Re: LIGO news

[Lawrence Crowell]

The KAGRA is set on one of the most seismic active areas of the world. My 
paper, publisher website https://www.mdpi.com/1099-4300/22/3/301 

 and 
arxiv https://arxiv.org/abs/2007.01106 

  
, requires a LIGO or LISA capable of detecting changes in metric with BMS 
symmetries. I read a report on how LIGO detectors are being deformed 
slightly in permanent ways. This could be a manifestation of BMS charge, 
but also instrument responses. With space based LISA this will be 
detectable.

LC

On Sunday, November 1, 2020 at 3:26:23 AM UTC-6 johnk...@gmail.com wrote:

> On Wednesday Ligo/Virgo released a more detailed analysis of the first 
> half of its third observational run which went from  April 1 2019  to 
> October 1 2019 which added 39 additional gravitational wave events bringing 
> the total number seen up to 50. The list includes the most powerful Black 
> Hole merger ever seen, the most distant, the largest Black Hole ever 
> detected by gravitational waves, 2 neutron star collisions, and something 
> it was either the most massive Neutron Star ever detected or the least 
> massive Black Hole ever detected. With all the improvements and the help of 
> Virgo in Italy they were finding on average one and a half events per week. 
> The second part of the run which went from October 2019 to March 2020 
> hasn't yet had a similar statistical analysis.
>
> LIGO Had to be shut down prematurely in March because of the pandemic, 
> it's not clear when they will be able to resume operations. It's a pity 
> they could've have gone on a little longer because about a month after 
> they shut down the new KAGRA Gravitational wave detector in Japan came 
> online, there could have been 4 widely spaced detectors running at the 
> same time. Although slightly smaller than LIGO (3 km arms rather than 4) 
> KAGRA has several features that LIGO doesn't have, It is deep underground 
> which reduces seismic noise by a factor of 100, and it's mirrors are 
> cryogenically cooled to 20 degrees Kelvin further reducing errors.
>
> Compact Binary Coalescences Observed by LIGO and Virgo During the First 
> Half of the Third Observing Run 
>
> John K Clark
>

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Re: LIGO detects the largest black hole merger yet

[Lawrence Crowell]

 

To be honest I have found the preponderance of black holes in the 30 to 60 
solar mass range to be odd. It would take a really large star to generate a 
black hole that massive. These would be red supergiant stars or stars such 
as the Pistol star. These are one in a many thousands of stars.

Yet it is not too hard to imagine a 20 solar mass BH that orbits another 
large star, where the star is consumed. So this results in a larger mass 
BH. This might then over time occur again. It is possible one of these BHs 
in the 85 + 66 solar mass BHs came from a prior BH merger. That does seem a 
bit improbable. Of course their merger into a 142 solar mass BH has 
produced a BH that is technically also “impossible.”

LC

On Wednesday, September 2, 2020 at 8:54:44 AM UTC-5 johnk...@gmail.com 
wrote:

> In today's issue of Physical Review Letters the two Lego detectors in the 
> US and the Virgo detector in Italy announced they had detected on May 21 
> 2019 the gravitational waves from the merger of two Black Holes of 65 and 
> 85 Solar masses which produced a Black Hole of 142 solar masses with 8 
> solar masses of matter being converted into the energy of gravitational 
> waves. It was the largest merger of Black Holes ever detected by 
> gravitational waves and one of the most distant at 11.3 billion light 
> years. An optical counterpart of this merger seems to have also been 
> detected so it must've happened in a region rich in gas and dust.
>
> It's not clear how the two progenitor black holes could've been made, 65 
> solar masses is really big, it's pushing the edge of the possible for a 
> single supergiant star to have produced according to our current 
> understanding of stellar evolution, and it's hard to see how they could 
> have themselves been formed by mergers 11.3 billion years ago of smaller 
> Black Holes in the short amount of time since the Big Bang. But science 
> thrives on mystery.
>
> A Binary Black Hole Merger with a Total Mass of 150 Suns 
> 
>
> John K Clark
>

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Re: LIGO detections that happened yesterday

[Lawrence Crowell]

On Friday, August 30, 2019 at 6:32:45 AM UTC-5, John Clark wrote:
>
> Puzzling signals seen by LIGO may be gravitational wave split in two 
> 
>
> John K Clark
>

This weak lensing is not surprising, but it could test some aspects of 
gravitation . What would be curious is if there is a strong lensing. A 
gravitation wave front with some Weyl curvature has a part of it wind 
around the intervening mass. This would result in multiple signals and a 
further delayed signal. The Weyl curvature is conformal, which is really a 
form of the Huygens' principle. This splitting of light and now 
gravitational waves by intervening gravitating masses is a sort of beam 
splitter. In effect these detections are to gravitational waves what 
classical optics is to light. 

LC

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Re: LIGO detections that happened yesterday

[John Clark]

Puzzling signals seen by LIGO may be gravitational wave split in two


John K Clark

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Re: LIGO detections that happened yesterday

[Lawrence Crowell]

On Thursday, August 29, 2019 at 5:53:04 AM UTC-5, John Clark wrote:
>
> Yesterday on August 28 2019 LIGO detected 2 Gravitational wave events just 
> 21 minutes apart, the first at 6:34:05 UTC and the second at 6:55:09 UTC, 
> the events were at the same distance, 6.4 billion light years, and they 
> were in the same general part of the sky. The events were seen in all 3 
> detectors in Louisiana, Washington State and Italy. LIGO now releases the 
> raw data of what they've found almost instantly so optical astronomers can 
> look for something, so no detailed computer analysis has been done yet, but 
> the early speculation is this is the first gravitationally lensed 
> gravitational wave detection.
>
> John K Clark
>

There appears to prior detections of this.

 
https://www.scientificamerican.com/article/has-ligo-seen-galaxy-warped-gravitational-waves/

A preprint on this physics is also at

https://arxiv.org/abs/1702.04724

Weak gravitational waves are similar to a bipartite entanglement of two 
photons. The only difference is a very weak coupling to mass instead of a 
much stronger coupling to electric charge. So gravitational radiation 
should be Einstein lensed, and in fact if the geodetic mapping of 
gravitational waves can be improved it is possible that forms of Einstein 
rings should be apparent.

LC

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Re: LIGO has ​already found another Gravitational Wave

[Lawrence Crowell]

On Tuesday, April 9, 2019 at 7:33:01 AM UTC-5, John Clark wrote:
>
> LIGO has only been back on for a few days but already they have detected a 
> new gravitational wave from a Black Hole merger slightly under 5 billion 
> light years away.  They've decided to stop most of the secrecy and report 
> things as soon as they find them, so they haven't finished calculating how 
> massive they were yet. 
>
> Just after turning back on another wave found 
> 
>
> John K Clark
>

Given the distance these may be pretty massive BHs.

https://www.newscientist.com/article/2199107-ligo-has-spotted-another-gravitational-wave-just-after-turning-back-on/

LC

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Re: LIGO

[John Clark]

On Mon, Apr 1, 2019 at 7:01 AM Lawrence Crowell <
goldenfieldquaterni...@gmail.com> wrote:

*>  I am going to think about this. The problem I see is that LIGO detects
> information in a gravity wave and converts that into our electronic
> information. If this information really drops as 1/r then from a Gauss' law
> perspective it means a gravitational wave propagating from its source
> produces information a the rate I(t) ~ r, for r the radius of the wave
> front. I have some problems with that.*


I don't see the problem with transferring information that way, you could
even do it with light although with a different method than LIGO's. The
inverse square law applies only for isotropic emitters, so with a perfect
zero divergent Laser beam the intensity of the beam would be constant and
independent of distance. Of course a real Laser will always have some
divergence and the intensity is proportional to the width of the beam, so
if it went far enough eventually it would start to follow the inverse
square law, but that distance could be large even by cosmological
standards. Blazars are a especially bright type of Quasar and some have
been spotted over 10 billion light years away. But Quasars are not
isotropic emitters and it is now thought that Blazars are fundamentally no
different from regular Quasars it's just that Blazars are so positioned
that we just happen to be looking straight down the throat of the Quasar's
beam.

LIGO gets around the inverse square law in a entirely different way, it
doesn't detect the RMS power of a wave it detects the peak to peak
displacement of a wave.

John K Clark

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Re: LIGO

[Lawrence Crowell]

I am going to think about this. The problem I see is that LIGO detects 
information in a gravity wave and converts that into our electronic 
information. If this information really drops as 1/r then from a Gauss' law 
perspective it means a gravitational wave propagating from its source 
produces information a the rate I(t) ~ r, for r the radius of the wave 
front. I have some problems with that.

LC

On Sunday, March 31, 2019 at 5:30:31 PM UTC-6, John Clark wrote:
>
> On Sun, Mar 31, 2019 at 5:06 PM Lawrence Crowell  > wrote:
>
> >> Yes but LIGO detects the peak to peak displacement of a wave not its 
>>> power or energy as cameras and radios do. And that means LIGO's ability to 
>>> detect wave producing things is reduced with distance much more slowly than 
>>> with telescopes that deal with electromagnetic waves. Peak-to peak 
>>> displacement is proportional to the Root Mean Square of the wave and the 
>>> RMS is proportional to the square root of the power. So if there is 4 times 
>>> less power in the gravitational wave (because the source is twice as far 
>>> away) the peak to peak displacement is only reduced by a factor of 2.
>>>
>>  
>
> > I guess you will have to give a reference on this.
>>
>
> From LIGO's website:  
>
> https://www.ligo.caltech.edu/page/facts 
>
> "*improvements will ultimately make LIGO's interferometers 10 times more 
> sensitive than their initial incarnation. A 10-fold increase in sensitivity 
> means that LIGO will be able to detect gravitational waves 10 times farther 
> away than Initial LIGO, which translates into 'sampling' 1000-times more 
> volume of space (volume increases with the cube of the distance. So 10 
> times farther away means 10x10x10=1000 times the volume of space)"*
>
> From: 
>
> https://dcc.ligo.org/public//P070082/004/P070082-v4.pdf
>
> "the gravitational wave field strength is proportional to the second time 
> derivative of the quadrupole moment of the source, and it falls off in 
> amplitude inversely with distance from the source"
>
> From:
>
> https://archive.briankoberlein.com/2016/02/19/how-close-is-too-close/
>
>
> *"**The amount of shift caused by a gravitational wave is due to its 
> amplitude, not its energy. While the energy of gravitational waves follow 
> the inverse square relation, the amplitude of gravitational waves follows 
> the inverse distance relation. In other words, if we were half as far away 
> from the merger we’d have seen four times the energy, but only twice the 
> shift."*
>
> And note that it is the shift that LIGO detect not energy. 
>
> > I can see in one sense what you are saying about RMS, but I don't think 
>> your quite correct still. The interferometer measures a quadrupole 
>> displacemement.
>>
>
> That just means as one leg of LIGO is moved to a maximum distance the 
> other leg is moved to a minimum distance, and the difference between the 
> maximum and minimum is what causes interference in the Laser beam that LIGO 
> detects. Needless to say that is not the way a radio receiver works and is 
> not way film detects light either.   
>
>  John K Clark  
>
>
>

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Re: LIGO

[John Clark]

On Sun, Mar 31, 2019 at 5:06 PM Lawrence Crowell <
goldenfieldquaterni...@gmail.com> wrote:

>> Yes but LIGO detects the peak to peak displacement of a wave not its
>> power or energy as cameras and radios do. And that means LIGO's ability to
>> detect wave producing things is reduced with distance much more slowly than
>> with telescopes that deal with electromagnetic waves. Peak-to peak
>> displacement is proportional to the Root Mean Square of the wave and the
>> RMS is proportional to the square root of the power. So if there is 4 times
>> less power in the gravitational wave (because the source is twice as far
>> away) the peak to peak displacement is only reduced by a factor of 2.
>>
>

> I guess you will have to give a reference on this.
>

>From LIGO's website:

https://www.ligo.caltech.edu/page/facts

"*improvements will ultimately make LIGO's interferometers 10 times more
sensitive than their initial incarnation. A 10-fold increase in sensitivity
means that LIGO will be able to detect gravitational waves 10 times farther
away than Initial LIGO, which translates into 'sampling' 1000-times more
volume of space (volume increases with the cube of the distance. So 10
times farther away means 10x10x10=1000 times the volume of space)"*

From:

https://dcc.ligo.org/public//P070082/004/P070082-v4.pdf

"the gravitational wave field strength is proportional to the second time
derivative of the quadrupole moment of the source, and it falls off in
amplitude inversely with distance from the source"

From:

https://archive.briankoberlein.com/2016/02/19/how-close-is-too-close/


*"**The amount of shift caused by a gravitational wave is due to its
amplitude, not its energy. While the energy of gravitational waves follow
the inverse square relation, the amplitude of gravitational waves follows
the inverse distance relation. In other words, if we were half as far away
from the merger we’d have seen four times the energy, but only twice the
shift."*

And note that it is the shift that LIGO detect not energy.

> I can see in one sense what you are saying about RMS, but I don't think
> your quite correct still. The interferometer measures a quadrupole
> displacemement.
>

That just means as one leg of LIGO is moved to a maximum distance the other
leg is moved to a minimum distance, and the difference between the maximum
and minimum is what causes interference in the Laser beam that LIGO
detects. Needless to say that is not the way a radio receiver works and is
not way film detects light either.

 John K Clark

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Re: LIGO

[Lawrence Crowell]

On Sunday, March 31, 2019 at 8:23:02 AM UTC-6, John Clark wrote:
>
> On Sun, Mar 31, 2019 at 8:43 AM Lawrence Crowell  > wrote:
>  
>
>> > An antenna or any receiver of electromagnetic waves in effect measures 
>> the displacement of electrons or equivalently a current is produced.
>>
>
> A radio receiver detects the power in a AC circuit, and that is the Root 
> Mean Square voltage times the Root Mean Square current. Unlike LIGO 
> radios don't detect peak to peak values.
>
> > A gravitational wave is measured according to strain, but a strain 
>> through distance has an energy content as well.
>>
>
> Yes but LIGO detects the peak to peak displacement of a wave not its power 
> or energy as cameras and radios do. And that means LIGO's ability to detect 
> wave producing things is reduced with distance much more slowly than with 
> telescopes that deal with electromagnetic waves. Peak-to peak displacement 
> is proportional to the Root Mean Square of the wave and the RMS is 
> proportional to the square root of the power. So if there is 4 times less 
> power in the gravitational wave (because the source is twice as far away) 
> the peak to peak displacement is only reduced by a factor of 2.
>

I guess you will have to give a reference on this. I looked at some 
references and I can't find anything on what you say here:

https://labcit.ligo.caltech.edu/~dhs/Adv-LIGO/old/interferometric-gray-paper.pdf

https://labcit.ligo.caltech.edu/~dhs/Adv-LIGO/old/interferometric-gray-paper.pdf
 
I can see in one sense what you are saying about RMS, but I don't think 
your quite correct still. The interferometer measures a quadrupole 
displacemement. There is the quadrupole tensor Q = 3d_id_j - d^2δ_{ij}, 
where fields are Q_{ij}/r^4. The distance to the source is r and the 
distance between the two inspiralling black holes is d. The displacement is 
given by the metric g_{ab} = δ_{ab} + h_{ab} for the ++ and xx 
polarizations. The ++ polarization metric will be h_{++} = 2d_+^2/r^2, for 
r the distance to the source, and the curvature is R_++ = ½h_{++}R = 
d_{++}/r^4. The Einstein space criterion the metric proportional to the 
Ricci curvature and the metric giving the displacement means the 
displacement is ~ 1/r^2.

LC


> > So gravitational waves have intensities that drops with the square of 
>> the distance
>
>
> I'm not disputing that, but that fact is not inconsistent with the fact 
> that LIGO's ability to detect gravitational wave sources only decreases 
> linearly with distance because with LIGO the key thing is peak to peak 
> displacement of the wave not its intensity.
>
> John K Clark
>
>
>
>
>>

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Re: LIGO

[John Clark]

On Sun, Mar 31, 2019 at 8:43 AM Lawrence Crowell <
goldenfieldquaterni...@gmail.com> wrote:


> > An antenna or any receiver of electromagnetic waves in effect measures
> the displacement of electrons or equivalently a current is produced.
>

A radio receiver detects the power in a AC circuit, and that is the Root
Mean Square voltage times the Root Mean Square current. Unlike LIGO radios
don't detect peak to peak values.

> A gravitational wave is measured according to strain, but a strain
> through distance has an energy content as well.
>

Yes but LIGO detects the peak to peak displacement of a wave not its power
or energy as cameras and radios do. And that means LIGO's ability to detect
wave producing things is reduced with distance much more slowly than with
telescopes that deal with electromagnetic waves. Peak-to peak displacement
is proportional to the Root Mean Square of the wave and the RMS is
proportional to the square root of the power. So if there is 4 times less
power in the gravitational wave (because the source is twice as far away)
the peak to peak displacement is only reduced by a factor of 2.

> So gravitational waves have intensities that drops with the square of the
> distance


I'm not disputing that, but that fact is not inconsistent with the fact
that LIGO's ability to detect gravitational wave sources only decreases
linearly with distance because with LIGO the key thing is peak to peak
displacement of the wave not its intensity.

John K Clark




>

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Re: LIGO

[Lawrence Crowell]

On Saturday, March 30, 2019 at 8:32:53 AM UTC-6, John Clark wrote:
>
> On Fri, Mar 29, 2019 at 8:05 PM Lawrence Crowell  > wrote:\
>  
>
>> > Weak gravitational waves are very similar to electromagnetic waves,
>>
>
> From a practical point of view there are 2 differences:
>
> 1) Our ability to detect electromagnetic waves decreases with the square 
> of the distance, but LIGO's ability to detect gravitational waves only 
> decreases linearly with distance because unlike film or CCD cameras LIGO 
> does not detect the energy in the wave it detects the displacement the wave 
> produces. 
>

An antenna or any receiver of electromagnetic waves in effect measures the 
displacement of electrons or equivalently a current is produced. This is 
associated by Maxwell's equation by electric and magnetic fields with 
energy. A gravitational wave is measured according to strain, but a strain 
through distance has an energy content as well.

Let us think about very weak gravitational waves. The metric for weak 
gravitational fields is a flat space metric plus a perturbing particular

g_{ab} = η_{ab} - h_{ab}.

This perturbing metric has 10 independent elements. We now eliminate the 
diagonal elements from the metric h_{ab} with a trace condition, which 
leaves only 6 independent variables. 

The Christoffel symbols are

Γ^a_{bc} = ½g^{ad}(∂_cg_{db} + ∂_bg_{dc} - ∂_dg_{bc}),

Where linear in the perturbing term this is

Γ^a_{bc} = ½(∂_ch^a_b + ∂_bh^d_c - ∂^ah_{bc}).

Now we compute the Riemann curvature tensor and eliminate the Γ^2 terms as 
O(h^2) and so we have

R^a_{bcd} = ∂_cΓ^a_{bd} - ∂_dΓ^a_{bc}

∂_b∂_ch^a_d - ∂^a∂_ch_{bd} + ∂^a∂_dh_{bc} - ∂_b∂_dh^a_c.

The first line above should look familiar for anyone who knows 
electromagnetic theory as a commutator of coordinates on a differential and 
gauge connection. 

The Einstein field equation may be written as R_{ab} - ½Rg_{ab} = 
8πGT_{ab}, as well as the form R_{ab} = 8πG(T_{ab}  - ½ Tg_{ab}) where the 
Ricci curvature and Ricci curvature scalar are computed with a lot of 
contraction on indices to get

□h_{ab} + ∂_a∂_bh - ∂_a∂_ch^c_b - ∂_a∂_ch^c_b = 8πG(2T_{ab} - ½ Tg_{ab}).

That is a complicated looking differential equation, but it is 
underdetermined. This equation has 6 variables and we need to eliminate 4 
of them. Now this requires a gauge-like condition as with electromagnetism. 
The standard one is Γ^a_{bc}g^{bc} = 0. which in our linearized gravity 
contains first order derivatives of h_{ab}. This looks similar to the 
Coulomb or Lorentz gauge in electromagnetism. This gauge condition is then 
∂^bh_{ab} = ½∂_ah and this eliminates lots of stuff as we get

□h_{ab} = 8πG(2T_{ab} - ½ Tg_{ab}).

This looks a lot more like a wave equation, where for T_{ab} = 0 in source 
free region this is □h_{ab} = 0, and the box is the d'Alembertian second 
order with 

∂^i∂_ih_{ab} - ∂^2_th_{ab} = 0

which is a familiar wave equation. This wave equation has not just one term 
but two, which correspond to the two helicity states of a gravitational 
wave. For a spherically symmetric wave the intensity will drop as 1/r^2 
from the point of origin. Waves at higher orders may have quadrupole and 
dipole terms and even higher, but for sufficient distance from the source 
it becomes more spherically symmetry FAPP. So gravitational waves have 
intensities that drops with the square of the distance far removed from the 
source.

This is the first order wave equation most used to compute expected 
gravitational waves at the LIGO. The complicated stuff is in using the 
2T_{ab} - ½ Tg_{ab} for the generation of gravitational waves by imploding 
matter. The collision of black holes means one needs to expand the terms 
with 

g_{ab} = η_{ab} - h^1_{ab} - h^2_{ab} - h^2_{ab} 

where these higher orders in h deviate from the linearity with orders 
below. This is similar to post-Newtonian formalism, but once you have 
h^1_{ab} you use those to compute h^2_{ab} linear in h^2_{ab}, but with O(( 
h^1_{ab})^2) terms, and then continue to the next order and … . Then to get 
professional about this these terms are expressed in orbital parameters or 
Euler angles etc. 

LC
 

>
> 2) It's easy for telescopes to determine the direction electromagnetic 
> waves are coming from but difficult to determine its distance, with LIGO 
> it's easy to determine the distance from the gravitational wave source but 
> hard to determine the direction it's coming from.
>
>  > The graviton is quantum mechanically much the same as biphotons that 
>> occurs with bunching or Hanbury Brown and Twiss physics. 
>>
>
> LIGO can not detect gravitons and even if the graviton exists I am 
> skeptical anyone will ever be able to detect it.
>
> > The main advantage of having a third LIGO is that now the source can be 
>> triangulated more accurately. 
>>
>
> It also increases sensitivity. If you get a small jump above the noise 
> level in just 2 detectors that may not be enough to reach the 5 sigmas 
> needed to claim a disco

Re: LIGO

[John Clark]

On Fri, Mar 29, 2019 at 8:05 PM Lawrence Crowell <
goldenfieldquaterni...@gmail.com> wrote:\


> > Weak gravitational waves are very similar to electromagnetic waves,
>

>From a practical point of view there are 2 differences:

1) Our ability to detect electromagnetic waves decreases with the square of
the distance, but LIGO's ability to detect gravitational waves only
decreases linearly with distance because unlike film or CCD cameras LIGO
does not detect the energy in the wave it detects the displacement the wave
produces.

2) It's easy for telescopes to determine the direction electromagnetic
waves are coming from but difficult to determine its distance, with LIGO
it's easy to determine the distance from the gravitational wave source but
hard to determine the direction it's coming from.

 > The graviton is quantum mechanically much the same as biphotons that
> occurs with bunching or Hanbury Brown and Twiss physics.
>

LIGO can not detect gravitons and even if the graviton exists I am
skeptical anyone will ever be able to detect it.

> The main advantage of having a third LIGO is that now the source can be
> triangulated more accurately.
>

It also increases sensitivity. If you get a small jump above the noise
level in just 2 detectors that may not be enough to reach the 5 sigmas
needed to claim a discovery, but if you receive the same small jump in 3
detectors it might do the job.

 John K Clark

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Re: LIGO

[Lawrence Crowell]

On Friday, March 29, 2019 at 6:36:24 AM UTC-6, John Clark wrote:
>
> Unless there is some last second glitch the 2 LIGO gravitational wave 
> detectors in the USA and the Virgo detector in Italy will go back online on 
> Monday. The 2 LIGO detectors will be about 40% more sensitive now after the 
> upgrade and the slightly smaller Virgo detector about 50% better. And, 
> because their ability to detect waves only decrease linearly with distance 
> not as distance squared, together they will be able to see gravitational 
> events in about 3 times the previous volume. They will run for a year 
> before being shut down for yet another upgrade.
>
> And if we're lucky before the end of the year a fourth detector, KAGRA in 
> Japan, may join the party; and although smaller than LIGO it might turn 
> out to be even more sensitive because unlike the other 3 it's built 
> underground and does not work at room temperature but is cooled down to 20 
> degrees Kelvin (-253 C, -425 F) . I think that is very cool, in more ways 
> than one.
>
>  John K Clark
>

I think there is a bit of confusion here. Weak gravitational waves are 
rather easily derived with what is termed linear Einstein field equations. 
By this it is meant that the connection coefficients appear only linearly, 
and the quadratic product of them that appears in the Riemann curvature 
tensor is small and ignored. The connection terms have coupling terms on 
the order O(G/c^2), and the square is O(G^2/c^4) which is negligible in the 
weak limit. Weak gravitational waves are very similar to electromagnetic 
waves, except there are two polarization or equivalently the helicity is 2. 
The graviton is quantum mechanically much the same as biphotons that occurs 
with bunching or Hanbury Brown and Twiss physics. That in turn is a bosonic 
version of the Pauli exclusion principle for fermions. 

The main advantage of having a third LIGO is that now the source can be 
triangulated more accurately. With only two detectors you can only 
determine the source is in some band stretching across the sky. Now the 
source of gravitational waves can be triangulated with the LIGO data.

LC

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Re: LIGO found a second Black Hole collision!

[spudboy100 via Everything List]

Unless there is a big breakthrough (engineering wise) in antihydrogen 
production, we will be waiting a while for anti-matter probes to visit barnards 
star. However, through accelerators and Penning traps we already have proof of 
principle. I think Robert Forward envisioned huge scale solar arrays to gather 
up the peta exa yotta - watts of solar power, floating photon catchers to spin 
up antimatter.   On this, for Forwards Starwisp, we"ll arrive at this sooner 
then later.

Sent from AOL Mobile Mail


-Original Message-
From: Brent Meeker 
To: everything-list 
Sent: Fri, Jun 17, 2016 08:56 PM
Subject: Re: LIGO found a second Black Hole collision!


There are a few problems though:  Keeping the anti-matter isolated from 
all matter, e.g. in a magnetic bottle.  Making the anti-matter; a 
process whose EROI has many zeros behind the decimal.  Getting useful 
thrust from the annihilation of matter/anti-matter which produces gamma 
rays.  Gamma rays tend to go through stuff rather than push them.

Brent

On 6/17/2016 5:45 PM, Hans Moravec wrote:
> milligrams of antimatter to energize tons of hydrogen reaction mass, it’s an 
> idea
>
>> On 160617, at 8:39 PM, Brent Meeker <> href="mailto:meeke...@verizon.net";>meeke...@verizon.net> wrote:
>>
>> Yeah, I was a friend of friend of Bob Forward and I once had dinner with 
>> him.  At the time though he was pushing anti-matter powered spaceships; 
>> which I thought was a crank idea.
>>
>> Brent
>>
>> On 6/16/2016 5:18 AM, Hans Moravec wrote:
>>>> On Jun 15, 2016, at 23:48 , Brent Meeker <>>> href="mailto:meeke...@verizon.net";>meeke...@verizon.net> wrote:
>>>>
>>>> When you look somewhere new, you see new things.  To bad Joe Weber didn't 
>>>> live to see this.
>>>>
>>>> Brent
>>> And Bob Forward (Robert L. Forward), who was once Weber's grad student, and 
>>> continued gravity related research and publication until his death in 2002.
>>>
>>>> On 6/15/2016 7:25 PM, John Clark wrote:
>>>>> After analyzing the data from LIGO's brief engineering run the scientists 
>>>>> there just announced they have found a second Black Hole merger. A Black 
>>>>> Hole of 14 solar masses merged with one of 8 solar masses and produced a 
>>>>> Black Hole of 21 solar masses and gravitational waves with 1 solar mass 
>>>>> of energy. It happened 1.4 billion light years away, about the same 
>>>>> distance as the first merger that was announced a few months ago, but the 
>>>>> signal was weaker because the Black Holes involved were smaller (14 and 8 
>>>>> vs 36 and 29) and also because the orbit of the Black Holes was more edge 
>>>>> on relative to the Earth. Edge on means the signal is weaker but it also 
>>>>> means it's easier to determine the spin, so unlike the first detection 
>>>>> this time we can say with certainty that at least one of the Black Holes 
>>>>> was spinning. And although weaker the signal lasted longer, almost a full 
>>>>> second versus a fifth of a second the first time because being smaller 
>>>>> the holes generated waves with higher frequencies that LIGO is more 
>>>>> sensitive to.
>>>>>
>>>>> And they're looking at at least one other suspected merger but they're 
>>>>> only 85% certain it's real and that's not good enough to claim discovery, 
>>>>> but there may be others so there may be a third announcement before long. 
>>>>> Not bad for observing for only 18 days. The instrument was running at 
>>>>> only one third power but that was still good enough to determine that 2 
>>>>> mirrors 4 kilometers apart had changed their distance by less than a 
>>>>> billionth of a nanometer. I can't wait for September when the 2 LIGOs get 
>>>>> back online and are joined by a third detector, VIRGO in Italy.
>>>>>
>>>>> >>>> href="http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.241103";
>>>>>  
>>>>> target="_blank">http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.241103
>>>>>
>>>>> John K Clark
>>>>> -- 
>>>>> You received this message because you are subscribed to the Google Groups 
>>>>> "Everything List" group.
>>>>> To unsubscribe from this group and stop receiving emails from it, send an 
>>>>> e

Re: LIGO found a second Black Hole collision!

[Brent Meeker]

There are a few problems though:  Keeping the anti-matter isolated from 
all matter, e.g. in a magnetic bottle.  Making the anti-matter; a 
process whose EROI has many zeros behind the decimal.  Getting useful 
thrust from the annihilation of matter/anti-matter which produces gamma 
rays.  Gamma rays tend to go through stuff rather than push them.


Brent

On 6/17/2016 5:45 PM, Hans Moravec wrote:

milligrams of antimatter to energize tons of hydrogen reaction mass, it’s an 
idea


On 160617, at 8:39 PM, Brent Meeker  wrote:

Yeah, I was a friend of friend of Bob Forward and I once had dinner with him.  
At the time though he was pushing anti-matter powered spaceships; which I 
thought was a crank idea.

Brent

On 6/16/2016 5:18 AM, Hans Moravec wrote:

On Jun 15, 2016, at 23:48 , Brent Meeker  wrote:

When you look somewhere new, you see new things.  To bad Joe Weber didn't live 
to see this.

Brent

And Bob Forward (Robert L. Forward), who was once Weber's grad student, and 
continued gravity related research and publication until his death in 2002.


On 6/15/2016 7:25 PM, John Clark wrote:

After analyzing the data from LIGO's brief engineering run the scientists there 
just announced they have found a second Black Hole merger. A Black Hole of 14 
solar masses merged with one of 8 solar masses and produced a Black Hole of 21 
solar masses and gravitational waves with 1 solar mass of energy. It happened 
1.4 billion light years away, about the same distance as the first merger that 
was announced a few months ago, but the signal was weaker because the Black 
Holes involved were smaller (14 and 8 vs 36 and 29) and also because the orbit 
of the Black Holes was more edge on relative to the Earth. Edge on means the 
signal is weaker but it also means it's easier to determine the spin, so unlike 
the first detection this time we can say with certainty that at least one of 
the Black Holes was spinning. And although weaker the signal lasted longer, 
almost a full second versus a fifth of a second the first time because being 
smaller the holes generated waves with higher frequencies that LIGO is more 
sensitive to.

And they're looking at at least one other suspected merger but they're only 85% 
certain it's real and that's not good enough to claim discovery, but there may 
be others so there may be a third announcement before long. Not bad for 
observing for only 18 days. The instrument was running at only one third power 
but that was still good enough to determine that 2 mirrors 4 kilometers apart 
had changed their distance by less than a billionth of a nanometer. I can't 
wait for September when the 2 LIGOs get back online and are joined by a third 
detector, VIRGO in Italy.

http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.241103

  John K Clark
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Re: LIGO found a second Black Hole collision!

[Hans Moravec]

milligrams of antimatter to energize tons of hydrogen reaction mass, it’s an 
idea

> On 160617, at 8:39 PM, Brent Meeker  wrote:
> 
> Yeah, I was a friend of friend of Bob Forward and I once had dinner with him. 
>  At the time though he was pushing anti-matter powered spaceships; which I 
> thought was a crank idea.
> 
> Brent
> 
> On 6/16/2016 5:18 AM, Hans Moravec wrote:
>>> On Jun 15, 2016, at 23:48 , Brent Meeker  wrote:
>>> 
>>> When you look somewhere new, you see new things.  To bad Joe Weber didn't 
>>> live to see this.
>>> 
>>> Brent
>> And Bob Forward (Robert L. Forward), who was once Weber's grad student, and 
>> continued gravity related research and publication until his death in 2002.
>> 
>>> On 6/15/2016 7:25 PM, John Clark wrote:
 After analyzing the data from LIGO's brief engineering run the scientists 
 there just announced they have found a second Black Hole merger. A Black 
 Hole of 14 solar masses merged with one of 8 solar masses and produced a 
 Black Hole of 21 solar masses and gravitational waves with 1 solar mass of 
 energy. It happened 1.4 billion light years away, about the same distance 
 as the first merger that was announced a few months ago, but the signal 
 was weaker because the Black Holes involved were smaller (14 and 8 vs 36 
 and 29) and also because the orbit of the Black Holes was more edge on 
 relative to the Earth. Edge on means the signal is weaker but it also 
 means it's easier to determine the spin, so unlike the first detection 
 this time we can say with certainty that at least one of the Black Holes 
 was spinning. And although weaker the signal lasted longer, almost a full 
 second versus a fifth of a second the first time because being smaller the 
 holes generated waves with higher frequencies that LIGO is more sensitive 
 to.
 
 And they're looking at at least one other suspected merger but they're 
 only 85% certain it's real and that's not good enough to claim discovery, 
 but there may be others so there may be a third announcement before long. 
 Not bad for observing for only 18 days. The instrument was running at only 
 one third power but that was still good enough to determine that 2 mirrors 
 4 kilometers apart had changed their distance by less than a billionth of 
 a nanometer. I can't wait for September when the 2 LIGOs get back online 
 and are joined by a third detector, VIRGO in Italy.
 
 http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.241103
 
  John K Clark
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>>> 
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> 
> 
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Re: LIGO found a second Black Hole collision!

[Brent Meeker]

Yeah, I was a friend of friend of Bob Forward and I once had dinner with 
him.  At the time though he was pushing anti-matter powered spaceships; 
which I thought was a crank idea.


Brent

On 6/16/2016 5:18 AM, Hans Moravec wrote:

On Jun 15, 2016, at 23:48 , Brent Meeker  wrote:

When you look somewhere new, you see new things.  To bad Joe Weber didn't live 
to see this.

Brent

And Bob Forward (Robert L. Forward), who was once Weber's grad student, and 
continued gravity related research and publication until his death in 2002.


On 6/15/2016 7:25 PM, John Clark wrote:

After analyzing the data from LIGO's brief engineering run the scientists there 
just announced they have found a second Black Hole merger. A Black Hole of 14 
solar masses merged with one of 8 solar masses and produced a Black Hole of 21 
solar masses and gravitational waves with 1 solar mass of energy. It happened 
1.4 billion light years away, about the same distance as the first merger that 
was announced a few months ago, but the signal was weaker because the Black 
Holes involved were smaller (14 and 8 vs 36 and 29) and also because the orbit 
of the Black Holes was more edge on relative to the Earth. Edge on means the 
signal is weaker but it also means it's easier to determine the spin, so unlike 
the first detection this time we can say with certainty that at least one of 
the Black Holes was spinning. And although weaker the signal lasted longer, 
almost a full second versus a fifth of a second the first time because being 
smaller the holes generated waves with higher frequencies that LIGO is more 
sensitive to.

And they're looking at at least one other suspected merger but they're only 85% 
certain it's real and that's not good enough to claim discovery, but there may 
be others so there may be a third announcement before long. Not bad for 
observing for only 18 days. The instrument was running at only one third power 
but that was still good enough to determine that 2 mirrors 4 kilometers apart 
had changed their distance by less than a billionth of a nanometer. I can't 
wait for September when the 2 LIGOs get back online and are joined by a third 
detector, VIRGO in Italy.

http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.241103

  John K Clark
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Re: LIGO found a second Black Hole collision!

[Hans Moravec]

> On Jun 15, 2016, at 23:48 , Brent Meeker  wrote:
> 
> When you look somewhere new, you see new things.  To bad Joe Weber didn't 
> live to see this.
> 
> Brent

And Bob Forward (Robert L. Forward), who was once Weber's grad student, and 
continued gravity related research and publication until his death in 2002.

> 
> On 6/15/2016 7:25 PM, John Clark wrote:
>> After analyzing the data from LIGO's brief engineering run the scientists 
>> there just announced they have found a second Black Hole merger. A Black 
>> Hole of 14 solar masses merged with one of 8 solar masses and produced a 
>> Black Hole of 21 solar masses and gravitational waves with 1 solar mass of 
>> energy. It happened 1.4 billion light years away, about the same distance as 
>> the first merger that was announced a few months ago, but the signal was 
>> weaker because the Black Holes involved were smaller (14 and 8 vs 36 and 29) 
>> and also because the orbit of the Black Holes was more edge on relative to 
>> the Earth. Edge on means the signal is weaker but it also means it's easier 
>> to determine the spin, so unlike the first detection this time we can say 
>> with certainty that at least one of the Black Holes was spinning. And 
>> although weaker the signal lasted longer, almost a full second versus a 
>> fifth of a second the first time because being smaller the holes generated 
>> waves with higher frequencies that LIGO is more sensitive to. 
>> 
>> And they're looking at at least one other suspected merger but they're only 
>> 85% certain it's real and that's not good enough to claim discovery, but 
>> there may be others so there may be a third announcement before long. Not 
>> bad for observing for only 18 days. The instrument was running at only one 
>> third power but that was still good enough to determine that 2 mirrors 4 
>> kilometers apart had changed their distance by less than a billionth of a 
>> nanometer. I can't wait for September when the 2 LIGOs get back online and 
>> are joined by a third detector, VIRGO in Italy. 
>> 
>> http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.241103 
>> 
>>  John K Clark
>> -- 
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> 
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Re: LIGO found a second Black Hole collision!

[Brent Meeker]

When you look somewhere new, you see new things.  To bad Joe Weber 
didn't live to see this.


Brent


On 6/15/2016 7:25 PM, John Clark wrote:
After analyzing the data from LIGO's brief engineering run the 
scientists there just announced they have found a second Black Hole 
merger. A Black Hole of 14 solar masses merged with one of 8 solar 
masses and produced a Black Hole of 21 solar masses and gravitational 
waves with 1 solar mass of energy. It happened 1.4 billion light years 
away, about the same distance as the first merger that was announced a 
few months ago, but the signal was weaker because the Black Holes 
involved were smaller (14 and 8 vs 36 and 29) and also because the 
orbit of the Black Holes was more edge on relative to the Earth. Edge 
on means the signal is weaker but it also means it's easier to 
determine the spin, so unlike the first detection this time we can say 
with certainty that at least one of the Black Holes was spinning. And 
although weaker the signal lasted longer, almost a full second versus 
a fifth of a second the first time because being smaller the holes 
generated waves with higher frequencies that LIGO is more sensitive to.


And they're looking at at least one other suspected merger but they're 
only 85% certain it's real and that's not good enough to claim 
discovery, but there may be others so there may be a third 
announcement before long. Not bad for observing for only 18 days. The 
instrument was running at only one third power but that was still good 
enough to determine that 2 mirrors 4 kilometers apart had changed 
their distance by less than a billionth of a nanometer. I can't wait 
for September when the 2 LIGOs get back online and are joined by a 
third detector, VIRGO in Italy.


http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.241103

 John K Clark
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Re: LIGO

[Brent Meeker]

And probably an even bigger deal if they aren't found.

Brent

On 2/9/2016 2:21 PM, Russell Standish wrote:

For one, gravity waves are a definite prediction of Einstein's General
Realativity. At some point, the sensitivity of gravity wave detectors
will be such that if they don't turn up, it will be a mjor
embarrassment for GR.

Then, if they do turn up, we can start to use it as another window on
the universe. For example, gravity wave detectors will be just the
pants to peer inside collisions of massive bodies such as neutron
stars and black holes. Also, it might give us good intelligence as to what's
going on in our galactic centre.

So yeah, if found, it'll be quite a big deal.

On Tue, Feb 09, 2016 at 02:44:48PM -0500, John Mikes wrote:

What difference does it make (to us) if something happens 50 or 650 million
lightyears away? - No matter if  _NOW_ or _THEN-in the deepest past_ .
Iwould be less benevolent and call those "rumors' rather fantasy (even if
supported by some human mathemaital considerations...)
John M

On Tue, Feb 9, 2016 at 10:57 AM, John Clark  wrote:


On Thursday at 10.30 EST (15.30GMT) the Laser Interferometer
Gravitation-Wave Observatory will announce if they've found gravitational
waves or not after its recent upgrade. Before the upgrade LIGO could detect
binary neutron star mergers 50 million light years away, after the
upgrade it could detect them 650 light years away, a volume over 2000 times
larger. The physics world is full of rumors.

  John K Clark

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Re: LIGO

[Russell Standish]

For one, gravity waves are a definite prediction of Einstein's General
Realativity. At some point, the sensitivity of gravity wave detectors
will be such that if they don't turn up, it will be a mjor
embarrassment for GR.

Then, if they do turn up, we can start to use it as another window on
the universe. For example, gravity wave detectors will be just the
pants to peer inside collisions of massive bodies such as neutron
stars and black holes. Also, it might give us good intelligence as to what's
going on in our galactic centre.

So yeah, if found, it'll be quite a big deal.

On Tue, Feb 09, 2016 at 02:44:48PM -0500, John Mikes wrote:
> What difference does it make (to us) if something happens 50 or 650 million
> lightyears away? - No matter if  _NOW_ or _THEN-in the deepest past_ .
> Iwould be less benevolent and call those "rumors' rather fantasy (even if
> supported by some human mathemaital considerations...)
> John M
> 
> On Tue, Feb 9, 2016 at 10:57 AM, John Clark  wrote:
> 
> > On Thursday at 10.30 EST (15.30GMT) the Laser Interferometer
> > Gravitation-Wave Observatory will announce if they've found gravitational
> > waves or not after its recent upgrade. Before the upgrade LIGO could detect
> > binary neutron star mergers 50 million light years away, after the
> > upgrade it could detect them 650 light years away, a volume over 2000 times
> > larger. The physics world is full of rumors.
> >
> >  John K Clark
> >
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-- 


Dr Russell StandishPhone 0425 253119 (mobile)
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Visiting Senior Research Fellowhpco...@hpcoders.com.au
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Re: LIGO

[John Mikes]

What difference does it make (to us) if something happens 50 or 650 million
lightyears away? - No matter if  _NOW_ or _THEN-in the deepest past_ .
Iwould be less benevolent and call those "rumors' rather fantasy (even if
supported by some human mathemaital considerations...)
John M

On Tue, Feb 9, 2016 at 10:57 AM, John Clark  wrote:

> On Thursday at 10.30 EST (15.30GMT) the Laser Interferometer
> Gravitation-Wave Observatory will announce if they've found gravitational
> waves or not after its recent upgrade. Before the upgrade LIGO could detect
> binary neutron star mergers 50 million light years away, after the
> upgrade it could detect them 650 light years away, a volume over 2000 times
> larger. The physics world is full of rumors.
>
>  John K Clark
>
> --
> You received this message because you are subscribed to the Google Groups
> "Everything List" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to everything-list+unsubscr...@googlegroups.com.
> To post to this group, send email to everything-list@googlegroups.com.
> Visit this group at https://groups.google.com/group/everything-list.
> For more options, visit https://groups.google.com/d/optout.
>

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