Creation of gravity waves

[DimaMazin]

Let's consider rotating rod in gravitational field of heavy body. Axis of rotation is perpendicular to the rod. Does the rotation of the rod create more detectable gravity waves when the rotation axis is a tangent of curvature of space of the heavy body than when the rotation axis is perpendicular to the tangent of curvature of space of the heavy body?

[Enthalpy]

Hi Dim!

 

what I can tell is that the Weber bar isn't capable of producing a detectable wave

https://en.wikipedia.org/wiki/Weber_bar

the best possible effect is a near-field which isn't a propagating wave.

 

I won't risk an opinion about the orientation in the heavy body's field. Just a guess: both effects being small, I expect them to add linearly.

[DimaMazin]

Hi Dim!

 

what I can tell is that the Weber bar isn't capable of producing a detectable wave

https://en.wikipedia.org/wiki/Weber_bar

the best possible effect is a near-field which isn't a propagating wave.

 

I won't risk an opinion about the orientation in the heavy body's field. Just a guess: both effects being small, I expect them to add linearly.

Hi!

My question was theoretical. If the same mass lose more energy in stronger gravity than in weaker gravity for gravity emission then vertically rotating rod creates stronger gravity waves than horizontally rotating rod with the same mass and shape,and the same point of rotation in gravitational field.

Edited April 11, 2016 by DimaMazin

[Enthalpy]

I'd strongly prefer a more knowledgeable person to answer...

 

From page 3 of Claudio Casciano Tesi di Dottorato, the emission depends on the second time derivative of the source's quadrupole moment. Since the moments add when you add more items (at least at the center of mass of the rotating bar) the existence and fixed position of an additional heavy body should make no difference.

 

Is that for not too strong fields only?

[Mordred]

The answer really depends on which mass your using.

 

If you use rest mass of the two objects or the enertial mass.

 

For the OP if you place the same dumbbells into a higher gravitational potential they would gain inertial mass. So they wouldn't be the same mass.

 

As they gain in inertial mass they would emit stronger gravity waves.

 

Remember GR teaches that inertial mass and gravitational mass are identical.

You can find the formula for radiated power

 

https://en.m.wikipedia.org/wiki/Gravitational_wave

 

under mathematics.

 

They provide a Newtonian style formula for power.

Edited April 13, 2016 by Mordred

[DimaMazin]

I'd strongly prefer a more knowledgeable person to answer...

 

From page 3 of Claudio Casciano Tesi di Dottorato, the emission depends on the second time derivative of the source's quadrupole moment. Since the moments add when you add more items (at least at the center of mass of the rotating bar) the existence and fixed position of an additional heavy body should make no difference.

 

Is that for not too strong fields only?

In my case rotating ends interact not only each other but with big mass too.

 

a/r³+a/r³ < a/(r-x)³ + a/(r+x)³