Their point, as I understand it, is that they used templates for data comparison. But I too fail to understand what is wrong with that.

There is nothing wronging with that. The template was validated using GR/SR and the expected signal of massive rotating bodies merging. All the paper proves is that you can process 'noise' in selective ways to produce a 'fake' signal. It's possible to filter the 'fake' signals because they would result in non-physical (per GR/SR) movements of massive bodies.

Here we have a GW and EM wave detection from the same event and source. All signals matched templates created using well tested theory.
https://www.ligo.org/detections/GW170817.php

 

What about the temporal agreement between the two sites? Just coincidence?

 

jpanhalt.......is that the problem......that there was NOT a corresponding noise shift/disturbance?

 

jpanhalt.......is that the problem......that there was NOT a corresponding noise shift/disturbance?

I only look at the first tweet, and the timing difference agreed.

 

http://www.preposterousuniverse.com...the-time-lags-of-the-ligo-signals-guest-post/

In this article I will go into some detail to try to refute the claims of Creswell et al. Let me start though by trying to give a brief overview. In Creswell et al. the authors take LIGO data made available through the LIGO Open Science Data from the Hanford and Livingston observatories and perform a simple Fourier analysis on that data. They find the noise to be correlated as a function of frequency. They also perform a time-domain analysis and claim that there are correlations between the noise in the two observatories, which is present after removing the GW150914 signal from the data. These results are used to cast doubt on the reliability of the GW150914 observation. There are a number of reasons why this conclusion is incorrect: 1. The frequency-domain correlations they are seeing arise from the way they do their FFT on the filtered data. We have managed to demonstrate the same effect with simulated Gaussian noise. 2. LIGO analyses use whitened data when searching for compact binary mergers such as GW150914. When repeating the analysis of Creswell et al. on whitened data these effects are completely absent. 3. Our 5-sigma significance comes from a procedure of repeatedly time-shifting the data, which is not invalidated if correlations of the type described in Creswell et al. are present.

https://github.com/spxiwh/response_to_1706_04191/blob/master/On_the_time_lags.ipynb

NOTE TO READER
You may have noticed that in an earlier version of this notebook (and in the blog post). I stated that it was difficult to adequately whiten the L1 data. It was pointed out by Alex Nielsen that in fact I had been using a noise power-spectral density estimate from the data containing GW170104 to whiten the data containing GW150914. Obviously using a power-spectral density estimate from data 1.5 years later will not allow me to whiten the data well. After fixing this and generating the power-spectral density correctly, now the Livingston data appears to be correctly whitened, and no correlations are present in the plots below.

This in no way affects my conclusions.

 

What about the temporal agreement between the two sites? Just coincidence?

That, I think, is the most important piece of evidence. And I believe people objecting to the discovery are actually complaining that the data processing has not been rigorous enough. So maybe this latest article has more to do with stirring controversy than with casting genuine doubt.

On the other hand, there already have been cases of scientists recanting their discoveries because they confused noise with the real thing. I guess we're just gonna have to wait and see...

 

On the other hand, there already have been cases of scientists recanting their discoveries because they confused noise with the real thing. I guess we're just gonna have to wait and see...

I am well aware of that sequence. When I was young, some chemists from another lab reported "cyclobutadiene" ( a 4-carbon alicyclic hydrocarbon with 2 double bonds -- something I was also working on). Think of benzene with just 4 carbons. Published, then retracted. As a young Turk hungry for publications, I quipped they got two publications out of nothing. I have more trust in the physicists doing gravitational wave research, but it happens.

John

 

And now, Ligo will publish its data analysis process. Fortunately, this time New Scientist has granted public access to the complete article:

https://www.newscientist.com/articl...paper-in-wake-of-new-scientist-investigation/

 

And now, Ligo will publish its data analysis process. Fortunately, this time New Scientist has granted public access to the complete article:

https://www.newscientist.com/articl...paper-in-wake-of-new-scientist-investigation/

I wait for their official reply in this 'new' paper but LIGO has published several papers (and source code) on the analysis process.

https://dcc.ligo.org/LIGO-T1700214/public
https://www.ligo.org/about/white_paper.php

 

https://www.nature.com/articles/s41...JWCA==&tracking_referrer=motherboard.vice.com

Atomic clocks that might detect gravitational waves.
.

 

Can't wait for atomic clocks to replace limit switches in elevators.

 

Can't wait for atomic clocks to replace limit switches in elevators.

interesting... you'd have to calibrate the clock to take into account the relativistic effect of the elevator's speed and the change in gravitational field as it moves up and down ...

 

Even while the first detection is being questioned and scrutinized, four more events are being announced:

https://www.sciencedaily.com/releases/2018/12/181203111617.htm

 

Even while the first detection is being questioned and scrutinized, four more events are being announced:

https://www.sciencedaily.com/releases/2018/12/181203111617.htm

Very detailed explanation of the detection system from that link. https://arxiv.org/pdf/1811.12907.pdf
Seems very unlikely these are continuous false alarms from processing artifacts.

 

Very detailed explanation of the detection system from that link. https://arxiv.org/pdf/1811.12907.pdf
Seems very unlikely these are continuous false alarms from processing artifacts.

I agree ... but I'd still like to see what the end verdict on the first detection is.

 

and what if they finally could realize the logic behind gravitional wave to control it with any kind of device?!
who gurantees avoiding misusage of this principles, like nuclear power?!

 

and what if they finally could realize the logic behind gravitional wave to control it with any kind of device?!
who gurantees avoiding misusage of this principles, like nuclear power?!

When has nuclear power been misused? Facts, not feelings.

 

When has nuclear power been misused? Facts, not feelings.

Thinking about a gravitative bomb instead of nuclear weapon that could swallow the whole world by that sound of "chrip" :/

 

Thinking about a gravitative bomb instead of nuclear weapon that could swallow the whole world by that sound of "chrip" :/

Gravitation is a conservative force, it's not energy you can release like a bomb.

edit:
For the pedantic. Yes, you can have gravitational energy in a gravity field. Gravitational bombs are from Star Wars.

 

Gravitation is a conservative force, it's not energy you can release like a bomb.

Sure you can: drop a piano on someone's head.

Energy is stored in the gravitational field, though it's many orders of magnitude weaker than the binding energies of the nuclear fields.