Earth seems to be the only world that has any. To be clear, the water molecule (H2O) is fairly abundant in the universe. But it is nearly always in either an ice or vapor state. Yet, the surface of Earth is 71% covered with the liquid form of this vital compound. As such, oceans, lakes, and rivers of water are (as far as we know) unique to Earth.
Earth has a dipole magnetic field, like Mercury, but a hundred times stronger. Magnetic fields naturally decay with time, and rather rapidly by secular standards. Hence, Earth’s magnetic field is confirmation of the biblical timescale. The exponential decay of Earth’s magnetic field suggests an age significantly less than 100,000 years.
Earth has geological features in common with the other planets. Earth has mountains and valleys, as do the other terrestrial planets. Earth has volcanos, much like Mars and Venus. Earth is made of rocky material with compositional similarities and differences from the other terrestrial planets.
Earth has a crust, a mantle, and a core – something that astronomers believe is true of all the terrestrial planets. But Earth’s crust appears to be unique, in that it is thin enough to be divided into plates that float on the mantle. Under the right conditions, these plates can move relative to one another – plate tectonics. As far as we know, Earth is the only planet with plate tectonics. This is extremely significant because most creation scientists believe that plate tectonic activity was the mechanism God used to power the global flood described in Genesis 7-8. God knew that the wickedness of mankind would increase, and that He would have to judge sin. So, God designed the Earth to be “floodable” – a feature apparently unique to Earth.
Like the other terrestrial planets, Earth has impact craters, apparently the result of meteor strikes. However, Earth has very few impact craters relative to the other terrestrial planets. Secularists believe that this is because plate tectonics and other geological activity have erased them. However, from a creationist perspective, it is possible that Earth never had that many craters – perhaps none at is origin. From Genesis we learn that God created the Earth on a different day from the other planets, and perhaps using a different mechanism. After all, God spent five of the six creation days forming and filling the Earth; but He made all the other planets on day four (Genesis 1:1-2, 14-19, 31). Earth is three days older than any other planet.[1]
We live in an amazing time. What a blessing that we have pictures of the Earth from above – something our ancient ancestors could have only imagined! Seeing the Earth from space reveals the astonishing beauty of this planet on which the Lord has placed the creatures that He made in His own image. Worlds like Mercury, Venus, and the moon certainly have a type of beauty. But it is a desolate beauty compared to the colorful richness of the Earth. We can so easily become complacent and take for granted the majestic beauty of this world with its mountains, oceans, rivers, waterfalls, and abundant fauna and flora. The other worlds of creation serve to remind us of the special beauty of our own planet.
At an altitude of 200 miles, astronauts on the ISS are treated to a spectacular view of only a section of the Earth.
The Moon
Earth has an unusual natural satellite – the moon. Although moons are very common in the solar system (six of the eight planets have moons), Earth’s moon has several characteristics that are remarkable. Although Earth’s moon is not the largest by any means, it is the largest moon relative to the size of its planet. That is, the diameter of the moon is over one fourth the diameter of Earth. The moon is about 400 times smaller than the sun, but is also 400 times closer to Earth than the sun is. For this reason, the moon appears about the same size as the sun as seen from the surface of Earth. This allows for total solar eclipses in which the moon fully covers the sun, with little left over. This configuration appears to be unique in the solar system. No other moon appears to be so precisely the size of the sun as seen from the surface of its planet.
The moon is tidally locked, meaning that it rotates at the same rate it revolves around Earth. Consequently, we always see the same side of the moon. In fact, all large moons do this, and so do many small ones. Such a configuration is energetically favorable, as it minimizes tidal torqueing on the moon. So, in this sense, the moon is quite typical.
However, the moon’s orbit is atypical and rather unique. All other large moons in our solar system, with one exception, orbit in the plane of their planet’s equator.[2] But Earth’s moon orbits very near the ecliptic – the orbital plane of the Earth, which is tilted relative to the equator by 23.5 degrees. This makes solar and lunar eclipses more common than they would be otherwise. But the moon’s orbit is tilted about 5 degrees relative to the ecliptic. If it were not tilted, then we would get a solar and lunar eclipse every month, and perhaps this would make them seem less remarkable and simply commonplace. The moon’s unusual orbit apparently has a stabilizing effect on Earth’s tilt – preventing the Earth from toppling in a random fashion over long time-scales. Although the degree of Earth’s tilt is stabilized by the moon, the moon does cause the direction of Earth’s axial tilt to precess over millennia. Ancient star charts confirm this effect.
The moon benefits life on Earth in multiple ways. The moon causes tides in Earth’s oceans which help stir nutrients essential for life.[3] Furthermore, many organisms navigate or otherwise depend on moonlight. The phases of the moon give us variety; they allow us to experience some nights in which we can easily navigate by bright moonlight, and others where the sky is much darker so that we can explore the universe beyond. The moon also helps us to measure time. The period of the lunar orbit is why we have twelve months in a year – the moon goes through its phases twelve times in a year, or once per month. The word month is derived from the word moon.
In 1969, human beings first set foot upon the moon. I have always found the Apollo space program to be fascinating, and one of humanity’s greatest technological accomplishments. To travel 250,000 miles into space, to land, and then walk on the surface of another world is amazing. What would it be like to walk on the lifeless desolate surface of the moon? To then look up into the black sky and see the Earth delicately suspended upon nothing as a small blue marble – knowing that it is home to billions of people and countless living creatures? Twelve people have experienced this to date and there are plans to return.
The Splendor of Earth
When Voyager 1 passed into the outer regions of the solar system in 1990, it turned its camera inward, and photographed the planets – a sort of “family portrait” of the solar system.[4] One of these images is the Earth, which from a distance of 3.7 billion miles appears as a tiny pale blue dot suspended in a sunbeam. It is a humbling picture, knowing that everyone who ever lived was confined to this tiny speck. The image was named the “pale blue dot” by Carl Sagan, who found the image very moving. So do I, but for very different reasons. To Sagan, the pale blue dot symbolized the utter insignificance of humanity. To me, it represents the magnificence of God and our utter dependence on Him. The same God who spoke the entire universe into existence deeply cares about the inhabitants of this pale blue dot, to the point that He was willing to die for them.
This coming Sunday is Easter and many Christians will celebrate the resurrection of our Lord – the same Jesus who spoke the worlds into existence. No doubt the Lord made all these amazing worlds for His glory and also perhaps for our enjoyment. We can marvel at the magnificence of Saturn’s rings, the enormous size of Jupiter, the stunning brightness of Venus. But salvation did not occur on these worlds. It was not on Jupiter or Saturn where the Lord became man and died and rose again. No, Earth is where God placed those special creations made in His own image. Earth is where God became man and died our death. God proved His power over death by raising Jesus from the dead on this planet we call home. Far more amazing than man walking on the moon is God walking on the Earth! And He offers forgiveness and salvation to all who will repent and trust in Him. Let us be extra grateful this Sunday that the Lord visited this pale blue dot.
[1] The stars were made on day four of the creation week. The Hebrew word for “stars” (kokhavim) would include planets. Hence, all the celestial luminaries – all the stars, moons, and planets (except Earth) were made on day 4.
[2] The one exception is Triton, a moon of Neptune, which orbits neither in the ecliptic nor around Neptune’s equator. Furthermore, Triton orbits retrograde – opposite the direction Neptune rotates.
[3] The sun also influences tides on Earth, but solar tidal forces are three times weaker than lunar tidal effects.
[4] Six of the eight planets were photographed. Mercury was too close to the sun to be detected, and Mars was in an unfavorable position and phase. So, they are missing from the family portrait.