You've seen the moon almost every night. Have you ever wondered how it was made?
I’m willing to bet that each one of us has spent some time gazing up at the moon. No matter our jobs or incomes or personal backgrounds, we all see the same moon. From crescent to full and back again, the moon is a steady presence in our world. But how did it get here?
Oxford professor of material science Sir Colin Humphreys suggests that there are two types of miracles. For the sake of clarity, let’s call these two types first order and second order. A first order miracle is purely supernatural, such as the virgin birth and the resurrection. A second order miracle is an occurrence that can be explained naturally, but whose timing results in exactly the right combination of circumstances to achieve a specific end.1
Could this second definition of a miracle apply to the formation of the moon?
This might seem like putting “religion” or the idea of the supernatural where it doesn’t belong. The Bible can say all it wants to about who made the moon, you might be thinking, but science explores how it may have formed.2 Well, let’s take a look at the latest science. Then you can decide if our moon might be classified as a miracle of the second order or if it was created, as naturalists maintain, by happenstance.3
For something to be a second order miracle, the timing and sequence of the celestial events must be uniquely arranged in such a way that a specific end is achieved—in this case, that specific end is a planet with an environment capable of sustaining life.
More Than a Night-Light or Romantic Icon
To appreciate why we need a moon and why it has to be precisely the way it is, let’s first review its importance.
The Bible says only that the moon serves as a “lesser light” by night and, along with the stars, as a marker to indicate the changing of the seasons. Of course, these were two very important things to the community of ancient Hebrew readers living without artificial lights.4
Scoff though we might at the “lesser light” reference, much of our modern population has no more understanding of the moon’s critical role in our existence than the early Israelites did. From song lyrics and poetic allusions, one might think the moon is little more than a romantic icon. But one could not be more wrong—as modern science reveals.
The Moon’s Gravitational Pull
Imagine the challenge of spinning a top. It takes just the right spin-and-yank action to set the top spinning successfully. When the top begins to wobble on its axis, you know it’s ready to come to a chaotic end. Without our moon in its current configuration, Earth itself—which also spins on an axis—would wobble like a top, causing catastrophic consequences for all life.5
The stabilization function requires that the ratio of the moon’s mass to the mass of Earth be large, as compared to that of other planets with moons. Because our moon is large compared to the moons of other planets, its gravitational pull overpowers that of other planets. Thus Earth’s axis of rotation is stabilized.6
One astronomer describes what life on Earth would be like if the tilt of Earth’s axis was instead like that of other planets:
When the North Pole was leaning sunward through the summer half of the year, most of the Northern Hemisphere would experience months of perpetually searing daylight. High northern latitudes would be subjected to searing heat, hot enough to make Death Valley in July feel like a shady spring picnic. Any survivors would suffer viciously cold months of perpetual night during the other half of the year.7
Without Earth’s tilt of 23.5 degrees (plus or minus 1 degree), rainfall would be much less well-distributed. Few places would be suitable for agriculture, and we would have much larger areas of desert punctuated by great flooding in other regions.8
The moon’s gravitational pull is also responsible for about two-thirds of the tidal effect on the oceans’ levels (the sun is responsible for the other third). While tides may seem a nuisance to some, they are vital to the ecology of the wetlands and bays where the sea–land nutrient mixing provides the basis for the food chain of sea life. Moreover, it is believed to be responsible for the deep sea currents that create milder climates in the northern latitudes (e.g., the Gulf Stream and Great Britain).9
Furthermore, through its gravitational pull, the moon slowed Earth’s rotation period (the period of time between sunrise one day to sunrise the next day) from its original estimated 4 to 5 hours to our current 24-hour day. Just imagine trying to get everything done for the day in only five hours.
Given the laws and constants governing nature, it’s fair to say: no moon, no us.
Theia, Theos, or Both?
Until recently, there was one standard model for how the moon was made. Now there are multiple models or theories, but all have this in common: our moon is the result of a fortuitous collision—very early in Earth’s history—of a large, planet-sized object (called Theia, from a Greek moon goddess) with Earth at just the right angle and speed.10 This scenario is referred to as the Theia Hypothesis.
A variation in any aspect of the standard model would have resulted in the creation of a moon that is incapable of helping to sustain life on Earth. Recently, astronomers have found a problem in the standard model that requires an even more complex set of “just right” variables than originally thought. As one author put it, “The main challenge is to simultaneously account for the pair’s dynamics—in particular, the total angular momentum contained in the moon’s orbit and Earth’s 24-hour day—while also reconciling their many compositional similarities and few key differences.”11
Could it be that something bigger is going on here? All these variables coming together on their own seems increasingly unlikely. Could the formation of the moon indeed be a second order miracle?
If you’ll allow me the pun, what if Theos (the Greek word used for the Christian God) used Theia to make our moon?
Reaction of the Science Community
The journal Nature is perhaps the most prestigious science publication in the world. It is also firmly rooted in naturalism, as its name implies.12 So it came as a surprise to read in a recent series of articles on the formation of the moon that leading moon formation theorists are voicing their uneasiness (“philosophical disquiet,” in the words of one) with the apparent fine-tuned circumstances that had to occur for our moon to be formed.13
This uneasiness is not the result of what critics of Christianity rightfully disdain as the God-of-the gaps mentality, in which Christians and other religious folk assign mysteries of nature to God. (For example, lightning—before its electrical nature was understood—was assumed to be from an angry God or god). To put it bluntly, the God-of-the-gaps reasoning is based on ignorance.
Instead, what we see with all forms of fine-tuning is that the more we learn about nature, the more we realize there is an underlying design that makes life possible. Along with the creation of DNA, the “just right” ratio of the mass of subatomic features, the expansion of the Big Bang, and what the fossil record reveals about the emergence of life, the formation of the moon is but one of many candidates for miracles of the second order.