Flase wrote:It's an interesting coincidence that the Moon and the Sun have the same apparent diameter from Earth. Some people don't believe in coincidences.
Could it be that some forces of nature made the Moon orbit at a distance where some resonance, gravitational or otherwise, exists with the Sun?
Fascinating, False. I was just going to bring that up.
It really is an incredible coincidence that two bodies so wildly different in size would be located at such distances from the Earth that they look identical in size. It is, indeed, quite fantastic.
Personally I rather doubt the idea of the resonance with the Sun, although I'm speaking purely from a gut feeling and not from any scientific knowledge. Even so, I think this amazing order of things tells us
something. For example, maybe it is good for life to be orbiting a star with the size, mass and temperature of the Sun from the same distance as the Earth.
(Yeah, that is good... habitable zone and all, duh... )
All right, yes, but maybe the Earth has also got a favorable size and mass, and even composition. I remain unconvinced that it would have been better for life if the Earth had had significantly more water than it actually does.
And maybe, who knows, maybe the Moon really has helped getting life going on the Earth, and maybe it has actually helped preserve life here, too. Maybe the Moon could only do that if its own size and mass was right for the "job".
As for the Earth-Moon distance, the Moon is actually receding slowly from the Earth, due to the fact that the Earth's rotation is slowing down. The Moon really is "putting the brakes on the rotation of the Earth". Let's hope the Earth never stops rotating, though, and never gets a "day" that is several weeks long. The consequences for the climate would be terrible, or at least I think so.
The fact that the Moon is slowly increasing its distance from us is a little sad, too. There will be fewer and fewer eclipses in the future, and eventually there will be none. It could well be that the Earth will not be habitable by the time when there are no more eclipses, not because of the Moon, but because of the Sun. The Sun is destined to grow larger, eventually making life on the Earth impossible.
We are lucky, though, that the Moon is slowly moving away from us. What if it had been the other way round? What if the Moon had been sinking lower and lower until it was torn apart by the Earth's gravity and crashed onto the Earth as the mother of all meteorite storms?
Today's (tomorrow's?) annular eclipse is a reminder of the amazing stability the Earth has enjoyed for many millions and possibly billions of years.
Ann