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Author Topic: Where does the energy of the earth's tides come from?  (Read 3338 times)

chuckspirit

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Where does the energy of the earth's tides come from?
« on: 28/02/2010 20:50:27 »
A young person recently asked me this question. Would someone like to give an answer, I couldn't.

As the moon circles the earth it lifts a zillion tons of water. This is energy can be used and disposed of in tidal generating facilities. This is observable energy. Has this energy diminished the Moon's size or speed?? Has this energy added to the earth's size and speed??  Now lets ask us; where does this tremendous amount of usable energy come from?? Do the currently defined laws of physics correctly define the source of this energy??

« Last Edit: 01/03/2010 00:41:07 by JP »

RD

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Re: Where does the energy of the earth's tides come from?
« Reply #1 on: 28/02/2010 21:13:59 »
The tidal energy comes from the kinetic energy (rotation) of the Earth-Moon system:
Earth's rotation about its axis slows as a result.
Quote
solar day becomes 1.7 ms longer every century due mainly to tidal friction
http://en.wikipedia.org/wiki/Leap_second

http://en.wikipedia.org/wiki/Moon#Ocean_tides
« Last Edit: 28/02/2010 21:15:32 by RD »

Robro

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Where does the energy of the earth's tides come from?
« Reply #2 on: 01/03/2010 16:08:23 »
As the moon continues to get farther away over time, I wonder if the tidal friction will decrease to a point where the length of a day will reach an equilibrium?

RD

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Where does the energy of the earth's tides come from?
« Reply #3 on: 02/03/2010 10:32:55 »
As the moon continues to get farther away over time, I wonder if the tidal friction will decrease to a point where the length of a day will reach an equilibrium?

Even if the moon disappeared there would still be tides caused by the sun's gravity.

Even if there was no water on Earth there would still be tidal friction via the liquid in the Earth ... http://en.wikipedia.org/wiki/Earth_tide

Even if earth was completely solid, with no water, its rotation would still slow because it is not perfectly spherical, (this is what has happened to our moon).
« Last Edit: 02/03/2010 10:48:04 by RD »

yor_on

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Where does the energy of the earth's tides come from?
« Reply #4 on: 02/03/2010 14:19:56 »
Yes Discover Dave, you're so right. I recently saw a suggestion using the jet streams for energy, but those jet streams control where Hurricanes/storms grows and diminish their possible strength, all kinds of weather etc. But it's the way our minds work I guess :) "Let's do it, if there's a problem we'll 'fix it' later." Macho BS, what those words stand for is "I don't give a f**. I'm not gonna be there anyway when the sh* hits the fan." jet streams

Take a look at Nasa's idea Turning the Tide to Energy
« Last Edit: 02/03/2010 14:32:49 by yor_on »

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Where does the energy of the earth's tides come from?
« Reply #4 on: 02/03/2010 14:19:56 »