posted on Nov, 11 2013 @ 11:34 AM
Yes, I know there's a bazillion threads on gravity already and my query is probably answered in one or other of them (but I can't be arsed wading
through them all).
I've recently been watching Wonders of The Universe, narrated by Professor Brian Cox; specifically, the episode about gravity, 'Falling'. The full
episode doesn't seem to be available yet on the web, just in case you were wondering why you can't see a video or even a link.
It's about 10 minutes into the episode and Cox is describing the gravitational effects of the Earth and Moon on each other.
Apparently, at some point in the remote past, the Earth's gravity caused waves of ROCK to ripple across the surface of the Moon; this rock 'wave'
was 7 metres high!
Now this is what I don't understand (bear with me, I'm a simple soul and my knowledge of physics goes no further than "O" Level standard).
So the Earth's gravity is sufficiently powerful to cause 7 metre high waves - not of water, but of ROCK - to ripple across the Moon's surface,
despite the Moon being almost a quarter of a million miles from the Earth.
The Earth's gravity seems to have very little effect on ME - and I'm on its surface!
I know that gravitational effect is contingent on mass and proximity, and that I'm obviously much less massive than the Moon...but I'm also a
quarter of a million miles closer to Earth than the Moon.
Or take something far more massive than me - a mountain, say.
If the Earth can exert such influence on lunar rock at such a distance, why doesn't it destroy mountains lying directly on its surface?