This is the reference:

PRL 116, 241103 (2016)

Best wishes,

Francois

Although I know, authors of that second experiment have admitted, after the publication of that paper, experimental data were not reliable. Consequently the absence of fanfare that instead there was after the first publication, similarly non reliable.

@ Daniele: reference?

Dear Francois,

I appreciate much your right request. because I was obliged to do further researches and now I would want to do a few clarifications:

1. there aren't references for that communication. In fact I read it in an interview to one of main authors of that experiment in daily newspapers,

2. that interview referred in actuality to another experiment: the research of a second Higgs boson.

I apologize for the mistake.

Thank you Francois 

I have examined the paper, unfortunately the data is very fuzzy, particularly the frequency and energy diagram.

But i would be grateful if you could keep me posted of any further more clear data

Andrew,

You can try going to the LIGO Open Science Centre for more info.

https://losc.ligo.org/tutorials/

https://losc.ligo.org/tutorials/

@All,

I would want to do some consideration on the effective experiment in question, after having thanked colleagues who gave precious references.

What disconcerts in these experiments LIGO is that gravitational waves that are observed in the process of measurement are produced always by fusion of two BH with mass (10-30) Sun mass that happens at milions or billions LY from the Earth and that reach the Earth with a weakest intensity. It is manifest that those GigaPhenomena are hard to verify, I would say still more hard than NanoPhenomena that happen in a particle accelerator.

Anyway I think if gravitational waves exist effectively, we would have to learn to produce those waves inside the Earth gravitational field, also with weakest intensity since GW that come from the fusion of BH and reach the Earth are weakest even if initially they would have to be greatest. In other words I don't understand the necessity to measure weakest waves that initially were greatest when we could measure directly weakest waves that are produced directly inside the Earth gravitational field.

As far as I understand. to have gravitational radiation, one needs bodies which *under the effect of their mutual gravitational attraction* orbit at a speed close to that of light. Thus, if the Sun were compressed to a few kilometers, then this would happen for a body orbiting the Sun immediately on its surface.

There are thus no bodies susceptible of emitting gravitational radiation even in the Solar system. One must look further, to very extreme situations, as done by LIGO.

DS: "What disconcerts in these experiments LIGO is that gravitational waves that are observed in the process of measurement are produced always by fusion of two BH with mass (10-30) Sun mass that happens at milions or billions LY from the Earth ..."

FL: "One must look further, to very extreme situations, as done by LIGO."

Shouldn't we look also much closer, e.g., to certain repetitive phenomena of characteristic strength and profile that possibly occur at the passive seismic mirror suspension, see references below?

https://www.researchgate.net/post/Are_signal_bursts_as_observed_at_LIGO_gravitational_wave_antennas_caused_by_stress_induced_relaxation_phenomena_in_seismic_suspension_fibres

According Newton: God, Pantokrator, is the responsible, in their conception theological voluntarism, of how does it work the universe. And, of course,God by revelation, transmits it to a chosen by him.

Einstein, much more rational and less religious than Newton, thought that if the gravity does exist, then, produces a gravitatory energy, ie, gravitatory waves or radiation.

LISA and LIGO are an experimental design very ambitious and expensive with the objective to verify the Einstein´s hipotesis, looking for clarify, definitively, this controversy.of 100 years.

May be, we never observe nothing, with the exception of falses positive. But, something will happen, we will have experimental results very difficults to understand. It is not easy the DATA interpretation. While, we will wait to Pantokrator send us a train of wave to confirm the Einstein´s hipotesis.

Regards

@ Daniele Sasso.

If you do the calculation based on Newtons (approximation) a= GM/R^2, using the standard Schwarzschild radius Rs = 2GM/c^2,  then the acceleration due to gravity at the event horizon on a minimum sized stellar black hole (3 solar masses):  a = 4 x 10^20 m/sec^2.

The same calculated acceleration on a 3 million stellar mass black hole (super-massive black hole at the centre of the galaxy) at the event horizon the acceleration is only 4 x 10^6 m/sec^2.

That is 14 orders of magnitude less.

Earth's gravitation is by comparison is a miniscule 9.8 m/sec^2

"Therein lays the explanation to your question..

@ Andrew,

In "Physics of Gravitational Fields" (pag.12) gravitational waves are generated by perturbations of a pre-existent gravitational field, including the Earth gravitational field. Physical features of the gravitational wave are

time acceleration: at = GM/r2

space acceleration: ar = SQRT[2GMro/r3(ro-r)]/2

duration: Tp = 2rSQRT[r(ro-r)/2GMro]

energy of the perturbation: Wp = GMm(ro-r)/ror

perturbation speed: cp = SQRT[GMro(ro-r)/2r3

where SQRT indicates the "square root", M is mass that generates the gravitational field, m is mass in free fall, ro is the initial point of fall,

Calculations demonstrate the fall of a body with m=100kg into the Earth gravitational field from an initial point ro=100km generates a perturbation and a gravitational wave that on the surface of the Earth has speed cp=705.7m/s and duration Tp=141.7s.

This could be a good starting point for a concrete discussion, independently of black holes and improbable fusions at Gigadistances in space and in time.

https://www.researchgate.net/publication/262058037_Physics_of_Gravitational_Fields

Article Physics of Gravitational Fields

The amplitude of the waves for an observer at distance R from two bodies of masses m1 and m2 orbiting with separation r is of the order of:

h+ = (1/R) (G2/c4) (2m1m2/r)

The factor G2/c4 makes the amplitude extremely small so large masses are needed and since they have to orbit at tens of Hz to be detectable with LIGO, it means the lowest mass sources are binary neutron stars. Lowere frequency detectors would be easier to test but that really means they have to be based in space.

For the Conservation Law of Energy and for other main principles of physics orbiting masses or orbiting charges don't emit energy, electromagnetic energy for orbiting charges and gravitational energy for orbiting masses. For the behavior of binary stars let me advise:

https://www.researchgate.net/publication/216670368_Relativistic_Theory_of_Black_Holes?ev=prf_pub

Article Relativistic Theory of Black Holes

DS: "... gravitational waves ... always by fusion of two BH with mass (10-30) Sun mass ... billions LY from the Earth ..."

FL: "One must look further, to very extreme situations, as done by LIGO."

JKF: "Shouldn't we look also much closer, e.g., to certain repetitive phenomena of characteristic strength and profile that possibly occur at the passive seismic mirror suspension?"

Downvote ok, arguments welcome !

@ Johan: I too prefer arguments to wild conjectures. Where are yours? Do you have a detailed analysis of a flaw in the data analysis system of LIGO? By all means, publish it, quickly! It is far too important to be limited to conjectural debate on RG!

@ Johan,

I live in Italy that is a very seismic territory. Any idea or hypothesis that can be able to foresee seismic events is for me a big idea. Do you think gravitational energy has an influence on seismic events?

FL: „I too prefer arguments to wild conjectures. Where are yours?“

I'm just trying to draw my conclusions from what I read in LIGO related papers:

(1) Relaxation phenomena in suspension fibres and related signal bursts are well known and have been investigated since long time, see e.g. first reference below.

(2) Glitch signal bursts of unknown origin with chirp type profiles as attributed to gravitational wave events that „never“ appear simultaneously at both LIGO detectors are routinely observed, see 2nd reference from March 2016 issue of LIGO Magazine, last paragraph on page 24.

(3) Rigorous discussion of relaxation phenomena in suspension fibres and connecting hardware is missing in GW150914 related papers.

My preliminary conclusion: As long as chirp type signal bursts of unknown origin are observed that cannot clearly be attributed to gravitational wave interference, and excess noise interference from suspension fibres and connecting hardware is excluded from discussion, any claim of having detected gravitational waves and black hole mergers has to be regarded inappropriate.

It´s in 

http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.241103

I hope it helps.

Carlos

@ Johan: Let us quote exactly what LIGO says: ``These glitches never appear at both interferometers at the same time, and differ just enough from the expected signature of a true gravitational wave signal that the searches can

distinguish between them.''

So now, let us assume that in some cases, the searches were not able to distinguish between a glitch and a true GW. Since glitches are local, there should be a large population of glitches which the search does not succeed in differentiating from a true GW signal, apart from the fact that they only appear at one of the two sites. Since such a phenomenon is not mentioned, we must assume it doe not occur, so that your scenario, given the data appears rather unlikely.

I read it slightly differently but I've previously worked on a neural net system. Suppose there is some external source of chirps that are generated by some of the on-site equipment. Since the same equipment is at both sites, individual chirps will be seen often and occasionally there will be roughly coincident events but the majority will occur at one site only. That means that the characteristics of those one-site events can be identified and accurate filters developed. It also means they can measure how often the filters get it wrong and knowing the single-site rate allows simple prediction of the coincident rate. Those figures are what produces the published probability charts, not estimates but well measured correlations.

https://losc.ligo.org/s/events/GW150914/P150914/fig4a.png

FL: "there should be a large population of glitches which the search does not succeed in differentiating from a true GW signal" ... "Since such a phenomenon is not mentioned, we must assume it doe not occur"

If such phenomenon is not explicitely mentioned, this doesn't neccessarily mean that it doesn't occur. I suspect that all glitches that are not identified as "true GW signals" by LIGO software are not mentioned but instead are automatically attributed to background noise.

GD: "Suppose there is some external source of chirps that are generated by some of the on-site equipment."

I don't speak of "external sources" but rather of "internal" ones like those having been identified by independent investigation in components of the passive (!) seismic suspension system, see e.g. reference below.

The article you cite is from 2002 and was a study looking into the possibility of using fused silica. The excess noise bursts discussed occurred in the previous steel suspension but as we know, fused silica is now used in LIGO. The report explains why that change was made.

The final statement in the report says:

• The preliminary measurements show that the effective temperature is close to room temperature, which means that the violin-mode oscillations averaged over longer time compared to the relaxation time, can be described as pure Brownian motion.

What that means is that the noise in the silica suspension was purely thermal and didn't show any transient bursts.

GD: "What that means is that the noise in the silica suspension was purely thermal and didn't show any transient bursts."

When your above suggestion holds true, how do you understand what is stated in March 2016 issue of LIGO Magazine, page 24, last paragraph, see reference below: "There are families of glitches that we frequently see but have not yet discovered the cause of."

Look at the example they gave of one they did identify:

• Disabling the refrigerator completely removed these glitches from the data!

That is an example of what I meant by an "external" source of chirps. Motor starts would understandably create EM interference of a swept frequency.

Note also the Q they quoted for the fused silica in the paper you cited, in excess of 107! Any transient would generate a fixed frequency in that.

GD: "That is an example of what I meant by an "external" source of chirps."

Note that the refrigerator signal stays at constant frequency, hence is not a chirp type signal as are the ones mentioned above.

GD: "Any transient would generate a fixed frequency in that."

Associated high Q resonant lines identified as "vibrational modes of suspension fibres" clearly stand out from LIGO background noise floor, cf. Figure 3 of GW150914 discovery paper.

JKF: Note that the refrigerator signal stays at constant frequency, hence is not a chirp type signal.

Correct, which makes it easy to distinguish them, but they also talk about "blip" glitches with a teardrop shape:

• For example, a class of glitches we have named ‘blip’ glitches appear at both sites which have a ‘teardrop’ shape in the time-frequency plane.

DC motor starts would be likely to generate a chirp, synchronous motors probably not, but I'm not suggesting that I know what causes the 'blips', just that those sorts of electromechanical devices regularly cause EMI problems. I work with sensitive radio receivers so it's something I encounter quite often.

JKF: Associated resonant lines clearly stand out from LIGO background noise floor, cf. Figure 3 of GW150914 discovery paper.

Yes and those are what are continuously excited by the suspension noise, that's why they won't be mistaken for chirps.

GD: "but they also talk about "blip" glitches with a teardrop shape"

Signals identified as due to "true GW events" also belong to the "blip glitch" family, cf. Figure 2 on page 25 of LIGO Magazine article cited above.

GD: (Resonant lines) "... are continuously excited by the suspension noise, that's why they won't be mistaken for chirps."

Of course, resonant lines will be excited as well by transients standing out from background noise.

Carlos Frajuca: "It´s in http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.241103"

There is no mention at all of possible interference from the passive seismic suspension system.

[revised - my previous answer commented on the active system]

JKF: There is no mention at all of possible interference from the passive seismic suspension system.

As I said in my previous reply, the reason they switched from steel to fused silica was because the study (which you cited) showed that the silica suspension didn't produce transients, just thermal noise. The very high Q factor means the energy is confined into the violin modes which, as you noted, are easily identified in the output, they affect only a single bin in the Fourier Transform.

GD: „The passive system ... anything it generates is just subsumed into the uncontrollable external noise.“

You exactly hit the point: The public, including people particularly interested such as you are, is made believe that the passive seismic suspension system is really „passive“, i.e. exposed merely to thermal noise. In fact, it is well known that this is not the case. Special investigations like the one cited above have been carried out during the past two decades in order to avoid confusion of transient events in the passive seismic suspension fibres and connecting hardware with expected gravitational wave (GW) events in LIGO type interferometers. Transient events typically occur in materials under tension stress due to crystal lattice dislocation and associated cracking.

It appears rather strange to me that phenomena of this type are completely blacked out from discussion in the 2016 GW discovery papers, while it is stated in 2016 LIGO Magazine: „There are families of glitches that we frequently see but have not yet discovered the cause of.“

GW (your revised post): "the reason they switched from steel to fused silica was because the study (which you cited) showed that the silica suspension didn't produce transients, just thermal noise."

I understand that fused silica was primarily introduced in order to reduce background noise, but transients still occur as is clearly stated by: „There are families of glitches that we frequently see but have not yet discovered the cause of.“

JKF: Transient events typically occur in materials under tension stress due to crystal lattice dislocation and associated cracking.

They can do and they did in the steel suspension but as I have pointed out three times now, the study which you cited earlier confirmed that the silica fibres didn't have that problem. Here again is their conclusion:

The preliminary measurements show that the effective temperature is close to room temperature, which means that the violin-mode oscillations averaged over longer time compared to the relaxation time, can be described as pure Brownian motion.

JKF: It appears rather strange to me that phenomena of this type are completely blacked out from discussion

It's a magazine article for goodness sake. The technical people have no doubt been looking at every source they can imagine but then they do the diagnostics, they might look at the characteristics of the transient and compare it with what a source would produce to rule out as many possibilities as possible, or in the case of the refrigerator, they might just switch it off and see if the glitches disappear. Obviously signals which last for a few milliseconds cannot originate from a system that has a Q of >107!

GD: "violin-mode oscillations averaged over longer time compared to the relaxation time, can be described as pure Brownian motion."

When averaging "over longer time" excitation by transient events, of course, cannot be distinguished from excitation due to Brownian motion.

GD: "Obviously signals which last for a few milliseconds cannot originate from a system that has a Q of >107!"

The Q factor may describe mechanically or thermally induced internal losses of the suspension material, but in no way precludes the occurrence of solid state transients under enhanced tensile stress.

Do you know what a Q factor is Johan?

George, are you suffering lack of arguments?

JKF: I understand that fused silica was primarily introduced in order to reduce background noise,

No, the Brownian motion caused by thermal noise is inherent in any material, you can't reduce it other than by cooling the suspension. The fact that the noise level matches the room temperature suggests there are at most a small number of transient noise events above the thermal background, probably none.

JKF: but transients still occur as is clearly stated by: „There are families of glitches that we frequently see but have not yet discovered the cause of.“

Certainly they occur and there are probably multiple different sources but like the refrigerator which they did identify, they are probably all external items that haven't been subject to any scientific studies, unlike the silica suspension.

GD: "they are probably all external items that haven't been subject to any scientific studies"

Suggestions based on "probably" type assumptions like the above one are suited to inhibit any further investigation and discussion of solid state relaxation phenomena and associated transient events in the passive suspension hardware under enhanced tensile stress.

Not at all, you took a statement from the magazine about transients from unknown sources and tried to give the impression that it related to the change to silica for the suspension.

If you want to talk about the suspension then my question remains, do you know what the Q factor describes?

GD: "you took a statement from the magazine about transients from unknown sources and tried to give the impression ..."

This was just a suggestion in view of well known phenomena in materials under tensile stress. What I complain about is that phenomena of this kind are obviously excluded from present discussion. Silica in no ways is free from phenomena of that kind, see references below. In the last reference we find the following statement on fused silica (FS):

"FS presents some drawbacks: the tensile strength (and, partially, the dissipation) is dominated by the cracks and defects present in the fibre surface."

In GW related papers displacements of the order 10-3 proton diameters are discussed. I don't think that effects due to solid state relaxation phenomena have ever been investigated at this level of sensitivity.

I have to ask again Johan, do you know what Q factor is and its relevance to the conversation?

JKF: What I complain about is that phenomena of this kind are excluded from discussion.

It isn't excluded Johan, we are discussing it. However, you seem to be intent on ignoring the fact that a study was conducted specifically to investigate this question for the proposed fused silica before it was adopted. The transients you are asking about were present in the previous steel suspension but were not present in the fused silica material.

JKF: Silica in no ways is free from phenomena of that kind, see references below.

Both of your references are irrelevant, they discuss defects in crystals while fused silica is an amorphous glass and highly elastic when suitably prepared. See the video at the bottom of the link.

p.s. I see you have added a third reference since I first posted this response. The paper discusses future possible use of monocrystalline silicon fibres which might be more suitable for a cryogenic suspension system that would reduce the thermal noise. Again it is irrelevant for a discussion of the presently used fused amorphous silica fibres.

http://www.translume.com/index.php/resources/item/186-fused-silica-material-properties

GD: "I have to ask again Johan, do you know what Q factor is and its relevance to the conversation?"

I don't understand what you mean by this question, and how the Q factor should prevent stress induced relaxation events and related signal bursts at the detector output. Note that my above citation taken from last reference explicitely relates to fused silica (FS).

JKF: I don't understand what you mean by this question, and how the Q factor should prevent stress induced relaxation events and related signal bursts at the detector output.

Q factor is the energy dissipated per cycle by damping divided by the energy stored. A Q of >107 at a resonant frequency of ~20Hz means that dissipating 1/e of the energy will take ~107/20 seconds or about 140 hours. How do you imagine a millisecond burst could be produced from a system with that decay time? That is why the Q has the effect of averaging the noise over a very long time scale. Transients have the effect of stimulating the ringing in this violin mode.

JKF: Note that my above citation taken from last reference explicitely relates to fused silica (FS).

Indeed but if surface cracks caused the fibre to fail, it would be very noticeable. Those defects place an upper limit on the mass that can be suspended, nothing to do with internal dislocations.

https://en.wikipedia.org/wiki/Q_factor#Definition

GD: "Transients have the effect of stimulating the ringing in this violin mode."

When transients occur right at the passive suspension hardware these will neccessarily release in parallel also some sort of signal at the GW detector output. Local relaxation and plastic deformation are well known to occur already at tensile stress far below the yield point.

JKF: some sort of signal at the GW detector output.

It stimulates the 20Hz resonance, but that is already being continuously stimulated by the Brownian noise.

JKF: Material relaxation and plastic deformation are well known to occur ..

Plastic deformation and relaxation don't produce bursts. The study found that in the fused silica, the performance didn't differ from the expected thermal noise.

If you want to look for the source of the "blip glitches", the myriad of other equipment on the site is a far better candidate, what you are suggesting would not produce signals bearing any resemblance to the spectrum of the glitches.

Sorry, George, I won't follow any longer discussion at this level of confusion, thanks anyway for your efforts.

OK, no problem Johan.

LIGO like LISA is another scientific fraud, large sums of public money involved.

Einstein Gravitation theory: Gravitation is a distortion of space-time, limited to the speed of light.

Ferent Gravitation theory: Gravitation is a force mediated by gravitons, not limited to the speed of light.

In Einstein Gravitation theory the gravitational waves have the speed of light, detected by LIGO.

In Ferent Gravitation theory the gravitational waves have the speed of the gravitons 10^17 m/s, not detected by LIGO!

Why the Graviton smaller 10^42 times than a Photon, can not travel faster than the speed of light?

Because you were brainwashed by your professors for 100 years, that nothing can travel faster than light!

In the last 100 years physicists did not understand Gravitation, the space pushes them into their chairs, like Dr. Kaku said, following Einstein gravitation theory!

 “I am the first who understood and explained Gravitation with high speed gravitons v = 1.001762 × 10^17 m/s, with Negative Momentum, Negative Mass and Negative Energy” Adrian Ferent

AF: In Einstein Gravitation theory the gravitational waves have the speed of light, detected by LIGO.

Correct.

AF: In Ferent Gravitation theory the gravitational waves have the speed of the gravitons 10^17 m/s,

Any theory which does not match observation is false, yours included. It is now time for you to stop spamming your failed attempt.

@AF

What makes you say that GR is wrong.?

Why is Ferent gravitation  have to be 10^17 m/sec?

Whys is it not c^2?

After 1 year research I realized that the graviton speed must be much higher than the speed of light to keep the constellations together!

The stars in constellations aren't "together", they are scattered at widely differing distances, they just happen to line up from where we are looking.

I am the first who discovered: If the gravitons have the speed of light will not be able to keep the constellations together.

@ Adrian

The question remains why is it  10^17 m/sec, and not c^2, which is 8.987551787  x10^16 m/sec (nearly your value), which would make for more sense and far more precise.

Think coincidence or not.

I would appreciate your precise derivation- but you need to explain it in  brief and perhaps conventional terms.

c2 is of dimension m2/s2.

You can read on page 13: 

The law of conservation of energy states that the total energy of an isolated system cannot change in time.

The Planck energy is nature’s maximum allowed matter energy for point-energy (quanta).

During the Big Bang, this means the Ferent energy, at Ferent wall, is equal with the Planck energy.

From here I calculated the speed of a free (not coupled) graviton!

https://www.researchgate.net/publication/299135595_Ferent_Gravitation_theory

I tried to link c with c^2 in different ways. For me constant c is more important than the speed of light in the Big Bang history.

Article Ferent Gravitation theory

Dear Andrew Worsley,

I can only direct you to the very recent (December 3) Séminaire Poincaré, "Ondes Gravitationnelles", especially to the talk by Michele Maggiore, "Exploring the Universe with GW", where she says: " During the first scientific run of the LIGO detectors, which continued until Jan. 2016, a second confirmed BH-BH coalescence, GW 151226, was detected on Dec. 26, 2015. It was then announced in June 2016, together with a third plausible event, whose statistical significance was however not sufficient to to claim a third discovery". For all this, she gives the ref. B.P. Abbott et al., Physical Rev. Lett. 16, 241103 (2016m), [arXiv:1606.04855], which I have not checked. You can also go to www.bourbaphy.fr, which will lead you to a video of the conference on Youtube.