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# Shapiro (or Shapiro-like) delay of GW signals (split)

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Did anyone answer this question?

The mass of an object is not "gravitational information"? If, let's say, a new particle appears in a place, or a star collide with an antimatter star, how the information about the new/missing mass/gravitational pull travels, faster than light would travel?

In swansont's link you can see:

• In Newtonian gravity, you can have instantaneous action at a distance. If I suddenly
replace the Sun with a 10, 000M! black hole, the Earth’s orbit should instantly repsond in
accordance with Kepler’s Third Law. But special relativity forbids this!
• The idea that gravitational information can propagate is a consequence of special relativity:
nothing can travel faster than the ultimate speed limit, c.

So, consider this: the delay is larger and measurable. When the signal passes each BH, it is delayed by 100 ms. ...

Why 100ms and not 300ms, or even 10s?

Let's consider t = the time needed for gravitational information from BH1 and BH2, when side by side, to reach the Earth observer (EO), and T = the orbital period for the last orbit before BH1 and BH2 merged.

1. At aprox. t + T/4 , gravitational information from BH1 is received by EO, while the one from BH2 (behind BH1) is Shapiro delayed with more than T, so it's on its way towards EO.

2. At t +T/2 we receive gravitational information from BH1 and BH2 (again side by side). The one from BH2 in step 1 is still on its way.

3. At aprox. t + 3T/4 , gravitational information from BH2 (now in front of BH1) is received by EO, while the one from BH1 (now behind BH2) is Shapiro delayed with more than T.

4. At t + T the merge is complete and the gravitational information from BH2 in step 1 and BH1 in step 3 are still on their way to EO.

Of course, things are not that simple (we still need GR for the full solution), but it is a good way to see how gravitational information (and gravitational pull) fluctuate at EO with 2 times the orbital frequency, due to Shapiro delay.

What does the above [dark matter/energy] have to do with Shapiro delay? The average energy/density of the intergalactic and interstellar medium isn't sufficient to cause a delay.

Not with Shapiro delay but with GR calculation (I asked: How you included dark energy, dark matter and Higgs field in your equations?). You think that the BBH region was DM/E free? Why?

Edited by DanMP

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Did anyone answer this question?

It seems to be answered in the bit of swansont's post you quote. No information can travel faster than the speed of light, so the changes to the mass would propagate at that speed.

Of course, things are not that simple (we still need GR for the full solution), but it is a good way to see how gravitational information (and gravitational pull) fluctuate at EO with 2 times the orbital frequency, due to Shapiro delay.

You haven't shown that this will cause "gravitational pull" to fluctuate (you have merely asserted that it will). Nor have you shown, quantitatively, that this effect will correspond to what is observed.

For example, why would the black holes get closer to one another (and the orbits increase in speed)?

Not with Shapiro delay but with GR calculation. You think that the BBH region was DM/E free? Why?

"Not sufficient" is not the same as not present. If you think that the presence of dark matter and/or dark energy is significant, please show the calculations to support it.

Edited by Strange
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Did anyone answer this question?

I think the answer is that if you violate physical law, the result is not necessarily knowable. A particle "just appearing" violates conservation of energy. Regardless, though, the information should travel at c. A matter/antimatter interaction would not change the energy present, just change the form of that energy.

As for the rest, it occurs to me that a serious problem would occur if there was a delay in the gravitational information. A BH could swing around in its orbit, but you are claiming a delay in the information, so there would necessarily be a retardation effect. It could even reach π phase delay, by which point I wouldn't be surprised to have the orbit completely disintegrate. What would happen if the attraction was directed at a point significantly offset from where the star was? You wouldn't have a circular orbit anymore, and possibly not a stable one.

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For example, why would the black holes get closer to one another?

This is a good question. You'll see the correct answer in my relativity.

(and the orbits increase in speed)

Angular speed.

"Not sufficient" is not the same as not present. If you think that the presence of dark matter and/or dark energy is significant, please show the calculations to support it.

"the presence of dark matter and/or dark energy is significant" if you want to understand things:

... all of physics is tied together; no one part stands alone.

... Even if it gives the right answer, that's purely accidental.

... it will fail horribly for ...

From here: https://en.wikipedia.org/wiki/Spacetime

In physics, spacetime is any mathematical model that combines space and time into a single interwoven continuum.

the effect you are invoking to explain it seems less intuitive than the "ripples in the fabric of space-time" used in the popular press.

To consider "ripples in the fabric of space-time" is as stupid as considering ripples in a number or in an equation.

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Why 100ms and not 300ms, or even 10s?

Let's consider t = the time needed for gravitational information from BH1 and BH2, when side by side, to reach the Earth observer (EO), and T = the orbital period for the last orbit before BH1 and BH2 merged.

1. At aprox. t + T/4 , gravitational information from BH1 is received by EO, while the one from BH2 (behind BH1) is Shapiro delayed with more than T, so it's on its way towards EO.

2. At t +T/2 we receive gravitational information from BH1 and BH2 (again side by side). The one from BH2 in step 1 is still on its way.

3. At aprox. t + 3T/4 , gravitational information from BH2 (now in front of BH1) is received by EO, while the one from BH1 (now behind BH2) is Shapiro delayed with more than T.

4. At t + T the merge is complete and the gravitational information from BH2 in step 1 and BH1 in step 3 are still on their way to EO.

Of course, things are not that simple (we still need GR for the full solution), but it is a good way to see how gravitational information (and gravitational pull) fluctuate at EO with 2 times the orbital frequency, due to Shapiro delay.

Even if this explains the frequency, it also implies the modulation problem I already explained, and which you have not addressed. Also, it only explains the frequency for edge-on observing, whereas the frequency predicted by GR is not restricted to this geometry.

"the presence of dark matter and/or dark energy is significant" if you want to understand things:

Strange was asking for evidence of a significant amount of one or both, not a hand-wave.

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This is a good question. You'll see the correct answer in my relativity.

So you admit it isn't explained by your Shapiro delay idea?

In which case, we come back to what the point is of a model that doesn't reflect reality?

"the presence of dark matter and/or dark energy is significant" if you want to understand things:

Perhaps you mean something different by "significant" than I do. Let me rephrase the question:

Please show, quantitatively, that the presence of dark matter and/or dark energy has a measurable effect on the gravitational waves produced by a pair of orbiting black holes.

Edited by Strange
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Please show, quantitatively, that the presence of dark matter and/or dark energy has a measurable effect on the gravitational waves produced by a pair of orbiting black holes.

I can and will show you that "dark matter and/or dark energy" were already included in GR. Where? In the postulates. So GR is based on "them". That's why GR calculations & solutions are OK. Only the understanding (ripples in spacetime) is horribly wrong.

Even if this explains the frequency, it ...

All I wanted in this topic was to be the first to mention the Shapiro delay idea. I admit that it is incomplete and that I cannot do better for now, so you may close the thread if you want.

P.S. Please change the title from "Shapiro (or Shapiro-like) delay of GW signals" to "Shapiro (or Shapiro-like) delay explanation for GW150914".

Edited by DanMP
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I can and will show you that "dark matter and/or dark energy" were already included in GR. Where? In the postulates. So GR is based on "them".

Dark matter and dark energy are NOT included in the postulates of GR (they weren't even known of at the time.)

But perhaps you could provide some evidence for this claim? (I assume not, as you never do.)

That's why GR calculations & solutions are OK.

However, none of this addresses (or is even relevant to) the question asked:

Please show, quantitatively, that the presence of dark matter and/or dark energy has a measurable effect on the gravitational waves produced by a pair of orbiting black holes.

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I can and will show you that "dark matter and/or dark energy" were already included in GR. Where? In the postulates. So GR is based on "them". That's why GR calculations & solutions are OK. Only the understanding (ripples in spacetime) is horribly wrong.

You're missing the point. You are being asked to show that there is a significant amount of dark matter and/or dark energy that you have to account for in the region of the black holes, that's somehow not already accounted for with their mass. You quoted "the total mass–energy of the universe contains 4.9% ordinary matter, 26.8% dark matter and 68.3% dark energy", but that's not to say that this fraction applies specifically near the black holes. It's up to you to show that this has any relevance to the discussion.

All I wanted in this topic was to be the first to mention the Shapiro delay idea. I admit that it is incomplete and that I cannot do better for now, so you may close the thread if you want.

"Incomplete" is a generous description.

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Dark matter and dark energy are NOT included in the postulates of GR (they weren't even known of at the time.)

Not known but present.

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Not known but present.

Because GR depends on energy. If a BH is 30 solar masses, we don't care about the composition. 30 solar masses is 30 solar masses.

So, again, what is the evidence that any of this matters?

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Not known but present.

So you are not going to support any of your claims? (As expected.)

1. Please provide some evidence that dark matter and dark energy are postulates of GR.

2. Please show, quantitatively, that the presence of dark matter and/or dark energy has a measurable effect on the gravitational waves produced by a pair of orbiting black holes.

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I can and will show you that "dark matter and/or dark energy" were already included in GR. Where? In the postulates. So GR is based on "them". That's why GR calculations & solutions are OK. Only the understanding (ripples in spacetime) is horribly wrong.

".

Not sure I follow your logic, You claim to have no problem with the EFE, yet at the same time don't understand that the ripples are geometric changes to the spacetime.

Then you wish to add your own explanation of a time delay(Shapiro delay ) to a metric that already included time dilation effects.

As Strange stated might help if you sit down and show the math.

Secondly dark energy is of too low an energy density to cause any dilation effects (it is included in the EFE)

So is dark matter As the EFE doesn't care which particles are involved.

The EFE uses mass/energy density.

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Because GR depends on energy. If a BH is 30 solar masses, we don't care about the composition. 30 solar masses is 30 solar masses.

So, again, what is the evidence that any of this matters?

If instead of 2 BHs we would have 2 stars, with the respective masses, we would receive the same "chirp"? The inspiral would be exactly the same?!?

DM is different than normal matter, so it is important to consider it at such when you calculate the inspiral, etc.. Did you? I'm still waiting for your response to my (prior) question:

... How you included dark energy, dark matter and Higgs field in your equations? ...

Until now you offered misinterpretations:

What does the above have to do with Shapiro delay? The average energy/density of the intergalactic and interstellar medium isn't sufficient to cause a delay.

hand-waves:

You're missing the point. You are being asked to show that there is a significant amount of dark matter and/or dark energy that you have to account for in the region of the black holes, that's somehow not already accounted for with their mass. You quoted "the total mass–energy of the universe contains 4.9% ordinary matter, 26.8% dark matter and 68.3% dark energy", but that's not to say that this fraction applies specifically near the black holes. It's up to you to show that this has any relevance to the discussion.

(Dark matter is gravitationaly attracted, so near BBH it should be a lot)

or, instead of answering my (prior) question, you ask me imperatively to answer another:

Please show, quantitatively, that the presence of dark matter and/or dark energy has a measurable effect on the gravitational waves produced by a pair of orbiting black holes.

disregarding this:

I can and will show you that "dark matter and/or dark energy" were already included in GR. Where? In the postulates. So GR is based on "them". That's why GR calculations & solutions are OK.

To show you how exactly the postulates included DM/E, I have to open a new thread, "Dark ... relativity". Until than I have to post my Fizeau & Sagnac explanation.

I have to insist with this:

Please change the title from "Shapiro (or Shapiro-like) delay of GW signals" to "Shapiro (or Shapiro-like) delay explanation for GW150914".

because the thread was opened in my behalf ... and the title does not reflect what I meant.

The EFE uses mass/energy density.

And how do you know DM density? It can compress? How much?

Edited by DanMP
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If instead of 2 BHs we would have 2 stars, with the respective masses, we would receive the same "chirp"? The inspiral would be exactly the same?!?

It would be different, because the stars would not get anywhere near as close to each other before merging. The gravitational waves would therefore be weaker and lower frequency. If you read the paper, you will see that is one of the reasons they know this was a pair of black holes and not neutron stars, for example.

DM is different than normal matter, so it is important to consider it at such when you calculate the inspiral, etc.. Did you? I'm still waiting for your response to my (prior) question:

You can't shift the burden of proof: it is your claim that they are important; you need to show that is the case.

or, instead of answering my (prior) question, you ask me imperatively to answer another:

disregarding this:

Because it is your claim, therefore you need to support it.

And all that is "disregarded" is a another assertion that you refuse to support.

And how do you know DM density?

This data is readily available. If it is important to your hypothesis, you should already have it.

Edited by Strange
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If instead of 2 BHs we would have 2 stars, with the respective masses, we would receive the same "chirp"? The inspiral would be exactly the same?!?

Not sure how you could have the same conditions without having black holes, so I doubt you would have the same signal.

DM is different than normal matter, so it is important to consider it at such when you calculate the inspiral, etc.. Did you? I'm still waiting for your response to my (prior) question:

You directed that question at Mordred. Why would you expect me to answer it?

Until now you offered misinterpretations:

hand-waves:

You're quoting two different people here.

(Dark matter is gravitationaly attracted, so near BBH it should be a lot)

Do you have any physics to back that up?

or, instead of answering my (prior) question, you ask me imperatively to answer another:

You're the one who brought the topic up, and made a claim. You should be prepared to justify it.

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It would be different, because the stars ...

Of course it would be different. That's the reason for my "?!?".

You can't shift the burden of proof: it is your claim that they are important; you need to show that is the case.

And you just confirmed (the obvious) that mass is not the only thing that matters in BBH calculations. You also can't deny that it was a lot of DM there. If you cannot show how GR calculation included DM (and DE), you have a problem, like swansont had with his idea that "we don't care about the composition".

This data is readily available. If it is important to your hypothesis, you should already have it.

Indirectly I have it, but please tell me more about it, if you know.

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And you just confirmed (the obvious) that mass is not the only thing that matters in BBH calculations. You also can't deny that it was a lot of DM there. If you cannot show how GR calculation included DM (and DE), you have a problem, like swansont had with his idea that "we don't care about the composition".

1. Please show some support for the claim that "it was a lot of DM there"

2. Please show that it is important to include this in the calculations.

3. Stop trying to shift the burden of proof (and stop being so evasive).

Edited by Strange
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You directed that question at Mordred. Why would you expect me to answer it?

Sorry, I posed the questions to all of you, not just you swansont.

Do you have any physics to back that up?

1. Please show some support for the claim that "it was a lot of DM there"

...

According to wikipedia

The standard model of cosmology indicates that the total mass–energy of the universe contains 4.9% ordinary matter, 26.8% dark matter and 68.3% dark energy.[3][4]

More from the same source:

The most widely accepted form for dark matter is that it is composed of weakly interacting massive particles (WIMPs) that interact only through gravity and the weak force.[11]

The distribution of dark matter in galaxies required to explain the motion of the observed matter suggests the presence of a roughly spherically symmetric, centrally concentrated halo of dark matter with the visible matter concentrated in a central disc.

The Milky Way is estimated to have roughly 10 times as much dark matter as ordinary matter.

So, DM seems to react to gravity and form a halo around big masses. BBH has a great mass, is within our DM/E dominated Universe, so it is very unlikely to be DE free and without a considerable amount of DM.

By the way, the Earth and LIGO are in the Milky Way and, according to the last quote, there is a lot of DM here ... How/where your calculations included this DM ?!? And I'm not talking about Shapiro delay, it's about your GR calculations for what happened at LIGO observers. Show me DM in your math please!

Edited by DanMP
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Sorry, I posed the questions to all of you, not just you swansont.

More from the same source:

So, DM seems to react to gravity and form a halo around big masses. BBH has a great mass, is within our DM/E dominated Universe, so it is very unlikely to be DE free and without a considerable amount of DM.

What this says is that DM forms a halo around the galactic BHs that have masses of perhaps a million solar masses or more, and that these halos extend far into space — they don't just hang out near the center. In comparison, the binaries do not have a great mass, and their orbital radius is quite small.

Even though the baryonic matter is a small fraction, it tends to clump together while dark matter does not, so the density of the precursor star and the subsequent black hole should be many, many, many times the density of dark matter in the vicinity. Meaning there is no reason to expect a large amount of dark matter nearby. Which is why you are being asked for specific evidence and physics to explain why you think this is so.

You haven't really shown anything other than your ability to Google some search terms and quote results that are only tangentially relevant to the discussion.

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So, DM seems to react to gravity and form a halo around big masses. BBH has a great mass, is within our DM/E dominated Universe, so it is very unlikely to be DE free and without a considerable amount of DM.

Please show your calculations that there is a "a considerable amount of DM" around a black hole.

By the way, the Earth and LIGO are in the Milky Way and, according to the last quote, there is a lot of DM here ... How/where your calculations included this DM ?!? And I'm not talking about Shapiro delay, it's about your GR calculations for what happened at LIGO observers. Show me DM in your math please!

Stop shifting the burden of proof. YOU claimed it is important. It is up to YOU to show that is the case.

But, if it will shut you up and help you focus on your responsibilities, read this: http://cdms.berkeley.edu/Education/DMpages/FAQ/question36.html

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What this says is that DM forms a halo around the galactic BHs that have masses of perhaps a million solar masses or more, and that these halos extend far into space — they don't just hang out near the center. In comparison, the binaries do not have a great mass, and their orbital radius is quite small.

Do you have reasons to believe that the BHs in BBH formed/existed outside a galaxy?

Or that DM density is constant throughout the halo?!?

Even though the baryonic matter is a small fraction, it tends to clump together while dark matter does not, so the density of the precursor star and the subsequent black hole should be many, many, many times the density of dark matter in the vicinity. Meaning there is no reason to expect a large amount of dark matter nearby. Which is why you are being asked for specific evidence and physics to explain why you think this is so.

DM density may be small in comparison with BH density, but its total mass in BBH region may be few times greater than baryonic matter mass, as it is in a galaxy. So you cannot rule it out from your calculations. Remember, DM is gravitationaly attracted ... It not compresses as much as baryonic matter does, but still can increase in density near the BHs.

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Damp this is your model. Therefore it's your responsibility to supply the data to support it.

NOT ours.

I know that the DM halo in the region will not cause any difference neither will dark energy.

I also know these two items are part of the EFE. But they won't come out and say this part is DM, this part DE.

The reason is you require a completely different set of calculations to determine the average energy/density of a system.

I'm am definitely not going to take you through an entire course.

The most I will do is offer direction to assist someone but I won't do their work for them.

The distribution profile for dark matter can be calculated (though this is done by LIGO in greater detail)

Is to use the NFW profile.

https://en.m.wikipedia.org/wiki/Navarro%E2%80%93Frenk%E2%80%93White_profile

However as Swansort has mentioned it doesn't clump.

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DM density may be small in comparison with BH density, but its total mass in BBH region may be few times greater than baryonic matter mass, as it is in a galaxy.

It is several times less than the mass of the normal matter in a galaxy.

Remind me why we should take your opinions seriously?

Remember, DM is gravitationaly attracted ... It not compresses as much as baryonic matter does, but still can increase in density near the BHs.

Are you ever going to show that this is as "important" as you claim?

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Do you have reasons to believe that the BHs in BBH formed/existed outside a galaxy?

Or that DM density is constant throughout the halo?!?

No, and I claimed neither of these things.

DM density may be small in comparison with BH density, but its total mass in BBH region may be few times greater than baryonic matter mass, as it is in a galaxy.

Then prove it. Show a valid calculation that would demonstrate this. because I think you will find that you are spectacularly wrong.

So you cannot rule it out from your calculations. Remember, DM is gravitationaly attracted ... It not compresses as much as baryonic matter does, but still can increase in density near the BHs.

You can't argue it's plausible from your (nonexistent) calculation. This would be a great example of a hand-wavy, non-rigorous claim from you. How about a little bit of science in the form of a calculation to back it up?

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