Energy in a Gravitational Wave

[Suppaman]

TL;DR Summary

The Gravity Waves we detect, how much energy do they have?

By the time the gravity wave reaches us it is very small in energy, I assume. We do not know how to make gravity waves in a laboratory but we have a place where we have a very sensitive gravity wave detector. If we had a lab set up a few blocks away we might be able to do various experiments that might make gravity waves. Over a hundred years ago we could make electromagnetic waves but we did not know what they were or what they would lead to, "radios" and more. If the energy in those gravity waves we detect is really very low in energy then some random experiment might be able to generate a very small but detectable gravity wave. If gravity waves are just distortions of "space" there might be some things that might cause them at the really low energy of the waves we do detect.

 

[phinds]

We do not know how to make gravity waves in a laboratory ...

Of course we do. We don't even need a laboratory. Just wave your hand around and you've made gravity waves. I think perhaps you mean something slightly different.

 

[Suppaman]

Orders of magnitude different. And, you say we are making gravity waves but we can not detect them so you are just assuming we do.

 

[berkeman]

(Thread title edited to correct "Gravity Wave" to "Gravitational Wave" -- Gravity waves are like waves on the ocean)

 

[phinds]

Orders of magnitude different. And, you say we are making gravity waves but we can not detect them so you are just assuming we do.

No, I am not assuming we do. We DO. The fact that we can't detect them is irrelevant to our ability to make them.

 

[Ibix]

Nevertheless, as phinds notes, we know exactly how to produce gravitational waves. We just can't throw around the energy needed to do so at detectable levels on demand.

A quick Google search for "power of gravitational waves" will give you an answer. The first detected event released about three solar masses' worth of energy with a peak power output of around 200 solar masses per second (if I did the unit transform right). You could also Google for the Hulse-Taylor binary star, whose orbital decay matches losses to gravitational radiation.

 

[snorkack]

How much energy do gravitational wave detectors actually absorb out of the gravitational wave?

 

[Suppaman]

Nevertheless, as phinds notes, we know exactly how to produce gravitational waves. We just can't throw around the energy needed to do so at detectable levels on demand.

A quick Google search for "power of gravitational waves" will give you an answer. The first detected event released about three solar masses' worth of energy with a peak power output of around 200 solar masses per second (if I did the unit transform right). You could also Google for the Hulse-Taylor binary star, whose orbital decay matches losses to gravitational radiation.

Yes, that was at the source of them but not at the detection point. My question was how much energy at the point of detection.

 

[Suppaman]

No, I am not assuming we do. We DO. The fact that we can't detect them is irrelevant to our ability to make them.

Would it be fair to say I know how to move objects by my thoughts (TK) but we do not have the ability to detect the movement?

 

[phinds]

Would it be fair to say I know how to move objects by my thoughts (TK) but we do not have the ability to detect the movement?

No, that would be moronic. There is no evidence for telekinesis. If you don't want to believe in the science, why are you on a science forum?

 

[Ibix]

How much energy do gravitational wave detectors actually absorb out of the gravitational wave?

Practically none, I would expect.

Yes, that was at the source of them but not at the detection point. My question was how much energy at the point of detection.

The same, divided by the surface area of a sphere of radius whatever the distance to the source is will give you an order of magnitude for the energy flux. It's probably not quite right since emission isn't isotropic and I don't recall off the top of my head if the source was far enough away to need to worry about cosmological redshift.

Would it be fair to say I know how to move objects by my thoughts (TK) but we do not have the ability to detect the movement?

There's a difference between a complete theory like GR, which does predict (tiny) gravitational wave emissions from waving your hands around, and total woo. We know that masses of a few kilograms have static gravitational fields (see the Cavendish experiment) and we know that masses in the few kilogram range can be used to detect gravitational waves. The latter, in particular, is significant because an antenna that can receive a signal and cannot emit one (however poorly) is difficult to imagine. So we have reason to believe that waving your hands produces gravitational waves, but none to believe in telekinesis.

 

[berkeman]

Would it be fair to say I know how to move objects by my thoughts (TK) but we do not have the ability to detect the movement?

"If you believe in psychokinetic powers, please raise my hand."

-Steven Wright, Kurt Vonnegut, and Emo Philips-

 

[Suppaman]

"If you believe in psychokinetic powers, please raise my hand."

-Steven Wright, Kurt Vonnegut, and Emo Philips-

er, CW is required for life. Now, if I did move your arm I am sure it would not be detectable. My first mentor was JWC.

 

[berkeman]

er, CW is required for life. Now, if I did move your arm I am sure it would not be detectable. My first mentor was JWC.

CW = continuous wave? clockwise?

 

[Suppaman]

CW = continuous wave? clockwise?

Morse code is no longer needed for your HAM radio license: www.arrl.org is displayed at the bottom of your post.

 

[berkeman]

Yeah, so how does that explain your post?

 

[Suppaman]

Practically none, I would expect.

The same, divided by the surface area of a sphere of radius whatever the distance to the source is will give you an order of magnitude for the energy flux. It's probably not quite right since emission isn't isotropic and I don't recall off the top of my head if the source was far enough away to need to worry about cosmological redshift.

There's a difference between a complete theory like GR, which does predict (tiny) gravitational wave emissions from waving your hands around, and total woo. We know that masses of a few kilograms have static gravitational fields (see the Cavendish experiment) and we know that masses in the few kilogram range can be used to detect gravitational waves. The latter, in particular, is significant because an antenna that can receive a signal and cannot emit one (however poorly) is difficult to imagine. So we have reason to believe that waving your hands produces gravitational waves, but none to believe in telekinesis.

My thought revolves around using the current GW detectors to detect GWs we might generate on earth. I think the experiments you described were not detecting GWs, just a mass near by.

 

[Suppaman]

Yeah, so how does that explain your post?

About the value of CW?

 

[berkeman]

About the value of CW?

er, CW is required for life.

Time to 'splain yourself...

 

[Suppaman]

Time to 'splain yourself...

As it is well known that only CW can communicate when all other methods fail. When voices are a babble and the noise is painful the narrowest bandpass will help focus the mind and communication will be accomplished.

 

[berkeman]

As it is well known that only CW can communicate when all other methods fail.

Not true for any EE-trained folks, but it's okay that you think that as just a HAM. No worries.

You have veered this thread into woo from a valid original post. To learn more about Gravitational Waves (not Gravity Waves), start with this Wikipedia intro article and follow some of the helpful references and links:

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

This thread is closed. 73