Re: Children of the Moon?
Astronomers and geologists have bandied this question about for decades now. The accepted answer has gone from "the moon is essential" to "the moon doesn't matter at all" to "it might matter to some degree".
Back in the 60s - before my time, just for the record
- it was generally agreed that the moon stripped away much of the Earth's early atmosphere. Without this effect Astronomers believed that the Earth would have ended up a searing, pressurized hell similar to Venus. This was overturned when it was discovered that outgassing from the Earth's interior adds far more to our atmosphere than the moon strips away; gas loss to the moon turned out to be largely inconsequential.
For a couple decades the prevailing opinion then became that the moon was little more than a pretty ornament.
Then came the argument that the moon stabilizes the Earth's precession (the "wobble" any tilted rotating body undergoes). There is no question that our planet precesses less due to the moon, but no one has yet shown that
more precession would have precluded life on Earth. Mars and Venus don't have oversized moons, and while more pronounced than the Earths, their precession isn't disasterous. Then again, both are largely uninhabitable for other reasons, so we really don't know what effect all that would have on the development of life.
But finally, the dominant theory of the moon's
origin came along. Most astronomers believe that a Mars-sized body colided with the then-moonless Earth about 4.5 billion years ago. At that point our planet was indeed headed the way of Venus, but the collission blasted away a huge portion of the Earth's crust and added gigajoules of energy to the system. The debris leftover from the collission formed the moon, and when things calmed down again the planetary environment was much different ... it was more hospitible to the formation of life in many, many ways.
So while the moon in its current state might or might not matter to life, the violent collision that created it looks like it definately does. Newly-formed terrestrial planets might all end up like Venus unless they experience a devastating impact early in thier history. Of course we can't know for sure, but it's the direction accepted theories are pointing nowadays.
Man, it's great to have discussions like this here. On most other forums I've posted to someone would be bringing up Velikovsky right now, forcing me to add another person to my "People to Kill" list.
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