An experiment to confirm that gravity is a bosonic force

[CraigD]

An experiment to confirm that gravity is a boson-mediated force.

 

The Standard Model of particle physics has been, in terms of experimental verification, arguably the most successful significant scientific theory in history.

 

Yet, the “standard” Standard Model describes only 3 of the 4 fundamental forces – the electromagnetic, the strong nuclear, and the weak nuclear. Attempts to include the 4th force – gravity – have been troubled, failing to gain widespread acceptance of the proposed boson known as the graviton. This omission severely limits the formalism available for branches of Physics like cosmology, and generally leaves science professionals and amateurs with a sense of unease.

 

In a post to the “Speed of light is limited by what?” thread, Southtown suggested that a light clock is a faulty design for a clock for measuring time dilation, but that an analog wrist watch might not be.

 

My initial reaction to this was to point out that an analog wrist watch is as much a light clock as the kind to which the term normally refers. According to the Standard Model, all of the forces involved in the movement of a spring-driven, analog wrist watch result from interactions of bosons, primarily photons of magnetic force between electrons and the quarks that compose protons and electrons in its atoms, and between the electrons in the atomic lattices that comprise the macroscopic parts of the watch. The light clock thought experiment applies as much to this much more complicated arrangement as to the usual, simplified one.

 

It then occurred to me that there is a kind of clock that’s movement does not, according to the “standard” Standard Model, involve boson interaction: A pendulum clock, which, in addition to the usual bosons, depends on the gravitational force.

 

I wonder – is it possible, in principle if not within the limits of practical experimental precision, to falsify the hypothesis that the gravitational force is due to the graviton, by detecting that the gravitational force producing a pendulum clock’s movement does not exhibit relativistic time dilation?

 

PS: I seem to have posted this thread in the wrong forum. It should be in "Physics and Mathematics"

[UncleAl]

1) All force mediators are bosonic by definition. A fermionic force mediator would suffer Fermi exclusion and not degenerately sum.

 

2) If gravitation were quantized gravitons would be spin-2 tensor bosons not spin-1 vector bosons. You would need quadrupole rather than dipole selection rules.

 

3) Since General Relativity assumes h=0, it cannot be quantized. Since the Standard Model assumes G=0, it is not relevant to gravitation. There is no observational evidence that gravitation is quantized. The weakness of gravitation, G as coupling constant, makes such an observation beyond technology as we know it or can imagine it.

 

Relativistic time dilation derives from spacetime geometry. The presence of a physical clock (oscillator, radioactive decay, biological ageing) is irrelevant. For a hanging pendulum with small angular swing (sin(theta)~theta),

 

T_small = 2(pi)sqr([L/a)

 

where "T" is the period, "L" is the suspension length, and "a" is the local acceleration (gravitational or inertial or both). Note that the pendulum bob's mass does NOT appear. Your proposed experiment is specifically excluded by the Equivalence Principle, and that is a founding postulate of General Relativity.

 

If the angular swing is large you get

 

T_large = T_small[1 + (1/2^2)sin^2(theta/2) + (1/2^2)(3^2/4^2)sin^4(theta/2) +...]

 

http://www.iit.edu/~smile/weekly/mp020502.html

http://www.ux1.eiu.edu/~cfadd/1350/13Oscill/Pend.html

[Qfwfq]

I wonder – is it possible, in principle if not within the limits of practical experimental precision, to falsify the hypothesis that the gravitational force is due to the graviton, by detecting that the gravitational force producing a pendulum clock’s movement does not exhibit relativistic time dilation?

There would be no point in such an experiment. Time dilatation is due to the Lorentz coordinate transformations. It means that the time interval between two events is greater than the proper time, in the coordinates other than those for which the two events have the same spatial coordinates. Nothing to do with how the clock works.

[Southtown]

Even though the topic and replies are all way over my head, I think I understand the error of my original question. Thanks all for much brain food.

[Southtown]

I don't claim to know any answers, but it seems I've heard some news that may be relevent to gravity being a boson force.

 

“

Total eclipses of the Sun by the Moon reach maximum eclipse about 40 seconds before the Sun and Moon's gravitational forces align. If gravity is a propagating force, this 3-body (Sun-Moon-Earth) test implies that gravity propagates at least 20 times faster than light.

 

The Earth accelerates toward a point 20 arc seconds in front of the visible Sun, where the Sun will appear to be in 8.3 minutes. Thus, the acceleration now is toward the true, instantaneous direction of the Sun now, and is not parallel to the direction of the arriving solar photons now.

” — [The speed of gravity - what the experiments say. T. van Flandern,

Physics Letters A

. vol.250, no.1-3, Page: 1-11 (1998)] (

alternate PDF document

)

 

Found at this site from UncleAl: http://spacescience.spaceref.com/newhome/headlines/ast12oct99_1.htm

[Southtown]

In a post to the “Speed of light is limited by what?” thread, Southtown suggested that a light clock is a faulty design for a clock for measuring time dilation, but that an analog wrist watch might not be.

Please, forgive my persistent ignorance. I can now understand how analog clocks would be just as distorted as light clocks. But how does the distortion of clocks require the equivalent dilation of time? Is time defined by clocks? It is measured that way, but is that proof that time itself dilates?

[Erasmus00]

Please, forgive my persistent ignorance. I can now understand how analog clocks would be just as distorted as light clocks. But how does the distortion of clocks require the equivalent dilation of time? Is time defined by clocks? It is measured that way, but is that proof that time itself dilates?

 

How else would you define time other then with a clock? You define distance with a ruler.

-Will

[Southtown]

How else would you define time other then with a clock? You define distance with a ruler.

-Will

No. That is merely how you quantify it. It exists outside of being measured.

[CraigD]

No. That is merely how you quantify it. It exists outside of being measured.

You're denying materialism, and affirming formalism (AKA "platonic realism").

 

Though this view is likely the healthier one, in human terms, it's not scientific.

[Erasmus00]

No. That is merely how you quantify it. It exists outside of being measured.

 

Yes, it exists, but it hasn't been fully defined. In science we deal with quantifications, deffinitions. All we can deal with are measurements, so its strange to say that just because the measurements dilate, the thing itself might not. We can never know that. All of what you know could be a reality, only the measurements your senses make change, everything else is static.

-Will

[Qfwfq]

Clocks do not run slower when they are moving. Any given clock is moving at all possible velocities including zero.

 

The makeup of the clock determines the difference between the time coordinates (time interval) of two "ticks" in proper time (in a coordinate system at rest with the clock). From a coordinate system not at rest with the clock the ticks will be further apart. We see the same interval, between the same two ticks, with different space coordinates and different time coordinates. The time interval is longer from our pov, this doesn't depend on how the clock works. It's a coordinate transformation.

 

For any class A of coordinate systems at rest with each other, a given pair of events will be separated by a certain time interval and a certain space interval. The space and time intervals will be different for other coordinate systems (not at rest with the ones in A).

 

Time does not dilate, this is but a manner of speaking.

 

We can never know that. All of what you know could be a reality, only the measurements your senses make change, everything else is static.

:Alien:

[Southtown]

All we can deal with are measurements, so its strange to say that just because the measurements dilate, the thing itself might not.

Because it's the bosonic force mediation that's distorted with motion. The measuring devices are not reliable. What's strange is to consider that time would distort subjectively.

[Erasmus00]

Because it's the bosonic force mediation that's distorted with motion. The measuring devices are not reliable. What's strange is to consider that time would distort subjectively.

 

If every clock (a person's heart, a wrist watch, etc) slows down then its merely semantics as to wether or not time or "the measurement of time" has slowed. As Douglas Adams once wrote "If it looks like a duck, and quacks like a duck, we have to at least consider that we have small aquatic bird of the family anatidae on our hands."

-Will

[CraigD]

If every clock (a person's heart, a wrist watch, etc) slows down then its merely semantics as to wether or not time or "the measurement of time" has slowed....

This gets to the intention of my starting post. Stating with the hypothesis that gravity has a boson (the graviton), I’m proposing that if a clock that used gravity was effected by relative velocity differently (or not at all), the hypothesis would be falsified. For instance, if gravity is due to a classical field - in short, if there’s a force that isn’t bosonic, and gravity is it.

 

Any gravity-measuring device would work for the experiment – a Cavendish torsion beam, for instance.

 

I’m not confident in my formalism (or lack of) – I haven’t had time to actually work it out, and am rusty and at the edge of my understanding of Relativity here, but have at least a hope that the experiment I’d describing is sensible.

 

I don’t expect to the graviton hypothesis will be falsified, and personally hope it’s true. The Standard Model is one of the most elegant theories I know, and one I hope to see grow into a true GUT/TOE.

[Erasmus00]

This gets to the intention of my starting post. Stating with the hypothesis that gravity has a boson (the graviton), I’m proposing that if a clock that used gravity was effected by relative velocity differently (or not at all), the hypothesis would be falsified. For instance, if gravity is due to a classical field - in short, if there’s a force that isn’t bosonic, and gravity is it.

 

You've made an assumption that time dilation is because of bosonic interactions, which in relativity isn't the case. Time dilation is a geometric effect of minkowski spacetime. Time dilates, which effects bosonic interactions and everything else. Even if gravity weren't a boson mediated force, we'd find that time dilation effected it.

-Will