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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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How does LIGO reduce noise below what it is detecting? [duplicate]

LIGO is designed to detect changes in length on the order of 10,000ths the scale of a proton. I know they are extremely well isolated from their surroundings, but how could we even approach isolation ...
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Why are the arms of the LIGO interferometer so long? [duplicate]

The LIGO experiment consists of two interferometers, where each one of them has two 4 km long arms. Within these, light is further trapped via Fabry-Pérot cavities to achieve a total path length of ...
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Is there any issue/concern for a slight wavelength shift of the laser light in the LIGO experiments? [duplicate]

A friend and I were having a discussion about the LIGO experiments and were wondering if there is any issue with the laser light undergoing a wavelength shift as a result of the gravitational wave? ...
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Producing an audible sound from the gravitational waves of the GW150914 event

As is said in the latest LIGO press realease, the detected gravitational waves vary with a frequency that is audible for us. The audio one can obtain from the detected data is actually plaied during ...
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Orientation of the LIGO Arms

The orientation of the interferometer arms at both sites are approximately Northeast-Southwest and Nortwest-Southeast, though I assume that, on account of the Earth's curvature, no pair of arms is ...
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G4v Gravitational Wave vs General Relativity vs LIGO Observation

CalTech emeritus professor Carver Mead produced an alternative prediction, to General Relativity, for gravitation wave observation which he published last year in anticipation of LIGO observations. ...
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LIGO event - energies involved?

So, we have two Black Holes merging shortly after LIGO turns on after the upgrade. Some questions: a) How lucky was it to see this event? What are the expected rate of occurrence? b) Was this event ...
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Why do detectors for gravitational waves have only two perpendicular arms, not three?

I wonder why detectors for gravitational waves have only two perpendicular arms, not three. Having three arms appears to allow for better detection of direction, or may even increase sensitivity (I ...
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How many galaxies could be the source of the recent LIGO detection?

The recent LIGO detection is pretty exciting, and a lot of people are asking whether there is a chance of optical detection of the black hole pair that created the signal. From a cursory reading of ...
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How were the solar masses and distance of the GW150914 merger event calculated from the signal?

The GW150914 signal was observed, giving us the frequency and amplitude of the event. Because LIGO has two detectors a rough source location could be derived. But how do these three factors allow for ...
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Can we see the famous black hole pair or its effect on other stars in any other means but LIGO?

If the source of LIGO's detection is a pair of black holes, can we see them using a traditional electromagnetic/neutrino/some other kind of telescope? Or can we see their effect on other stars in ...
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LIGO discovery: if the space “time” metric is changed, how is it measured? [duplicate]

Regarding the wonderful 2016 news about gravitational waves. Travel time in one arm of the LIGO is ~ 30μs. A gravitational wave affects the arm for some few hundred of these laps. Then for example ...
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Could discovered gravitational waves in fact be an aether wind? [duplicate]

Proving the existence of gravitational waves might revolutionise cosmology, but the method used by LIGO is quite similar to the famous Michelson-Morely interferometer built more than a hundred years ...
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In GR what is a “source-frame mass”?

In the recent LIGO paper, "GW150914: First results from the search for binary black hole coalescence with Advanced LIGO, (LIGO Scientific Collaboration and Virgo Collaboration)", they refer to the ...
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How does LIGO account for curvature of Earth?

Using an earth curvature calculator, I found that at a distance of 4 km (the length of LIGO's arms), more 1.26 m is hidden by the horizon. When constructing LIGO, did they account for the curvature of ...
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How is it that distortions in space can be measured as distances? [duplicate]

Imagine yourself and anything you're able to perceive to be drawn onto a rubber band. Any means of determining distances would be affected by the stretching/contracting of the rubber band. The ...
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1answer
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How did LIGO detect the source location of the black holes mentioned to be the cause of today's announcement?

Today LIGO announced discovery of Gravitational waves. What method was used to determine the source location of the waves?
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Einstein's original papers predicting gravitational waves? [closed]

I came across the original handwritten papers in which Einstein predicted gravitational waves1: and since LIGO announced they've detected a signal confirming the predictions I was wondering if ...
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How strong were the gravitational waves that LIGO detected at the source?

Congrats to the LIGO team on the announcement of their discovery of gravitational waves! The articles I've read say that the distortion we see here is much smaller than a proton. What about at the ...
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Why is the detection of gravitational waves so significant?

LIGO has announced the detection of gravitational waves on 11 Feb, 2016. I was wondering why the detection of gravitational waves was so significant? I know it is another confirmation of general ...
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Isn't LIGO basically measuring the luminiferous aether?

I am bit confused about this one. I am not very acknowledgeable about gravitational waves and LIGO. But if it is basically a Michelson interferometer and can detect shifts in vacuum, doesn't this ...
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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 ...
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LIGO sensitivity in terms of minimum received power per area

I've been looking at LIGO figures for gravitational wave sensitivity here and it seem to be displayed in an adimensional strain ratio (which I assume that is more or less equivalent to metric ...
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Is it possible that a gravitational wave of spacetime hit the solar system? [closed]

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 ...
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1answer
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LIGO Gravitational Waves [closed]

Has LIGO detected any gravitational waves yet, or any hints of them? Is it just that LIGO is not sensitive enough or are we now entering disconfirmation territory? If we never detect gravitational ...
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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 ...
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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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What is the status of gravitational wave searches? [closed]

What is the status of gravitational wave searches such as LIGO?
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How do the LASERs in LIGO realize that space has expanded as a gravitational wave passes by?

I read an article on LIGO, and I heard it mentioned that it is a nontrivial argument to say that the effect can be measured by interferometry. What happens to space as the wave passes? Does the light ...
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What makes us think we can actually detect gravitational waves?

This refers to the discussion about gravitational waves for the YouTube video LIGO Gravitational Wave Observatory. I have two questions: When the gravitational wave passes through the space where ...
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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 ...