As far as I know the moon came into existence from a collision between a very new earth and some other fairly large object. And it’s bigger relative to the earth than your average moon and it’s been around here for a long time.
I’ve been searching a bit, and I’ve found a couple of things:
[ul]
[li] The moon causes stronger tides (but I already knew that)[/li][li] Because of the strong tides, the earth rotation is slowed down, and the rotation of the moon around the earth slows down too (which presumably means the rotation of the earth will match the rotation of the moon around the earth, eventually).[/li][li] From 2: this link says that a faster rotating earth would mean stronger winds. Is that true? The wind isn’t always blowing west is it?[/li][li] Also from 2: the tides cause all kinds of oceanic currents.[/li][/ul]
Questions:
[ul]
[li] Is there any kind of material in the earth that’s wasn’t there before the collision?[/li][li] How much difference has all this made from an evolutionary point of view? Would/could humans have evolved? Would anything? No Moon, no life on Earth?[/li][li] If we get rid of the moon slowly (i.e. piece by piece, or just move it slowly further away) over a couple of thousand years how much of a pickle would be in? I’m saying slowly because if we did it all at once I bet it would cause some drastic climate changes - so we probably need a bit of time to adjust.[/li][/ul]
[QUOTE=Superfluous Parentheses]
[li] How much difference has all this made from an evolutionary point of view? Would/could humans have evolved? Would anything? No Moon, no life on Earth?[/li][/quote]
It has made a lot of difference.
One of the biggest effects has been that the moon has acted to keep the Earth “upright”. The other planets, lacking a large moon, tend to wobble a lot, to the point where they spend millenia with their poles almost directly facing the sun. That means that one hemisphere will be in perpetual daylight and the other in perpetual darkness. That sort of situation would make it very difficult for advanced life to evolve, and it may well make it impossible for life to evolve at all.
The second effect the moon has had is that of moping up stray debris. The moon makes the Earth effectively much larger, so the Earth-moon system managed to sweep up most of the major meteors in our path fairly fast. Without that the Erath woudl probably have been hit with meteors regularly enough to prevent life evolving until very recently, or at least advanced life.
Immediately the effects would be pretty limited. There would be some massive extinctions of animals that depend on tides or lunar cycles for breeding, but most systems would remain functional.
The real effect would come when the the Earth started to wobble on its axis. Would you really want live on a world where the days and nights are years long?
Indeed. Without the moon, poets would have to use something else in the sky to construct rhymes, say Venus … that could have some unfortunate consequences.
Only true because the “average” moon circles a gas giant, mainly Jupiter or Saturn. Charon is so huge relative to Pluto that they basically revolve around each other (Since Pluto was downgraded from “planet,” is Charon still a moon?).
Luna provides a degree of nighttime illumination; nothing to sneeze at. IIRC, Ramsey Campbell wrote a short story about how little the moon does for us, but I think we’d miss it.
Surly there must be nocturnal species that wouldn’t have thrived without the moon. And I’m guessing there would be domino effects through to daytime animals that are part of the food chain. I’m not sure which species mind you. But there must be some lunar responsibility for bats, cats, skunks, scorpions and the like.
Wasn’t there some famous story about North American Indians winning a battle against the white mane because they waited for the full moon to attack? Or perhaps it’s just apocryphal.
[li] How much difference has all this made from an evolutionary point of view? Would/could humans have evolved? Would anything? No Moon, no life on Earth?[/li][/Quote]
There probably wouldn’t be any life on land, since the rise and fall of the tides allowed sea life to come ashore.
Little by little we are losing the moon, not piece by piece but it strays farther and farther away steadily. I’m not sure how much the earth’s rotation will have slowed by that point.
The moon made it a lot easier for Kepler and Newton to figure out the things they figured out. Without it, our modern understanding of gravity might have come along a lot later.
A faster rotating Earth would have stronger Coriolis forces. That would cause winds to be stronger.
How much faster the Earth would be rotating is hard to say. For one, we aren’t sure how fast the Earth was rotating before the Big Splash. And while there may not have been lunar tides without the Moon, there would have been solar tides which would have done some slowing.
The moon makes night becomes bright.If the moon was painted silver it would shine brighter therefore giving us more daylight per annum. The moon rotates around the Earth, so half the day it’s out of sight.