Questions tagged [gravitational-waves]

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Are there any time-periodic solutions to Einstein's equations apart from black holes?

Are there any solutions to Einstein's equations which are periodic in time? A black hole only has mass, charge and angular momentum according to the no-hair theorem. (Although this might just mean in ...
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Gravitational waves interference lensing

Is it possible to detect gravitational waves interference pattern in space, using a telescopes alone or a telescope coupled by gravitational lensing?
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Can the vibrations from the Earth affect gravitational wave detectors?

I was very interested in gravitational wave detectors and how they work exactly. From what I know they set up two lasers with mirrors set up to cancel each other out. Then if movement is detected from ...
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On what timescale does gravitational wave emission circularise an orbit?

Gravitational waves remove both energy and angular momentum from a binary orbit. Both rates are enhanced in non-circular (eccentric) orbits and I presume that (like tidal friction) the net effect will ...
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Significance of the LIGO experiment with respect to length contraction

it might be best to first detail my (admittedly limited) understanding of the LIGO experiment. a beam of light is split along two 4Km evacuated pipes then reflected back where their interference ...
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Could a black hole and a white hole cause gravitational waves, if orbiting one another?

I have been puzzled by an idea that I came across while reading about white holes. But I've only just started learning about white holes, so my knowledge is severely limited. It seems I also can't ...
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Two black holes colliding (classical mechanics)

I had this question come up in my exam where two identical black holes are in orbit around each other. There is a loss of energy via gravitational waves : $$\frac{d E}{d t} = kr^4\omega^6$$ where $k$ ...
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Energy of an event for a human observer at a distance of 1 astronomical unit to physically feel the gravitational waves using inverse square law?

I'm asking this question to satisfy my curiosity about how much energy (in joules) it would take for a human astronaut to feel a gravitational wave from a distance of 1 astronomical unit (AU) from two ...
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Gravitational wave behavior [duplicate]

My guestion is since we have now detected gravitational waves can gravitational waves go through interference (ie destructive or constructive interference) with each other like other waves?
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Propagation of gravitaional waves near black holes [duplicate]

As we know near black holes light gets strongly deflected. And if the gravity of the black hole is strong enough, the light can move in circles around the black hole. How the gravitational wave ...
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How can gravitational waves from such a long distance affect the beam of light?

Even if it does affect it should affect all the surrounding object making it impossible to detect any change. It would be like keeping a man and a scale in a room, and if a gravitational wave is ...
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Do mass and motion affect space-time differently?

Mass is said to create curvatures in space-time thereby creating gravity, yet technically the smallest movements, even on Earth, create gravitational waves. Are there different "types" of disturbances ...
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Bound on large extra dimensions using gravitational waves

Are there proposed observations using gravitational waves which put a bound on the size of large extra dimensions (say in the context of ADD model)? The claim in the ADD paper is that you cannot ...
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Would a free falling object hits by gravitational wave accelerate towards the source however briefly?

Gravity is acceleration so I would imagine an object that is in free fall to experience a force when hits by the gravitational wave but in which direction is my question?
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Could gravitational wave permanently distort a region of space time?

Imagine a flat spacetime being disturbed by a gravitational wave from a very distant source, say given enough time would that flat spacetime recovers meaning it must be at the same state as before, ...
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Why does spacetime propagate gravitational waves?

Setting the scene: If I drop a stone into water, the stone will create a depression in the water that the surface tension of the water and gravity (so says the Wiki article: Dispersion (water waves)) ...
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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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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 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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Are the masses of merging black holes correlated?

LIGO/VIRGO recently released data on observed "gravitational wave transients", mostly BH-BH mergers. The data includes a plot of the primary and secondary mass (the primary mass is defined as the ...
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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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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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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 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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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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Why do numerical relativity papers show $\ddot{h}_\times$ instead of $h_\times$ for gravitational waves amplitude?

I am very confused about why numerical relativity papers, when talking about gravitational wave extraction, usually plot the real part of the fourth Weyl scalar, $\Psi_4$, instead of its double ...
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91 views

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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1answer
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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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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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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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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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Would two objects orbiting each other emit gravitational waves on every direction or only on their plane of rotation?

Imagine a system where two massive objects are orbiting each other, something like a binary black hole or neutron star system. Such a system should emit gravitational waves. I'm curious on the ...
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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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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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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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1answer
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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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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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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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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 ...