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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Gravitational wave on two masses connected by a spring

Consider two masses $m_1$ and $m_2$ that are connected by a spring. Mass 1 follows the worldline $x_1(\tau)$ while mass 2 follows $x_2(\tau)$. Note that the argument $\tau$ is the proper time in the ...
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The Force of Gravitational Waves

How could one calculate and derive the "force" or displacement and stretching of an object due to gravitational waves?
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Mass in GW in TT frame

In the book Gravitational waves vol 1 by Maggiore page 17 it is argued that the coordinate position of a test mass does not change in the TT-frame if the test particle was at rest. I understand the ...
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The “Force” of Gravitational Waves [duplicate]

Could someone show how to calculate and derive the force or "displacement" of a mass under a gravitational wave? Thanks.
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The M2 brane of M theory creates the Type IIA string and D2; the M5 brane creates the D4 and NS5. What are the other objects grouped with the D0?

Type IIA string theory is related to M theory with the 10th spatial dimension compactified on a circle.  The origin of the F1 string, D2 brane, D4 brane and NS5 branes is simple: they come from the M2 ...
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Are there any subtle differences in the gravitational waves emitted from NSNS, NSBH and BHBH of identical masses?

LIGO has detected several NSNS and NSBH merger events. However, it’s difficult to tell their identities directly unless the neutron stars are very light in an NSNS merger (such as GW170817) or the ...
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What’s the maximum amount of angular momentum a neutron star can carry?

For Kerr black holes, the spinning rates can be described by a normalized spin parameter $a=cJ/GM^2$, which takes any values between 0 and 1 regardless of the masses of the black holes. If we use the ...
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Gravitational wave physics and their nature [closed]

I have recently learned about and have derived gravitational waves from general relativity while watching a lecture. I have many questions. All the professor did was show the nature of the metric ...
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Why can't the speed of gravitational waves be greater than the speed of light if the universe can expand faster than the speed of light?

Since the expansion speed of the universe can be greater than the speed of light, why can't gravitational waves, which also uses space as the medium, travel faster than the speed of light?
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Questions re significance of 2016 and 2020 LIGO observations

Phys. Rev. Lett. 116, 061102 (2016) - "Observation of Gravitational Waves from a Binary Black Hole Merger" (https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.061102) reports that ...
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The velocity of gravitational waves or the velocity of the effect of gravity [duplicate]

If the sun disappears from the solar system, the earth will remain revolving for 8 minutes and will not be freed from the sun's gravity until after 8 minutes because the speed of the effect of gravity ...
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Bounds of a black hole's spin

What are the bounds of a black hole's spin? Is it -1 to +1? Also where do I find the information about spin1x, spin1y, and spin1z? What are their bounds? What are their i.e. spin1x, spin1y, and spin1z ...
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What would a theoretical non-rotational artificial gravity generator look like? [closed]

Assuming we invented a device that can create gravitational waves or bend spacetime (or through any non-motion related phenomenon) and produce artificial gravity, would it pull everything towards a ...
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Could we detect gravitational waves emitted outside particle horizon?

As we can see from a normal spacetime diagram like below, there's an overlap of the area within the event horizon and the area outside the particle horizon. Could we detect gravitational waves from ...
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Why gravitational waves, which could be inferred as related to dark matter interactions, are not yet detected by LIGO/VIRGO instruments?

LIGO/VIRGO instruments are functioning already for quite a while and since then they captured already quite a few instances of gravitational waves which were inferred as products of interactions such ...
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Does the ringdown phase of a black hole merger ever stop?

When binary black holes merge they emit gravitational waves in three stages, the inspiral in which the two black holes shed angular momentum through gravitational waves at a rate that becomes ...
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Gravitational wave and 1st law of thermodynamics

Introduction: A prediction of the general relativity is that any moving mass produces fluctuation in the space-time fabric, commonly referred as Gravitational-Wave. This prediction was recently ...
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