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# Gravity Waves3

Let's put one of those stick-slip devices into orbit
 (-2) [vote for, against]

This is another proposed experiment regarding things already presented in the "Gravity Waves" and "Gravity Waves2" posts. One thing needs to be cleared-up right away, however, and it is a point of "terminology".

There are two phrases that average folks think are completely interchange-able: "gravity waves" and "gravitational waves". The actual topic of these posts has been "gravitational waves" --"gravity waves" are a very different thing (see link). Nevertheless, partly because of common usage, and partly because of all the editing that would need to be done in those other posts, I shall continue to refer to "gravitational waves" as "gravity waves", at least in the Title here.

The main hypothesis to test is the notion that a gravitational wave might be emitted during the physical impact of one mass against another, and that a gravitational wave can carry some Momentum off. In this particular Idea, we shall start with a known type of gadget that works using something called the "stick-slip phenomenon" (see link).

The simplest version of the gadget (this relies on gravity so can't work in Space) has a solid block resting on the ground, and a kind of tower at one end of the block. From the top of the tower descends a hammer. The head of the hammer contacts a side-wall of the solid block; the end of the hammer's handle is on a rotate-able shaft at the top of the tower. A mechanism rotates the shaft and the hammer is moved away from the block.

After the hammer is moved away far enough, the mechanism then lets the hammer loose, to swing downward freely, and impact the block. The impact overcomes friction and causes the block to move a small amount.

We can re-design that gadget to use springs instead of gravity, for moving the hammer toward the block. Our re- design also needs to ensure other things are completely balanced out (like Angular Momentum). Here is a partial ASCII sketch:
|-|------------
|-|----------------------
|-|------------

The top and bottom horizontal lines represent the body of the Block. The vertical lines represent the Hammer Head, and the middle horizontal line represents the Hammer Handle, a simple shaft passing through the body of the Block.

Now consider a rack-and-pinion (see link). We want our Hammer Handle to be the Rack, and we want our mechanism (not shown) to rotate two decent-diameter Pinions, one on either side of the Rack. We also want the two Pinions to be deformed in a special way--a few gear teeth are removed from a crucial location.

So, the mechanism slowly rotates the two Pinions, causing the Hammer Handle to move the Hammer Head away from the Block. Springs (not shown) would cause the Hammer Head to be pulled back toward the Block, but they can't do it until the "toothless" sections of the Pinions rotate into non-action....

We now take this Device and launch it into Orbit. It is carefully oriented and placed to be stationary relative to things surrounding it (like the interior of the International Space Station). We now remotely activate the Device in order to find out if anything unexpected can happen.

IF the hypothesis being tested has any validity, then the force of impact should generate a gravitational wave and carry a small amount of Momentum away. This leaves the remaining Momentum of the Device unbalanced, and *that* should be observe-able in the zero-gee environment, especially since the effect should be cumulative with multiple impacts.

The Device might also be taken outside through an air lock and tested there, just in case the atmosphere inside the ISS affects the outcome of the Experiment.

 — Vernon, Nov 08 2013

Two types of G-waves http://astroengine....ats-the-difference/
As mentioned in the main text. [Vernon, Nov 08 2013]

Stick-slip phenomenon http://jnaudin.free.fr/html/abssldrv.htm
As mentioned in the main text. [Vernon, Nov 08 2013]

Rack and Pinion http://en.wikipedia...iki/Rack_and_pinion
As mentioned in the main text. [Vernon, Nov 08 2013]

Impacts and Gravitational Waves http://web.archive....01%20Manuscript.pdf
Here is General Relativity being used to show how "matter under stress" (such as happens during an impact) might be expected to radiate a gravitational wave. [Vernon, Nov 08 2013]

Simple Quantum Gravitation http://vernonnemitz...on-131braj0vi27a-2/
As mentioned in an annotation. Near the bottom of this article is a table showing a "negative mass nullification event" in a bunch of Reference Frames, along with resulting left-over amounts of Kinetic Energy, and possible Velocities for that "momentum quantum". [Vernon, Nov 08 2013, last modified Nov 09 2013]

Drop and Stop Test Drop-and-Stop_20Test
As mentioned in an annotation. [Vernon, Nov 08 2013]

Another stick-slip device FARTRRRR-R-R-R
Accelerate metallic ions gently and decelerate them in a tungsten target [neelandan, Nov 19 2013]

Tricky to surf.
 — not_morrison_rm, Nov 08 2013

Depends how big they are, [nmrm].
 — pocmloc, Nov 08 2013

 You do notice the bit where even your crackpot source for information on reactionless drives points out that stick slip drives are not one, right?

We've been over this. If such things occurred at a mechanical scale, we would be able to detect them in every day devices. We can't. They don't.
 — MechE, Nov 08 2013

 To clarify, it is possible that this device will produce (extremely minute) gravitational waves, since it has accelerating masses. This wave would not be directional, nor would it sap momentum from a particular direction of movement, since both the hammer and the anvil accelerate. Therefore, it would not leave "the momentum of the device unbalanced".

In addition, basic orbital perturbations would be more than sufficient to outweigh and expected change in momentum of the device. Additionally, the deformation of the hammer and anvil would likewise swamp any results from any gravitational waves. Therefore this is not sufficiently precise to detect such waves if they do exist, nor will it provide any net form of acceleration.
 — MechE, Nov 08 2013

[MechE], please don't confuse different Theories/Hypotheses. "Normal" GR theory says nothing about stressed matter; it only talks about acceleration and/or gravitation. I completely agree that any gravitational waves from this Device, resulting from acceleration, will be insignificant. The hypothesis to test here, however, involves rate-of-change of acceleration, "jerk", remember? So, the 4th link here shows how the stress of jerk, during an impact upon matter, might result in rather-more-significant gravitational radiation. At least with respect to the zero-gee environment, anyway.
 — Vernon, Nov 08 2013

 I was trying to give you the benefit of the doubt, and not assume that you were basing your entire idea on one poorly referenced and un-published and unpeer-reviewed paper.

 If you are, in fact doing so, than ignore my clarification bit, and I return to the fact that we would detect forces on the level you are discussing in every car crash test, every bullet impact test, every everything we do on a daily basis, and we don't.

We have had this exact discussion, repeatedly and extensively, and there is nothing new in this "idea" that makes it worth rehashing yet again.
 — MechE, Nov 08 2013

 [MechE], I've stated elsewhere that there appear to be as many as six different starting points in Physics from which it is possible to conclude those more-significant gravitational waves might be able to exist.

 The starting point in Quantum Mechanics involves individual particles and the notion of "negative mass", a hypothetical but not-known-to-be- impossible thing. Look at this interaction: (m) (v)--->(poof!)<---(-m) (-v)

 You can easily see that if the masses and velocities have equal and opposite magnitudes, then the interaction yields 0 mass left over, 0 kinetic energy left over, but ALL the momentum left over. What *form* can that momentum have???

 If the interaction is viewed in a slightly different Reference Frame, such that the velocities are not exactly equal and opposite, then some kinetic energy will be left over, along with, still, *all* the momentum. So now the leftover *thing* can possess both momentum and kinetic energy, yet not possess mass.

 One way of being consistent about this thing's kinetic energy, when it is Zero in the original equal/opposite interaction, is to think of a "momentum-possessing thing" that is moving at zero velocity. When it moves at any other velocity, *then* it also possesses kinetic energy (the product of the velocity and the momentum). The thing is not "energy in motion" like a photon; it is instead pure "energy OF motion".

 I once worked out an overview of how *that* mass-less momentum-possessing thing, "a quantum of momentum", could be used to explain the Gravitational Force, in terms of "exchanges of virtual particles", per the rules of Quantum Mechanics. And therefore I am talking about "gravitons" as well as momentum-quanta --which, whenever they exist "en masse", could form a "gravitational wave".

 The main relevant notion of the above is simply that momentum might be able to exist independently of ordinary mass or energy. I'm aware that in General Relativity, Momentum is given as much fundamental importance as Energy, yet nowhere is it portrayed as being able to have an *independent* existence, the way Energy can (as photons, for example).

 Do you know of any rationale why Momentum should *never* be able to exist independently of Mass or Energy? So far as I'm aware, nobody has such a rationale --and therefore the notion is worthy of exploration --and experimentation, regarding ways to generate it without negative mass being involved!

By the way, we have elsewhere (see "Drop and Stop Test" link) discussed the NON-obviousness of the evidence that needs to be found to support the notion that "jerk" can lead to effects that ordinary considerations of "acceleration" don't predict. So why are you saying the effects would actually be easy to detect?
 — Vernon, Nov 08 2013

 Because the results would be an apparent violation of conservation of energy. At the magnitudes involved in Einsteinian gravitational waves, it is below our ability to detect (yet). If there is a significantly higher output source, that missing energy is readily detected.

And that is the same conclusion we've reached every time you have re-written this concept.
 — MechE, Nov 08 2013

If gravity waves, should we wave back?
 — MaxwellBuchanan, Nov 08 2013

It's the polite thing to do.
 — Alterother, Nov 08 2013

And does dark matter?
 — MaxwellBuchanan, Nov 08 2013

[MechE], instrumentation designed to precisely make the measurements you are talking about are not tough enough to survive things like automobile crashes and bullet impacts. So, just because some hypothetical "missing energy" might be in range of our detection abilities, that doesn't mean we can yet actually do it in practicality.
 — Vernon, Nov 09 2013

I suppose measuring gravity comes down to the precis measurement of a gap containing a void in spacetime which can't contain the wave effect. In any normal gap the transfer test itself will be affected as the wave rolls through.
 — wjt, Nov 09 2013

 [Vernon] Yes it is. 500g capable, with micro-g sensitivity exist. More to the point, bullet impacts are frequently measured by measuring the impact on the target. That's exactly where you would detect this.

This ignores more extreme cases like the energy coming out of a CERN collision, where the results match theoretical models without any need to account for the sort of term you are proposing.
 — MechE, Nov 10 2013

[MechE], are you saying that that 500g-capable, micro-g sensitive device is the thing that the bullet hits?
 — Vernon, Nov 11 2013

It's the thing that's built into the bullet, or artillery shell, or car. And into the thing said object hits. Precisely measuring impact forces is not something that is exactly unusual.
 — MechE, Nov 12 2013

Well, this is the first I've heard of anything with such sensitivity surviving that sort of impact. Can you provide a link? Thanks!
 — Vernon, Nov 12 2013

 Even IF a perfectly gravity-wave emitter existed, it would STILL be useless for thrust. (At least, unless you plan to break either conservation of energy or conservation of momentum).

 Gravity waves CAN carry momentum, it's true. But this momentum is directly related to their energy, via the standard equivalence of e = pc. This means that a gravity-wave thruster is essentially equivalent to a photon thruster, with energy requirements of three hundred freaking megawatts for one lousy newton of thrust. If you want to put out more thrust than that for a lower energy expenditure (using a gravity-wave thruster), then you're going to have to break conservation of energy and have greater energy output than input, because the momentum carried by a gravity wave is always related to the energy it carries by that relationship.

 This is assuming it's possible to get unbalanced gravity-wave thrust out of stick-slip devices, which I doubt. (That said, there may be ways to get unbalanced emission of gravitational waves - some research indicates that superconducting sheets could be used as a "mirror" for gravitational waves.)

 But even IF you had a perfectly efficient, 100% unidirectional gravity-wave emitter, it would be functionally useless for thrust!

(And Vernon, if you really MUST insist on getting a net thrust out of jiggling objects, I recommend you look up E. B. Woodward's research on the Mach effect.)
 — Hive_Mind, Nov 12 2013

[Hive Mind], I do know about Woodward's work. It is another of the "as many as six different starting points in Physics" that I mentioned earlier.
 — Vernon, Nov 12 2013

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