Questions tagged [ligo]

The Laser Interferometer Gravitational-Wave Observatory (short LIGO) is a large interferometer used for the detection of gravitational waves. Use this tag for questions about this specific installation; for questions more generally about the properties of gravitational waves or gravitation, use [gravitational-waves] and/or [general-relativity]

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Distance to source of GW 150914

Looking at the original paper on this gravitational wave, PRL 116, 06112 (2016), it is difficult to determine how they estimated the distance to the source. Can anyone provide some explanation? They ...
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Searching for an "intuitive" explanation about how gravitational waves can be detected by a laser interferometer like LIGO

Since LIGO's first detection of gravitational waves, I have been searching for an intuitive way -as long as intuition can be useful in relativity, which often it isn't- to understand how the detector ...
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Does a core collapse supernova emit detectable gravitational waves?

I've read that LIGO will be the first thing to detect a "nearby" core collapse supernova, because the neutrino pulse travels slower than light, and the light is trapped inside the star for ...
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Rotating binaries viewing geometry

I am reading this article and looking at eq. (4). I am not sure how the expressions in terms of the viewing angle $\iota$ and the phase $\Phi$ are achieved. It looks to me like it has nothing to do ...
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LIGO's upper-bound on the Michelson-Morley null result?

LIGO is essentially a Michelson-Morley experiment. What is its measured upper-bound on the fringe shift? The most recent Michel-Morley experiment "Michelson–Morley experiment#Subsequent ...
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Frequency dependence of noise at advLIGO

Here's a picture showing how different sources of noise affect the sensitivity of LIGO I'm trying to understand the frequency dependence of each curve. I'll specifically focus on seismic noise, ...
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Contraction in SR vs GR

I've always had a bit of fuzziness concerning relativistic contraction which I will try to put into words. Iiuc in SR, moving objects contract in the direction of their travel, as measured by rulers ...
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Gravitational waves on rigid bodies

I have a question on gravitational wave (GW) detection. I would assume that gravitational waves do not impact rigid bodies. I mean, GWs should be extremely weak with respect to electromagnetic forces ...
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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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Why does shot noise rise with frequency in LIGO sensitivity?

In plots of the sensitivity of the LIGO interferometer, photon shot noise is the dominant noise source at the high frequency end, e.g. this graphic: It appears to rise roughly in linear proportion ...
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Graph Interpretation of Gravitational Waves

In the image is the data recorded by the LIGO's 2 observatories in USA. What is its interpretation? I mean what does the zig zag lines represent? Similarly, what does the blond red and blue lines (...
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How does LIGO detect accurate time differences if gravitational waves are also compressing and stretching the light waves-specific confusion below [duplicate]

I was watching this veritaserum which explains my question at 5:55 https://www.youtube.com/watch?v=iphcyNWFD10 saying that the speed of light is much faster so will pass through the arms multiple ...
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Did LIGO measurements prove that the speed of gravity equals the speed of light?

This question about the speed of light prompted my own question. In the linked question it is asked if there is experimental proof that the speed of gravity equals the speed of light. I was surprised ...
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Could LIGO detect an Alcubierre drive being used within 10 light-years of the Solar system? [closed]

Maybe this question is too speculative... But is it possible that LIGO would detect the ramp-up and ramp-down of an Alcubierre drive being used within 10 light-years of the Solar system? Also, if the ...
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How does LIGO work?

LIGO is described as working as an interferometer, like a Michelson-Morley interferometer but with many reflections along the arms to increase the sensitivity. In MMs work it was assumed that the ...
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Frequency sensitivity of gravitational wave interferometer with its armlength and with mass of the mergers

To the best of my knowledge, LIGO is capable of observing gravitational waves (GW) from stellar mass black hole (BH) mergers but not mergers of supermassive black holes. In order to detect the latter ...
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Tidal effect on interferometry

Interferometry relies on the change in the phase of two orthogonal light beams reflected back to the source point. Assume there is an interferometer at the equator, one mirror is planted 1 mile due ...
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3rd Dimension on LIGO

The LIGO interferometers are 2 dimensional, they have $4\rm\ km$ legs that are perpendicular to each other. Could a 3rd $4\rm\ km$ leg either with a straight up tower or deep into the earth, provide ...
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Can the LIGO detectors sense continental drift?

I know the detectors can sense earthquakes and the movement of the Pacific Ocean, and given the sensitivity of the arms to detect gravitational waves, it makes sense that they should detect ...
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Paper about signal-to-noise ratio for LIGO/VIRGO

I am looking for a recent paper in which the signal-to-noise ratio for the ground based advanced LIGO/VIRGO interferometers is discussed, on the same line of this paper (dated 2006 by E. Berti et al.) ...
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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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Are the LIGO and VIRGO results consistent with the black hole statistics predicted by cosmology?

Have LIGO and VIRGO recorded enough gravity wave events to cross-check the black hole populations predicted by astrophysics and cosmology? Basically, we now have another experimental tool to verify ...
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How to interprete the gravitational wave measurement?

I saw this picture: the LIGO measurements of a gravitational wave. I have a few questions about the graphs. First the graph with residual, what does that mean? If the data of Hanford is projected on ...
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How does LIGO cover the whole sky?

This article says that "[LIGO] is an omnidirectional gravitational-wave detector that monitors the entire sky." But how is that possible with just two flat detectors? If both locations detect a wave ...
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Do the gravitational wave moves the Ligo's mirror or the photon in the laser beam?

On NASA website there is an animation showing a signal is detected when the gravitational wave shifts the mirrors about, causing the laser to go out of phase. Do gravitational wave actually shifts the ...
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Was ever observed a black hole - neutron star merger?

I remember that a few months ago the news of a possible a black hole-neutron star merger detected with LIGO/VIRGO was diffused. Was this discovery confirmed?
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How do out of phase tell us the amplitude of gravitational wave?

When gravitational waves hit the 2 mirrors in LIGO and causes the signals to switch between in-phase and out-of-phase, it should only show the changes in frequency. What about the amplitude of the ...
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Would relativistic LIGO hear different chirp?

Imagine a binary blackholes merger about 100 Mpc away and LIGO's relativistic twin is orbiting Earth at close to speed of light, I wonder would both LIGO and its twin show different results? For this ...
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LIGO Observation Reconciled with Falling Object Never Seen to Cross Event Horizon

I've read that an observer watching an object fall toward a black hole will never see it cross the event horizon. For example, see the following Stack Exchange question. How can anything ever fall ...
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What causes a black hole ringdown and why can it prove the no-hair theorem?

When two black holes merge, they will produce the so-called ringdown before forming a new black hole, even the newly created black hole produces some sort of tones due to the force of the impact, but ...
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Can we tell how far away is the source of gravitational wave from the chirp alone? [duplicate]

From the analysis of chirp from Ligo and some other similar detector it is possible to tell the mass but can we also find out how far away too? or we need to look up into the sky and compare the ...
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Gravitational waves detection using lunar retroreflectors

According to Wikipedia, the wavelength of a gravitational wave is about 600,000 km. The Earth moon distance is about 384,400 km. Considering that the latter is roughly half the former, it seems to ...
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Can Ligo tell a blackhole and neutron star of same mass throughout the inspiral? [duplicate]

I am wondering what if a massive blackhole which is say thrice as massive as our Sun is gobbling up a neutron star also happens to be of the exact same mass, so in this scenario can Ligo be able to ...
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Can we measure the amount by which LIGO black hole mergers warp space itself, relative to the mass of the merger?

In our day and age we can calculate the mass and maximum volume of a black hole. With LIGO we can also now calculate by how much is space warped, relative to the distance to a black hole merger, such ...
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Should LIGO have been impacted by Lorentz contraction?

What bearing would or could Lorentz-Fitzgerald length contraction have on Ligo detections? Was this accounted for?
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Why does an interferometer with mirrors even work? [duplicate]

My understanding is being thwarted by something basic I am missing. One starts with a light beam that is split into two perpendicular paths. There are two light paths that travel some distance. The ...
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Does frequency of light change in the LIGO interferometer arms?

There are a number of questions on the internet and on this site asking about how the LIGO interferometer measurement works given that the gravitation wave stretches both the length of the ...
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LIGO test masses in free fall

I know that the LIGO test masses are considered to be in free fall. However, they are supported by pendula. I thought that free fall means the only acting force is gravity - doesn't the tension in the ...
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How Does LIGO’s Splitter Mirror Cause Two Different Frequencies When a GW is Present?

When a gravitational wave is present in LIGO, how does the splitter mirror work to send out a different frequency than the laser frequency on the arm perpendicular to the laser direction? What are ...
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What does it mean to hear the gravitational waves?

In last few years, I watched a lot of YouTube videos claiming that gravitational waves can be and has been heard. They also play a short audio signal. How do experiments such as LIGO replicate the ...
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How do LIGO and Virgo know that a gravitational wave has its origin in a neutron star or a black hole?

It is being said that gravitational-wave detectors are now able to distinguish neutron star waves from those originating from black holes. Two Questions: How do LIGO and Virgo know that a ...
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Could the LIGO design be also used to detect spacetime distortions (curvature) caused by a small gold sphere?

Suppose you put a gold sphere inside the LIGO interferometer, not in the path of the laser beams, but sufficiently close to  (in the vicinity of) one of the laser beams. Would the spacetime distortion ...
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How much more precise would LIGO have to be?

The planets and a spinning black hole both drag their local frames and thus generate gravitational waves The amplitude should be proportional to the size of the celestial body, while the frequency of ...
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What comes out of binary black holes at end of inspiral?

When 2 blackholes are orbiting each other so close that they lose more energy in form of gravitational wave, this process is inspiral and is unstoppable until it explodes. This is an extremely violent ...
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Is it possible (either in practice or in principle) to produce images with a LIGO-type gravitational "telescope"?

I was reading an article in the newspaper today that referred to LIGO (and gravity-wave measurements in general) as "a new type of telescope". That got me thinking -- as I understand it, LIGO uses ...
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Why do external observers see LIGO results if an object falling into a black hole never reaches the event horizon? [duplicate]

If I throw a clock towards a black hole, its time slows down, it is redshifted, and according to many theories it never reaches the event horizon from my point of view. How is it then, that a star can ...
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black hole chirp physics

I have read that the chirp frequency in the first LIGO data is related to the period of the orbit of merging black holes. I have also read that that the frequency is related to time-dependent ...
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Significance of the LIGO experiment with respect to length contraction

it might be best to first detail my (admittedly limited) understanding of the LIGO experiment. a beam of light is split along two 4Km evacuated pipes then reflected back where their interference ...
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How can gravitational waves from such a long distance affect the beam of light?

Even if it does affect it should affect all the surrounding object making it impossible to detect any change. It would be like keeping a man and a scale in a room, and if a gravitational wave is ...
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Bound on large extra dimensions using gravitational waves

Are there proposed observations using gravitational waves which put a bound on the size of large extra dimensions (say in the context of ADD model)? The claim in the ADD paper is that you cannot ...
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