Joel Kontinen
When an article in Nature is called Lunar Conspiracies and begins with the sentence “Current theories on the formation of the Moon owe too much to cosmic coincidences,” we might expect some interesting revelations.
And we do not have to wait in vain. Robin Canup writes:
“The Moon is more than just a familiar sight in our skies. It dictates conditions on Earth. The Moon is large enough to stabilize our planet's rotation, holding Earth's polar axis steady to within a few degrees. Without it, the current Earth's tilt would vary chaotically by tens of degrees. Such large variations might not preclude life, but would lead to a vastly different climate.”
One could also mention some other benefits of the Moon, for instance, its size and distance from Earth determine how big tides we have. Without tides marine life would sooner or later come to an end, and our planet could turn into Mars’ twin.
In other words, the Moon looks designed to maintain life on Earth.
A big problem with Moon origin theories is that they do not correspond to facts. They do not explain the Moon’s composition.
Summing up the failure of impact theories, Ms. Canup asks:
“Is the origin of our Moon a rarer event than we believed, or are we missing something?”
However, she is unwilling to let go of impact theories. If a Mars-like body did not collide with the early Earth, why not a Venus-like body? she suggests.
Somehow, this sounds even more like fiction.
Source:
Canup, Robin. 2013. Planetary science: Lunar conspiracies. Nature 504, 27–29 (5 December ).
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