Questions tagged [gravitational-waves]

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Where do gravitational waves and general relativity coincide? [closed]

In the first ten seconds of this video (https://www.youtube.com/watch?v=iphcyNWFD10) the host says that gravitational waves were the result of two black holes merging. That would seem like there is ...
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Does a non-wobbling rotating black hole produce gravitational waves if it were to suddenly accelerate its rotation?

My understanding is anything that have mass and accelerate produce gravitational wave however small, suppose I have a rotating black hole and nothing orbits it and it's spin suddenly accelerates. Does ...
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Does LIGO accounts for Sagnac effect?

After reading Sagnac effect one thing immediately come to my mind is LIGO, I only read that the team building LIGO have already considered the curvation of Earth surface but what about Earth's ...
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Can gravitational lensing also applied to gravitational wave?

We know light travels in a straight line but spacetime around an object with mass is curved, anyhow I'm wondering gravitational wave going at speed of light could also be bended by stars and probably ...
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Can higgs field ripples like gravitational wave?

Gravitational wave are produced when 2 massive objects orbit each other at high speed or collide, how about higgs field? can it ripples and what sort of event can cause it to ripple?
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What is the experimental evidence for the gravitational field having positive energy density?

Recent direct observation of gravitational perturbations attributed to merging black holes and merging neutron stars has reliably confirmed the existence of gravitational waves. The observed fact that ...
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Why does the 'sticky bead argument' for (gravitational waves carrying energy) work?

Throughout much of the 20th century there was debate about whether Gravitational Waves were real, and whether or not they carrier energy and could be detected. It is often presented that Feynman's '...
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Do gravitational wave produce varying electromagnetic waves? [closed]

When gravitational waves produce electromagnetic waves, do they produce them of the same frequency or of varying wavelength?
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How to interpret results of stationary phase approximation in GW case?

As time increases, the amplitude and frequency of the GW signal also increase. But after using the stationary phase approximation, the signal is proportional to ${1/f^{7/6}}$, where $f$ is the GW ...
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What is the shape of a gravitational wave form?

What is the shape of a gravitational wave as it hits the Earth, particularly the time portion. Does time start at normal speed, then slow slightly, and then return to normal speed? Or does it start ...
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How are sound waves and gravitational waves different?

What is the difference between sound waves and gravitational waves? The source term in GR as I understand it is the energy-momentum tensor which contains pressure, which makes me think sound is a ...
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How do gravitational waves agree with Lorentz invariance?

Following is a simple but incorrect explanation for gravitational waves. My question is what is wrong with it? I'd like to say that a gravitational wave is a periodic variation in the local ...
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What was the major discovery on gravitational waves made March 17th, 2014, in the BICEP2 experiment?

The Harvard-Smithsonian Centre for Astrophysics held a press conference today to announce a major discovery relating to gravitational waves. What was their announcement, and what are the implications? ...
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Gauge invariance of pseudo stress-energy tensor of gravitational waves

The pseudo stress-energy tensor of gravitational waves is given by $$T_{\mu\nu}^{(\mathrm{G}\mathrm{W})} = \frac{1}{32\pi}\left\langle \partial_{\mu} \bar{h}_{\alpha\beta} \partial_{\nu}\bar{h}^{\...
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Can LIGO be explained in terms of gravitons?

If electromagnetic waves from a star are so faint, all that can be detected are single photons on a photographic plate. For the LIGO experiment, the gravitational waves were so weak, I would have ...
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Do gravitational waves add mass to black hole?

Due to the recent discovery of gravitational waves by LIGO I was wondering suppose a black hole stood between a gravitational wave then due to the fact that black hole can attract every thing then ...
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Gravitational refraction

I recently used another venue to ask about the speed of gravity, specifically if the speed of gravity is constant or if it is subject to refraction when passing through media, akin to light. The ...
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Does linear memory effect encode in the gravitational waves?

I read from a few papers that the gravitational memory effect has linear and nonlinear parts: $$\Delta h^{TT}=\Delta h^{TT}_{linear}+\Delta h^{TT}_{nonlinear}$$ and the nonlinear part is encoded in ...
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Constructing Gravitational waves with gravitons

Suppose I want to construct a gravitational wave as a coherent sum of many gravitons. It's easy to think of what the frequency distribution of the gravitons should be, as all the LIGO discoveries more ...
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What is the interaction of gravitational waves?

Please excuse my lack of knowledge about the subject but, If gravitational waves travel thru the fabric of space time do they interact with each other? Meaning do they create interference patterns ...
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How would a passing gravitational wave look or feel?

In a hypothetical situation I'm still sitting in a coffee shop but a gravitational wave similar to the three reported by LIGO passes through me from behind. The source is much closer though, so this ...
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Can gravitational waves orbit a black hole?

Assume (for the sake of simplicity) a Schwarzschild black hole (non-rotating, non charged). This black hole has a photon sphere in $r=1.5r_s$, where photons may travel in a circular orbit. Will a ...
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Would pilot-wave gravity reconcile Bohmian mechanics with relativity? [closed]

I was reading Can Bohmian mechanics be made relativistic? from 2016 that attempts to reconcile Bohmian mechanics with relativity. It’s conclusion says: Is such a theory then fundamentally—and/or ...
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Is a GASER a theoretical possibility? [closed]

This question (basically an analogy ) is inspired by several questions and answers that appeared on stackexchange.  We first define GASER, for the purpose of this question. GASER - gravitational (...
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What is the upper bound for the index of refraction of space?

It seems that gravitational waves and gamma waves travail at about the same speed, arriving within seconds of each other over distances in the ranges of $10^6$LY. Naively, I would assume this caps the ...
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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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Why does the LIGO observation disprove higher dimensions?

I recently read this article which claims that last year’s LIGO observation of gravitational waves is proof that, at least on massive scales, there cannot be more than three spatial dimensions. I ...
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Interaction with Gravitational Radiation

I have a question about hypothetical gravitational radiation. To put it simply, is there any sort of material or field or other force which can interact with it? I'm thinking about lenses and mirrors ...
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How would be effect gravitational field of an accelerated object?

We have a mass in space and it is accelerating until 0.7C (which gives it nearly 50% mass equivalence in momentum.) I'd like to hope to understand the changes in gravitational fields after ...
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Collision of charged black holes

Suppose there are two charged black holes which collide to form a bigger black hole. But when they combine, a lot of potential energy of the system is lost/gained depending on their charges (the ...
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Would warp bubbles emit gravitational Cerenkov radiation in general relativity?

Inspired by the gravtiomagnetic analogy, I would expect that just as a charged tachyon would emit normal (electromagetic) Cerenkov radiation, any mass-carrying warp drive would emit gravitational ...
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Gravitational waves energy source in linearized theory

By linearizing the metric in the following way (approach in most textbooks): $g_{\mu\nu}=\eta_{\mu\nu}+h_{\mu\nu}\text{ with } |h_{\mu\nu}|\ll 1$ and choosing the transverse-traceless gauge a wave ...
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Could black holes be formed by highly energetic gravitational waves?

Could the gravitational waves released by two merging black holes contain enough energy to produce another black hole?
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Can spacetime be thought as a field associated with gravitons?

Researching, I found that gravitational waves are generated by the changing in time of the quadrupole moment of mass of a system - source. They travel at speed of light, and they perturbate the ...
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How does general relativity eliminate the Newtonian action at a distance? By the mediation of which “carriers”?

I found in Wikipedia the following statement From a Newtonian perspective, action at a distance can be regarded as: "a phenomenon in which a change in intrinsic properties of one system induces a ...
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Does rotation always slow down in general relativity?

Suppose I have a rotating object in empty space. Will it lose angular momentum due to interactions with spacetime? The most obvious case if if the object has a quadrupole moment. Then the quadrupole ...
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Is there a way to describe gravitational waves and time-dependent gravitation without tensors?

I have been reading about gravitational waves, and they fascinate me. However I struggle to follow the mathematics behind it, because they are described using tensors, index gymnastics, et cetera. Is ...
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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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Do gravitational waves affect light?

Gravity "bends" light, predicted with theory of relativity and subsequently observed: how does gravity and gravitational waves achieve this effect, and shouldn't this effect be present wherever there'...
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Why do gravitational waves or electromagnetic waves exist?

Maxwell equations or Einstein field equations imply the existence of electromagnetic waves and gravitational waves. How can these waves persist on (vacuum) space if they radiate (and loose) energy?
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Folded strings or hidden preons as black hole interior: signals with gravitational waves?

Suppose the black hole interior (non-kerr, kerr-like,...) is made of some kind of subsubatomic stuff (e.g., folded strings or superstrings, folded branes, buches of preonic pregeometry or whatever). ...
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Plane wave propagating in de Sitter spactime

Around a flat background, a plane wave propagating in the $z$ direction is given by $h_{\mu\nu} = \epsilon_{\mu\nu} \cos(\omega t -kz)$. What is the generalisation of this to a de Sitter background?...
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Quadrupole moment tensor definition

I'm not sure what the proper definition of the quadrupole moment tensor is. In the book on gravitational waves by Maggiore, the definition is $$M^{ij}=\int d^3x T^{00}x^ix^j. \tag{3.37}$$ ( Maggiore,...
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What is the most massive symmetric black hole pair that can pair produce during their collision?

Gravitational waves produced by inspiraling black holes have a similar inverse dependence on mass that the strength of the gravitational field outside of the event horizon has. For example, look at ...
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Gravitational waves & cosmological redshift

Are gravitational waves streched by the expansion of the universe in the same way as EM radiation is? In that case how does one differentiate between a gravitational wave from a given event (say ...
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How much mass is in gravitational waves?

Like photons, I understand gravitational waves to have no rest mass but mass due to their energy. Are gravitational waves a significant part of total mass and what are the main components (black hole ...
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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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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 ...