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Questions tagged [gravitational-waves]

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Gravitational brehmsstralung

I have read this pdf, and its 5th paragraph, where it talks about gravitational brehmsstralung. https://www.researchgate.net/publication/243311274_Gravitons_in_Minkowski_space-...
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Are we closer to a theory of everything thanks to the detection of gravitational waves?

A couple of weeks ago I heard an astronomer explain that one of the latest detections of gravitational waves was accompanied by simultaneous detections of the same astronomical event in various other ...
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Does a graviton in vacuum have a rest frame?

I have read these questions: Does a photon in vacuum have a rest frame? Based on dmckee's answer, the answer is no to a photon's rest frame. In the modern view each particle has one and only one ...
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Gravitational waves of an oscillating Schwarzschild black hole

Gravitational waves are produced by an accelerated mass, similar to the production of light waves by an accelerated charge. The amount of gravitational energy released from a rotating object can be ...
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Are Gravitrons still hypothetical? [duplicate]

With the dectection of gravitational waves, can it be assumed that gravity works in the same way as the other fields? If so, isn’t the gravitron a proven part of QFT? Because the wikipedia page says ...
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Do gravitational waves lose energy through interaction with i.e. matter or magnetic fields? [duplicate]

Gravitational waves dilute while traversing space like any other radiation, and their amplitudes are proportional to r-2, that's a basic. But do they lose energy while traversing through matter or ...
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The June 23 issue of New Scientist says gravitational waves twist when they travel, and do so counterclockwise. Why?

Also, the same article then says that if gravitational waves ever did move in a clockwise fashion, it means the black holes slammed into each other much more rapidly. Huh?
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Does heat radiation also produce gravitational waves?

My question is as it sounds. We know that in a vacuum, materials radiate away their heat energy. To my understanding, this is the result of charged particles losing their energy to produce photons. ...
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Quadrupole Radiation pattern in GR

What is the equation that can be used to show the quadrupole radiation pattern in general relativity? if one wants to plot the quadruple radiation in GR, what should be done?
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Factor of 4 (or 2) in the gravitoelectromagnetic (GEM) Lorentz-force law. Which is correct? Why is it there?

I realize that the Gravitoelectromagnetic equations (GEM) are derived from the Einstein field equation (EFE) in the degenerate case of reasonably flat spacetime, which is the case for the propagation ...
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Does Earth emit Gravitational waves?

We know about bohrs model and his vagaue postulate challenging Rutherford for discrete orbits and not emitting electromagnetic waves during this. Extending this idea to our solar system, does earth ...
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Can gravitational waves be emitted from single neutron stars?

I wonder whether GWs can be produced and emitted by single neutron stars, since it is known that typically they must be emitted by a binary system of them. If so, can the source be an isolated cool ...
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Slowdown of gravitational waves measurement

As far as I can understand, the gravitational waves also slow down on interaction with matter similar to light rays. I am trying to understand if we can measure this? Suppose we put two detectors on ...
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How does tensile loading and shear stress contribute to gravity?

Both, tensile loading and shear stress are represented in the Stress-Energy Tensor and hence are sources of gravity. As I understand it (please correct if wrong) tensile loading implies forces ...
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1answer
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Are gravitational waves the slowest waves known to science?

Consider that two celestial bodies orbit have a frequency of one rotation every 50,000 years, it means that the periodicity of the gravitational wave sensed by a distant observer is about 50k years. ...
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Is the signal detected by LIGO a result of the merging of the horizons or the singularities?

Regarding gravity waves, some YouTube videos show simulations of the gravity waves detected by LIGO in August of 2017. Is the "chirp" the result of the merger of the event horizon or the merger of ...
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How are black hole masses calculated from gravitational waves? [duplicate]

I would like to know what data is used from gravitational wave detections to calculate black hole masses and how. Also, what else can you deduce from gravitational wave detections? What was the exact ...
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Quantum gravity and inspirals by emission of gravitational waves [closed]

Should we expect that quantum gravity, just as quantum theory forbids the decay of the fundamental level, avoids the collision of gravitationally bound systems at small scales, despite they emit ...
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Approximating a linearized gravitational wave expression

This is in the context of gauge fixing condition for obtaining linearized gravitational waves. $g_{ab}=\eta_{ab}+h_{ab}$ and $h_{ab}$ is the small perturbation that stands for the gravitational wave. ...
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Is there a “magnetic gravitational” field? [duplicate]

Electromagnetic waves, in the classical sense, are due to oscillations in two different fields. They propagate at the speed of light, and they can be described by a set of differential equations. ...
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Do non-uniformly rotating axially symmetric bodies emit gravitational waves?

In the first reply to this question it is written that: There is no gravitational waves for a uniformly rotating axially symmetric body, because the metric doesn't depend on time.[..] The ...
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How does LIGO detect Gravitational Waves if they bend both space and time?

Please note that this is not an inquiry into the mechanisms of technology that LIGO uses to detect gravitational waves. Also, I am not a flat-earther. I was watching physicists vs. flat-earthers ...
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Pendulum usage in gravitational wave detectors

I've read that pendulums are (or were) used to calibrate the distance between the mirrors in a gravitational wave detector. In principle pendulums are supposed to be moving in just one plane no matter ...
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Has anyone ever tried to derive gravitoelectromagnetic waves equation?

Has anyone ever tried to derive gravitoelectromagnetic waves equation? As we know, there is Maxwell-like equation in gravity. Has anyone here ever formulated gravito electromagnetic waves equation ...
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Could LIGO detect two simultaneous gravitational waves?

Hypothetically if two (or more) gravitational waves were passing through the LIGO detector at the same instant, can the LIGO team deduce from the data that there were two simultaneous waves passing? ...
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1answer
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What does it mean by $h_{\mu\nu}$ having “gauge symmetry”?

$$\partial^\rho \partial_\rho h_{\mu\nu} - \partial_\mu \partial^\rho h_{\rho\nu} - \partial_\nu \partial^\rho h_{\rho\mu} + \partial_\mu \partial_\nu {h^\rho}_\rho = 0$$ Here $h_{\mu\nu}$ is a ...
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How is the approximate gravitational wave stress energy momentum tensor not 0?

In Section 35.7 of Misner, Thorne, and Wheeler, p. 955, an "effective" stress energy momentum tensor for gravitational waves is defined: $$T^{\text{GW}}_{\mu \nu} = \frac{1}{32 \pi} \left< \bar{h}...
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Gravitational waves and Possible distortions in time?

Straight off, i know similar questions have been asked at How close would you have to be to the merger of two black holes, for the effects of gravitational waves to be detected without instruments? ...
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Gravitational wave equations? [closed]

I am looking for a set of equations, one to calculate GW amplitude in watts and one to calculate frequency... I believe I have located the correct frequency equation yet I cannot find a source for ...
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2answers
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Red-shifting due to emitting gravitational waves

Light waves exert their own gravitational pull and must be emitting gravitational waves, losing energy in the process. Does this mean that light becomes red-shifted as it travels even without the ...
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Theory of physical vacuum (ether) [closed]

Recently, I came across this : Theory of physical vacuum (ether) Postulate. All fields and material objects in the Universe are various perturbations of physical vacuum, which is dense ...
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Proper time elapsed along a worldline

The question is about the following metric describing the gravitational wave propagating along the $z$ direction: $$ds^2=-dt^2+(1+h(t,z))dx^2+(1-h(t,z))dy^2+dz^2$$ where $$h(t,z)=H\cos{k}(t-z).$$ $...
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Effective stress-energy tensor for a gravitational wave, compared to static semi-Newtonian case

There is a calculation that I had been thinking for a long time of working out to my own satisfaction, both because of its intrinsic importance and because it seemed like it would be fun. This was to ...
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Is Gravity Cumulative

This is to tie in with a previous question >The Sun's Orbit - Is it What We Think? Are gravitational waves cumulative? and if so how does this affect our galaxy and other astronomical bodies? Now ...
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Why gravitational waves are not part of thermal phenomena?

Electromagnetic waves are part of thermal phenomena in the form of thermal radiations. But why gravitational waves do not show up as a thermal phenomenon, for example, why gravitational waves do not (...
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Do gravitational waves diminish over time/distance?

Just wondered how they compare to sound waves, naturally they travel at the speed of light, but I was wondering if they diminish over time like sounds waves. Cheers.
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Do you create gravitational waves by clapping your hands?

I was thinking that given that GW's can be created by the merger of both black holes and neutron stars I don't see why any two colliding objects wouldn't also be able to create gravitational waves, ...
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Is it possible that the LIGO results are anomalies? [duplicate]

Since it was reported recently that the supermassive black holes at the centres of galaxies may in fact be as many as 20,000 smaller black holes I wondered if, if these black holes collide with one ...
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1answer
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Visualising Gravitational waves

I'm studying General relativity, and I want to clarify the qualitative nature of how gravitational waves propagate. Simple is best, so I want to imagine a single binary black hole system orbiting in ...
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About the “Spindown problem”

I am studying General Relativity, following the lessons too, and some days ago the professor mentioned, in a very "fancy and quick" way a thing called "the spindown problems". For what I understood, ...
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Do stars amplify or refract gravitational waves?

I am curious if stars (or other massive bodies) amplify or refract gravitational waves in a manner similar to the following. Amplification In the case of amplification, do massive bodies affect ...
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Why are both LIGO detectors nearly co-aligned? [duplicate]

A lot of the papers I've been reading say that's the case, so we needed VIRGO to analyze the polarization of the GWs, but not a single one of them explains the reasoning behind this decision. Why ...
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How do the LIGO facilities know that their gravitational waves have not been distorted by other events and other waves?

Several black hole collisions have been detected. How do they determine if the gravitational waves have been strengthened or weakened by interaction with other event waves?
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What causes the 20 second period in LIGO data?

I download LIGO data on GW150914 (gravitational waves) via the code in Mathematica ...
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Damhsa Theory: Can gravitational waves really affect the long term climatic evolution of Earth?

As a glaciologist I'm often involved in topics related to the long-term climatic evolution of Earth, and to the factors that can trigger or end ice ages. Recently, I came across the paper "Applying ...
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Gravitational Potential Energy irony

While calculating potential energy of an object with respect to Earth which equals work done to bring it from infinity to that point. The gravitational force and displacement are in same direction, ...
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How much uncertainty has the relic graviton background?

In the paper https://www.osti.gov/biblio/6051438-relic-gravitational-waves-extended-inflation, it is mentioned that inflation predicts that a relic graviton background is about 0.9 K (cf. cosmic ...
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Is a seismic gravity perturbation a gravitational wave?

Powerful enough earthquakes generate gravity perturbations that propagate at $c$ and can be detected by sensitive enough seismographers. See, e.g., this news in Nature: In the latest paper, Vallée ...
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If two black hole mergers happen close enough would there be any interesting effects due to their waves constructive and destructively interfering?

If two pairs of black holes were to merge at the same time in the same plane within close proximity (small odds) what effects could be observed due to their waves constructively and destructively ...
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What causes primordial gravitational wave in the early universe?

Is it collision between primordial black holes or perhaps big bang itself, I read that if we can observe very first polarized light e.g. CMBR etc then inflation theory is proven. So my question is ...