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