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3
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2answers
54 views

Why are they building eLISA and what implications would it have?

I understand that the next step after LIGO is to plan and build eLISA, I understand that out in space there are a lot less interferences compared to Earth which makes it a good way to detect things we ...
2
votes
3answers
143 views

Gravitational wave contribution of the Hawking radiation from a black hole

Black holes are expected to radiate like a perfect black radiator at the Hawking temperature, which means that they'll emit all particles according to the relevant formulas one can derive using ...
28
votes
10answers
10k views

How does Zumberge's 1981 gravitational measurements relate to gravitational waves?

Gravitational waves were discovered 35 years ago without fanfare in 1981/2 by Zumberge, R L Rinker and J E Faller, then completely ignored. See: "A Portable Apparatus for Absolute Measurements of ...
3
votes
0answers
68 views

Gravity vs Gravitational Waves

I thought I had a reasonable understanding of relativity, the speed of light speed limit, and how this stuff related to gravity. Then I read through all the answers/comments for this question: How ...
1
vote
0answers
35 views

Gravitational wave equations worked out

Is there a website where gravitational wave equations are worked out numerically? I would like to experiment with mass configurations but can't find examples.
0
votes
0answers
15 views

Would colliding Magnetars create Gravito-Magnetic waves? [on hold]

Using similar physics involved in creating the gravitational waves, would a similar thing happen but create Gravito-magnetic waves with magnetars colliding? What effect would this wave have on ...
0
votes
0answers
24 views

Non equilibrium black hole radiating away energy and angular momentum, with total energy and angular momentum conserved

The question refers to whether mass (i.e., energy) and angular momentum can be considered to have been carried away by the gravitational radiation in the hole settling down. And whether those entities ...
0
votes
2answers
99 views

A spin zero graviton?

Why can the graviton not be a spin 0 particle? On a similar note why can it not be a spin 4, spin 6 particle?
4
votes
4answers
198 views

Binary black hole merger viewed from inside the event horizon

How did the metric evolve inside the event horizons of the black holes whose merger caused the GW150914 signal? In principle the Schwarzchild metric of a non-rotating black hole is known inside the ...
4
votes
1answer
87 views

Gravitational waves from neutron star - neutron star merger

How is neutron star-neutron star merger different from Black Hole-Black Hole merger and what information can be extracted from gravitational waves emitted by these processes?
3
votes
2answers
586 views

Producing gravitational waves in labs

Can gravitational waves be created on very small region of vacuum with quadruple movement of atom or subatomic particles?
3
votes
2answers
247 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 ...
0
votes
0answers
16 views

Why is graviton not found yet? [duplicate]

Why is graviton not found yet? Newton said gravity pulls us, Einstein said space is bent and it pushes us, hawking predicts the existence of graviton and 'hawking radiation'. How far are we from ...
0
votes
1answer
58 views

Do Gravitational Waves disprove superluminal Alcubierre drive?

I am not a physicist. But... does the rate at which gravitational waves travel set an upper limit to the "speed" of a ship propelled with Alcubierre drive? Or does it present a relativistic trick ...
10
votes
1answer
365 views

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 ...
3
votes
3answers
133 views

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 ...
5
votes
2answers
157 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 ...
1
vote
0answers
21 views

Why '1+log slicing condition' and 'Gamma Driver Shift Condition' were successful in black hole simulations?

The 1+log slicing and Gamma driver shift conditions are I want to know if there is a specific reason why these conditions were used most for Black Hole simulations in Numerical Relativty. And how ...
2
votes
1answer
61 views

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 ...
1
vote
0answers
37 views

Can Bose-Einstein Condensates reflect gravitational waves?

This is a question based on the paper by Raymond Chiao in 2002 where it is stated: One of the conceptual tensions between quantum mechanics (QM) and general relativity (GR) arises from the clash ...
3
votes
0answers
37 views

Can gravitational waves observed far from a black hole tell us anything about the multipole moments of a dynamical horizon?

In a paper by Ashtekar et al in 2013 on the approach to the final state to a stationary black hole they study the evolution of the multipole moments of dynamical horizons, which relax away (except for ...
8
votes
3answers
2k views

Gravitational waves frequency

When people quote the discovery of gravitational waves no reference seems to be made to the frequency, presumably this is about the current state of detectors. Or are the frequencies detected the ...
-3
votes
0answers
40 views

Beyond gravitational waves- what now? [duplicate]

Now that the existence of gravitational waves has been established, what is the position regarding the incompatibility of general relativity and quantum mechanics in the creation of matter? Has this ...
0
votes
1answer
25 views

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 ...
0
votes
0answers
23 views

shouldn't a photon traversing the vacuum always be associated with a gravitational wave?

In perusing the linearized Einstein equation, it appears that even a classical electromagnetic plane wave would always have to be associated with a tensor perturbation to the background spacetime. ...
2
votes
2answers
83 views

Can gravitational waves diffract off massive objects?

Can gravitational waves diffract off massive objects? If so, how much mass is needed to significantly disturb the waves propagation?
0
votes
1answer
43 views

Could it in theory be possible to produce AM and FM gravitational waves?

I'm borrowing the concept of a radio and having fun with space-time, my argument is that since gravitational wave have amplitude and frequency it is very much similar to electromagnetic wave such as ...
3
votes
1answer
148 views

What would happen if a gravitational wave hit me?

What would happen if a gravitational wave hits me? Will it affect me or will something else happen?
3
votes
3answers
158 views

Large gravitational waves

The recently detected gravitational wave at LIGO were extremely small - requiring a $1 billion interferometer to even detect its presence as it passes Earth. The gravitational constant G is small: ...
-8
votes
4answers
286 views

Why didn't LIGO wait for a second observation of a gravitational wave? Are not reproducible results fundamental to science? [closed]

Wikipedia states, "Reproducibility is one of the main principles of the scientific method." So why did LIGO ignore a main principle of the scientific method? My whole life I have been taught that ...
12
votes
3answers
1k views

LIGO flawed by the identical expansion of laser wavelength and arms in presence of a gravitational wave?

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 ...
35
votes
7answers
5k views

What are gravitational waves made of?

The following facts are what I think I know about gravitational waves: Distortion of space-time moving away from a source at light speed. Produced by very powerful event in the universe such as ...
4
votes
1answer
105 views

Do gravitational waves travelling through a medium produce sound?

Say Alice decided to orbit dangerously close to a couple of black holes circling each other. She is in a heavily enclosed astronaut suit, as is Bob, who is floating much further away. Assuming Alice ...
1
vote
2answers
62 views

What did we learn by detecting a gravitational wave? [duplicate]

In February 2016 the LIGO team announced that they had detected gravitational waves on 14 September 2015. As far as I know, we already knew that gravity propagates at the speed of light. So two black ...
1
vote
1answer
65 views

If we could perfectly control gravitational waves, could we play music with them? [closed]

Sound is just a kinetic wave propagating through a medium, right? In that case, if we had the ability to make gravitational waves exactly as we want them, could we play music to an observer some ...
1
vote
1answer
51 views

Can gravitational wave be blue/red shifted?

I'm picturing a simple scenario: 2 black holes about to merge and they are receding away from us at constant speed. (I like to negate the rate of expansion of space and assume universe is perfectly ...
0
votes
3answers
316 views

Apparent non-aberration of gravitational waves

Since GR assumes that gravitational waves travel at speed $c$, we expect we would be able to some day detect an aberration effect similar the that of light. Of course, gravitational waves are so tiny ...
1
vote
2answers
71 views

If gravitons are 'real' and analogous to photons are they also being 'stretched' by the universe's expansion?

Since photon wavelengths are stretched by our expanding universe, appearing to us as a redshift, would graviton wavelengths similarly be stretched? For that matter, do gravitons even have a ...
3
votes
2answers
173 views

If space can expand faster than light why can't gravitational wave?

I heard that gravitational wave is the measure of stretchiness of space time, so since there is no limit to how fast space can stretch what about gravitational wave?
1
vote
1answer
52 views

Classical gravitational waves, again [duplicate]

I'm basically duplicating this question, because I'm not satisfied with the answer. Here's why I'm not satisfied. If we know that "gravity travels at a finite speed", then it seems obvious that it ...
0
votes
2answers
303 views

What are the benefits of Gravitational wave studies?

Gravitational waves were first predicted by Albert Einstein and later indirectly confirmed in an number of experiments. Recently leading physicists announced that they may have a 'solid' proof that ...
0
votes
0answers
66 views

What is the explicit form of $\tau^{\alpha\beta}$ in the linearized Einstein field equations $\Box h^{\alpha\beta}=-16\pi\tau^{\alpha\beta}$?

If we let $h^{\alpha\beta}=\eta^{\alpha\beta}-g^{\alpha\beta}\sqrt{|det(g)|}$ then, according to wikipedia, the Einstein Field Equations become $$\Box h^{\alpha\beta}=-16\pi\tau^{\alpha\beta},$$ where ...
13
votes
2answers
307 views

Did merging Black Holes in GW150914 give up entropy and information to the gravitational waves, since they lost 3 solar masses?

Since the final Black Hole (BH) had 3 solar masses less of mass than the original binary BH, it seems the 2 BHs lost mass, and with it event surface area, entropy, and information. If that came from ...
0
votes
2answers
100 views

Gravitational waves from an oscillating mass

If you drill a hole through the earth and drop a mass down it, it will oscillate back and forth as it moves through the hole from one end to the other. Does this motion create gravitational waves (I ...
9
votes
2answers
1k 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, ...
16
votes
2answers
2k views

How can I read off the fact that gravity is associated with spin-2 particles from the 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 $$S=\int \! \mathrm{d}^4x \,\sqrt{|g|} \, \mathcal{R} \, \, \, ?$$
13
votes
2answers
2k views

The LIGO Gravitational Wave Detection: have deep-mantle earthquakes been ruled out? [duplicate]

Everywhere I've looked so far that talks about the possibility the LIGO detection was an earthquake, involves being ruled out due to the large distance between the two LIGO sites. Two identical ...
5
votes
3answers
392 views

Is there absolute proof for gravitational waves?

As you probably know gravitational waves seem to have been proven unless you've been living under a rock for the past day. The experiment involves the reflecting off mirrors and waves of light and it ...
1
vote
3answers
252 views

How are gravitational waves exactly produced?

I was thinking about gravitational waves, and I found out that I may have a doubt about their production. Assuming the whole calculations find a wave-like solution to be understood, I was wondering ...
0
votes
1answer
45 views

The LIGO Gravitational Wave Detection: How frequent in the observable universe? [duplicate]

The currently detectable interval of black hole mergers is on the order of seconds or fractions of seconds. So each black hole merger, no matter how long the end to end process, is only detectable by ...