Re: Life on Earth
Always wondered how precise and coincidental the factors must have been for the Moon to end up with the perfect Orbital Velocity required to keep it in orbit and not crashing back down to Earth.
It's interesting that this relatively tiny body is able to exert gravitational force on our Earth to make the tides happen, and yet the Earth, which is massively bigger than the Moon, doesn't have the gravitational pull to see the Moon crash into us. Figure that one out !
The answer will be that the Moon is magically travelling at a fast enough speed that it balances the Earth's gravity and so stays in orbit.
But how could that perfect orbital speed have been achieved in the first place?
If the Moon were an initial part of the Earth and was flung out into space then how come it didn't just keep on travelling into space? If it had enough velocity to escape Earth's gravitational pull then why didn't it keep on going?
Alternatively if the Moon was created by Earth colliding with another planet or huge body then again it would have been flung out. Why didn't it keep on going?
I think the precision needed for any body to remain in orbit is quite significant. The Space Station (ISS) has to maintain such an orbit and so has to constantly maintain a very specific speed relative to its distance from Earth.