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Are LIGO team measuring shock waves rather than gravity waves

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#1 bcgilbert

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Posted 17 October 2020 - 08:36 AM

Are the LIGO team measuring shock waves rather than gravity waves, gravity waves are 40 orders of magnitude weaker than electromagnetic(EM) waves, and detectors several orders of magnitude less efficient than EM detectors.   Shock waves are similar to and related to sound waves and can travel through the intergalactic medium at high speed.   They would be generated in neutron star collisions etc. and the LIGO detectors could be detecting them.

 

Food for thought

 

Barry



#2 Jim Davis

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Posted 17 October 2020 - 08:50 AM

What intergalactic medium? Travel at high speed? The first double neutron star collision detected also produced electro-magnetic radiation which was detected at various wavelengths by various telescopes. This arrived at almost the same time, so the gravitational waves moved at the speed of light. Can shock waves move through intergalactic medium at the speed of light?


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#3 bcgilbert

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Posted 17 October 2020 - 08:51 AM

Krauss was one of the founding fathers of radio astronomy and certainly new his onions.

 

 

Attached File  kraus on gravity waves.pdf   254.65KB   17 downloads

 

Puzzled with doubts

Barry


Edited by bcgilbert, 17 October 2020 - 09:09 AM.


#4 rms40

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Posted 17 October 2020 - 08:59 AM

Barry, I am becoming really skeptical of much of our current cosmology. I wonder if we are in our own Ptolemaic times in many areas.

 

I came across P. M. Robitaille's Sky Scholar videos on youtube not long ago. Worth a look. He proposes a liquid metallic hydrogen Sun (and stars). If true, that would require a huge change to our current cosmology. I am looking at both sides of the argument.

 

Randall



#5 bcgilbert

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Posted 17 October 2020 - 09:04 AM

What intergalactic medium? Travel at high speed? The first double neutron star collision detected also produced electro-magnetic radiation which was detected at various wavelengths by various telescopes. This arrived at almost the same time, so the gravitational waves moved at the speed of light. Can shock waves move through intergalactic medium at the speed of light?

No they can't, but the question still remains how can you detect gravity waves given the incredible path loss and inefficiencies in an environment where the noise power is many orders of magnitude higher than the signal?

 

I also don't understand this comment "What intergalactic medium?"

 

Barry



#6 bcgilbert

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Posted 17 October 2020 - 09:29 AM

Barry, I am becoming really skeptical of much of our current cosmology. I wonder if we are in our own Ptolemaic times in many areas.

 

I came across P. M. Robitaille's Sky Scholar videos on youtube not long ago. Worth a look. He proposes a liquid metallic hydrogen Sun (and stars). If true, that would require a huge change to our current cosmology. I am looking at both sides of the argument.

 

Randall

I believe we have abandoned the scientific method and are in a disneyland / Holywood can do anything mode, we are riding on the back of engineers who are quietly achieving, while theoretical physicists are off with the fairies, taking the credit for engineering hard work.

They're talking about a big accelerator on the moon, why, the Higgs boson has not satisfied them, it has given rise to more problems than it solved.  And inflation what rubbish is that?

 

 

End of rant

 

Barry



#7 EJN

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Posted 17 October 2020 - 01:02 PM

Are the LIGO team measuring shock waves rather than gravity waves, gravity waves are 40 orders of magnitude weaker than electromagnetic(EM) waves, and detectors several orders of magnitude less efficient than EM detectors.   Shock waves are similar to and related to sound waves and can travel through the intergalactic medium at high speed.   They would be generated in neutron star collisions etc. and the LIGO detectors could be detecting them.

 

Food for thought

 

Barry

 

LIGO was the brainchild of Kip S. Thorne, who got his PhD from John Wheeler. I actually met him and got a chance to talk to him in the late 90's at Fermilab. This was before he won the Nobel Prize.

 

I have Thorne's book, which devotes a chapter to LIGO. You should read it. Then read the graduate school level textbook Gravitation by Thorne, Misner, & Wheeler, the standard in the field.

 

I do not see how LIGO could see a signal from an intergalactic shockwave. Gravitational waves have a quadrupole moment, which is what LIGO is designed to detect. 

 

Yes noise is a problem, which is why LIGO has 2 interferometers, one in Washington state, the other in Louisiana. Only events detected simultaneously at both locations are considered for further analysis. Also, the length of each arm of the Fabry-Perot Michelson interferometer is 4 miles, but the beam is reflected between 2 optical flats 64 times before being recombined, for a beam length of 256 miles. A third interferometer in Italy, called VIRGO, is operational and is included in the LIGO network.

 

Additionally, gravitational wave events have a unique signature which distinguishes them from shock waves. They have 3 phases - inspiral, coalescence, then ringdown.

 

 

thorne.jpg

 

 

What was predicted in 1993 closely matched what LIGO detected. Which is why Kip Thorne now has a Nobel Prize for physics.

 

thorne2.jpg


Edited by EJN, 17 October 2020 - 10:19 PM.

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#8 EJN

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Posted 17 October 2020 - 09:50 PM

Hasn't Newtonian Mechanics actually fallen to the more accurate perspective of General Relativity?

 

Fallen is really the wrong word. Newtonian gravitation is referred to as the weak field limit of GR.

 

For example, the code used on the Apollo navigation computers used Newtonian dynamics to compute the spacecraft trajectory, because the calculations are easier that way, and the difference between Newtonian gravitation and GR was less than a puff of a maneuvering thruster.

 

Only near a massive object (like the sun) does the difference get big enough to be significant. That's why Mercury is the only planet which exhibited a measurable difference from Newtonian predictions. And even something as straightforward as calculating the orbit of a planet is far more complicated in GR.


Edited by EJN, 17 October 2020 - 10:38 PM.

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#9 bcgilbert

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Posted 17 October 2020 - 10:04 PM

What intergalactic medium? Travel at high speed? The first double neutron star collision detected also produced electro-magnetic radiation which was detected at various wavelengths by various telescopes. This arrived at almost the same time, so the gravitational waves moved at the speed of light. Can shock waves move through intergalactic medium at the speed of light?

 

 

The correlation between radio astronomy detections and gravity wave detections is suspicious.   The speed of light in the intergalactic medium (IGM) is slower than in a perfect vacuum, to the extent that even different frequency components from an event arrive at different times, this is due to the fact that particles and dust effectively change the refractive index of the IGM for electromagnetic radiation (EM).    The arrival times for gravity waves in the dusty IGM is unknown at this time,   A one percent difference in arrival times between EM and gravity waves for an event at 10^9 light years would be 10^7 years.

 

Large cataclysmic events have shock wave velocity estimates as high as 0.7 C.

 

Just sayin

Barry



#10 bcgilbert

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Posted 17 October 2020 - 11:35 PM

LIGO was the brainchild of Kip S. Thorne, who got his PhD from John Wheeler. I actually met him and got a chance to talk to him in the late 90's at Fermilab. This was before he won the Nobel Prize.

 

I have Thorne's book, which devotes a chapter to LIGO. You should read it. Then read the graduate school level textbook Gravitation by Thorne, Misner, & Wheeler, the standard in the field.

 

I do not see how LIGO could see a signal from an intergalactic shockwave. Gravitational waves have a quadrupole moment, which is what LIGO is designed to detect. 

 

Yes noise is a problem, which is why LIGO has 2 interferometers, one in Washington state, the other in Louisiana. Only events detected simultaneously at both locations are considered for further analysis. Also, the length of each arm of the Fabry-Perot Michelson interferometer is 4 miles, but the beam is reflected between 2 optical flats 64 times before being recombined, for a beam length of 256 miles. A third interferometer in Italy, called VIRGO, is operational and is included in the LIGO network.

 

Additionally, gravitational wave events have a unique signature which distinguishes them from shock waves. They have 3 phases - inspiral, coalescence, then ringdown.

 

 

attachicon.gifthorne.jpg

 

 

What was predicted in 1993 closely matched what LIGO detected. Which is why Kip Thorne now has a Nobel Prize for physics.

 

attachicon.gifthorne2.jpg

 

 

I do not see how LIGO could see a signal from an intergalactic shockwave. Gravitational waves have a quadrupole moment, which is what LIGO is designed to detect.

The quadrupole moment is needed to enable radiation of gravity waves to occur in the first place, we know that shock waves radiate by some mechanism, therefore why wouldn't LIGO detect them as noise, remember LIGO relies on pattern recognition more than noise reduction, it is plagued by noise due to its obscene sensitivity.

 

I do not see why shock wave patterns should be vastly different to gravity waves at the moment, maybe you know a lot about shock waves, do tell.

 

Then there's that 40 orders of magnitude to deal with, maybe radio astronomers could follow their lead and go for obscene sensitivity and to heck with the resultant noise, and use pattern recognition, only trouble is, you invariably find what you seek and similar patterns tend to turn up in nature in different disciplines, not to mention your your signal processing artifacts, Gibbs phenomenon for example.

Errant use fourier transforms and other signal processing tools can give rise to time reversed Gibbs waveshapes (damped oscillations in reverse) these waveshapes look remarkably similar to the pattern templates used by LIGO team

 

Still curious

Barry


Edited by bcgilbert, 17 October 2020 - 11:41 PM.



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