Did Gravitational Waves Ring a Bell in 1987?

The hunt for gravitational waves continue, but unfortunately all gravitational wave hunters around the world are churning up nothing. Just noise. Could it be that this consequence of Einstein’s theory of General Relativity is horribly flawed? Probably not. Still, the search for these elusive waves has foxed physicists for many years. It has even come to the point that the laser interferometers used in an attempt to detect the tiny (and I mean TINY) changes in distances (as when the gravitational wave passes through us, space-time experiences a minuscule compression or expansion) have become so precise, the director of Fermilab thinks a German-UK gravitational wave detector is starting to detect the quanta of space-time itself.

However, do you ever get the feeling that we might be trying too hard? What if gravitational waves have already been detected? Say if these notoriously difficult ripples in space-time were detected over 20 years ago without using a laser interferometer? It turns out that an overlooked scientist may have found the answer to the gravitational wave problem by using nothing more than some aluminium bars and a well-timed supernova…

I’ve been a little harsh about the search for gravitational waves in the past, but it seems that although gravitational waves are predicted to exist, no matter how hard we try to find them, the perturbations just aren’t there. In many cases it is understandable to want to gather more data, exposure time is critical in this kind of experiment, but physicists really did not think that we would still be trying to find the first gravitational wave signal after so much international investment and so much time.

However, when I was seven years old, probably playing in the garden with my new Lego set, Joe Weber, a physicist at the University of Maryland, detected a signal matching the characteristics of what he thought was a gravitational wave. What’s more, Weber’s detection coincided with the famous supernova SN1987A (an event theorized to generate some powerful wave action). As gravitational waves are calculated to travel at the speed of light, the light from SN1987A and an intense burst of gravitational waves should have coincided.

Weber had set up an apparatus of several massive aluminium bars designed to vibrate when a powerful gravitational wave passed by. Although his theory appeared to be sound, physicists calculated that Weber’s numbers were out by several orders of magnitude; his equipment couldn’t possibly detect gravitational waves, it wasn’t sensitive enough. He was ignored.

However, as pointed out in a recent paper written by Asghar Qadir, a physicist at the National University of Sciences and Technology in Rawalpindi, Pakistan, there may be certain conditions when a gravitational wave energy is enhanced. Qadir estimates that the gravitational wave energy could be enhanced by a factor of 10⁴, an amplification detectable by Weber’s experiment.

According to Qadir, it is all dependent on the asymmetry of the event that generated the gravitational waves in the first place. So far, only first-order effects have been examined, but in certain conditions, second order effects come into play, amplifying the waves. Oddly enough, SN1987A was a supernova that detonated in a way that might have generated these second order effects, meaning that Weber may have detected a signal after all.

Although this is by no means definitive proof that Weber’s experiment worked, it wouldn’t be a bad idea to reassess the gravitational wave detection methods as so far, interferometers costing hundreds of millions of dollars have turned up very little in the way of gravitational waves, perhaps it’s time to give the aluminium rods a chance…

Source: arXiv blog