We all know that pendulums eventually stop as a result of energy loss primarily due to friction.
Tides exhibit harmonic motion as well do they not ? They are also a function of gravity just like the pendulum.
Now the tidal phenomenon has existed I presume for billions of years expending enormous energy,(which some dream of harnessing for electricity) yet there does not appear to be any let down in the total energy exhibited by the system.
I would therefore assume that energy required to continually lift the surface of the oceans must be constantly inputted to maintain the ballance. ** How is this energy introduced to the tidal phenomenon ?**
Not sure if this answers what you’re asking, but the gravitational pull of the moon is what “lifts” the water. As the moon orbits the earth, it pulls this lifted bulge around with it.
Indeed there is energy expended in the tides. It is dissipated in the Earth as heat, and results in a loss of energy in the Earth-Moon system’s angular momentum. As a result, the Moon is slowly moving away from the Earth and the rate of rotation of the Earth is slowing.
Tidal friction is slowing things down, but really, really slowly. The Moon is moving so amazingly fast, and it has so much inertia `locked away’ in its huge mass, that it can keep going for billions of years more despite tidal friction. (In fact, all stellar bodies are moving at quite a clip, and the only reason the sky looks so stable is because we’re moving right along with them.)
Remember what an orbit is: An extended fall. When something has enough lateral momentum, it can cancel out the effects of gravity (which is a constant mutual acceleration towards a specific center of gravity) almost exactly, reaching a very stable balancing point where acceleration is balanced by inertia. Eventually, acceleration wins, but it an take an extremely long time.
The arth will return the favor and soon will be always presenting the same side to the moon. Then the moon will be invisible from half of the earth and constantly visible from the other half. I don’t expect to live long enough to see it though.
The basic priciple of what has been outlined above is true.
The tidal forces on the earth use up about** 2.5x10[sup]17[/sup] Watts** [cite]
This energy comes from the rotation of the earth and the kinetic energy of the moon. The net result is that the moon ends up in a slightly higher orbit. the Earth-Moon distance increases with about 4cm/year [I can’t find a reputable non-creationistic cite, but this has been discussed here before.]
(Compare the figure above with human energy consumption. Currently about 2x10[sup]12[/sup]W. )