I knew I saw this somewhere
Scout

The following diagram shows how the moon causes tides on Earth:




In this diagram, you can see that the moon's gravitational force pulls on water in the oceans so that there are "bulges" in the ocean on both sides of the planet. The moon pulls water toward it, and this causes the bulge toward the moon. The bulge on the side of the Earth opposite the moon is caused by the moon "pulling the Earth away" from the water on that side.

If you are on the coast and the moon is directly overhead, you should experience a high tide. If the moon is directly overhead on the opposite side of the planet, you should also experience a high tide.

During the day, the Earth rotates 180 degrees in 12 hours. The moon, meanwhile, rotates 6 degrees around the earth in 12 hours. The twin bulges and the moon's rotation mean that any given coastal city experiences a high tide every 12 hours and 25 minutes or so.





"Scout" wrote in message ...
I was hoping you could solve this riddle.
But I'll toss in my oversimplified guess: the moon's gravity attracts the
water closest to it resulting in high high tide on the moon side of earth,
and also pulls the earth away from the water on the far side, resulting in a
low high tide on the side farthest from the moon.
Scout


"Nav" wrote in message
...
Yes, so...

Cheers


Scout wrote:

If the center of mass was the only factor involved, wouldn't the bulge be
on one side of the earth only?
Scout

"Nav" wrote in message
...

Yes, you can. Where is the center of mass of the earth moon system?

Cheers

Peter S/Y Anicula wrote:


We can certainly look at the gravitational force from the moon and the
gravitational force of the earth seperatly, and then ad the two, to
have a look at the combined forces.

Peter S/Y Anicula


"Nav" skrev i en meddelelse
...


Well Peter, I have to disagree there. The gravitational force acts

only


toward the center of mass of the system. This cannot by itself

produce


two bulges. To clarify this, try imagining the forces of gravity in

2D


on a piece of paper. In all cases, water would be pulled toward the
center of the Earth-Moon pair. This would lead to less water on the

far


side and more water as you move toward the moon... -two bulges would

not


be present.

Cheers