Warped spacetime around BH and the barycenter

[Robittybob1]

Another error that I'm noticing is they are not animating the BHs orbiting a barycenter. They seem to draw them as if they are going around a geometric center but they ought to be orbiting at different radii. So we should be able to see two lines of gravitational waves per orbit but each one is coming away from a specific body in orbit so the strength of that wave will reflect some property of that mass.

 

The more massive BH will be orbiting closer to the barycenter so the distance it's GW has to go is further so it will be the one tending to be closer to the wave ahead of it. Can you see this paired effect in the chirp frequency pattern? Is the trailing wave larger or smaller in strength? Which body gives off the most GE? Both are losing PE and gaining KE but they are proportional to mass, but also inversely to distance fallen, so it is hard to predict which body gives off the greater amount of radiation.

I'll have to go and study the chirp.

Edited March 10, 2016 by Robittybob1

[Strange]

Another error that I'm noticing is they are not animating the BHs orbiting a barycenter. They seem to draw them as if they are going around a geometric center but they ought to be orbiting at different radii.

 

These may be animations of black holes of equal mass. Does it say they are not?

 

There is one (on the black-holes.org site) that shows two black holes with very different mass and that clearly shows the smaller one flying around the larger one (which wobbles slightly).

 

And, please, you are not seeing errors. You cannot tell me that your "gut feel" about what these simulations should look like trumps thousands of hours of programming work by experts and further thousands of hours of supercomputer time.

[Robittybob1]

 

These may be animations of black holes of equal mass. Does it say they are not?

 

There is one (on the black-holes.org site) that shows two black holes with very different mass and that clearly shows the smaller one flying around the larger one (which wobbles slightly).

 

And, please, you are not seeing errors. You cannot tell me that your "gut feel" about what these simulations should look like trumps thousands of hours of programming work by experts and further thousands of hours of supercomputer time.

They generally show one with a larger EH which is proportional to mass. Does the chirp frequency show us the pattern? The two BH masses were fairly even but the mass difference should show up in the orbital radius. What is the clue that gives them the ability to tell us their relative sizes? This radius difference is proportional to the mass over the combined mass, but the heavier one will definitely have a smaller radius than the lighter one (thats some inverse relationship).

https://upload.wikimedia.org/wikipedia/commons/f/f2/Orbit2.gif

https://en.wikipedia.org/wiki/Barycenter#Two-body_problem

 

Edit: "radius is proportional to mass over the combined mass".

Edited March 10, 2016 by Robittybob1

[swansont]

They generally show one with a larger EH which is proportional to mass. Does the chirp frequency show us the pattern? The two BH masses were fairly even but the mass difference should show up in the orbital radius. What is the clue that gives them the ability to tell us their relative sizes? This radius difference is proportional to the mass over the combined mass, but the heavier one will definitely have a smaller radius than the lighter one (thats some inverse relationship).

https://upload.wikimedia.org/wikipedia/commons/f/f2/Orbit2.gif

https://en.wikipedia.org/wiki/Barycenter#Two-body_problem

 

Edit: "radius is proportional to mass over the combined mass".

You have to dig a little, but they give a reference.

http://arxiv.org/pdf/0810.1767v2.pdf

 

"The first spectral numerical simulations of 16 orbits, merger, and ringdown of an equal-mass nonspinning binary black hole system are presented."

 

There is no error. I agree with Strange — if that's your inclination, the first reaction should be maybe you are misunderstanding or misreading something, or (as in this case) making a bad assumption. In fact, in this case you might conclude that the masses must be equal because of what you observed. Then you can check to see if that's the case. But that's something you need to be doing.

[Robittybob1]

You have to dig a little, but they give a reference.

http://arxiv.org/pdf/0810.1767v2.pdf

 

"The first spectral numerical simulations of 16 orbits, merger, and ringdown of an equal-mass nonspinning binary black hole system are presented."

 

There is no error. I agree with Strange — if that's your inclination, the first reaction should be maybe you are misunderstanding or misreading something, or (as in this case) making a bad assumption. In fact, in this case you might conclude that the masses must be equal because of what you observed. Then you can check to see if that's the case. But that's something you need to be doing.

I was thinking the animations were not representing the actual situation, whereas the frequency of the chirp is the actual recording (that bit is not animated) So if they are animating equal mass BHs, well I now can see why they are orbiting the geometric center.

OK it was a raw idea but it has revealed something about the animations. It obviously would make them harder to do if they were unequal masses orbiting a barycenter. That was basically my point anyway.

I'll look into later, thanks.

[Strange]

It obviously would make them harder to do if they were unequal masses orbiting a barycenter. That was basically my point anyway.

 

I don't think it would. Adding more parameters (spin, more than one black hole, etc) will make a difference but I don't think it will make a very great difference if the masses are the same or not.

[Robittybob1]

 

I don't think it would. Adding more parameters (spin, more than one black hole, etc) will make a difference but I don't think it will make a very great difference if the masses are the same or not.

There are many versions of the animations now but it was interesting to go back and watch the animation in the OP

it has different masses orbiting at different distances with the yellow always further out than the red line so I'll presume purely from basics physics that would be showing up in the g-radiation peaks there will be two peaks closer together followed by a larger gap then two more peaks etc. They certainly fail in their animation of the

G-waves it looks like they have stopped in their tracks. I'll have to find the spread out display of the chirp and see if that slight change in frequency can be picked up.

Edited March 10, 2016 by Robittybob1

[Robittybob1]

http://journals.aps.org/prl/pdf/10.1103/PhysRevLett.116.061102 on page 2 there are the reconstructed (wavelet) diagrams where they seem to have taken the background interference out of the "chirp". If you look at the tallest peak would you all agree it is the 7th crest after the 0.3 sec timeline?

Would you say the period between the crests 3&4, 5&6, 7&8 crests look a little closer than expected compared to the preceding ones between peaks 2&3, 4&5, 6&7?

 

Obviously the frequency is rising as the merger progresses but there seems to be a hint of a grouping of the crests.

I would say this is expected due to the G-Rad coming from BH closer to the barycenter having to travel just that little bit further to get to the LIGO recorder, so the signal from the more massive BH is slightly delayed. Would that be the advanced wave followed by the delayed wave as a grouping? (Reading the chart from left to right) Any suggestions?

Looking at a site Strange linked to on another thread emphasises the effect I am trying to describe. These are just pure animations but it shows the grouping of the G-rad waves.

Look at the "Highly precessing binary black hole run" at http://www.black-holes.org/explore/movies

From that animation we might be able to tell which phase of the quadrupole precedes the other as it reaches LIGO.

LIGO receives the signal from the left to the right. The white line precedes the red line. The white is the wave from the lower mass BH, which I called "advanced" above so in each group the advanced precedes the delayed wave.

Is this what I said above? Yes.

Edited March 11, 2016 by Robittybob1

[swansont]

http://journals.aps.org/prl/pdf/10.1103/PhysRevLett.116.061102 on page 2 there are the reconstructed (wavelet) diagrams where they seem to have taken the background interference out of the "chirp". If you look at the tallest peak would you all agree it is the 7th crest after the 0.3 sec timeline?

Would you say the period between the crests 3&4, 5&6, 7&8 crests look a little closer than expected compared to the preceding ones between peaks 2&3, 4&5, 6&7?

 

Obviously the frequency is rising as the merger progresses but there seems to be a hint of a grouping of the crests.

I would say this is expected due to the G-Rad coming from BH closer to the barycenter having to travel just that little bit further to get to the LIGO recorder, so the signal from the more massive BH is slightly delayed. Would that be the advanced wave followed by the delayed wave as a grouping? (Reading the chart from left to right) Any suggestions?

 

 

 

But these are moving at c, and we know the distances are on the order of 100 km. L/c = ∆t If we use 300 km, the difference is a millisecond

[Robittybob1]

 

 

 

But these are moving at c, and we know the distances are on the order of 100 km. L/c = ∆t If we use 300 km, the difference is a millisecond

Good point, but on the first BH merger (the chirp) the delay was barely noticeable, so we might be just seeing that millisecond difference but on that second animation the orbiting distances would have been considerably greater (greater difference in mass and/or orbiting faster, but they are just guesses for there was no scale to read), maybe that is why the delay was greater. What was the frequency of the BH merger orbit? 100 Hz rising to 250 Hz at beginning of the ringdown or 4 - 10 millisecs per orbit so if the waves were delayed by 1 millisecond could we see it? It is still possible. The rapidly changing orbital rate definitely makes it harder to identify.

What are your thoughts on the stability of the barycenter? Do you think the barycenter remains steady through all this? From the GE output graphs they tend to show both bodies losing the same amount of energy. If that energy was in some way related to mass loss doesn't that imply the barycenter is shifting toward the heavier object?

 

I think it is definite that the strength of the GE wave for each BH is comparable. Do you agree with that observation? I'll have to take it step by step for it is just too hard to think of the consequences of the barycenter shifting in an binary system, I just don't know the physical effects that would eventuate. Any ideas?

Edited March 11, 2016 by Robittybob1

[Strange]

I think it is definite that the strength of the GE wave for each BH is comparable.

 

I don't know if you can treat it as a wave for each BH. It is a result of the entire system; I guess the results for a binary black hole are quite different from a single black hole going in a circle (which is physically impossible, so no one will have simulated it!)

 

I'll have to take it step by step for it is just too hard to think of the consequences of the barycenter shifting in an binary system, I just don't know the physical effects that would eventuate. Any ideas?

 

The barycentre is not a real thing. It is a result of the interaction of the bodies, not a cause of anything. In some models, the barycentre might be used as a reference point and so can't move, by definition.

 

The first video on this page shows a system with a large amount of precession, it is not clear if that causes the barycentre to shift.

http://www.black-holes.org/explore/movies

Edited March 11, 2016 by Strange

[Robittybob1]

 

 

I don't know if you can treat it as a wave for each BH. It is a result of the entire system; I guess the results for a binary black hole are quite different from a single black hole going in a circle (which is physically impossible, so no one will have simulated it!)

 

 

The barycentre is not a real thing. It is a result of the interaction of the bodies, not a cause of anything. In some models, the barycentre might be used as a reference point and so can't move, by definition.

 

The first video on this page shows a system with a large amount of precession, it is not clear if that causes the barycentre to shift.

http://www.black-holes.org/explore/movies

 

The orbital pattern on that one is hard to follow. It even looks like its orbit changes direction. I didn't even know that was possible.

The barycenter is always on a line between the CoM of each body. It is the point on which the centripetal forces would operate from. So in that animation it is definitely shifting.

I just checked if both BHs lose mass at an equal rate the barycenter moves toward the heavier body.

[Strange]

The orbital pattern on that one is hard to follow. It even looks like its orbit changes direction. I didn't even know that was possible.

 

I assume that is a result of the angular momentum of the black holes (kinda like a gyroscopic effect but even more complicated).

[swansont]

Good point, but on the first BH merger (the chirp) the delay was barely noticeable, so we might be just seeing that millisecond difference but on that second animation the orbiting distances would have been considerably greater (greater difference in mass and/or orbiting faster, but they are just guesses for there was no scale to read), maybe that is why the delay was greater. What was the frequency of the BH merger orbit? 100 Hz rising to 250 Hz at beginning of the ringdown or 4 - 10 millisecs per orbit so if the waves were delayed by 1 millisecond could we see it? It is still possible. The rapidly changing orbital rate definitely makes it harder to identify.

 

 

What second merger? There is only one BH paper. You have to make it absolutely clear what you are referencing here — we can't read your mind.

 

If a simulation has no scale to read, then you can't make any inference about the scale! It's a non-starter.

 

I just checked if both BHs lose mass at an equal rate the barycenter moves toward the heavier body.

 

Why would they?

[Robittybob1]

 

 

What second merger? There is only one BH paper. You have to make it absolutely clear what you are referencing here — we can't read your mind.

 

If a simulation has no scale to read, then you can't make any inference about the scale! It's a non-starter.

 

Why would they?

In this part of the discussion we have linked to two sites one the BH merger and the other BH mergers using simulation , both links in this post http://www.scienceforums.net/topic/93875-warped-spacetime-around-bh-and-the-barycenter/page-2#entry910467. I hadn't made inferences about the scale in the animation but the timing of the waves only, see post #33.

Why would they lose mass? Is that your question? The merging BHs did lose mass. In just 0.3 seconds or less they radiated away 3 solar masses of it. Mass-energy equivalence.

 

Why would they lose mass? If they are radiating energy they are losing mass.

The barycenter changes as the mass changes as consequence of how it is calculated and the physics.

https://en.wikipedia.org/wiki/Barycenter#Two-body_problem

 

r = a * m1/(m1 + m2)

a = distance apart, r = distance to barycenter, m1, m2 are the binary masses.

 

Why would they lose mass at an equal rate? Was that your question? Why would each member of the binary produce G-rad at an equal rate, even when their masses, speeds and radii are different? That is the question I was trying to answer. If the waves are of equal strength as measured by Advanced LIGO can we deduce they are radiating equal amounts away per orbit from each body in the binary?

 

My initial assessment is yes "they lose mass at an equal rate".

So then I'm asking what do others think?

 

Trouble was if they lose mass at an equal rate the barycenter changes and that will cause some imbalance in the binary orbit. If they were equal in mass then the barycenter would not change.

 

OK so if there was 2 equal mass BHs in binary orbit, the barycenter is not changing (AFAIK) yet they still radiate GE so G-rad is not due to barycenter changes. We can just about rule that one out.

 

I assume that is a result of the angular momentum of the black holes (kinda like a gyroscopic effect but even more complicated).

I see the reason now. If the orbit precesses severely the orbital plane can turn over so you are seeing the orbit from the "other side", so what looked clockwise now appears anticlockwise.

Edited March 11, 2016 by Robittybob1

[swansont]

Why would they lose mass at an equal rate? Was that your question?

 

Yes. I was hoping you had some actual physics to back this up, seeing as this is in "relativity" and not "speculations"

[Robittybob1]

Yes. I was hoping you had some actual physics to back this up, seeing as this is in "relativity" and not "speculations"

In #3 I asked for the thread to moved if you thought it was in the wrong section. http://www.scienceforums.net/topic/93875-warped-spacetime-around-bh-and-the-barycenter/#entry910042

I still feel the evidence is there, the G-Rad comes from both bodies in proportion to their mass and acceleration, except for the times when the orbits become chaotic. The principle of mass energy equivalence means the energy is in a form of mass.

The Chirp graphs and the animations produced by reliable sources seem to confirm both bodies produce an equal strength GE wave.

The figures of mass loss during the BH merger back it up.

 

What have I seen others on the forum say?

1. All the mass was in the Event Horizon.

2. All the mass loss was at the ringdown (right at the end in a single moment).

3. All the energy loss is from the orbital energy

 

OK all these alternatives seemed speculative to me for there was never any evidence given for them.

I know it seems strange to say the 2 BH binary lose mass as their orbits decay, but I don't think it is an impossible situation, for there is evidence suggestive of the barycenter changing position resulting in disruption of the orbital features of the lighter BH as seen in the chirp wave pattern.

Edited March 12, 2016 by Robittybob1

[swansont]

OK all these alternatives seemed speculative to me for there was never any evidence given for them.

 

 

You never give evidence for your claims, so that seems hypocritical.

 

But the big difference here is that the people presenting the solutions have scientific bona-fides of some sort. You don't. You don't really get to arbitrarily accept or dismiss what others say in preference to your own ideas.

[Phi for All]

My initial assessment is yes "they lose mass at an equal rate".

So then I'm asking what do others think?

 

!

Moderator Note

Please save this type of speculations for the appropriate section. There is a difference between "This is my assessment, am I right?" and "Do they lose mass at an equal rate?" The leap at conclusions/assessments is NOT rigorous enough for Relativity. Please stop forcing speculation into this discussion. A little bit more effort is all it takes to change your "assessments" into legitimate inquiry.

 

Please take this on board. And resist the urge to respond off-topic to this modnote.

[swansont]

 

I still feel the evidence is there, the G-Rad comes from both bodies in proportion to their mass and acceleration, except for the times when the orbits become chaotic.

 

 

That's not what you claimed earlier, so this is not a "still". This is a new claim. So, do you have scientific backing for this, or is this another gut reaction? (Which Phi has reminded you is off-limits here).

[Robittybob1]

 

 

That's not what you claimed earlier, so this is not a "still". This is a new claim. So, do you have scientific backing for this, or is this another gut reaction? (Which Phi has reminded you is off-limits here).

There is the direction of space idea to explore yet. I have just woken up and replying to you ATM. We see the arrows with the directions of space on the animations and I'd need to understand what effect that has on all our measurements. Do you understand those arrows?

 

@Swansont could you please make your claims and questions more clear please? Take this post you say I "claimed" something earlier, that is not that clear as there have been many things claimed earlier, so I end up guessing what you are on about.

I find I am spending a lot of effort to be really clear in what I say in reply to any of your questions.

 

 

You never give evidence for your claims, so that seems hypocritical.

 

But the big difference here is that the people presenting the solutions have scientific bona-fides of some sort. You don't. You don't really get to arbitrarily accept or dismiss what others say in preference to your own ideas.

Behind the scenes I am looking at LaTex so soon hopefully I will be able to present more math in my replies. This whole discussion that has been going on over several threads now has been an enormous learning curve for me.

My claims are in some way based on looking at the LIGO graphs and taking actual measurements from them. The effects I'm talking about seem to be visible to the eye, but so far no one has said whether they see the same differences as I do. If you or anyone else said they can't see those differences that I speak of, I would then need to show them in some other way, but I'm not getting enough feedback to know where the discussion is going.

Edited March 12, 2016 by Robittybob1

[Strange]

I still feel the evidence is there, the G-Rad comes from both bodies in proportion to their mass and acceleration

 

I very much doubt it is as simple as that. I would remind you (again) that it takes hundreds of hours of supercomputer time to calculate what happens. If it were as simple as you want it to be, they would be wasting their time.

 

 

My claims are in some way based on looking at the LIGO graphs and taking actual measurements from them.

 

This is, to be honest, an idiotic waste of time.

[Robittybob1]

 

I very much doubt it is as simple as that. I would remind you (again) that it takes hundreds of hours of supercomputer time to calculate what happens. If it were as simple as you want it to be, they would be wasting their time.

 

 

This is, to be honest, an idiotic waste of time.

How do you know that is not what is happening within their programs already? Look at their animations which are completely computer generated and these results are very noticeable. The GW graphs at the bottom of the animation were absolutely equal even when the 2 BHs were considerably different in mass.

Do you accept that one series of peaks comes from one body and the next one to it from the other body? Like two graphs overlying each other.

 

I feel a little bit offended by that comment. Other than the results from the LIGO graphs what have they to go on. All the information is in the results recorded by these two machines and they make their calculations from those recordings.

Edited March 12, 2016 by Robittybob1

[swansont]

There is the direction of space idea to explore yet. I have just woken up and replying to you ATM. We see the arrows with the directions of space on the animations and I'd need to understand what effect that has on all our measurements. Do you understand those arrows?

I have no idea what you're talking about. I'm not asking for clarification here — I have no desire to go down yet another rabbit hole. (Or Robbit hole, as it were)

 

@Swansont could you please make your claims and questions more clear please? Take this post you say I "claimed" something earlier, that is not that clear as there have been many things claimed earlier, so I end up guessing what you are on about.

I find I am spending a lot of effort to be really clear in what I say in reply to any of your questions.

bold added - this is one of the problems.

 

Behind the scenes I am looking at LaTex so soon hopefully I will be able to present more math in my replies. This whole discussion that has been going on over several threads now has been an enormous learning curve for me.

My claims are in some way based on looking at the LIGO graphs and taking actual measurements from them. The effects I'm talking about seem to be visible to the eye, but so far no one has said whether they see the same differences as I do. If you or anyone else said they can't see those differences that I speak of, I would then need to show them in some other way, but I'm not getting enough feedback to know where the discussion is going.

 

I don't think LaTex knowledge is the root of the problem. It's an impediment for posting equations, but you have to be able to understand the equations to have a fruitful discussion.

 

Analyzing graphs doesn't sound like a particularly useful way to gain insight into the science.

[Robittybob1]

I have no idea what you're talking about. I'm not asking for clarification here — I have no desire to go down yet another rabbit hole. (Or Robbit hole, as it were)

...

....

Analyzing graphs doesn't sound like a particularly useful way to gain insight into the science.

What do you think about the the diagrams in this article? http://jila.colorado.edu/~ajsh/insidebh/waterfall.html

Especially the ones titled "The Schwarzschild waterfall" and the "The Reissner-Nordström waterfall"

Edited March 12, 2016 by Robittybob1