Any area's that may need to be further investigated to justify the confidence rating of 99.99994% (5.1 sigma) that this was the first observation of gravitational waves? Which seems rather high for theoretical dark stuff that theoretically makes up 95% of the unseen universe that before the Gravity Wave 150914 had not been directly observed.
Could there be equipment, theories or computer modelling that might incorrectly interpret the LIGO Gravity Wave signal? An electromagnetic wave that lasted less than 0.2 seconds and was so minuscule to detect?
LIGO signal possible errors list
Below are some areas for concern raised by scientists. If you know of any more in other articles or have any ideas yourself please either make a comment below (you can make a comment as a guest without having to sign up for anything or give any information) or contact the site.
- Black Hole Gravity Waves computer modelling and theories - garbage in, garbage out?
- LIGO mirrors tolerance, scale of GW150914 signal and detectors precision
- Gravity Wave direction and LIGO detectors location
- Signals strength difference between the 2 LIGO observatories
- Correlated noise signals?
Garbage in, Gospel out
One area of concern or possibility of producing the wrong information are all the computer mathematical models of all the theories used to reverse engineer the whole LIGO event - what the BBH system was like before, what happened to the Binary Black Hole system during and the end of the signal chirp.
There is an old computer programming saying of GIGO - garbing in, garbage out (or for those from the UK - rubbish in, rubbish out). Now with the rise of computer models for all sorts of science but especially astrophysics it has been upgraded - garbage in, gospel out.
The science had already been decided - only a merger between 2 black holes could produce the effect and the signal. Nothing else in the whole universe could or would be considered to create the effect.
It seems quite amazing that through the common looking EM signal that astrophysicists and computer models have created such a precise and incredible detailed account of what happened. And even then the result of the two black holes system and merger was a theoretical surprise as it broke current theories on size limits - garbage in, garbage out?
Claes Johnson, Professor of Applied Mathematics:
the conclusion is drawn by computer simulations and modelling that this extremely minute effect as a "ripple in the fabric of space-time", was the result of a very specific extremely gigantic invisible explosion 1.3 billion light years away shining brighter than all stars in all galaxies for 0.25 seconds in the form of gravitational waves.
We see a combination of a biggest possible cause/input and a smallest possible effect/output in a certain mathematical model. The conclusion comes from using this mathematical model in inverse form, where a smallest possible signal is used to identify a biggest possible origin of the signal.
This means that the mathematical model in inverse form is extremely ill-posed and as such cannot be used to draw conclusions. To do so requires that all alternative explanations of the zero signal can be eliminated, and it is then not enough to just say that no other explanation immediately suggest themselves, that is to draw conclusions from ignorance with the precision of the conclusions increasing as the ignorance or stupidity grows.
Absurdity of Modern Physics: LIGO Gravitational Wave Detection as Ill-posed Problem | Claes Johnson
LIGO mirrors tolerance
Dr Hilton Ratcliffe, the rebel physicist and astronomer, discussed in a Thunderbolts video the theoretical problems with the precision of the LIGO Test Masses (mirrors). There is a full text version (very similar) of his speech.
Best precision mirror surfaces are polished to match the ideal nearly parabolic surface to about 25 nanometres. A nanometre is a millionth of a millimetre.
The most precisely polished astrophysical mirrors like those used in LIGO have 25 peaks nanometre above and below the theoretical surface plane of the mirror. Meaning that some parts of the mirror can be 50 nanometres further from or closer to the point of observation. 50 nanometres is a billion times bigger than the gravitational waves signature.
Because of this it is practically impossible to measure the distance between the two mirrors in each interferometer to the required tolerances, so they've had to take an average which is no more than a guessed approximation.
Hilton Ratcliffe: "Discovery" of Gravitational Waves | Thunderbolts
For those interested in the LIGO mirror (Test Masses as they are referred to) then the Advanced LIGO Test Masses and Core Optics pdf has a lot more information and graphics about them.
The mirrors are coated with dozens of layers of optical coatings and polished to nanometer smoothness. Again, this level of precision is required to ensure that LIGO’s laser has a clean, stable, and perfectly tooled reflective path to follow as it travels through the interferometer making around 400 reflections. Without these precautions, detecting a gravitational wave would be impossible.
LIGO Optics | LIGO
Einstein was skeptical that gravitational waves would ever be detected because the predicted waves were so weak. Einstein was right to wonder – the signal detected on September 14, 2015 by the aLIGO interferometers caused each arm of each L-shaped detector to change by only 2 billionths of a billionth of a meter, about 400 times smaller than the radius of a proton.
Gravitational Waves Discovered: Top Scientists Respond | US News
This is an immensely delicate experiment: the effect being sought is so tiny that it "shakes" the mirrors through a distance less than a millionth of the size of a single atom.
Gravitational waves: Einstein was right | Telegraph
LIGO must be unbelievably sensitive to measure this change in the length of the legs ... less than the size of a soccer ball compared with the span of the Milky Way.
Gravitational Waves Discovered from Colliding Black Holes | Scientific American
Signal source location and velocity
There was a delay of seven thousandths of a second between the two Laser Interferometer Gravitational-Wave Observatories receiving the GW150914 signal. Gravitational Waves have to travel at the speed of light.
This means that the Gravitational Waves signal source did not come from above the two LIGO's. The GW150914 signal first hit Livingston Louisiana USA (L1) and then travelling through the Earth it hit Hanford Washington USA (H1) about 0.007 seconds later. Distance between the LIGO detectors at Hanford and Livingston is about 3000 km over Earth's curvature. Radius of Earth is about 6370 km. Direct linear distance between them is about 2500 kilometers. The speed of light (in a vacuum) travels about 300 kilometers (185 miles) in one millisecond.
Bibhas De in the Thunderbolts video says:
To produce anywhere near the anticipated time delay of 8.3 millionths of a second it would have to meet two critical criteria. Firstly it would have to almost exactly aligned with the line drawn through the Earth's crust between Livingstone and Hanford. Secondly the wave would have to propagate through 2500 kilometers of rocky crust without degrading in the in the slightest.
But barring such cosmic conspiracy the source located 1.3 billion light years away one would expact a delay much much less than the theoretical 8.3 milliseconds or the measured 7ms. Infact, one may expect only a a microsecond delay, 7000 times smaller than LIGO found.
Signal amplitude difference between detectors
Bibhas De in the Thunderbolts video says:
The two detectors are seeing the same thing, the exact same "wavefront" passing through them 7 milliseconds apart.
The Livingstone detector is recording a lower signal level in the main body of the arrival. Elsewhere before the arrival and after the signal is passed, the two detectors the similar strengths.
This could be readily ascribed to instrumental differences between the detectors. If so, we should simply be able to linearly expand the blue signal and make it match up with the red signal everywhere, but clearly this does not work.
Correlated noise signals
Like the whole thing this potential error may be something or nothing.
Now a team of independent physicists has sifted through this data, only to find what they describe as strange correlations that shouldn’t be there. The team, led by Andrew Jackson, a physicist at the Niels Bohr Institute in Copenhagen, claims that the troublesome signal could be significant enough to call the entire discovery into question. The potential effects of the unexplained correlations “could range from a minor modification of the extracted wave form to a total rejection of LIGO’s claimed [gravitational wave] discovery,” wrote Jackson in an email to Quanta. LIGO representatives say there may well be some unexplained correlations, but that they should not affect the team’s conclusions.
... The main claim of Jackson’s team is that there appears to be correlated noise in the detectors at the time of the gravitational-wave signal. This might mean that, at worst, the gravitational-wave signal might not have been a true signal at all, but just louder noise.
... The technical issues at stake here have to do with the extreme difficulty of the measurements that LIGO attempts to make. Gravitational waves are exceedingly faint, so to catch them LIGO was built with the ability to measure a change in distance just one-ten-thousandth the width of a proton. Lots of little bumps and vibrations can mimic a gravitational-wave signal, so LIGO uses two observatories, 3,000 kilometers apart, which operate synchronously, each double-checking the other’s observations. The noise at each detector should be completely uncorrelated — a jackhammer going off in the town near one detector won’t show up as noise in the other. Yet if a gravitational wave swoops through, it should create a similar signal in both instruments nearly simultaneously.
Strange Noise in Gravitational-Wave Data Sparks Debate
There are doubts about these doubts though ...
But not everyone believes that the correlations are real. Harry, in his rebuttal, points out that Jackson’s team could have misused a common data-processing technique called the Fourier transform. The Fourier transform separates a data signal into a collection of simpler waveforms. The error, Harry writes, has to do with the technical assumption that the input data signal be “cyclical,” repeating itself without any breaks or discontinuities. For example, a cyclical sound wave would be the repetition of a sound clip without a pop in between each repetition. A signal that isn’t cyclical cannot be analyzed through the Fourier transform without introducing subtle errors. Otherwise, the so-called Gibbs phenomenon distorts the input signal’s frequencies, thus decreasing the accuracy of the ensuing analysis.
Since real-life data is almost never cyclical, anyone doing Fourier analysis must first execute an array of cleanup jobs on the raw data. “It looks like some of the results [of Jackson’s team] had to do with not pre-filtering the data before taking the Fourier transform,” said David Shoemaker, a physicist at the Massachusetts Institute of Technology and spokesperson for the LIGO Scientific Collaboration, echoing Harry’s public analysis.
Strange Noise in Gravitational-Wave Data Sparks Debate