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2
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2answers
25 views

Does shortening the path length of an excited Etalon do work? What about LIGO?

Start with a high-Q etalon excited on-resonance with a laser for a time long enough that it has built up an essentially stable standing wave. There is a constant outwards-directed force on each mirror,...
3
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3answers
145 views

Transfer of energy from gravity back to other “more familiar” forms of energy?

In this question I've mentioned an account of the recently reported 2nd observation of gravitational waves, LIGO and Virgo Collaborations, Phys. Rev. Lett. 116, 241103, 15 June 2016, where 1 of the ...
5
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2answers
177 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 ...
0
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1answer
47 views

Can revolving movement also generate gravitational waves? [on hold]

If an object revolves around a circular path at the speed of light could it still generate gravitational waves and what would be the simulation in inner area?
2
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2answers
35 views

What cosmic event would have to occur for us to notice gravitational waves in everyday life? [duplicate]

I read that gravitational waves are so tiny that we need extremely precise equipment to detect them. I am no physicist, but GR really intrigues me and I was wondering about two things: How powerful ...
30
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3answers
2k views

How much mass can colliding black holes lose as gravitational waves?

Concerning the recent detection of gravitational waves produced by colliding black holes, it has been reported that a significant percentage of the combined mass was lost in the resulting production ...
0
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0answers
44 views

Is there any primordial gravitational wave(form) that could explain dark energy?

First, I asked myself the question: Is there any gravitational waveform, however fantastical, that could explain dark energy. I suppose for a ubiquitous gravitational wave to be an explanation for ...
4
votes
3answers
121 views

Does a planet/star itself lose mass when it 'emits' gravitational waves?

Orbiting planets and stars can create gravitational waves, as seen with the LIGO. But are they also losing mass-energy. Beside that, the kinetic energy associated with their orbital angular momentum ...
13
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1answer
405 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 ...
0
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0answers
17 views

What position are the BOSEMs in LIGO measuring?

As I understand it, the quadruple pendulum of LIGO is also actively positioned, in addition to the seismic damping of the ISI. What I don't understand is: relative to what are the BOSEM sensors ...
2
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1answer
113 views
0
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2answers
1k 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?
5
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3answers
176 views

Do gravitational waves propagate backwards in time?

Gravitational waves are spacetime waves, which stretch and squeeze both space and time. Since relativity puts space and time (almost) on an equal footing, it seems to me that since gravitational waves ...
4
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2answers
271 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 ...
6
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1answer
116 views

Why gravitational waves are not produced by objects moving at constant velocity?

Gravitational wave is produced by change in gravitational field, source. If something is moving away from me at constant speed, its gravitational field will vary. But why only accelerating bodies ...
5
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2answers
135 views

Gravitational waves in other dimensions

I know this question is purely speculative, as we don't know if more dimensions do exist and also we do not know if gravity is indeed stronger in other dimensions (if they were to exist). But, one of ...
1
vote
1answer
55 views

How do gravitational waves transfer momentum?

In Electromagnetism I understand it in terms of the Lorentz force: the E-component of the field causes the charge to respond infinitesimally with a $\vec{v}$ in the E-direction such that the $\vec{v}\...
5
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2answers
591 views

Are there weak force waves?

In the same way as there are electromagnetic and gravitational waves that update the information on their respective field, is there an analogue for the weak and strong forces?
1
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1answer
45 views

Distortion of interference pattern at LIGO

Does the vibration due to the earthquakes distort the interference pattern of LIGO's interferometer?
5
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2answers
51 views

Gravitational waves: simulations of signal

I am self-learning GR. I was wondering if there is any open source software to help learn more about the signal processing of gravitational waves. E.g. a software that injects a signal into random ...
4
votes
1answer
114 views

Does gravitational waves add mass to black hole?

Due to the recent discovery of gravitational waves by LIGO I was wondering suppose a black hole stood between a gravitational wave then due to the fact that black hole can attract every thing then ...
5
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2answers
109 views

What is the uncertainty in the one solar mass radiated away as pure energy? (Gravitational waves)

edit: Thanks to the comment below - I learned that the PLR is available to read http://journals.aps.org/prl/pdf/10.1103/PhysRevLett.116.241103. In it, ref. 5 links to this preprint dated June15, 2016: ...
1
vote
1answer
45 views

Determining the direction of origin for gravitational waves

For LIGO's first gravitational wave detection, GW150914, the signal first reached Livingston, LA and then about 7 ms later reached Hanford, WA. Based on the sequence it was stated that black-hole ...
3
votes
1answer
135 views

How to read numbers reported in this LIGO paper?

I am not sure how to read the numbers in this excerpt from the abstract of GW151226: Observation of Gravitational Waves from a 22-Solar-Mass Binary Black Hole Coalescence: Are the +/- small ...
3
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1answer
76 views

Is there high ring-down frequencies in LIGO's recent discovery?

This question is from Physics overflow: question in physicsoverflow. I am reading LIGO's new discovery of gravitational waves by black hole merger. During the merger, two phases are not hard to ...
25
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2answers
3k views

Why were the GW detections at Livingston and Hanford separated by 7 ms if the light travel time between them is 10 ms?

How did a gravitational wave travel from Livingston, Louisiana to Hanford, Washington in 7 milliseconds, when they are separated by 10 milli-light seconds (3002 km)?
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1answer
179 views

Why does Ligo's second detection of gravitational waves and a black hole merger look absolutely nothing like the first? [closed]

Why does Ligo's reported second detection of gravitational waves and a black hole merger look absolutely nothing like the first detection announced in Februaray? Here is the data from the first LIGO ...
2
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1answer
40 views

Can we repulse metter by specially crafted gravitational waves?

Assuming we could generate arbitrary gravitational wave patterns (somewhat like we can do with electromagnetic radiation now), what effects would we be able to achieve? In particular, would it be ...
0
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0answers
22 views

High Amplitude, Low Frequency Gravitational Waves

Theoretically, how would a Gravitational Wave with a Sufficiently High Amplitude/Intensity such that it were easily measurable or larger, and a frequency low enough such that the wavelengths were ...
4
votes
2answers
169 views

How well can we localize gravitational wave sources?

A recent question cited a story about the recent gravitational wave detection saying that we can use the gravitational wave sensing to find supernova earlier in their process of collapse: [with ...
0
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1answer
41 views

Gruchestein Effect?

I overheard that name in a conversation, but not very clearly. I can't find anything on Google, probably because of my spelling is completely wrong. Does anybody knows about an effect with a similar ...
0
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0answers
21 views

Need a mass to accelerate to create gravitational waves?

For a charged particles which travels through an electric field it only emits photons when it is accelerated. It undergoes a change of momentum, and the law of conservation of momentum requires some ...
1
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1answer
35 views

Can an electron make quadrupole gravitational waves?

A gravitational wave is a quadrupole wave. Now when an electron is accelerated it usually emits a photon. But can an electron also emits an gravitational wave? If so how does it 'make' an quadrupole ...
-4
votes
1answer
65 views

Gravitational waves (linearized gravity) [closed]

Even in the Schwarzschild metric we can write $g_{uv}=\eta_{uv}+h_{uv}$ where $h_{uv}$ is very small. So after some coordinate transformation (using gauge freedom) we can simplify the Einstein ...
8
votes
3answers
1k views

How are the 4 km arms of LIGO measured so accurately?

The arms of the LIGO interferometer are 4 km long. Now, LIGO functions by measuring phase difference between two beams of light comming (as in Michaelson's Interferometer) to a sensitivity of $10^{-18}...
12
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4answers
1k 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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3answers
88 views

Why do we say gravitational waves are analogous to sound?

In every popsci discussion of gravitational waves, the waves are said to be like "sound", and that gravitational waves allow us to "hear" the universe. Despite this, I have no idea how gravitational ...
1
vote
1answer
79 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 ...
2
votes
1answer
77 views

Will the speed of gravity and the speed of light always be the same?

I have been considering the following though experiment: If the entire sun were to disappear at once, would we feel it first due to the sudden drop in gravity or see it first? The answer I have come ...
0
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1answer
45 views

Why do LIGO use a quarter wavelength for detecting gravitational waves?

I have already researched into this and I am left slightly confused still. I have gathered that the use of a quarter wavelength is to turn a linearly polarised wave into a circularly polarised wave. ...
4
votes
3answers
365 views

Is there any alternative theory that gets rid of gravitational waves, yet fits all data?

Is there any theory that gets rid of gravitational wave and still matches with all correct predictions made by standard physics theories? (e.g. General Relativity)
1
vote
1answer
56 views

Could gravitational waves have a large entropy in quantum gravity?

The question is broad, and we still don't know what is quantum gravity. But let me be more specific. In the question (on this site, see below) on whether gravitational waves have entropy the answers ...
6
votes
1answer
130 views

Gravitational wave and string theory

I'm new to physics and have been reading about fundamental and textbook physics text, which is the Young & Freedman University Physics (good book). I'm little skeptical towards string theory as ...
8
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2answers
185 views

Do gravitational waves have entropy?

We know, according the current understanding of black holes and General Relativity, as well as quantum fields in General Relativity, that black holes have an entropy proportional to the area of the ...
0
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2answers
76 views

Speed of gravitational waves and light

We all know that speed of gravitational waves (GW) and that of light in space are exactly the same (= $c$). We also know that space is medium for GW. Does that mean space is also the medium for ...
2
votes
1answer
31 views

Does an object creates gravitational waves when only accelerating in one direction?

I know from reading about the gravitational waves detected by Ligo, that when an object has angular acceleration, it produces gravitational waves. I'm wondering if an object creates gravitational ...
2
votes
1answer
66 views

Do gravitational waves radiate isotropically?

Do gravitational waves radiate equally in all directions? If so, is this an inherent property of all gravitational waves or is it just due to how they are normally produced? In other words, in a ...
4
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3answers
121 views

Prospects for detection of gravitons?

With the announcement of the detection of gravitational waves, questions about the implications proliferate. Some relate to the possible existence of gravitons. The analogous relationship between ...
0
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0answers
21 views

LIGO Gravitational Wave Discovery and Gravitons [duplicate]

Now that gravitational waves have been detected, how hard will it be to detect a graviton? Will the equipment have to be more sensitive or are the difficulties more complicated than that?
29
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3answers
2k views

Could (old) LIGO have detected GW150914?

The merging black hole binary system GW150914 was detected in only 16 days of aLIGO data at a signal level that appears to be well above the detection threshold at around 5 sigma. There are no further ...