In 1987, Joe Weber, a physicist at the University of Maryland, claimed to have detected gravitational waves at exactly the same moment that other astronomers witnessed the famous supernova of that year, SN1987A.
His equipment consisted of several massive aluminium bars that were designed to vibrate in a unique way when a large enough gravitational wave passed by.
His claims were ignored largely because other physicists calculated that gravitational waves ought to be several orders of magnitude too weak to be picked up by this kind of gear. (And he’d made several similar claims throughout the 60s and 70s that others had failed to repeat.)
But Weber’s claims may have to be re-examined, says Asghar Qadir, a physicist at the National University of Sciences and Technology in Rawalpindi, Pakistan. He points out that predicting the strength of a gravitational wave is by no means easy and until recently, only first order effects have been considered.
He and colleagues have now worked out that in certain circumstances, second order effects can enhance the waves. But this only happens when there is a certain kind of assymetry in the event that created the waves.
But get this: the assymetry can enhance the waves by a factor of 10^4.
He also points out that SN1987A is aspherical in exactly the way that might create this enhancement. So if SN1987A generated gravitational waves, Weber would have been perfectly able to detect them.
Qadir concludes: “The claim of Weber to have observed gravitational waves from [SN1987A] needs to be re-assessed”.
By all accounts, Weber was a careful experimenter who got something of a rough deal for his efforts (the most comprehensive telling of the tale is in a book called Gravity’s Shadow by Harry Collins) .
Weber died in 2000 but it wouldn’t do any harm to re-examine his work in the light of this development.
Ref: arxiv.org/abs/0903.0252: Gravitational Wave Sources May Be “Closer” Than We Think
If a second order effect gives 10^4, what does a third order effect give?
This article has been added to the Astronomy Link List.
Gravitational waves are somewhat tricky business even in context of Aether theory. In analogy to water surface waves the gravitational waves should correspond the underwater sound waves. These waves are spreading by much higher speed with compare to surface waves, which corresponds the light waves. From this follows, gravitational waves are tachyons and they could penetrate whole observable Universe in few seconds.
Unfortunately because gravitational waves are spreading in higher number of dimensions, they should spread and disperse a much faster then the waves of vacuum (i.e. the light). By my opinion these waves corresponds the virtual photons, which are responsible for Casimir force. Because gravitational waves disperse readily, the cannot be detected at large distances. This explains, why we detected only noise in GW detectors.
Nevertheless, even bellow water surface a subtle portion of sound can spread along surface of large scale density fluctuations, which are serving like waveguides. These sound waves are used whales for navigation and they’re of transversal character.
By my opinion just these gravitational waves can be detected at cosmic scales, where they spread along surfaces of density fluctuations of vacuum, i.e. along streaks of dark matter.
Is the author implicitly claiming that LIGO is 10,000 less sensitive than what it could be for the same price?
Why doesn’t the acronym LIGO appear in the article at all?
I haven’t spent a fully sufficient amount of time with Qadir’s article but right now I think it’s pure bullshit.
Weber was a hack. Don’t waste your time.
“Is the author implicitly claiming that LIGO is 10,000 less sensitive than what it could be for the same price? ”
Uh, no.
“Why doesn’t the acronym LIGO appear in the article at all?”
Because it’s completely irrelevant? It didn’t exist when data on the SN1987A nova was collected.
Are you implicitly claiming that LIGO is so fucking super-awesome that it can detect gravity waves THROUGH TIME?!?!?!!!111@awesome
Yeah, I didn’t think so.
“I haven’t spent a fully sufficient amount of time with Qadir’s article but right now I think it’s pure bullshit.”
You didn’t even spend sufficient time with the above summary to realize that the 10^4 increase refers to wave strength from the source event rather than some magical property of the detection equipment — so why should anyone care what you think about the actual article?
thanks, zephir, I always wondered what the source of the casimir force was. do you think that non-positive fluctuations of the vacuum, i.e. the dark energy, could be related to values of gravity corresponding to strings leaking vibrating energy outside the universe, in analogy to a tire losing pressurized air?
[…] Were gravitational waves first detected in 1987? […]
LIGO is relevant because it is more sensitive than Weber’s bar and can see much further out than it.
A 10^4 enhancement factor would imply that these exotic supernovas would be visible to LIGO all the way to Virgo cluster and beyound. This is a lot of stars (Virgo cluster alone consists of 1300 galaxies) and this would imply that a detection would have been found and made public by now.
As this did not happen, we can confidently state that if a 10^4 enhanced events exist they are exceedingly rare – my guess would be below 1 in a billion years for a Milky Way galaxy.
That was a quick and uninteresting read. The argument is that apparently under this ‘asymmetry’, gravitational waves are cylindrical rather than spherical.
Yeah, ok. I’m not holding my breath for this bullshit.
LIGO didn’t exist in 87.
Concerning the Lubos Motl question: yes, here’s such posibility (although the 1:10.000 sensitivity increasing couldn’t be expected in real time). The LIGO Laboratory is building Advanced LIGO using a homodyne detector. This detector is designed to improve the sensitivity of LIGO 1 by more than a factor of 10 and it should be operational in 2014. Another level of improvement of signal/noise ratio (by factor of 3 – 5) can be achieved by using of squeezed light feature, for example – compare the analysis bellow.
http://www.ligo.caltech.edu/docs/G/G030088-00.pdf
..in analogy to a tire losing pressurized air..
By AWT the observable universe can be interpreted by interior of collapse, so it should undergo a gravitational collapse like every other star, thus increasing its density, which manifests itself like expansion of space-time from insintric perspective of observer inside it.
So if you consider gravitational collapse of stars due radiation energy leak as an analogy of tire losing air, then answer may sound yes.
But the pressure inside of Universe should increase, instead of decrease. In this point tire analogy doesn’t work quite well, because the collapsing universe behaves rather like soap foam bubble leaking air. Inside of bubble pressure increases with decrease of diameter, because its surface (mem)brane is infinitelly “elastic”.
ERRATA: ..”universe can be interpreted by interior of collapsar” (a thing similar to black hole, but of finite diameter and supposedly shinning like common star – I mean a quasar or something similar).
[…] arXiv blog Bookmark and […]
What’s assimetry?
http://www.urbandictionary.com/define.php?term=assymetry
The Early History of Gravity Waves
In the late 1960s and early 1970s Joseph Weber claimed that he had detected gravity waves (Weber 1969; Weber 1970; Weber, Lee et al. 1973). One problem was that the rate of detection was far in excess, by a factor of 1000, of what was expected by calculations based on Einstein’s General Theory of Relativity. Nevertheless, Weber’s results were sufficiently credible that several experimental groups attempted to replicate his findings. None were successful. In this case, the physics community was forced to compare Weber’s claims that he had observed gravity waves with the reports from six other experiments that failed to detect them. The results presented by Weber’s critics were not only more numerous, but they had also been carefully cross-checked. The groups had exchanged both data and analysis programs and confirmed their results. The critics had also investigated whether or not their analysis procedure, the use of a linear algorithm, could account for their failure to observe Weber’s reported results. They had also used Weber’s preferred procedure, a nonlinear algorithm, to analyze their own data, and still found no sign of an effect. They had also calibrated their experimental apparatuses by inserting acoustic pulses of known energy and finding that they could detect a signal. Weber, on the other hand, as well as his critics using his analysis procedure, could not detect such calibration pulses.
There were, in addition, several other serious questions raised about Weber’s analysis procedures. These included an admitted programming error that generated spurious coincidences between Weber’s two detectors, possible selection bias by Weber, Weber’s report of coincidences between two detectors when the data had been taken four hours apart, and whether Weber’s experimental apparatus could produce the narrow coincidences claimed. It seems clear that the critics’ results were far more credible than Weber’s. Weber did not agree and offered various answers to the criticisms, which the physics community did not find plausible or compelling. By 1975 a consensus had been reached that Weber’ claim was unsubstantiated.
The most detailed history is
Collins, H. (2004). Gravity’s Shadow. Chicago: University of Chicago Press.
For a very different view than Collins see
Franklin, A. (1994). “How to Avoid the Experimenters’ Regress.” Studies in History and Philosophy of Modern Physics 25: 97-121.
For Collins answer see
Collins, H. (1994). “A Strong Confirmation of the Experimenters’ Regress.” Studies in History and Philosophy of Modern Physics 25(3): 493-503.
For a participants account see
Levine, J. L. (2004). “Early Gravity-Wave Detection Experiments, 1960-1975.” Physics in Perspective 6: 42-75.
Weber, J. (1969). “Evidence for Discovery of Gravitational Radiation.” Physical Review Letters 22: 1320-1324.
Weber, J. (1970). “Anistropy and Polarization in the Gravitational-Radiation Experiments.” Physical Review Letters 25: 180-184.
Weber, J., M. Lee, D. J. Gretz, et al. (1973). “New Gravitational Radiation Experiments.” Physical Review Letters 31: 779-783.
[…] En 1987, Joe Weber pudo ser el primer científico en detectar directamente ondas gravitacionalesarxivblog.com/?p=1271 por mezvan hace pocos segundos […]
Zephyr,
Your post was the most interesting for me, could you recommend a few books that will give me basic overview of all of the points you made in your post? I’ve had pre-calculus math and physics courses and read a few general QM books.
Thanks,
Mike
Hi Mike, most of properties of water surface and bubbles are illustrated in Victorian era textbooks of physics. All claims quoted by phrase “By AWT” are particle model based speculations of mine. They’re of emergent nature, i.e. they’re adopted to common points of many theories at the same moment. For example, tachyonic character of gravity waves is required by holographic theory to be able to work.
[…] Another interesting discovery is that a researcher back in 1987 who claimed to have detected gravity waves coming from a nearby supernova may have been correct.
Give me a break with this nonsense. Whether LIGO existed in 1987 is completely irrelevant if there is a factor of 10,000 at stake.
LIGO is surely more times sensitive than all gadgets in 1987 than Supernova 1987 was stronger than explosions we can see every year.
This is a crackpot sequence of papers.
I’m sorry to say that I may have information that will put Weber’s claims to rest once and for all… you see, I’ve consulted my logbook for the day of SN1987A’s supernova, and it turns out I had some… ah, how can I say? some spectacularly explosive activity of my own. (Yes, the logbook is similar to the logbook kept by anyone with IBD as bad as I have it.)
My hypothesis is that the rumblings of my digestive system corresponded precisely to the resonant frequency of Weber’s experimental gear… and lets face it, I was a lot closer to Weber than some distant star. Do the math on THAT second order effect!
[…] the physics arXiv blog » Blog Archive » Were gravitational waves first detected in 1987? – In 1987, Joe Weber, a physicist at the University of Maryland, claimed to have detected gravitational waves at exactly the same moment that other astronomers witnessed the famous supernova of that year, SN1987A. […]
[…] Were gravitational waves first detected in 1987? the physics arXiv blog Back in 1987, the physicist Joe Weber claimed to have detected gravitational waves at the same moment that the rest of the scientific world were detecting the supernovae SN1987A. At the time it was thought that gravitational waves were too weak to be detected in this fashion, but now there are claims to revisit his work to see if there was any merit in his research. […]