Ligo Definition and 97 Threads

Don't know if this is the right forum, but I'll give it a try: If you build a bridge over a gorge that's a couple km deep the middle of the bridge would be as far away from the mountains on both sides as possible (and therefore as far away from the mountains' gravitational field as possible)...

From this morning's Economist briefing: The Laser Interferometer Gravitational-Wave Observatory—the world’s most sensitive device for spotting gravitational waves—starts up again on Wednesday after a three-year hiatus for upgrades. LIGO is designed to detect subtle ripples in space and time...

I read that the LIGO detector in the US was able to detect a difference of less that the length of a proton, or maybe even less than this. How is this possible? The perpendicular arms won't be the same length down to the nearest proton length. Also, at such small lengths the microclimate on each...

Hello Is the distortion of spacetime by gravitational waves directly related to the contraction of objects in motion predicted by special relativity ? In other words Besides the existence of the gravitational waves , did the LIGO experiment definitely confirm the contraction of the bodies in...

As I understand, the gravity wave detection system is possible due to the change in length of the two arms, as a wave passes, thus changing the distance the light beams travel. As this distance changes, the time of flight will change in relationship to each other. This difference is then...

[Moderator's note: Spun off from previous thread due to new question.] I have read here: http://backreaction.blogspot.com/2016/02/everything-you-need-to-know-about.html?m=1 That there is a proportionality between the size of LIGO arms and the wavelength of gravitational waves that it can...

What is the scale of magnitude of gravity, that a modern Cavendish like laser detector of gravity pull between small daily size objects can detect in comparison to the magnitude of gravitational wave a LIGO like detector can detect? Will such a modern Cavendish like device measurements be...

LIGO India EPO (Education and Public Outreach) team is hosting a series of talks on Youtube. No registration or any formalities; just tune into the LIGO India EPO Youtube channel and you can attend the lectures. Following is the list of upcoming talks: 20th April: Speaker: Prof. Ajith...

Hello! I am not sure I understand how the heat from the lasers get dissipated in LIGO, at the mirrors. Given the high power of the lasers, the mirrors heat up, but the setup is in vacuum, so it is difficult to get rid of that heat. How do they make sure that the mirrors don't get too much damage...

Here is the most recent one:

This link https://www.ligo.org/about.php and this link https://my.ligo.org/census.php show me the list of participating universities in LIGO. I am currently doing research under a professor at my university who is a member of LIGO. Neither of the above links lists the names of the individual...

I'm just a layperson with a keen interest a couple of notches above popular science. As far as I understand SpaceTime is an attribute where if you change one attribute (space or time) then the other attribute is affected. E.g. as you approach the speed of light, the time passing of other things...

Sorry if the question has been already answered, but I didn't manage to find it. Let's go back to ligo detection of gravitational waves, my question is the following: if space time changes its texture due to a gravitational effect, all the rulers (and clocks) in that spot will be affected, so...

With all the earthquakes going on in CA - and that the last one (7.1 mag) was strong enough to possibly trigger a small quake along the LA coast (i.e., as in LouisianA, not Los Angeles) - I was wondering about this. These instruments are so sensitive that they have to pick something up, even in...

On 28 November 2018, a lecture was given by Dr. Rainer Weiss (2017 Nobel Prize Winner for Physics) at the Ontario Science Centre, Toronto. The lecture was about his work with the Laser Interferometer Gravitational-Wave Observatory (LIGO). In his lecture talked about quadruple pendulums or...

Does anyone know, and is there an instrument that could?

Is it a fair prediction to state that in the next several years or so, globally, there will be major investments into gravitational wave research, and many more ‘LIGOs’ being developed? Is it a good idea to venture into that area of physics?

If someone wanted to pursue a career in gravitational wave physics, and work at places like LIGO, studying astrophysical objects such as black holes and neutron stars, etc. What are some key courses/skills that person should take/learn as an undergraduate, and graduate student?

Since it's detection of GW150914, How many BH BH mergers has it detected and how many BH NS mergers has it detected, Is it living up to the potential detection's that are predicted?

I am doing a term paper on G. Waves and I have a couple of questions about them. - How do we know that the G. Waves detected by LIGO on September 14, 2015, come from 1.5 billion light years? - How is Einstein's Theory related to them?

This computer simulation shows the collision of two black holes, as observed for the first time ever by the LIGO on September 14, 2015. The black holes in the animation are based on the actual data from the collision as detected by LIGO. (Simulating eXtreme Spacetimes (SXS) Project (http://www.black

On September 14, 2015 LIGO made scientific history by detecting gravitational waves for the very first time. The signal received by LIGO was converted into an audible sound.

LIGO is most sensitive to a GW from directly above/below. As a transverse wave hits an arm why don't the laser source and the mirror move in unison -- thereby covering up the distorted motion?

I mean do they only detect gravitational waves?, if yes then why spending so much money on this big machine, just to detect something(i know that proving such a beautiful theory is a great achievement), but what next, i mean what other benefits they got after detecting gravitational waves

I'm puzzled that the stretching of space by a gravitational wave stretches the LIGO arm but not the light within it. Because we are told that the red shift of a distant galaxy is caused by light being stretched by the expansion of space (the universe).

I'm aware that the LIGO system uses interferometry but I'm confused how it works in this case. Do they test both beams of light? Or do they use one beam to test the wavelength of the other and see the difference? Also it is sensitive up to 10 e-18 meters, is that for the change in wavelength or...

https://en.wikipedia.org/wiki/LIGO#/media/File:Simplified_diagram_of_an_Advanced_LIGO_detector.png The axis on the bottom of the graph depicts frequencies between 20-1000 Hz which are sound waves. Again, how can a sound wave (gravity waves) propagate in the near vacuum of stellar space...

How does one determine/calculate the masses, orbital period, and separation of two merging neutron stars from the characteristics of its gravity wave LIGO signal? And how does this information allow one to calculate the distance to the galaxy that housed the merger? And how can one calculate...

This thread is to serve as - a collection of theories that have been falsified by and/or have had new constrained placed on them by the ongoing gravitational wave measurements. - a place to discuss the further constraining/falsifying of still existing models using GW data. I'll start by posting...

Surprisingly, I have not been able to find an answer to this question. How did scientists know where to build LIGO so that it would be able to find merging black holes in the sky? I assume LIGO is a permanent instrument so that it cannot be pointed to various parts of the sky, like an ordinary...

Im sure you guys see a lot of this. I only come here when google has let me down for several hours. How does LIGO know where the waves are coming from? My guess is that they can get an idea of the direction of the wave based on how the arms are stretched of compressed. Thanks.

LIGO will unveil new developments in its search for gravitational waves ... but no details as yet ... Peter

Roger Penrose, July 2017. Correlated "noise" in LIGO gravitational wave signals: an implication of Conformal Cyclic Cosmology

Hi, I was looking for a second opinion on this article regarding LIGO's gravity waves and if it made sense or not. https://www.forbes.com/sites/startswithabang/2017/06/16/was-it-all-just-noise-independent-analysis-casts-doubt-on-ligos-detections "Analysis of the data attributed the signal to...

From LIGO website re how gravity waves are measured: "The arrival times change because when the arms of the interferometer change lengths, so too do the distances the light waves travel before exiting the interferometer. What gravitational waves do not change, however, is the speed of light...

Homework Statement In-phase light from a laser with an effective power of 2x105J and a wavelength of 1064nm is sent down perpendicular 4km arms of the LIGO detector. (i) Determine the number of photons traveling in the interferometer arms. (ii) Assuming the detector is sensitive enough to...

Ivette Fuentes and her group are attempting to use phonon excitations in BECs to detect gravitational waves. Their GW-detector is called MAGA, which stands for Micrometre Antenna for Gravitational-wave Astronomy. Here's a video of her explaining it: More from their blog:

I would have a question to LIGO. How can LIGO detect the source of a gravity wave? It's a 2-dimensional detector, which has a certain length and a certain width, but no height. How does LIGO know the direction and distance of the source, and if this source is on the one side of LIGO or exactly...

Has anyone analysed the LIGO merger detection http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.116.061102 in the context of the BH information paradox? Is there any evidence that the gravitational waves carried any information that could compensate for the change in areas of the initial...

I suspect it has a very noisy pick up from back ground gravitational radiation, what source is the most likely candidate for this back ground radiation?

First let me be clear, I am not questioning GR or the detection of gravitational waves by LIGO, I am trying to improve my own understanding of GW to the point where I can offer a graphic illustration (web video) showing what they do as they pass us to help others understand them. I started this...

https://www.sciencedaily.com/releases/2016/06/160615134951.htm From science daily Date: June 15, 2016 Source: Johns Hopkins University Summary: When an astronomical observatory detected two black holes colliding in deep space, scientists celebrated confirmation of Einstein's prediction of...

Gravitational wave stretches and shrinks space. Why Laser light in Ligo arms changes frequency, and not wavelength.Is it some clear explanation? If even frequency would not be changed than spacetime is not changed, I suppose. What cannot be measured, cannot exist.

http://news.mit.edu/2016/second-time-ligo-detects-gravitational-waves-0615 This seems to be the year of black holes, between LIGO, and new theories of black holes being 2D objects instead of 3D masses. Anyway, I thought this was very interesting news and wanted to share :)

Re: the second LIGO detection, from Symmetry: “Because of their lighter masses compared to the first detection, they spent more time—about one second—in the sensitive band of the detectors.” As an absolute (albeit deeply fascinated) novice here, I'm unclear as to why lighter masses would allow...

Since the thread In LIGO’s pulse, how much comes from BH merging/ inspiraling where I questioned the late ‘ringdown’ part of the LIGO signal, scientists have pointed out that the main pre-merging signal could indicate various types of binary compact objects, including gravastars of similar mass...

Sorry for the amateurish setup that follows. Here's my thought experiment. Consider a 2-dimensional universe on the Cartesian plane. Earth is located at point (0,0). There is a binary system {A,B} oscillating around (1,1). To simplify, assume that the oscillation is 1-dimensional and occurs on...

The inspiralling oscillations of ~20ms period (reducing to ~5ms) appear much stronger than the ringdown of ~ 3ms period (noisy, at resolution limit). Merger happens at ~440ms in the figure of Abbott et al. (Phys Res Lett link.aps.org/doi/10.1103/PhysRevLett.116.061102). This would agree with...

I read that they found gravity waves that have the frequency of 35 to 250 hz but are not these frequencies that of sound waves? I thought sound does not propagate in vacuum or is there a new kind of gravity vacuum that contains a gravity ether or dark matter?

Hello all, I was thinking about the speed of light and why it's constant and it brought me to the principle of the LIGO experiment for which I have an assumption that I want to verify. I'm a novice at this so please bear with me. From what I know, the LIGO experiment splits an emitting light...