Our astonishment is magnified by the fact that our moon, which is virtually unique in our solar system in terms of the ratio of its size to that of the earth and its proximity to the earth, has to have almost exactly the properties it has in order for life to be sustained on earth.
Like the story of Goldilocks and the three bears who sampled her porridge, everything about the collision had to be just right. Check out this computer simulation of the collision:
Robin Canup, the author of one of the more popular theories on the moon's origin, wrote that, "Current theories on the formation of the Moon owe too much to cosmic coincidences."
And earth scientist Tim Elliott observed that the degree and kinds of complexity and fine-tuning required by lunar origin models appear to be increasing at an exponential rate. Among those who study lunar origin, he notes, "the sequence of conditions that currently seems necessary in these...versions of lunar formation have led to philosophical disquiet."
Ross adds that,
Thanks to the exquisitely fine-tuned nature of this impact event, the collision:If we didn't have a moon like the one we have we wouldn't be here, and yet the existence of our moon is such a highly improbable occurrence that anyone who studies it is almost overwhelmed by how fortuitous it is.
- Replaced the earth's thick, suffocating atmosphere with one containing the perfect air pressure for efficient lung performance, the ideal heat-trapping capability, and the just-right transparency for efficient photosynthesis.
- Gave the new atmosphere the optimal chemical composition to foster advanced life.
- Augmented the earth's mass and density enough to allow it to gravitationally retain a large, but not too large, quantity of water vapor for billions of years.
- Raised the amount of iron in the earth's core close to the level needed to provide the earth with a strong, enduring magnetic field (the remainder came from a later collision event). This magnetic field shields life from deadly cosmic rays and solar x-rays.
- Delivered to the earth's core and mantle quantities of iron and other critical elements in just-right amounts to produce sufficiently long-lasting, continent-building plate tectonics at just-right levels. Fine-tuned plate tectonics also performs a crucial role in compensating for the sun's increasing brightness.
- Increased the iron content of the earth's crust, permitting a huge abundance of ocean life that, in turn, can support advanced life.
- Salted the earth's interior with an abundance of long-lasting radioisotopes, the heat from which drives most of the earth's tectonic activity and volcanism.
- Produced the moon, which gradually slowed the earth's rotation rate so that eventually advanced life could thrive on earth.
- Left the moon with a just-right mass and distance relative to the earth to stabilize the tilt of the earth's rotation axis, protecting the planet from rapid and extreme climatic variations.
- Created the moon with the just-right diameter and the just-right distance relative to the earth so that, at the narrow epoch in solar-system history when human life would be possible, humans on earth would witness perfect solar eclipses, which would help them make important discoveries about the solar system and universe.
No wonder, then, that many of the people who study it, astronomers like Ross, believe that the earth/moon system, just like virtually every other aspect of cosmic architecture, is not an accident, but is rather the intentional product of an unimaginably intelligent and powerful engineer.
There's much more in Ross' article. It was written nine years ago which leads one to wonder how much more we know about the moon today that adds to the breathtaking scope of coincidences than was known in 2014.
