"Donal" wrote in message
...
"Martin Baxter" wrote in message
Donal wrote:
So why does the moon seem to have a greater impact on the

tides?

Well duh! Remember F=G*(m'*m")/(d^2),


Emmm... Huh?

What the hell does that mean in English?

Did you not take physics in school?

Sadly, I didn't!

With hindsight, I suspect that I had a poor teacher who managed to make the
subject appear much duller than it really is.

My high school physics teacher was possibly the worst teacher I ever had - a
true nut case who shouldn't have been left alone with children. Fortunately I
found much better teachers in college.



I've still got a suspicion that if we expand your equation, we will find
that the sun has a greater gravitational influence on the earth than the
moon does.

Yes, its does. The direct gravitational pull of the Sun is enormous, much
larger than the Moon's. However, the tides are caused by the difference in pull
between the near side and the far side. Since the Moon is a lot closer, that
difference is more significant. If you remember any calculus, you'd know that
differentiating a 1/r^2 function yeilds a 1/r^3 function. The inverse cube of
the Sun's distance becomes a tiny number compared to the Moon's. The net
result is that the Moon's effect on the tides is 2.2 stronger than the Sun's.