Questions tagged [gravitational-waves]

For questions about the propagation of waves carried by space-time, for instance as described by general relativity. Not to be confused with gravity waves, such as ocean surface waves.

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Why does linear motion not emit gravitational waves? [duplicate]

Gravitational waves have been detected emanating from the decaying orbits of massive bodies, such as binary neutron star or black hole systems. To my understanding, two such bodies in what would ...
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What does determine the frequency of gravitational waves caused by inflation?

It is theorized that during inflation gravitational waves are produced. See this article by Guzzetti, Bartolo, Liguori, and Matarrese (Cornell University). Or this one by Liu, Guo, Cai, and Shiu (...
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How do they calculate the distance merging massive bodies are away from earth using just the gravitational waves? [duplicate]

I guess the title sums up my question nicely. So, how do physicists/cosmologists/scientists determine the distance two or more merging bodies are away from earth given just their emitted gravitational ...
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Equivalence Principle and Gravitational Waves

From my understanding, the equivalence principle says that it is impossible to know if you are moving or are stationary (and everything else is moving around you). Do gravitational waves violate this? ...
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Are gravitational waves subject to gravitational lensing? [duplicate]

Can gravity be focused by large massive objects?
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Elastic modulus of space-time? [duplicate]

Intuitively, a wave is something that propagates through an elastic medium (except possibly for ocean waves); is it possible to consider space-time as such a medium? And if so, what would its elastic ...
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Does a gravitational wave let my coffee spill? [closed]

An observer holds a cup of coffee that is filled to the brim at the moment a gravitational wave passes by. Should the observer be worried about spilling coffee because of the gravitational wave? If so,...
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Transverse traceless gauge in linearized GR

I'm reading about gravitational waves and I'm wondering how we know we can always go to the transverse and traceless gauge? Going to the de Donder gauge is fine, I can follow that, but then showing ...
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Why does an accelerated charge emit electromagnetic radiation, but an accelerated (point) mass does not radiate gravitational radiation?

For example, an accelerated electron will emit EM radiation, but will not emit gravitational radiation. A common argument used is that the gravitational monopole represents the total mass-energy of a ...
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Does matter follow the curvature of space-time?

How is matter affected by the warping of space-time? Does it expand and contract, follow the curvature of space? What happens the shape/volume/density of matter when it enters a gravity well, or ...
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How does Zerilli come up with this solution?

I am studying the paper "Gravitational field of a particle falling in a Scharzschild geometry analyzed in tensor harmonics" by Zerilli. The author calculates the gravitational radiation ...
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Looking for this particular reference

I am studying this paper: Gravitational radiation from a particle infalling radially into a Schwarzschild black hole by Davis et al. It deals with the calculation of the energy spectrum of the ...
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What difference does the wavelength and/or frequency of a gravitational wave make? On the detector, for instance?

When they talk about the arms of LIGO or Virgo stretching by a thousandth of the width of a proton, they always emphasize that this is the wave's amplitude, not wavelength... The wavelengths are ...
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How to derive this $\dfrac{dT}{d\tau}$?

I am studying the paper "Gravitational field of a particle falling in a Scharzschild geometry analyzed in tensor harmonics" by Zerilli. The author calculates the gravitational radiation ...
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Does particle travelling near to speed of light in non uniform acceleration produces gravitational wave?

If $$m= \frac{ M }{ \sqrt{ 1- \frac{ c ^ { 2 } }{ v ^ { 2 } } } } $$ So if a particle travelling near to speed of light should have variable mass is it possible that it can produce ...
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LISA acceleration noise formula

In the Laser Interferometer Space Antenna (LISA) mission proposal document, section 4.2 (page 17) there is a formula for the test mass acceleration noise level: \begin{equation} S_a^{1/2}\leq 3\cdot ...
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Can one body push another body away by sending gravitational waves towards it?

In the weak field limit, gravitational radiation can be treated by the linearized theory and then its properties are very much like those of electromagnetic radiation, except we are dealing with the ...
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Do gravitational waves bounce the space upwards?

I will try my best to explain. When I think about waves, I generally tend to first visualize a stable and flat two-dimensional surface, in position 0. When a normal sine wave travel through it, it ...
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Does any moving object create gravitational wave?

Is it possible that all moving particle release gravitational wave? I was trying to study gravitational wave and a question stuck in my mind. If any mass can bend space time and is moving it will also ...
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How close can two black holes in a binary system get, before they merge?

Sorry if this question is too elementary, as is my level, but I'm wondering how close two supermassive black holes can get and should the Keplerian rotational frequency at that point equal to the ...
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What counts as a gravitational wave?

Non-physicist asking. Suppose two massive bodies approach each other at great speed. They pass non-destructively past each other and continue on, in their new directions. Does the gravitational force ...
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General Relativity: Non-static stable solution of an infinite multi-body system

If you take Einsteins field equation with a homogenous (and isotropic) mass density, no pressure, no cosmological constant and a flat, non-expanding spacetime, the result is a collapsing space-time (...
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What is meant by the transverse nature of gravitational waves?

Gravitational waves, like the electromagnetic waves, are also transverse. By transversality of the EM waves, we mean that ${\vec E}\cdot\vec{k}={\vec B}\cdot\vec{k}=0$ i.e., the accompanying electric ...
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Why is gravitational wave production in early Universe disfavoured for crossovers?

Production of gravitational waves in the early Universe (for example, in the electroweak phase transition) is favoured only if the Universe undergoes a first-order phase transition but not favoured if ...
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Do all black holes mergers and kilonovae produce chirp?

It seems to me that during the final merger of 2 massive objects there will be a chirp, a sharp increase in the intensity and then it is cut off signaling the merging process is completed. I am ...
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Energy density of gravitational waves

If the mass is small enough, we can approximate to the GEM (gravitoelectromagentism). In this apporximation, we can calculate the energy density of gravitational field, such as $u_g=-\frac{g^2}{8\pi G}...
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Dark matter and gravitation

Dark matter does not interact with the electromagnetic force, however does interact with the gravitational force. Do we know if there are any big ‘clumps’ (like a star) of dark matter? If they exist (...
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How powerful must a gravitational wave be, to be audible to a human? [duplicate]

Sufficiently powerful gravitational waves can excite an eardrum and be heard. How powerful would the waves have to be for a human to actually hear them, and what would be the side-effects of that ...
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Does the Landau-Lifshitz pseudotensor contain all non-linear terms in $h_{\mu\nu}$?

I was recently reading up some literature on gravitational waves in curved spaces and came across the following confusion. Basically starting from the Einstein Field Equation (EFE), $$G_{\mu\nu} = 8\...
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If two black holes about to collide head on, will there be interference pattern in the space in between?

Imagine massive object such as 2 non spinning blackholes accelerate towards each other, just before they collides I wonder what would the region of space in between them would look like? Will it be ...
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Cosmological consequences of the mass-energy content of gravitational waves

This paper published in 1969 indicates that a majority of the mass-energy of the universe may be contained in gravitational waves: "Turning next to phenomena on a galactic scale, we find it ...
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How can we imagine gravitational waves?

When we say waves, we usually imagine soothings like a sin wave, with a crest and a trough. But we can't use the same logic with gravitational waves, can we? Because if gravitational waves had a crest,...
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Gravitational waves cause by photons?

I was reading this question (Why does Light get caught by Gravity, when both are travelling at the Speed of Light?) and it brought me to the following: Can photons create gravitational waves? My ...
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Gravitational waves emitted by accelerating rocket

What is the gravitational wave luminosity of a rocket with mass $m$ (kg) accelerating at $\Delta v$ (m/s$^2$)? Intuitively, I expect the luminosity (in Watt) to depend on the mass and acceleration. ...
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Are gravitational waves absorbed or scattered by matter?

Is there an equivalent non vacuum medium of propagation for GW's? Can GW's be absorved or damped? Reflected? Can we perform a double slit experiment on GW's?
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What factors affect the strength of gravitational fields, to what proportion and magnitude?

I have been doing a physics depth study on the topic of "how gravitational waves affect the phase shift of light (in a vacuum)" and have found it difficult to find a source, at least one I ...
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How is the Hubble constant $H_0$ determined from gravitational waves? [closed]

I’ve already posted this question on the Astronomy stackexchange, but now I see I can post it here too (since there is a tag cosmology and the community is larger here). If this isn’t allowed, please ...
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What means “Standard Sirens” associated to Gravitational Waves observable(s)?

We know the Gravitational Waves (GW) provide a new way to observe the Universe. Now, we face a new era for cosmological and astrophysical researches. I know that it is possible to obtain the ...
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How should I interpret the 'Location area (deg^2)' table on Wiki's 'List of gravitational wave observations' page? Is it in 'square degrees'?

Wikipedia's page for 'List of gravitational wave observations' has a location table called 'Location area (deg^2)'. Just to be sure, if you click on 'deg^2' it takes you to the 'square degree' page......
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How far the gravitational waves can travel?

How far the gravitational waves can travel? Does it depend on the mass which is converted to energy in a black hole/neutron star merger? If there is a finite distance, were we lucky to be in the range ...
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Do gravitational waves cause time dilation or not?

There are a lot of questions on this site about gravitational waves and time dilation, and some of the answers are contradictory. I have read this question: Do gravitational waves cause time ...
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Planck length compression of gravitational waves due to gravitational time dilation

I've made an error in my thinking somewhere concerning gravitational waves in the following thought experiment, and would appreciate knowing where I went wrong: Consider two overlapping gravitational ...
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Gravitational waves of spherical body with mass $M$ which collapses to a black hole with mass $m<M$

Consider a body with spherical symmetric mass distribution in asymptotically flat space with a total mass $M$. Assume it collapses to a black hole with mass $m<M$. Does this body emit ...
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Increasing observable universe size using primordial gravitational vaves

Using photon decoupling, the size of the observable universe is generally evaluated as being around 45 billion light-years at current time. When, and if we can detect primordial gravitational ...
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Gravity at light speed

my question in regards to light. Since gravity warps space time, and we have discovered gravitational waves. Would the light at the front of the wave, be traveling faster than lightspeed? Essentially ...
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Operatorial CTP / in-in formalism for sourced GW production?

Introduction / context - The inflationary paradigm of modern cosmology is a very powerful and predictive framework in which we can trace the primordial cosmological perturbations as originated by zero-...
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How does detection of Gravitational Waves affect Quantum Gravity Research?

After detection of gravitational waves in 2015, what are it's implications on quantum gravity theories? Are there any quantum gravity predictions validated through GW detection?
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Hyperbolic orbit to keplerian orbit

How do I model a two body system that is initially travelling on an unbound orbit (hyperbolic so negative semi major axis) but then becomes a bound orbit (eccentric elliptic, so positive semi major ...
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How do tidal forces change gravitational waves

If there is a binary of two neutron stars, they are going to be deformed because of the tidal forces. I suppose that it will cause a change in the movement of the stars and that will cause a change in ...
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Can you detect gravitational waves emitted by quark stars?

Quark stars are a bit like neutron stars, they have very large masses and small radii. Can we detect gravitational waves emitted in a binary of two quark stars or the gravitational waves from a not ...

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