Why No Data from Gravitational Wave Detectors? (ICHEP)

When I was a postgraduate student at the University of Glasgow I was sometimes taken down into the basement to see a remarkable experiment. It was a Gravitational Wave Detector and at that time in 1982 it was the state of the art. They never recorded any positive signal but since then some more impressive GWDs have been constructed including the two LIGO detectors and VIRGO which have arms several kilometers long. 

One talk at ICHEP that I could not see because it was not webcast was “Gravitational wave detectors: First astrophysical results and path to next generation” by Fabien Cavalier. The slides end with a nice quote from Kip Thorn who has been one of the major players in getting LIGO up and running:  “[I]nterferometers should detect the first waves in 2001 or several years thereafter (…)” It is now 2010 and still no gravitational waves have been detected.

To be fair to Kip Thorn we need to quote at least the full sentence from which this quote was taken. We find it in gr-qc/9506086: “If the source estimates described in this review article are approximately correct, then the planned interferometers should detect the first waves in 2001 or several years thereafter, thereby opening up this rich new window onto the Universe.” So the fair interpretation is that the estimates of gravitational waves used in 1995 were not approximately correct. LIGO and VIRGO have set upper limits on how many gravitational wave sources there are. These are the “First astrophsysical results” from the title. Unfortuneatly nobody ever got a Nobel Prize for negative observational results even though they can be very important constraints for theorists.

The most promising sources for GWDs are inspiraling black hole pairs of neutron stars. These would produce a very characteristic signature in the detectors.

5 Responses to Why No Data from Gravitational Wave Detectors? (ICHEP)

  1. Huping Hu says:

    We have not only theorized but also experimentally proven that gravity is the manifestation (an aspect of) quantum entanglement. Please see:

    http://ptep-online.com/index_files/2007/PP-09-03.PDF .

    Also see:

    So, it is my opinion that there is no gravitational wave since as the manifestation of quantum entanglement, gravity is instantaneous just as Isaac Newton hypothesized. Of course, other researchers also pointed out that there is no gravitational wave.

    Maybe the money used on detecting gravitational waves should be put into other use.

    I’d like to hear from someone out there.

    • philipgibbs says:

      Yes good point, another explanation would be that gravitational waves don’t exist. If that is the case then the most direct way to prove it would be to increase the sensitivity of the detector until it is clear that it should be detecting something from observed events such as gamma ray bursts. So it would still be worth spending the money.

      On the theroetical side you would also need an alternative explanation for the obeserved effect by Hulse-Taylor on the speed of binary pulsars.

  2. Personally, I believe that history is about to repeat itself. The interferometer used in the Michaelson–Morely experiment failed miserably, and so too will interferometer based gravitational wave detectors. There’s nothing wrong with the interferometer itself, but rather the theory behind it is at fault.

    To see why, go to:

    It will be interesting indeed to see how long it takes scientists to realize that interferometers will NEVER be able to detect gravitational waves.

  3. A negative result concerning gravitational waves would be much more valuable than positive and might help to get out from the recent dead end in quantum gravity theories. Phil already mentioned the Hulse-Taylor binary forcing to take gravitational radiation very seriously.

    In my own totally crackpottish Universe would have large hbar and decay to bunches of ordinary gravitons. The signal from bunches would be naturally interpreted as noise having nothing to do with the expected continuous stream of gravitons.

%d bloggers like this: