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Author Topic: Is there proof gravity can not be a energy source?  (Read 68240 times)

Omnibus

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Re: Is there proof gravity can not be a energy source?
« Reply #60 on: February 09, 2011, 05:01:56 PM »
4 statements above, 2 false assertions due to ignorance or stupidity. 

There is energy in the gravity field. Gravity is not force.
When two bodies attract one each other, and accelerate, energy is taken from their gravitational field, whose energy density decreases while the field redistributes in space, changing of topology due to the bodies movement.
Gravity field energy density is: D = g²/(8*pi*G). 
It is the same as the energy density of an electric field (1/2*epsilon0 * E2) or magnetic field (1/(2*mu0) * B2). It is a general law when fields are the source of 1/r2 forces.

Now the above is nothing short of sheer crap. There's a reason why I'm so adamant when telling off this confused element going by the handle @exnihiloest. His aggressive confusion and incompetence can be really damaging for people already confused enough to be pounced by another blind leading the blind.

The formuli above are akin to gravitational potential energy. The fact that a body in a gravitational field placed at rest at a given position in this field has gravitational potential energy does not at all mean that gravity is a source of energy. It is absolutely not true that a body at rest in a field of gravity does anything to the gravity, depleting it in some way. Nor does a body deplete gravity when moving under the action of that force. It has to be understood once and for all, there is potential energy connected with gravity (as with other fields detived from a potential) but gravity is not a source of energy, it is not a pool of energy which can be depletednto do work. Gravity is force which is different from energy and that force can do work provided it induces displacement of a body with mass. Therefore, not only there's no proof that gravity is a source of energy but such proof cannot even be sought for because energy and force are incompatible when trying to equate them.

tagor

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Re: Is there proof gravity can not be a energy source?
« Reply #61 on: February 09, 2011, 05:35:07 PM »
So the question is answered.


a well-known proof is Hydroelectricity
 
look at the strong rain falling on the ground and you see the power
 
and look at the Gwatt of electricity produced ( approximately 20% of the world's electricity )
 
                                        ************  THE END  ************

                                           (PLEASE let it be the end of this thread)

 
http://en.wikipedia.org/wiki/Hydroelectricity

ResinRat2

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Re: Is there proof gravity can not be a energy source?
« Reply #62 on: February 09, 2011, 06:34:23 PM »

a well-known proof is Hydroelectricity
 
look at the strong rain falling on the ground and you see the power
 
and look at the Gwatt of electricity produced ( approximately 20% of the world's electricity )
 
                                        ************  THE END  ************

                                           (PLEASE let it be the end of this thread)

 
http://en.wikipedia.org/wiki/Hydroelectricity

I thought it was over but I guess not.

The actual energy for this comes from the sun that evaporates the water and runs the weather cycle that brings in the rain and deposits the water at higher elevations so a waterfall can exist. So the energy is only indirectly produced from gravity.

exnihiloest

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Re: Is there proof gravity can not be a energy source?
« Reply #63 on: February 09, 2011, 08:32:14 PM »
...
look at the strong rain falling on the ground and you see the power
 ...

It is not a proof. The solar energy is the primary source of rain: water evaporation, then condensation, fall on earth and the cycle continues. The energy of gravity is not concerned, it is balanced, the same mass of water that falls, had been raised before by the sun energy.


exnihiloest

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Re: Is there proof gravity can not be a energy source?
« Reply #64 on: February 09, 2011, 08:57:02 PM »
Now the above is nothing short of sheer crap. There's a reason why I'm so adamant when telling off this confused element going by the handle @exnihiloest. His aggressive confusion and incompetence can be really damaging for people already confused enough to be pounced by another blind leading the blind.

http://tinyurl.com/4h7n5pn

Quote
The formuli above are akin to gravitational potential energy. The fact that a body in a gravitational field placed at rest at a given position in this field has gravitational potential energy does not at all mean that gravity is a source of energy. It is absolutely not true that a body at rest in a field of gravity does anything to the gravity, depleting it in some way. Nor does a body deplete gravity when moving under the action of that force. It has to be understood once and for all, there is potential energy connected with gravity (as with other fields detived from a potential) but gravity is not a source of energy, it is not a pool of energy which can be depletednto do work. Gravity is force which is different from energy and that force can do work provided it induces displacement of a body with mass. Therefore, not only there's no proof that gravity is a source of energy but such proof cannot even be sought for because energy and force are incompatible when trying to equate them.

Blah blah blah, an act of faith asserted arbitrarily, not scientific because refutable elements are not provided. I don't discuss Coran sourats.


pinobot

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Re: Is there proof gravity can not be a energy source?
« Reply #65 on: February 09, 2011, 08:59:36 PM »
Of course the sun is the source of the energy but the sun lasts for billions of year, how long does something have to last to be able to be called perpetual motion. If you wait long enough eventually all atoms will fall apart and nothing is perpetual.   

Omnibus

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Re: Is there proof gravity can not be a energy source?
« Reply #66 on: February 09, 2011, 09:19:54 PM »
Confusion and incompetens @exnihiloest calls science. What is there to refute when confusion in @exnihiloest is so blatant, as I already explained?

exnihiloest

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Re: Is there proof gravity can not be a energy source?
« Reply #67 on: February 09, 2011, 09:27:09 PM »
...
Does that make gravity Energy ? - No, it is an acceleration that needs a mass to be raised by expending Energy [Input Energy] from something else before it can give back that same Energy [Output Energy].
...

Hi Fletcher. I agree. Nevertheless there is an exchange of energy: the potential energy is stored in the gravitational field or recovered from it. This is not obvious because we always think about objects whose mass (and gravitational field) can be neglected when comparing to the mass of the earth.
 
This becomes obvious when we think of bodies of equal mass.
Suppose the universe with two identical planets far from one each other. Their gravitational field fills the whole space. Now they are attracted and accelerate toward one each other. When they are near from one each other, the gravitational field at about mid distance between them, is reduced or null because their gravity is of opposite direction. But at the same distance from each planet, it was strong when they were at their start point.
 
Thus:
At the start point, at near distance from the planets, there was a strong gravity field.
At the end point, in some areas of space there is a reduced field, even a null field (between the planets).
And energy has been obtained.
We can deduce from this case and from the analogy with electric or magnetic fields and their energy density, that the energy is conserved and has been exchanged between the field and the work done to move the bodies.
It is easy to calculate that the energy density of the gravitational field is g²/(8*pi*G), by the same methode as calculating the energy density of the electric field (1/2*epsilon0*E2) from the work to move between different potentials.
 
In other words the potential energy of bodies depends on the topology of the field in which they are placed. When they move, the field topology changes. When the movement produces energy, the field is globally lowered, what can be verified by integrating its energy density over the whole space:  the quantity of energy that it has lost is the same as the work which has been gained.
This applies in the context of Newton mechanics, not GR.



Omnibus

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Re: Is there proof gravity can not be a energy source?
« Reply #68 on: February 09, 2011, 09:50:32 PM »
Hi Fletcher. I agree. Nevertheless there is an exchange of energy: the potential energy is stored in the gravitational field or recovered from it. This is not obvious because we always think about objects whose mass (and gravitational field) can be neglected when comparing to the mass of the earth.
 
This becomes obvious when we think of bodies of equal mass.
Suppose the universe with two identical planets far from one each other. Their gravitational field fills the whole space. Now they are attracted and accelerate toward one each other. When they are near from one each other, the gravitational field at about mid distance between them, is reduced or null because their gravity is of opposite direction. But at the same distance from each planet, it was strong when they were at their start point.
 
Thus:
At the start point, at near distance from the planets, there was a strong gravity field.
At the end point, in some areas of space there is a reduced field, even a null field (between the planets).
And energy has been obtained.
We can deduce from this case and from the analogy with electric or magnetic fields and their energy density, that the energy is conserved and has been exchanged between the field and the work done to move the bodies.
It is easy to calculate that the energy density of the gravitational field is g²/(8*pi*G), by the same methode as calculating the energy density of the electric field (1/2*epsilon0*E2) from the work to move between different potentials.
 
In other words the potential energy of bodies depends on the topology of the field in which they are placed. When they move, the field topology changes. When the movement produces energy, the field is globally lowered, what can be verified by integrating its energy density over the whole space:  the quantity of energy that it has lost is the same as the work which has been gained.
This applies in the context of Newton mechanics, not GR.

Another piece of total crap. The sorry individual @exnihioest will not stop spewing it, evidently. The gibberish that element is cluttering the thread with has to be nipped in the bud.

There's absolutely no evidence (and there can never be because of the very essence of the concept of fields)  of exchanging energy between bodies at rest with each other neither there is evidence for exchanging energy between stationary withe respect to each other electric charges. Like I said, all these formuli regarding electric and magnetic field are only concerning the potential to do work (consider a charged capacitor) and in no way prove that gravitational, electric or magnetic fields are energy sources. Like I said, it is absolutely not true that there's any exhausting of gravity acting between two stationary bodies of the same size. To assert the opposite is as unscientific as to claim that pigs can fly. As for the gravity formula give, that must be rejected out of hand because it has been "derived" at by one of the most non-scientific bs science has ever had to deal with.

exnihiloest

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Re: Is there proof gravity can not be a energy source?
« Reply #69 on: February 09, 2011, 09:55:13 PM »
Of course the sun is the source of the energy but the sun lasts for billions of year, how long does something have to last to be able to be called perpetual motion. If you wait long enough eventually all atoms will fall apart and nothing is perpetual.

I agree. The sun energy would be enough for humans if we could get it easily.
2/3 of the earth are oceans, so the surface of water that can be evaporated is enormous.
But if we want directly use the sun energy, we have to cover vast surfaces of the earth with panels. In the best case, the sun provides about 1KW/m2. We must divide by 2 due to the alternating day/night. We must divide again by 1 to 1.5 depending on the regions, due to weather conditions. We finally must divide by 3 to 6 due to the solar panel efficiency. Therefore it is not satisfying to cover thousands of Km2 of earth to get energy. It would be possible in space, but not now because of terrible technological problems.



Omnibus

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Re: Is there proof gravity can not be a energy source?
« Reply #70 on: February 09, 2011, 10:04:08 PM »
It is absolutely not true that gravity is derived from Sun's energy or that work done under the action of force of gravity when inducing displacement has anything to do with the energy of the Sun. How long is such confusion going to govern this thread? Solar energy is a topic separate from energy obtained during displacent caused by gravity. Make no mistake about that.

exnihiloest

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Re: Is there proof gravity can not be a energy source?
« Reply #71 on: February 09, 2011, 10:08:42 PM »
Another piece of total crap. The sorry individual @exnihioest will not stop spewing it, evidently. The gibberish that element is cluttering the thread with has to be nipped in the bud.
...
http://tinyurl.com/4h7n5pn

A lack of around 20 IQ points separates Omninut from the most of the other participants. With such a gap, it is well known that communication is not possible.



exnihiloest

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Re: Is there proof gravity can not be a energy source?
« Reply #72 on: February 09, 2011, 10:16:39 PM »
It is absolutely not true that gravity is derived from Sun's energy
...

Completely crazy.   Nobody said that!  ::)
There is a very very big difference between what is said and what Omnibus "understands".
 


Omnibus

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Re: Is there proof gravity can not be a energy source?
« Reply #73 on: February 09, 2011, 10:45:20 PM »
@exnihilosest's incompetence is rampant and the only recourse he has is ad hominem, as evident.

If nobody said that gravity is derived from Sun's energy then why Sun's energy is being discussed  in the context of the question posed here? Solar energy on the one hand and gravity on the other are incompatible in the present discussion. You don't need to spell out that there's connection. The very fact that Sun's energy is discussed in the present context is nothing but incompetence. Let alone giving as an argument a formula "related" to gravity which has no meaning whatsoever. How is an incompetent element such as @exnihiloest to know that said formula has no physical meaning? No way, of course. Like I said, his incompetence is rampant and to conceal that and appear learned he would slap any random formula he has heard of.

brian334

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Re: Is there proof gravity can not be a energy source?
« Reply #74 on: February 09, 2011, 11:46:28 PM »
When the sun sends energy to earth it causes water to evaporate and rise,
The air goes up, the air expands, the water vapor condenses. Next the earths energy/gravity pulls the water down.
The suns energy/light makes the water go up, and the earths energy/gravity makes the water come down.
Case closed gravity is a form of energy.