# The Naked Scientists Forum

### Author Topic: Do gravitational waves propagate faster than light waves?  (Read 21057 times)

#### JP

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##### Re: Do gravitational waves propagate faster than light waves?
« Reply #75 on: 11/01/2011 05:36:10 »
3. Causing and maintaining this distortion, in spite of spacetime's natural tendency to resist it, requires no energy.

This is where the rubber sheet analogy breaks down.  A rubber sheet is naturally flat because there is a resistive force keeping it that way.  To bend it, you need to provide a force to overcome this.  Just putting something on the sheet isn't enough--you have to push it into the sheet with force to get the sheet to bend.

Space-time and gravity isn't like this.  Just having mass there is enough to bend space-time.  There is no additional force required to create or maintain the bending.  To use a mechanical engineering term, things are in static equilibrium, so no additional energy is required to keep them this way.

Causing the distortion in the first place would require energy, but this is accounted for by mass-energy equivalence.  The mass has energy associated with it, and it is this energy that accounts for creating the curvature in the first place.

#### Foolosophy

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##### Re: Do gravitational waves propagate faster than light waves?
« Reply #76 on: 11/01/2011 05:38:05 »
It certainly cant be with the stochastic nuerosis that Quantum Physicists are inflicted by.

Why not?

,,,the fundamentals of QED are based upon the admission of "error" - that's why ridiculous counter intuitive conclusions are spawned. (the fact that QED has great predictive accuracy and is a useful mathematical tool is not relevant)

How is it founded upon the admission of "errors"?  Can you give specific examples?  (I'm not saying you're wrong here--there are reasons not to think that QED is the full story, but these claims seem a bit strong from what I know of it.)

Stochastic methods are based on the quantification of errors

Thats what the statistical nature of QED is founded upon

Ah.  That's the problem.  It isn't based on quantifying errors.  It's built on probability from the ground up, not on quantifying errors.

QED is not a deterministic theory that is based on first principles

Quantum behaviour that is explained using probability is a temporary approach that offers non-sensical irrational approximations and estimates of what is really going on in the atomic and sub-atomic worlds

Although QED generates accurate predictions, its conclusions are insane and should not be taken literally.

QED is on its last legs. It will be superceded in the next 2 or 3 centuries by a deterministic theory that can be validated using first principles and basic logic and rationale
« Last Edit: 11/01/2011 05:41:58 by Foolosophy »

#### yor_on

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##### Re: Do gravitational waves propagate faster than light waves?
« Reply #77 on: 11/01/2011 15:54:14 »
Maybe you are right in a way Foolosophy. I read somewhere that the Eskimos had 2-300 word describing snow. that's what I expect to happen in QM too. We will find new descriptions that suddenly will make a new sense to us. But I expect us to need to modify what we call a 'linear' behavior to fit this new paradigm.
==

Still, I don't see the beef you have with it. Do you accept Heisenberg uncertainty principle? Why? If you want to find a deterministic logic built on Newtonian principles you will have to refute it. Starting to think of it I'm sure I can find a lot examples like that. Indeterminacy as we see it Foolosophy is only as we see it. That's what the Feigenbaum constant tells me.

(Sorry, used the wrong name. Slept overlong, again, corrected now though:)
« Last Edit: 11/01/2011 16:07:11 by yor_on »

#### imatfaal

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##### Re: Do gravitational waves propagate faster than light waves?
« Reply #78 on: 11/01/2011 18:16:28 »
2. If the mass were suddenly removed, spacetime would revert to its undistorted state.

Not sure this is a valid statement at all Bill. Even a gedanken needs to follow some rules - masses do not suddenly disappear.  If one postulates a complete transfer to energy, then this energy will cause exactly the same distortion in spacetime as its corresponding mass did (although some it will then radiate away).  With the conservation of energy there is just no way you can correctly ask/answer that question.  If you change the rules to ask the question then you cannot use the rules to answer it.

#### Bill S

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##### Re: Do gravitational waves propagate faster than light waves?
« Reply #79 on: 11/01/2011 19:21:01 »
Quote from: Bill
If the mass were suddenly removed, spacetime would revert to its undistorted state.

I read in a P S book (don't remember which one)an account of what the Earth would experience if the sun suddenly vanished.  The author was not suggesting that this was a physical possibility, it was more in the nature of a thought experiment (OK,gedanken, if you will).  My intention was simply to impute an elasticity to spacetime, not to suggest magical effects.

Quote from: JP
This is where the rubber sheet analogy breaks down.  A rubber sheet is naturally flat because there is a resistive force keeping it that way.  To bend it, you need to provide a force to overcome this.

I was trying to avoid the rubber sheet, but since you mention it, I agree that "To bend it, you need to provide a force".  If I sit on a trampoline I cause an indentation, the "force" causing and maintaining this is gravity, but gravity is not a force and expends no energy. (?)

#### Bill S

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##### Re: Do gravitational waves propagate faster than light waves?
« Reply #80 on: 11/01/2011 19:30:48 »
Quote from: JP
“There is no additional force required to create or maintain the bending”……… “Causing the distortion in the first place would require energy”.

Is it me, or is there a contradiction here?

#### Geezer

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##### Re: Do gravitational waves propagate faster than light waves?
« Reply #81 on: 11/01/2011 21:47:48 »
Quote from: JP
“There is no additional force required to create or maintain the bending”……… “Causing the distortion in the first place would require energy”.

Is it me, or is there a contradiction here?

I don't see a contrdiction.  For example, it required energy to put the Moon in orbit around the Earth (possibly as the result of a collision with another large object) but once the Moon began to orbit the Earth, regardless of the model you choose, no additional energy or force is required.

The graviational effect is similar to a piece of string that connects the two objects.

#### Bill S

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##### Do gravitational waves propagate faster than light waves?
« Reply #82 on: 12/01/2011 01:38:54 »
Let's focus in a little.

"no additional force required to create...the bending"

"Causing the distortion in the first place would require energy"

Still no contradiction?   It's late at night, I might not be thinking straight.

#### JP

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##### Do gravitational waves propagate faster than light waves?
« Reply #83 on: 12/01/2011 02:02:01 »

You need to put a mass there to create the bending initially.  E=mc2, so that matter is energy.  Therefore you need energy to create the bending.  But that mass is all the energy you need (if we assume you somehow created the mass from energy at that point, so you didn't need to push it there).

Once the mass is there no further energy needs to be put in and the bending will stay forever.

#### The Naked Scientists Forum

##### Do gravitational waves propagate faster than light waves?
« Reply #83 on: 12/01/2011 02:02:01 »