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Exclusive: Grave doubts over LIGO’s discovery of gravitational waves

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https://www.newscientist.com/article/mg24032022-600-exclusive-grave-doubts-over-ligos-discovery-of-gravitational-waves/

Exclusive: Grave doubts over LIGO’s discovery of gravitational waves

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Sensationalisitc headlines? My thoughts? Whatever the outcome, in my view it again supports the scientific methodology as superior to anything we have.

 

I'll let those far more initiated in this sort of stuff to offer comments, rather then my own. Interesting to say the least.

[Perhaps someone could E-Mail aLIGO or VIRGO for a comment?]

 

 

https://arstechnica.com/science/2018/10/danish-physicists-claim-to-cast-doubt-on-detection-of-gravitational-waves/

Danish physicists claim to cast doubt on detection of gravitational waves

LIGO responds: "There is absolutely no validity to their claims."

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https://arstechnica.com/science/2018/10/danish-physicists-claim-to-cast-doubt-on-detection-of-gravitational-waves/

extract:

"Then, in 2014, the BICEP2 collaboration—which hunts for telltale signatures of gravitational waves in the cosmic microwave background (the leftover radiation from the Big Bang)—announced it had detected indirect evidence of these ripples in the fabric of spacetime. Much fanfare ensued. Within weeks, however, serious doubts had begun to emerge. Ultimately, it turned out that the BICEP collaboration had mistaken clouds of cosmic dust for a signal.

The blow was crushing. The gravitational-wave community was sufficiently burned by the BICEP2 debacle that LIGO opted for extreme caution and secrecy—ironically a big part of the reason the collaboration is viewed with distrust in some quarters. Its researchers spent several months between the signal detection and the official announcement in February 2016 to double, triple, and quadruple check their analysis to guard against another false detection.

So how could this happen again?

First, it's highly unlikely that it has happened again. But the answer is that separating signal from noise is very, very difficult in this kind of analysis. The signal is extremely faint (on the order of a billionth of a billionth the diameter of an atom); that's why you need such sensitive detectors to pick them up at all.

Also, the Universe is actually a pretty noisy place. "The problem isn't so much the absolute weakness of the waves; the problem is that there are many other disturbances that also wiggle the interferometer," physicist Sabine Hossenfelder wrote at Forbes back in 2017—the first time Jackson's false-signal claims were making the rounds."

https://arxiv.org/pdf/1811.00364.pdf

"The recent discovery by Advanced LIGO and Advanced Virgo of a gravitational wave signal from a binary neutron star inspiral has enabled tests of general relativity (GR) with this new type of source. This source, for the first time, permits tests of strong-field dynamics of compact binaries in presence of matter. In this paper, we place constraints on the dipole radiation and possible deviations from GR in the post-Newtonian coefficients that govern the inspiral regime. Bounds on modified dispersion of gravitational waves are obtained; in combination with information from the observed electromagnetic counterpart we can also constrain effects due to large extra dimensions. Finally, the polarization content of the gravitational wave signal is studied. The results of all tests performed here show good agreement with GR".

CONCLUSIONS:

Using the binary neutron star coalescence signal GW170817, and in some cases also its associated electromagnetic counterpart, we have subjected general relativity to a range of tests related to the dynamics of the source (putting bounds on deviations of PN coefficients), the propagation of gravitational waves (constraining local Lorentz invariance violations, as well as large extra dimensions), and the polarization content of gravitational waves. In all cases we find agreement with the predictions of GR. The upcoming observing runs of the LIGO and Virgo detectors are expected to result in more detections of binary neutron star coalescences [84]. Along with electromagnetic observations, combining information from gravitational wave events (including binary black hole mergers) will lead to increasingly more stringent constraints on deviations from general relativity [25, 26], or conceivably potential evidence of the theory’s shortcomings.

Edited by beecee

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The paper critical of the aLIGO/VIRGO claims............

https://arxiv.org/pdf/1706.04191.pdf

On the time lags of the LIGO signals:

Abstract.

rXiv:1706.04191v2 [astro-ph.IM] 9 Aug 2017

To date, the LIGO collaboration has detected three gravitational wave (GW) events appearing in both its Hanford and Livingston detectors. In this article we reexamine the LIGO data with regard to correlations between the two detectors. With special focus on GW150914, we report correlations in the detector noise which, at the time of the event, happen to be maximized for the same time lag as that found for the event itself. Specifically, we analyze correlations in the calibration lines in the vicinity of 35 Hz as well as the residual noise in the data after subtraction of the best-fit theoretical templates. The residual noise for the other two events, GW151226 and GW170104, exhibits similar behavior. A clear distinction between signal and noise therefore remains to be established in order to determine the contribution of gravitational waves to the detected signals.

 

Concluding remarks:

Ideally, the search for gravitational waves should be separated into two independent phases. An initial template-free step should identify candidate events and demonstrate that they are of astrophysical origin. The second step, which will inevitably involve comparison with general relativistic calculations, should attempt to determine the physical nature of the event. Fortunately, the LIGO GW150914 event is sufficiently strong that it can be seen in both the Hanford and Livingston detectors without templates and that the cross correlation is high. The evidence that this event is astrophysical lies primarily in the fact that this cross correlation is maximized by an inversion of the Livingston data and a 7 ms shift of the record that is within the allowed ±10 ms window. The results of Section 3 suggest, however, that similarly strong agreement between the Hanford and Livingston detectors can be obtained from time records constructed exclusively from narrow resonances in the Fourier transform of the data. In spite of efforts to “cleanse” the data of the effects of these resonances, their strength renders it difficult to be certain that there has not been significant “leakage” of these effects to neighboring frequencies. The strong and unexpected correlations in the phases of the Fourier coefficients noted in Section 2 may be indicative of such leakage. It has been reported for both GW150914 and for GW170104 that the residual noise following from the subtraction of the template from the cleaned data is consistent with Gaussian noise and does not contain features characteristic of gravitational wave signals. (See [1] and [5], respectively) This is taken to imply that there are no biases in the modeling of the waveforms. While our findings do not contradict the previous statement about near Gaussianity during the time of the events, this is to be contrasted with the present demonstration that the residuals show apparent correlations between the detectors. It is striking that these correlations are maximized by applying nearly the same time shifts as found for the GW events themselves — for all three GW events reported to date.

The purpose in having two independent detectors is precisely to ensure that, after sufficient cleaning, the only genuine correlations between them will be due to gravitational wave effects. The results presented here suggest this level of cleaning has not yet been obtained and that the detection of the GW events needs to be re-evaluated with more careful consideration of noise properties.

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My first thoughts are, why has this supposed doubt just raised its head?

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No one prepared to offer any thoughts on this? Does that mean I can safely conclude that it was just some sensationalistic media propaganda and that the claim doubting the detection of gravitational waves was/is totally invalid?

 

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I have read a couple of articles about this. I doubt their criticisms are correct but it is good that there are people willing to analyse and challenge the data like this. It can only make the science stronger. 

The New Scientist headline is typically sensationalist - confirming it's place as the Daily Mail of science!

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4 minutes ago, Strange said:

I have read a couple of articles about this. I doubt their criticisms are correct but it is good that there are people willing to analyse and challenge the data like this. It can only make the science stronger. 

The New Scientist headline is typically sensationalist - confirming it's place as the Daily Mail of science!

Yeah my thoughts exactly Strange, and why I did preface my first remarks with that this is what science is all about and why the scientific methodology reigns supreme despite some unfounded criticism. The announcements of the discoveries of these gravitational waves did take some time to be revealed, but this was simply due to the cautionary aspect taken by the scientists at aLIGO, particularly after the BICEP2 premature announcement.

  

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On 11/17/2018 at 1:29 PM, beecee said:

No one prepared to offer any thoughts on this? Does that mean I can safely conclude that it was just some sensationalistic media propaganda and that the claim doubting the detection of gravitational waves was/is totally invalid?

 

Thanks beecee for bringing this to my attention and also for all the other science news you post. 

I don't think it was just "sensationalist media propaganda" although there was an element of that in the story. I think Strange (above) got it about right. I think it is safe to assume for now that gravitational waves have been detected. After all the visual confirmation was the smoking gun IMO. Also I have a lot of respect for David Shoemaker who is on the team.

Meanwhile people are out doing science with these results.

https://ras.ac.uk/news-and-press/research-highlights/gravitational-waves-merged-hyper-massive-neutron-star

Quote

 

The initial observations of GW170817 suggested that the two neutron stars merged into a black hole, an object with a gravitational field so powerful that not even light can travel quickly enough to escape its grasp. Van Putten and della Valle set out to check this, using a novel technique to analyse the data from LIGO and the Virgo gravitational wave detector sited in Italy.

snip

 

Van Putten comments: “We’re still very much in the pioneering era of gravitational wave astronomy. So it pays to look at data in detail. For us this really paid off, and we’ve been able to confirm that two neutron stars merged to form a larger one.”

 

Gravitational wave astronomy, and eking out the data from every detection, will take another step forward next year, when the Japanese Kamioka Gravitational Wave Detector (KAGRA) comes online.

 

 

Also the next wave of observations is on its way!

https://www.ligo.caltech.edu/page/observatory-status

Quote

 

The LIGO and Virgo teams are working on improving the performance of their instruments, with the objective of starting the third observing run (O3) early in 2019. 

Snip

Open Public Alerts in O3

The LIGO-Virgo (LV) Collaborations will issue Open, Public Alerts (OPA) for gravitational-wave transient event detections, starting with the next observing run of the instruments early in 2019. OPAs will enable the physics and astronomy community to pursue multi-messenger observations of gravitational-wave sources and maximize the science reach of the gravitational-wave instruments, in consistency with our data management plan.

 

Wish we could get interesting stuff like this to go on for 10 pages.:wacko:

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22 minutes ago, Outrider said:

Thanks beecee for bringing this to my attention and also for all the other science news you post. 

. I think it is safe to assume for now that gravitational waves have been detected. After all the visual confirmation was the smoking gun IMO. Also I have a lot of respect for David Shoemaker who is on the team.

Meanwhile people are out doing science with these results.

 

Also the next wave of observations is on its way!

 

Wish we could get interesting stuff like this to go on for 10 pages.:wacko:

Firstly, thanks for the appreciation and interest. The rest of the remarks of yours are I agree, 100% correct. I would also add the Event Horizon Telescope and LISA as two more up and coming experiments that will add knowledge to gravitational waves research.  

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https://www.ligo.caltech.edu/news/ligo20181120

Winners of the 2018 Award for Excellence in Detector Characterization and Calibration Are Announced

News Release • November 20, 2018

The LIGO Laboratory congratulates Derek Davis of Syracuse University and T.J. Massinger of Caltech for winning the first LIGO Laboratory Award for Excellence in Detector Characterization and Calibration.

The LIGO gravitational wave detectors have registered gravitational wave signals from multiple black hole mergers and the spectacular collision of two neutron stars since Advanced LIGO first began observing in 2015. Davis and Massinger’s work to reduce the noise present in LIGO detector data was key to making these discoveries possible by allowing searches to more easily distinguish the signatures of true astrophysical gravitational wave events in noisy detector data.

By improving how deep in space the LIGO-Hanford detector could sense by up to 50%, at least three gravitational wave signals were confidently detected during Advanced LIGO's second observing run (O2) that would not have been otherwise. Their efforts are an outstanding example of the detector characterization work needed to lay the groundwork for future discoveries in gravitational wave astrophysics and multi-messenger astronomy.

Davis and Massinger will share a $1000 prize and are invited to present colloquia at one of the the LIGO Laboratory sites (LIGO-Hanford, LIGO-Livingston, Caltech, or MIT) to share their achievements with LIGO Laboratory members. They will each receive an award certificate at the LIGO-Virgo Collaboration meeting in March 2019.

Derek Davis is currently a Ph.D. student at Syracuse University. As a part of the LIGO Scientific Collaboration, they serve as the Event Validation Lead for the LIGO Detector Characterization group, leading follow-up investigations of candidate gravitational-wave detections.

T.J. Massinger is currently a postdoctoral scholar at Caltech. He earned his PhD in 2016 from Syracuse University. Within the LIGO Detector Characterization group, he serves as instrument science lead and as a liaison to the compact binary coalescence data analysis working group.

Read more about the LIGO Laboratory Award for Excellence in Detector Characterization and Calibration.

Find a list of excellent LIGO Detector Characterization and Calibration projects that earned honorable mention for the 2018 award.

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"Grave doubts?"   As if the discovery (or non discovery) was a living creature, or even human which/who had died?  This is another example of many scientists taking themselves far too seriously.  Among the top professionals I'm sure they'll never have set the discovery up as anything except a possible occurrence which will take a lot more confirmation and many more occurrences to set on a table as edible.

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2 hours ago, coffeesippin said:

"Grave doubts?"   As if the discovery (or non discovery) was a living creature, or even human which/who had died?  This is another example of many scientists taking themselves far too seriously.  Among the top professionals I'm sure they'll never have set the discovery up as anything except a possible occurrence which will take a lot more confirmation and many more occurrences to set on a table as edible.

Not at all. The discovery of gravitational radiation has been a long held prediction of GR since its inception, and obviously re-enforces GR even further. It achieved the Physics Nobel for its prime discoverers. 

Gravitational waves also are a new window in the research activity that cosmologists can and will be able to study the universe with. Why theoretically speaking, we could very well discover gravitational waves from the BB itself, with the potential to possibly answer the why and how that have been asked for so long.

https://www.ligo.caltech.edu/news/ligo20181017

LIGO Scientists Awarded New Horizons in Physics Prize

News Release • October 17, 2018

Today, three LIGO scientists were awarded the 2019 New Horizons in Physics prize “for research on present and future ground-based detectors of gravitational waves.”

Lisa Barsotti (Principal Research Scientist at the MIT Kavli Institute), Matthew Evans (Associate Professor of Physics at MIT), and Rana Adhikari (Professor of Physics at Caltech) will share this year’s prize. All three are key members LIGO’s collaboration.

This is the seventh year that Breakthrough Prizes have been awarded. According to their website, “The Breakthrough Prize in Fundamental Physics was founded in 2012 by Yuri Milner to recognize those individuals who have made profound contributions to human knowledge. The … Prize aims to celebrate the best scientific work and inspire the next generation of scientists.”

Given the discoveries that LIGO has already made, and the promise of many more to come, the award was well deserved. All of LIGO and its collaborators congratulate their colleagues on this exciting recognition.

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8 hours ago, coffeesippin said:

"Grave doubts?"   As if the discovery (or non discovery) was a living creature, or even human which/who had died?  This is another example of many scientists taking themselves far too seriously.  Among the top professionals I'm sure they'll never have set the discovery up as anything except a possible occurrence which will take a lot more confirmation and many more occurrences to set on a table as edible.

I don't understand what you mean. Obviously, all scientific theories and observations are treated as more or less provisional. 

But why is having serious doubts wrong? Why does having serious doubts mean it is taken too seriously?

In completely baffled by your comment. 

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Nature of STC? 
While weighing importance of the discovery of grawaves (short form of gravitational waves) we have to pay attention to the STC also because according to the LIGO people ripples were caused by the in-coming grawaves on the STC. But STC doesn’t seem to be real as per recent evidences noted below.
1) Theme of the 5th conference on the nature and ontology of Space-Time (May 2018, Albena, BULGARIA was STC: Real or Imaginary? – http://www.minkowskiinstitute.org/conferences/2018
2) Contrasting views of John Wheeler and Rainer Weiss. According to a famous quote of John Wheeler, matter tells space how to curve. In short space has to be flexible so that it can be curved by a massive star. On the other hand, Rainer Weiss said (in the interview with the Nobelprize.org) that space is enormously stiff and cannot be squished easily. Such contrasting views of leaders of GR can confuse prospective graduates of physics and public, including heads of funding bodies. It is to be noted that physics community celebrated the year 2005 in the name Einstein himself for the popularization of physics.
3) Picture of STC in a typical book of GR. The said picture contains a massive star on a 2D fabric, like trampoline, and warping it down. Actually, use of 2D fabric is illogical because neither we can sense space nor time. In fact, visualization of STC in a book of GR is logically similar to the visualization of a ghost in a horror movie, as I have said in Space Research Today # 195.
In view of these points, I think that the discovery of grawaves is still on a shaky footing – though it has been awarded the nobel Physics Prize in 2017.

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1 hour ago, Dileep V. Sathe said:

Nature of STC? 
While weighing importance of the discovery of grawaves (short form of gravitational waves) we have to pay attention to the STC also because according to the LIGO people ripples were caused by the in-coming grawaves on the STC. But STC doesn’t seem to be real as per recent evidences noted below.

I assume STC is space-time continuum?

Quote

1) Theme of the 5th conference on the nature and ontology of Space-Time (May 2018, Albena, BULGARIA was STC: Real or Imaginary? – http://www.minkowskiinstitute.org/conferences/2018

 Electromagnetic waves do not need a physical medium in order to propagate. Why would gravitational waves?  

Quote


2) Contrasting views of John Wheeler and Rainer Weiss. According to a famous quote of John Wheeler, matter tells space how to curve. In short space has to be flexible so that it can be curved by a massive star. On the other hand, Rainer Weiss said (in the interview with the Nobelprize.org) that space is enormously stiff and cannot be squished easily. Such contrasting views of leaders of GR can confuse prospective graduates of physics and public, including heads of funding bodies. It is to be noted that physics community celebrated the year 2005 in the name Einstein himself for the popularization of physics.

Without an examination of the details (i.e. science), it's not clear that these views are contradictory. Prospective graduates of physics would likely be investigating the physics, where such subjective description give way to mathematical models.

 

Quote

3) Picture of STC in a typical book of GR. The said picture contains a massive star on a 2D fabric, like trampoline, and warping it down. Actually, use of 2D fabric is illogical because neither we can sense space nor time. In fact, visualization of STC in a book of GR is logically similar to the visualization of a ghost in a horror movie, as I have said in Space Research Today # 195.
In view of these points, I think that the discovery of grawaves is still on a shaky footing – though it has been awarded the nobel Physics Prize in 2017.

The objections to these observations should be based on questions about the science, not on the ontological underpinnings. This is posted in Astronomy and Cosmology, not Philosophy.

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2 hours ago, Dileep V. Sathe said:

2) Contrasting views of John Wheeler and Rainer Weiss. According to a famous quote of John Wheeler, matter tells space how to curve. In short space has to be flexible so that it can be curved by a massive star. On the other hand, Rainer Weiss said (in the interview with the Nobelprize.org) that space is enormously stiff and cannot be squished easily. Such contrasting views of leaders of GR can confuse prospective graduates of physics and public, including heads of funding bodies.

There is no conflict there. Both statements are true (in as much as they are analogies, and therefore not true at all) and both are consistent.

Diamond is very hard, but it still deforms.

Here is a paper that analyses the "stiffness" of space and confirms that it is, indeed, very stiff (about 1020 times stiffer than steel): http://physics.princeton.edu/~mcdonald/examples/stiffness.pdf

 

3 hours ago, Dileep V. Sathe said:

3) Picture of STC in a typical book of GR. The said picture contains a massive star on a 2D fabric, like trampoline, and warping it down. Actually, use of 2D fabric is illogical because neither we can sense space nor time. In fact, visualization of STC in a book of GR is logically similar to the visualization of a ghost in a horror movie, as I have said in Space Research Today # 195.

These are visualisations, just that. They are intended to help those who don't understand the science get a vague idea of that it is about. The fact that they are not terribly realistic doesn't invalidate the science.

 

3 hours ago, Dileep V. Sathe said:

In view of these points, I think that the discovery of grawaves is still on a shaky footing

I don't think your confusion and lack of understanding has any impact on the validity of the discovery. Sorry.

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5 hours ago, Dileep V. Sathe said:

In view of these points, I think that the discovery of grawaves is still on a shaky footing – though it has been awarded the nobel Physics Prize in 2017.

You really don't have any points of the nature you describe, and as adequately explained by Strange. It was awarded the Nobel because it is a great discovery and could potentially open up a whole new field for cosmological studies. 

Actually, the only possible doubts are whether the discoveries of these gravitational waves fit the GR description better then other  gravity models, and that "small doubt" I believe will in time be eliminated as further discoveries are made, and even more technologically advanced instruments and probes dictate.

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Another article on this: https://arstechnica.com/science/2018/12/two-independent-analyses-confirm-ligos-discovery-of-gravitational-waves/

Quote

Now Quanta is reporting that two independent analyses have been completed that confirm that detection. This should lay any doubts about the momentous discovery to rest.

“We see no justification for lingering doubts about the discovery of gravitational waves,” the authors of one of the papers, Martin Green and John Moffat of the Perimeter Institute for Theoretical Physics, told Quanta. That paper appeared in Physics Letters B in September. A second paper by Alex Nielsen of the Max Planck Institute for Gravitational Physics in Hannover, Germany, and three coauthors, was posted to the physics preprint site arXiv.org last month and is under review by the Journal of Cosmology and Astroparticle Physics.

But some drama still remains. Andrew Jackson, group spokesman for the skeptical physicists at the Niels Bohr Institute in Copenhagen, Denmark, is refusing to accept the results of the two independent groups' analyses. 

 

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1 hour ago, Strange said:

Thanks Strange. This whole aspect actually shows totally how ridiculous are the many claims of stubbornness by science and scientists,  by those pushing non mainstream or alternative issues, notably of course, when their own version/take is shown to be questionable.

Certainly also, if any criticism can be leveled at science at times, it would be over enthusiasm and  prematurely claiming before  sufficient research into the accuracy of such results, as per the BICEP2 results. Noting of course, that it was science itself and the Planck contingent that showed those results to be contaminated. 

Obviously and correctly, this was foremost in the minds of those involved with aLIGO and the time it took for the final analysis of the first gravitational waves discoveries to be released publicly.

Edited by beecee

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