**All of them (and maybe lots or even all of LIGO folks) are missing that the two LIGO detectors aren't predicted to see signals that are exactly proportional to each other**
At a Forbes blog, Sabine Hossenfelder uncritically promotes a combative Danish paper in her article

Was It All Just Noise? Independent Analysis Casts Doubt On LIGO's Detections

It is all about a fresh paper

On the time lags of the LIGO signals

by Andrew Jackson and pals (Creswell, von Hausegger, Liu, and Naselsky). They say that the LIGO discoveries could be noise or based on completely fake data (as Bulgarian crank Pentcho Valev helpfully says under Hossenfelder's article).

ATdotDE and

Telescoper claim to be agnostic.

Has everyone lost his or her mind? Please give me a break.

When the first LIGO discovery was released in February 2016, I downloaded the raw data from both LIGO detectors sampled at 4096 Hz, wrote and ran all the required codes in Mathematica (that did especially the filtering of frequencies and the whitening), and

discovered my own LIGO gravitational wave. I am absolutely certain that the probability that such clear signal-like events occur by chance is negligible. Also, the gravitational waves are the only conceivable signal that can make the delay between the two detectors this small. Any seismic or similar process would almost certainly lead to a much longer delay, basically because the vibrations would spread through the Earth by the speed of sound etc.

Andrew Jackson et al. is saying that "something is wrong" because "the residual noise from LIGO-LA and LIGO-WA detectors are correlated and have the same delay" but this correlation between these two "noises" shouldn't exist.

Except that this statement is wrong. The residuals aren't just noise. They're the difference between the best fit and the actual observation. But the best fit isn't the same thing as the actual gravitational wave.

In particular, as I have emphasized from the very beginning, the two detectors – LIGO-LA and LIGO-WA – are directed in somewhat different directions, so they basically observe different polarizations of the gravitational wave. Because that gravitational wave is rather general – it is neither circularly polarized, nor linearly polarized – the two detectors that basically measure the linearly polarized components in two different directions must yield somewhat different signals.

## No comments:

## Post a Comment