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

[Robittybob1]

I thought I see what some recent papers say about the Shapiro effect: http://arxiv.org/pdf/0711.3041.pdf

 

 

. The observed phase in the detector
frame, φ(t), is in general a more complicated function of time due to the variable time
delay δt = T − t. The delay δt contains components arising from the Earth’s orbital
motion (for which |δt| ≤ 8.5 min.), from the Earth’s sidereal motion (|δt| ≤ 43 µs), and
from the general relativistic Shapiro delay (|δt| ≤ 120 µs) for signals passing close to the
sun [85].

and http://www.nature.com/nature/journal/v467/n7319/abs/nature09466.html

 

The Shapiro delay is a general-relativistic increase in light travel time through the curved space-time near a massive body 7. For highly inclined (nearly edge-on) binary millisecond radio pulsar systems, this effect allows us to infer the masses of both the neutron star and its binary companion to high precision 8, 9.

 

.

Edited March 16, 2016 by Robittybob1

[Robittybob1]

That second quote is worth investigating for it sounds very similar to a binary black holes.

Footnote 7

http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.13.789 [You permission to view this one]

Footnote 8

http://iopscience.iop.org/article/10.1086/449311/meta;jsessionid=1D8E4622AA6C3DDA76E9403E722853B2.c1.iopscience.cld.iop.org

http://iopscience.iop.org/article/10.1086/449311/pdf

[swansont]

That second quote is worth investigating for it sounds very similar to a binary black holes.

 

Except that it's not. It's talking about the Shapiro delay of the pulsar signal.

[Strange]

And the difference is that the pulsar signal is produced independently of the state of the system (i.e. it is local to the pulsar; and not due to general relativistic effects of the binary system). The emitted signal can then be affected by the gravitational effects (changing space-time curvature) of the black hole as it passes by.

 

On the other hand, the gravitational waves from a pair of black holes are a general relativistic effect caused by the massive changes to space-time in the system (not produced as pulses from each black hole separately, for example). As such, any calculation of the generation of these waves will take into account the entire effects of changing curvature of space-time (this includes any effects that you might be able to separate out in different circumstances, such as Shapiro delay).

 

Trying to say that these waves would be affected by Shapiro delay is bit like looking at sound waves and then asking how they are affected by the changing air pressure caused by the sound - they are the changing air pressure.

[DanMP]

This is the formula for chirp mass. You can see both masses are included.

Chirp mass?

 

Of course both masses are included ... when you calculate orbital frequency. And chirp frequency is twice the orbital frequency, because:

If this delay is big enough (minutes, hours), in the final seconds before merging, the "gravity well" of the BH in the front appear to mask the gravity pull of the BH in the back. So we have/"see" M1+M2 when the BH's are side by side and M1 or M2 when they are one in front of the other. This alternance of apparent mass produces the waves, the signal we detected.

There are two maxima (M1+M2) and two minima (M1 or M2) per orbit.

The angle of observation was not what you claim. The references that you have previously provided show that we were looking "down" at the orbital plane, not sideways on.

First, it was you who noticed:

That is about the probable angle of the orbital plane to our line of site .... Duh.

Second, when BHs are very close, as they were during last 2-4 orbits (the chirp), we still have Shapiro delay even when they are not exactly "side on". It's not the BH that "masks", is its "gravitational well" or "EH", and they are bigger then the BH ...

 

You can see that the signal increases towards the end, probably because the masking effect is bigger when very close.

 

The characteristics of the signal were exactly that predicted by GR - this would include any delays or distortions to the waveform caused by the self-interaction of the gravitational waves with the local curvature of space time - these non-linear effects are one reason why these things are to hard to model and require hours of supercomputer time.

Shapiro delay is part of mainstream relativity, so yes, the GR prediction probably included it.

 

But with my Shapiro delay idea you don't have to explain someone the whole math behind "hours of supercomputer time". It is simple, logical, intuitive and in agreement with GR.

[Strange]

But with my Shapiro delay idea you don't have to explain someone the whole math behind "hours of supercomputer time". It is simple, logical, intuitive and in agreement with GR.

 

I haven't seen your calculations that confirm that you produce identical inspiral and ringdown waveforms as the full solution. Which post was that in?

[DanMP]

I haven't seen your calculations that confirm that you produce identical inspiral and ringdown waveforms as the full solution. Which post was that in?

 

I explained GWs (specifically the one and only signal we received), not the whole thing, not the calculation of BBH. Of course GR is needed to identify and describe how BBH was, but from there on GWs can be explained as I did. My explanation is not an alternative to GR, but a way to understand what GR produced.

 

What you are asking is like "show me how you calculate, using rubber sheet analogy for gravitational wells, the orbit of Mercury". You use GR to calculate. A simple explanation is just a (possible) way to present GR effects to non-physicists or physicists not involved in GR.

 

Maybe after we'll receive more signals, my explanation will fail. But maybe not. Let's wait for more facts.

[swansont]

 

Of course both masses are included ... when you calculate orbital frequency. And chirp frequency is twice the orbital frequency, because:

There are two maxima (M1+M2) and two minima (M1 or M2) per orbit.

You should then see a frequency modulation as the delay changed; the proposed delay would have a different size for each BH since their masses are unequal. But we don't see that – the frequency continues to increase in frequency in a smooth fashion.

[Mordred]

Danp I think you missed a key detail.

 

The two maxima and minima affect the polarization not the the chirp rate.

 

The formulas for chirp rate are actually fairly simple.

[Robittybob1]

 

Except that it's not. It's talking about the Shapiro delay of the pulsar signal.

The binary nature of the orbiting bodies was the similarity. The masses of the bodies involved are different. I read that paper looking to see if the methods they used could be useful to DanMP and I couldn't see how to use their methods. They had multiple recordings to compare timings of hundreds of signals compared to the BBH chirp which only gave approx 10 waves before the merger. Some of these waves could have shown Shapiro delay if there was precession occurring.

In their case they had a system with the lowest recorded angle of inclination whereas GW150914 or GW 150914 was probably very inclined.

OK they were measuring the pulsar signal and Dan would be trying to see the timing of the GW signal (but both signals travel at the speed of light).

[DanMP]

You should then see a frequency modulation as the delay changed; the proposed delay would have a different size for each BH since their masses are unequal. But we don't see that – the frequency continues to increase in frequency in a smooth fashion.

The delay must be more than the length of the chirp (0.2s). That's all it takes for part of the mass to disappear from the chirp. As the separation between BHs diminishes, more mass seems to disappear, increasing the strength of the signal.

 

The frequency "continues to increase in frequency in a smooth fashion" because the orbital frequency does.

[Mordred]

Yes but your both missing The fact that neither BH emits the chirp. The chirp is from the spacetime interactions between both BH's. So why would you have Shapiro delay?

Edited March 17, 2016 by Mordred

[Robittybob1]

 

I haven't seen your calculations that confirm that you produce identical inspiral and ringdown waveforms as the full solution. Which post was that in?

I can't immediately see the ringdown being affected by Shapiro time delay but there was a signal being produced so it is possible during the ringdown too.

[DanMP]

Danp I think you missed a key detail.

 

The two maxima and minima affect the polarization not the the chirp rate.

 

I don't understand. Please elaborate.

[Mordred]

The delay must be more than the length of the chirp (0.2s). That's all it takes for part of the mass to disappear from the chirp. As the separation between BHs diminishes, more mass seems to disappear, increasing the strength of the signal.

 

The frequency "continues to increase in frequency in a smooth fashion" because the orbital frequency does.

Did you even look at the equations for chirp?

 

This is already part of the equations. None of the 5 equations in that pdf require Shapiro delay and they also don't require supercomputers. (Not for chirp itself)

 

I don't understand. Please elaborate.

Pages 6, 7 and 8.

http://www.physics.usu.edu/Wheeler/GenRel2013/Notes/GravitationalWaves.pdf

 

The maxima and minima aspects deal with the TYPE of waveform. Not the rate each wave is emitted. (Quadrupole)

 

Chirp is covered on page 10. Which is the rate each waveform is emitted

Edited March 17, 2016 by Mordred

[Robittybob1]

Yes but your both missing The fact that neither BH emits the chirp. The chirp is from the spacetime interactions between both BH's. So why would you have Shapiro delay?

Could the transmission of the "spacetime interactions" be affected by the arrangement of the two orbiting masses?

When the two masses are inline with our (LIGO) line of site (regardless of their inclination) what part of the GW chirp signal are we seeing? Is it a minimum or a maximum on the chirp signal?

[Mordred]

Could the transmission of the "spacetime interactions" be affected by the arrangement of the two orbiting masses?

When the two masses are inline with our (LIGO) line of site (regardless of their inclination) what part of the GW chirp signal are we seeing? Is it a minimum or a maximum on the chirp signal?

The Maxima/minima determine the TYPE of waveform QUADRUPOLE.

 

The rate and number of waveforms determine the chirp

[Robittybob1]

 

You should then see a frequency modulation as the delay changed; the proposed delay would have a different size for each BH since their masses are unequal. But we don't see that – the frequency continues to increase in frequency in a smooth fashion.

They would have to show that one part of that frequency change was more or less than expected. The frequency is changing because the orbit is decaying so the expected rate of orbit change maybe able to be calculated so we could see if the signal matched this.

[swansont]

The delay must be more than the length of the chirp (0.2s). That's all it takes for part of the mass to disappear from the chirp. As the separation between BHs diminishes, more mass seems to disappear, increasing the strength of the signal.

 

The frequency "continues to increase in frequency in a smooth fashion" because the orbital frequency does.

 

 

So how does a delay fit into this? The energy loss is continuous and the orbital frequency continually increases, which accounts for the signal we see. But you are proposing a perturbation on top of that in the form of a delay caused by a signal passing close to each BH. You seem to agree that this perturbation signal is absent from the data.

They would have to show that one part of that frequency change was more or less than expected. The frequency is changing because the orbit is decaying so the expected rate of orbit change maybe able to be calculated so we could see if the signal matched this.

 

The signal matches the model. We already know this.

[DanMP]

Yes but your both missing The fact that neither BH emits the chirp. The chirp is from the spacetime interactions between both BH's. So why would you have Shapiro delay?

Not waves but gravitational pull. See here: http://www.physics.usu.edu/Wheeler/GenRel2013/Notes/GravitationalWaves.pdf

The idea that gravitational information can propagate is a consequence of special relativity: nothing can travel faster than the ultimate speed limit, c.

 

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?

[Robittybob1]

 

 

So how does a delay fit into this? The energy loss is continuous and the orbital frequency continually increases, which accounts for the signal we see. But you are proposing a perturbation on top of that in the form of a delay caused by a signal passing close to each BH. You seem to agree that this perturbation signal is absent from the data.

 

The signal matches the model. We already know this.

Exactly, but there was a degree of mismatch. Was it in the order of 10%? The signal matches the model to what percentage?

From memory if was 90% but this could be found and confirmed later.

Dan used the term "smooth rate", and you say "continually increasing" but it is a continuously increasing rate. It definitely not a linear increase. Can we say it is an exponentially increasing rate?

[Strange]

I explained GWs (specifically the one and only signal we received), not the whole thing, not the calculation of BBH. Of course GR is needed to identify and describe how BBH was, but from there on GWs can be explained as I did. My explanation is not an alternative to GR, but a way to understand what GR produced.

 

But you haven't shown that your explanation corresponds to reality. I don't see how such an explanation is useful. Especially when 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.

 

If you just want a descriptive analogy, then you might as well talk about two fish swimming in circles on the surface of a pond.

[DanMP]

But you haven't shown that your explanation corresponds to reality.

 

I did:

 

Here: http://arxiv.org/pdf/1511.01901.pdf

 

I found this:

For reasonable distances of closest approach (see, e.g, discussion in [4, 5, 10]), the amplitudes of these effects are of the order of 100 ms−10 s.

 

[Strange]

 

I did:

 

 

How does some range of delays to electromagnetic radiation relate to the creation of gravitational waves?

And how does that equate to gravitational waves (a) being radiated in all directions and (b) shrinking and stretching objects in orthogonal directions (i.e. having a particular polarization) and ( c) increasing in frequency?

 

You are effectively making an analogy equivalent to one BH alternately eclipsing and being eclipsed by the other. But that is inaccurate and doesn't tell us anything about the nature of gravitational waves.

[swansont]

Dan used the term "smooth rate", and you say "continually increasing" but it is a continuously increasing rate.

 

Which would not be the case if Dan's model were correct. The delay would be fluctuating up and down. We should see additional modulation of the signal, but we don't.

 

It definitely not a linear increase. Can we say it is an exponentially increasing rate?

That would require deciphering the math.

 

Can anyone answer that question for that is where we will see the change in the chirp waveform if it is going to show a Shapiro time delay by delaying the onset or making the onset earlier of the maximum or the minimum part of the waveform. Or it may even show up as a widening of one part of the curve.

 

 

This has been answered numerous times. There is no separate Shapiro delay. If there was, we would not see the results that we saw.

 

If you or Dan disagree, then come up with a freaking model to predict what the waves should look like.