First, there is little doubt that gravitational waves exist and are there for us to try to detect them.
Second, a high energy spiked release is the best chance of detecting these waves.
So the detection of the gravitational wave by LIGO reported today should not be surprising, but would be commendable. All the glorying that is going on would be in order.
But let us look at the key diagrams reproduced below from the PRL paper. The detectors at Hanford WA and Livingstone LA detected the wave 7 ms apart. In the bottom panel, this time difference has been removed (by shifting one curve) and the two curves have been plotted together for comparison. The inversion was needed to bring the detectors in phase.
So far so good.
(1). There can be hardly any question that the two detectors are seeing the same thing (the exact same “wavefront” passing through them 7 ms apart.)
(2). The Livingston detector is recording lower signal level in the main body of the arrival. Elsewhere (before the arrival and after the the signal has passed) the two detectors seem to be recording the smiliar 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.
(For the signal to be from gravitational waves, the EXACT equality of amplitudes at the two detectors is an absolute requirement. Conversely, non-equality says unambiguously that this is NOT gravitational wave.)
Two conclusions are possible:
(1). Gravitational wave has been observed but there is a lot of ‘splaining to do that has not been done in the PRL paper.
(2). Something other than gravitational wave has been observed and the difference in amplitude in the main body of the signal is real.
Lastly, there is a lot of talk of Big Bang in connection with today’s report. For example, James Gates – Presidential Science Advisor – got on BBC and plugged Big Bang on the back of LIGO. This is utter nonsense. LIGO discovery has absolutely nothing to do with Big Bang or inflation or dark matter or dark energy or such other crap.
NOTE ADDED 02/12/2016:
A LIKELY SOURCE OF LIGO SIGNAL
To sort out item (2) above, consider among other possibilities the well-studied effect of geomagnetically induced currents in long metal structures. Such currents would be induced effectively in the 2 km long LIGO metal vacuum tubes. These currents in the Earth’s magnetic field will create stresses on the tubes. These stresses – though vanishingly small for all purposes – may still be non-negligible for LIGO response (in some complicated way), given the extraordinary sensitivity of the instrument. The time-scale and the form of the signal seem suspiciously right for this. Furthermore, September 14, 2015 was a day specifically noted for geomagnetic disturbances. Since these disturbances originate in the ionosphere, they would affect both detectors.
CONTINUED IN THE NEXT POST ->