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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?

Assume two black holes in the most common size range, spiraling into each other until they merge. The event releases significant amounts of energy via gravitational waves, which warp the space-time. ...
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3answers
130 views
+50

Could future experiments on “Gravitational Casimir Effect” confirm the existence of gravitons?

From Casimir effect, we know that when two plates are placed very close to each other in vacuum, they attract each other because the quantum fluctuations that press on the two plates' outer surfaces ...
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0answers
53 views

Newtonian oscillator in a box [on hold]

To help me understand relativistic momentum and gravity effects, I would like comments on this artificial example. Inside a box, two equal masses m are connected by an ideal spring and allowed to ...
3
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1answer
46 views

The ADM Energy of Gravitational Waves?

I have been looking for books about this question for several days. However, almost all books use Landau–Lifshitz pseudotensor to calculate the energy of Gravitational Waves.And they said the result ...
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2answers
215 views

Gravitational waves as information carriers

Is it possible to utilize gravitational waves as a delivery system for information between two observers straddling the event horizon of a black hole? And why ?
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0answers
35 views

What are the alternative explanations for the indirect evidence of gravitational waves?

Even though the consensus is that gravitational waves almost definitely exist, it has been well documented that there is no direct evidence. My question; what are the alternatives to gravitational ...
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0answers
16 views

Transverse Trace-less quadrupole

In Gravitational radiation, it is convenient to work with "transverse traceless quadrupole tensor". However there are three terms: "quadrupole moments" , "reduced quadrupole moment" and "transverse ...
4
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1answer
122 views

Is inflation theory really dead?

I know the title is little bit challenging but maybe most of you heard about the last BICEP2 paper on February. As I have read about it here and here. My understanding is, BICEP2 results released on ...
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0answers
35 views

For gravitational wave from twin stars, how was the tidal effect counted?

As the primary indirect evidence, the work on calculating the rotational slow down earned the 1993 Nobel prize. However, I cannot find any where mention how the work deal with the tidal effect. Are ...
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0answers
34 views

Would a directional “graviton” emitter violate any known laws of physics?

Setting aside that we don't known what the mediating partial in quantum gravity looks like and have no way to manipulate it, what would the implications be of a directional graviton source be? Would ...
3
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1answer
76 views

Why are nonrelativistic methods used in binary pulsar systems (gravitational waves)?

Although gravitational waves are a subject of the General Relativity, why do most books use Newtonian equations of motion for power radiated and rate of change of eccentricity calculations? In most ...
3
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1answer
91 views

Does all matter emit gravitational waves all the time?

I understand that gravitational force is a result of the curvature of spacetime and that the analogy with electromagnetic waves falls apart at a certain point. However, I have been confused when ...
9
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1answer
199 views

Can curvature waves in f(R) theories explain gravitational lensing in cluster collisions?

The Einstein-Hilbert action leading to Einstein's equations is $$S\sim\int R \sqrt{-g}\, {\rm d}^4 x$$ There is a class of modifications of Einstein's relativity called $f(R)$ theories of gravity ...
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1answer
144 views

Geodesic Deviation between Test Particles from Gravitational Wave

I'm having trouble understanding how Carroll (Spacetime and Geometry, p.296) explains the effect of a passing gravitational wave on test particles. If we have two geodesics with tangents $\vec{U}$, ...
6
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1answer
129 views

Can gravitaitonal waves orbit each other to form a standing wave?

Since gravity waves are a type of propagation of energy of some sort, they ought to induce their own gravitational field. I'm assuming this extra gravitational force / curvature is independent from ...
3
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1answer
97 views

Should gravitational waves be discovered already?

Gravitational waves are not discovered directly (yet). But does this have any consequences? Should we suspect out theories are wrong or not yet? I found some data about gravitational waves suspected ...
3
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1answer
89 views

Gravitational wave solutions to the Einstein field equations

It is well known that general relativity predicts gravitational waves, but I would like to know how. What solution(s) to the Einstein field equations yield something which can be interpreted as a ...
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3answers
63 views

Can gravitational waves be directly detected [closed]

Is it possible to something as problematic as that and with what tech it is possible?
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1answer
105 views

If gravitational waves exist are they technically just another form of light/electromagnetic wave?

I would imagine a gravitational wave would have very similar characteristics to electromagnetic wave, what kind of differences are there?
6
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0answers
113 views

Monopole Gravitational waves exist?

GR says that monopole gravitational radiation does not exist. I understand the reasons for this. However there is this effect (which seems to me to have the hallmarks of a wave). Paper at arXiv: ...
4
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1answer
100 views

Can LIGO measure anything?

LIGO, Laser Interferometer Gravitational-Wave Observatory, is a large-scale physics experiment aiming to directly detect gravitational waves. The device measures the phase shift laser beams. If I ...
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1answer
128 views

Do Gravitational Waves Actually Repel Spacetime?

I read something explaining that g-waves actually repel space-time. It described the following. Mass bends space-time creating gravity. An object like the sun, if it suddenly disappeared the ...
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1answer
152 views

Is it possible that a gravitational wave of space - time hit the solar system?

I went (on vacation) to the beach, The sea was very calm (just like solar system) There was one person in a fishing boat, Suddenly a huge wave came to shore... Is it possible that a gravitational ...
0
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1answer
20 views

Why doesn't linear wave theory produce phase velocities that agree with each other?

I'm not sure I understand the dispersion relationship for water waves. According to Wikipedia, the wavelength of ocean wave at arbitrary depth is given by: \begin{equation} ...
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2answers
724 views

Can colliding gravitational waves create a black hole?

Whether gravitational waves are real or just a coordinate freedom was argued in the early days of GR. Eventually the conclusion was that they were real. And if they are 'real' then I'm curious if... ...
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0answers
45 views

Can a gravitational wave produce oscillating time dilation?

I was reading about gravitational waves and about laser based detectors. I also read this. As mentioned in the answer, when ever there is a deformation in spacetime, doesn't it also create a minute ...
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5answers
6k views

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? ...
8
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1answer
635 views

warp drive with gravitational waves in the nonlinear regime

gravitational waves are strictly transversal (in the linear regime at least), also their amplitudes are tiny even for cosmic scale events like supernovas or binary black holes (at least far away, ...
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1answer
43 views

Are there other places to look for the gravitational wave, other than space?

The recent BICEP2 announcements about the existence of gravity waves made the news, and made a big pitch for cosmic inflation, in the process they also claimed to detect the existence of gravitational ...
8
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3answers
280 views

Do two photons traveling in opposite directions emit gravitational waves?

Do two photons traveling in opposite directions emit gravitational waves? If so, does it mean that any volume filled with photon gas will eventually degrade into graviton gas? In other words, if flat ...
4
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2answers
974 views

Is my interpretation of how a gravitational wave is formed correct?

I'm sure many here are familiar with the following image showing the 2D representation of how the fabric of spacetime is warped by the presence of mass:- Can this fabric be interpreted as an ...
4
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1answer
96 views

Can light produce weak gravitational waves?

I have read online that light can produce a weak gravitational field (for example antiparallel beams should, in principle, attract weakly). This made me wonder if light can produce minute ...
2
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0answers
34 views

Can a general n-body system emit gravitational waves?

I know that (for example) binary neutron stars can emit radiation in the form of gravitational waves. This question got me thinking about the case of three or more objects. I wrote in my answer that ...
2
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1answer
89 views

Thermal gravitational radiation and its detection

To my poor knowledge on the topic, the gravitational waves that are most likely to be detected by LIGO or other experiments do not have thermal spectrum. But I'm not certain. I know that Hawking's ...
11
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2answers
772 views

Why gravity is a spin-2 field? How can I read the spin from Einstein-Hilbert action?

I have often heard that the gravitational field has spin $2$. How can I read the spin of the field from the Einstein-Hilbert action $$S=\int \! \mathrm{d}^4x \,\sqrt{|g|} \, \mathcal{R} \, \, \, ?$$
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1answer
741 views

Can gravitational waves be red-shifted?

Whenever the Doppler effect is mentioned, it's typically in the context of sound waves or electromagnetic radiation. On the cosmological scale, red-shifting is also important because of the enormous ...
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4answers
247 views

Applications of the Linearized Einstein Field Equations (EFE)

Look up linearized Einstein field equations anywhere and the first thing you'll see will be a discussion of gravitational waves. Using the linearized EFE's is pretty handy when studying gravitational ...
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0answers
78 views

What are the current experimental restrictions of the possible speeds of gravitation?

Somewhere I read that the Hulse-taylor binary pulsar can not differentiate between competing theories assuming different speeds of gravity. Is it mathematically true in general, that the orbital decay ...
2
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1answer
57 views

Specific problems with the quadrupole formulation of gravitational radiation

the quadrupole formula has some counterintuitive consequences, when analysing the power output averaged over a period $$ P = \langle \frac{d^3 Q_{ij}}{dt^3} \frac{d^3 Q_{ij}}{dt^3} \rangle $$ ...
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1answer
68 views

Do gravitational waves travel on geodesics in GR? If yes, why?

I think, the answer is probably yes, but it can be answered by somebody who knows GR much better than I do. In case of a positive answer, can we say that gravitational radiation will be bent around ...
0
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1answer
79 views

Why don't atoms emit gravitational waves?

Atom's do not seem to emit gravitational waves. But they do contain changing mass quadrupoles, though very small ones. Obviously, the probability for emission of such waves is very small, as the ...
2
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1answer
54 views

Accelerating masses lose energy?

If I understand this correctly, accelerating charges lose energy in the form of EM waves because they change the electric and magnetic fields, which "costs" energy. Does that mean that accelerating ...
0
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2answers
111 views

Particles Associated With Gravitational Waves

I've been reading about linearized GR and the study of gravitational waves, and an odd thought popped into my head. According to wave-particle duality (admittedly, usually used in quantum mechanics!), ...
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2answers
382 views

Gravitational waves detection, any news? [duplicate]

Is the detection of gravitational waves a reality with nowadays technology? Are there recent news?
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2answers
283 views

gravitational waves and inflation theory

I am not a technical guy and I have no scientific knowloedge in physics but I have been reading books, watching videos in order to understand our cosmology and ...
11
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2answers
372 views

Is there a good chance that gravitational waves will be detected in the next years?

Is there a good chance that gravitational waves will be detected in the next years? Theoretical estimates on the size of the effect and the sensitivity of the newest detectors should permit a ...
0
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1answer
96 views

Why point mass leaves it's own gravitational well? [closed]

I suppose that point mass has its own gravitational well. Why this point mass is still attracted by other gravitational waves. I expect that this point mass is surrounded by "gravitational hills". Why ...
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3answers
651 views

Since there are gravitational lenses, are there gravitational mirrors?

Gravitational lensing is an observed phenomenon. Can one have a gravitational mirror? A slightly unrelated question: Can gravitational waves be reflected?
2
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2answers
207 views

Noise in laboratory sources of gravitational waves

Suppose you wanted to detect gravitational waves from a lab source (I know, any reasonable man-made source will be several orders of magnitude below detection technology, but humor me for a second). ...
1
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2answers
122 views

Why does the earth have to feel a pull when something falls?

Heck, I'm not even worried about the speed of a reaction. But remember that if I fall towards the earth, with a force, the earth has the same force exerted upon it in the opposite direction. I was ...