h a l f b a k e r yNot so much a thought experiment as a single neuron misfire.
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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.
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]
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Annotation:
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Depends how big they are, [nmrm]. |
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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? |
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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. |
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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". |
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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. |
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[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. |
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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. |
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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. |
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We have had this exact discussion, repeatedly and
extensively, and there is nothing new in this
"idea" that makes it worth rehashing yet again. |
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[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. |
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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)
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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??? |
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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. |
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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". |
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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". |
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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). |
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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! |
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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? |
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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. |
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And that is the same conclusion we've reached every
time you have re-written this concept. |
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If gravity waves, should we wave back? |
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It's the polite thing to do. |
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[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. |
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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. |
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[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. |
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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. |
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[MechE], are you saying that that 500g-capable,
micro-g sensitive device is the thing that the bullet
hits? |
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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. |
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Well, this is the first I've heard of anything with such
sensitivity surviving that sort of impact. Can you
provide a link? Thanks! |
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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). |
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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. |
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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.) |
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But even IF you had a perfectly efficient, 100%
unidirectional gravity-wave emitter, it would be
functionally useless for thrust! |
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(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.) |
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[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. |
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