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Rob Sheldon: What’s behind the gravitational wave rumors

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spacetime curvature/Johnstone, CC

From Nature:

Gravitational-wave rumours in overdrive

What is the gossip?

Has giant LIGO experiment seen gravitational waves?
The rumours suggest that the Advanced Laser Interferometer Gravitational-Wave Observatory (LIGO), a US laboratory with detectors in Washington and Louisiana, has spotted a signal of gravitational waves. These are ripples in the fabric of space-time that, according to Einstein’s theory, are produced by cataclysmic events such as the merging of two black holes or two neutron stars.

Whispers of a possible detection were first tweeted in September by cosmologist Lawrence Krauss, at Arizona State University in Tempe. The most specific rumour now comes in a blog post by theoretical physicist Luboš Motl: it’s speculated that the two detectors, which began to collect data again last September after a $200-million upgrade, have picked up waves produced by two black holes in the act of merging. More.

Krauss? Now a credible source?

Dr Sheldon
Rob Sheldon

We asked physicist Rob Sheldon, who wrote back,

I think the subtitle says it all: “Physicists say they’ve heard that the LIGO observatory may have spotted the signature of merging black holes”

Which I will paraphrase “Outsiders heard a rumor that there is a hint of possible news.”

So the real question is why this is published at all? The answer is very simple- 24 years and $620M in hardware (I’m sure salaries push that over $1bn) without a signal.

It isn’t just that senior scientists are retiring without seeing any benefit from their work. It isn’t even that 4 generations of graduate students have had to write their PhD thesis on simulation results. I think more significantly, a new generation of bureaucrats have arrived in NSF who don’t think LIGO will ever return the investment. Think CERN upgrade, WIMP searches like LUX, even Gravity Probe B. These big ticket items promised the moon and the stars and provided tenure-track positions, but never delivered. The desperation is palpable.

The most recent funding of $200M upgrade was completed in Aug 2015, and that’s when the rumor started. If LIGO behaves like most big detectors, then the first year is spent getting the glitches out and writing the software to analyze the data. So to have a rumor begin in September is not a good sign, sort of like getting a pair of East German boots manufactured on the end of the month.

Nor is the type of signal discovered, a “neutron star merger event”, a good sign. Unfortunately, these events are a blip about 2 seconds long, and they don’t repeat. They have been modeled incessantly, but never observed unless one believes gamma-ray burst (GRB) events are such events. Talking to the scientists who built the Gamma-ray Burst Monitors (GBM) on the last two NASA missions, it seems unlikely that these events are indeed merging neutron stars. Nevertheless, the LIGO team optimistically uses the ~100/year GRB event rate to estimate how frequently they should see a signal. So the rumor would confirm three or four independent assumptions that are widely held to be true–which is a good sign that it is just a rumor.

Other than discovering and refining the software to remove more “artifacts” from the data, there isn’t much they can do to make the August signal any better. I would guess that if they had any confidence in this preliminary data, they would have made an announcement by now.

But many in the consortium think that the new sensitivity of the Advanced LIGO should give them a valid signal about once or twice a year, so why not wait for a real one? And of course, the real clincher would be to have the GBM see a Gamma-Ray Burst at exactly the same time and same place as LIGO. Then everyone would exhale a huge sigh of relief and break out the champagne.

What is my Bayesian probability estimate for this LIGO signal? It’ll never happen, though I will be happy to celebrate my proven fallibility.

Why? Because there are too many features of the standard model that are pure fudge–dark matter, dark energy, flatness, horizon, ahelicity, etc.

For example, if the universe had a large magnetic field, then all the support for gravity waves could be attributed to magnetic Alfven waves with far less effort. Likewise for inflation, baryonic acoustic modulations, event horizons, Lithium 7 abundances, proton decay, etc., they are all fixes to the standard models. One simple change to the metaphysics (the beginning assumptions), and the entire house of cards starts to crumble.

The standard model, despite what you may have heard, is extremely fragile, and that is yet another reason that billions of dollars has been spent at CERN, at LIGO, at LUX, trying hard to shore up the foundations of the initial physics assumptions. And yet, to quote the New Year’s predictions of famous physicists (published in Edge), the big news of 2015 is the lack of news in 2015.

All of this make me believe that is 2016 announcement is akin to the pronouncement of physicists of 1890, who never suspecting the Quantum revolution, said “the superstructure of physics is complete, all that is needed is to tidy up some loose ends…”

See also: Gravitational wave detection could be a false alarm (Guardian)

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Comments
Everyone: Gravitation is instantaneous (i.e., non-local) in its action: "The most amazing thing I was taught as a graduate student of celestial mechanics at Yale in the 1960s was that all gravitational interactions between bodies in all dynamical systems had to be taken as instantaneous. . . . Indeed, as astronomers we were taught to calculate orbits using instantaneous forces; then extract the position of some body along its orbit at a time of interest, and calculate where that position would appear as seen from Earth by allowing for the finite propagation speed of light from there to here. . . . That was the required procedure to get the correct answers." ("The Speed of Gravity - What the Experiments Say" , Tom Van Flandern, Physics Letters A, 250 (1-3) (1998) pp. 1-11) Another one is: "Measurement of the Speed of Gravity" by Yin Zhu . The Abstract from Appendix B, in part, says: "It indicates that the gravitational force of the Sun acting on the satellite is from the present position of the Sun [i.e., no aberration] and that the speed of the gravitational force is much larger than the speed of light in a vacuum. If you want more details, see http://scripturalphysics.org/4v4a/ADVPROP.html#TheSpeedOfGravityBrianFraser
October 2, 2016
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Mapau @ 1
It’s all wishful thinking, of course. There is a tremendous amount of political energy being spent on proving the correctness of GR as opposed to falsifying it. This is not science. Gravity will be found to be an instantaneous, nonlocal phenomenon caused by energy conservation. Newton was right to assume that gravity was instantaneous. The only reason that Einstein predicted gravity waves is that the did not believe in “spooky action at a distance.” He was proven wrong:
Gravitational Waves Detected 100 Years After Einstein’s Prediction https://www.ligo.caltech.edu/news/ligo20160211 LIGO Does It Again: A Second Robust Binary Black Hole Coalescence Observed https://www.ligo.caltech.edu/news/ligo20160615 Einstein correct again. Mapau wrong, again.Charles
October 2, 2016
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Aceofspades25:
@Mapou Do you have any evidence which leads you to believe that Gravity will be found to be an instantaneous, nonlocal phenomenon? Or is this just a faith position? I’m not exactly familiar with the science here but the speed of gravity wiki page lists a two experiments that have so far demonstrated that gravity propagates at a finite speed which is in the region of the speed of light. https://en.wikipedia.org/wiki/Speed_of_gravity If I’m torn between trusting some random creationist of the internet without evidence verses physicists with evidence, I’m going to do the rational thing and go with the physicists who have evidence.
Newtonian physics assumes that gravity is instantaneous. If it weren't, all orbits would be unstable. In spite of claims to the contrary, Newtonian gravity is extremely accurate. It is so good, in fact, it is the physics used by NASA to send probes around the solar system. All they have to do is factor in the speed of light and everything works great. It works because gravity is instantaneous. Relativists, by contrast, have to do a neutron dance and sacrifice a furry animal to make GR work. In order to explain why the orbits of planets are stable, they just throw science out of the window. They claim (without any evidence, of course) that the momentum and direction of travel of a gravitational source body (e.g., the sun) are somehow transmitted to distant orbiting bodies (e.g., planets) and this is how the orbiting bodies know which way to move. It's worse than voodoo. There is no science in it. There is absolutely no question in my mind that those so-called experiments that prove that the speed of gravity is close to the speed of light are scientific frauds. They are all lies. Physicists are worse than Darwinists when it comes to protecting their sacred cow. The biggest problem with Einsteinian physics is political. This is a field where researchers go out of their way to prove a theory as opposed to falsifying it. This gravitational wave experiment was not designed to disprove GR but to buttress it. Karl Popper is turning in his grave as I write.Mapou
January 15, 2016
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http://math.ucr.edu/home/baez/physics/ParticleAndNuclear/photon_mass.htmlkairosfocus
January 15, 2016
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Stars do NOT convert mass into energy. The total mass remains constant, as does energy. Of course, as a star burns its mass does go down, as it releases energy in the form of radiation. But the photons, that are the radiation, have got this mass, which for a photon is given by m = hf/Ce f is the frequency in Herts h is planks constant 2.45*10-37 Btu per Hert Ce is Einsteins factor, the speed of light squared, 19.7 Btu per pound. m is the mass in poundschris haynes
January 15, 2016
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@mahuna, you write: > So, since E=mc^2, if the universe SUDDENLY converts some huge mass into energy (which of course stars do all the time), then it should be possible to detect the CHANGE in Gravity based on the extinction of the Mass. Apparently this (i.e., the sudden loss of gravity) has NEVER been observed, which leads to fundamental questions about HOW Newton’s Gravity exerts force at a distance without any OBSERVABLE evidence of that force. According to GR, it is actually energy warps the fabric of space time. Mass warps the fabric of space time because objects with mass have energy bound up within them. Simply converting one form of energy into another (through the process of fusion) will do nothing to affect the local gravitational field. @Mapou Do you have any evidence which leads you to believe that Gravity will be found to be an instantaneous, nonlocal phenomenon? Or is this just a faith position? I'm not exactly familiar with the science here but the speed of gravity wiki page lists a two experiments that have so far demonstrated that gravity propagates at a finite speed which is in the region of the speed of light. https://en.wikipedia.org/wiki/Speed_of_gravity If I'm torn between trusting some random creationist of the internet without evidence verses physicists with evidence, I'm going to do the rational thing and go with the physicists who have evidence.Aceofspades25
January 15, 2016
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Mahuna, There is no action at a distance because there is no distance/space. It's an illusion. If space exists, where is it? IOW, there is nothing spooky about "action at a distance" because distance is only apparent. But don't tell that to mainstream physicists, though. You'll be laughed at and ridiculed. But Immanuel Kant was right about space and time. They are mental creations that cannot be empirically detected.Mapou
January 14, 2016
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I think we need to get straight that if Gravity propagates through space, then there should be a constant bombardment of something like "gravity waves" every single instant of time. The problem of not being able to detect any waves has been explained by the CONSTANCY of gravity from existing matter. So, since E=mc^2, if the universe SUDDENLY converts some huge mass into energy (which of course stars do all the time), then it should be possible to detect the CHANGE in Gravity based on the extinction of the Mass. Apparently this (i.e., the sudden loss of gravity) has NEVER been observed, which leads to fundamental questions about HOW Newton's Gravity exerts force at a distance without any OBSERVABLE evidence of that force. We should also be able to detect the arrival of a "wave" of gravity following the conversion of a huge bundle of energy (or even a teeny one) directly into NEW matter. That is, there should SUDDENLY be more Gravity than existed a second ago. I have to believe that it would be MUCH cheaper to set up experiments that attempt to measure the conversion of mass into energy during a thermonuclear explosion. Since we have good equations for estimating the mass actually converted to energy as "yield", it should be reasonably simple to detect the sudden disappearance (negative gravity waves? a change in the amplitude of the existing waves?) of the mass. But, hey, my degree is in Geography.mahuna
January 14, 2016
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It's all wishful thinking, of course. There is a tremendous amount of political energy being spent on proving the correctness of GR as opposed to falsifying it. This is not science. Gravity will be found to be an instantaneous, nonlocal phenomenon caused by energy conservation. Newton was right to assume that gravity was instantaneous. The only reason that Einstein predicted gravity waves is that the did not believe in "spooky action at a distance." He was proven wrong: quantum nonlocality is a fact. Nonlocal interactions are the norm, not the exception.Mapou
January 14, 2016
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