Ligo Definition and 97 Threads

I'm a structural engineer in Mississippi and I love all aspects of cosmology. I want to learn all I can about gravity wave technology. I was not expecting the level of detail that a single event is revealing. It's very interesting that they expect to see gravity waves from objects other than...

Hi, previously at Cardiff Uni, now at Buckingham, I'm still interested in gravitational fields, waves, Einstein, LIGO and all that.

Hi everyone, I have applied to the LIGO summer program. But I'm not from Caltech. I'm wondering if anyone has heard back from Caltech yet. Thanks

LIGO announced the detection of gravitational wave event GW150914, which coincided with the numerical waveform predicted by GR. The PRL paper says "Using fitting formulas calibrated to numerical relativity simulations, we verified that the remnant mass and spin deduced from the early stage of...

Is another subforum for Ligo, I see nothing in here(? My main question is on all the popular media reports i have only seen the one pulse, the now famous chirp If the thing works why isn't it swamped with signals??

Quite unexpectedly, it seems that the Fermi Gamma-ray Burst Monitor spotted what appears to be a hard gamma-ray burst about 0.4s after the LIGO GW event, lasting about 1s: http://arxiv.org/abs/1602.03920 This is not expected from a black hole merger (and as a black hole sceptic, I find it very...

As we all know, the LIGO collaboration published a paper recently on the first direct observation of a binary merging black hole system. From the observed signal, they were able to infer the black holes' masses and their distance from Earth. However, the fact that they can estimate masses and...

I have a couple of questions regarding the new detection of signals believed to be gravitational waves at LIGO 1. Two similar signals were detected at both facilities. Why does the Livingston signal appear to be weaker than the Hanford signal? 2. The signal in Livingston was reported to have...

LIGO reported the announced event with a redshift of 0.6 < z < 1.3. With no em radiation event reported (AFAIK), does anyone know how they have determined the redshift? I understand how they could measure the pre-merger, chirp and ring-down frequencies with good accuracy. In order to determine...

I understand that the LIGO experiment was very lucky to find a very strong signal of a very energetic event (binary black hole merger). Having into account the non-negligible possibility that the signal may be spurious or some problem in the data adquisition, how much time must pass before we...

I'd like to understand the details behind the LIGO experiment a bit better: How do scientists know that the gravitational waves detected by LIGO originated from two specific black holes (located a billion light years away)?Does the LIGO result confirm the existence of black holes?Was it only...

A question from a physics laymen to those more advanced: if eLIGO detects gravitational waves by the difference to the combined laser wavelengths (a difference to the destructive interference pattern following curvature of space-time in each individual pathway), how is it that the lasers...

Each of the two BHs in the collision brought in matter and energy prior to merge, neither emitting any significant energy prior to merge. Same for the combined BH after merger was complete. So, my question is, what is the source or mechanism for the 3 Sun M worth of energy release into...

Like many others, LIGO made me curious about gravitational waves. I found the paper: Nonlocal Gravity: Damping of Linearized Gravitational Waves http://arxiv.org/abs/1304.1769 I'm having difficulty understanding. Does that mean that damping is implicit in the terms of the tensors? Does it...

As the length distortion due to a gravitational wave as it passes by Earth is on the order of the dimension of an atom, or << a wavelength of light, can someone describe in a general sort of way what measurement steps are employed to detect such small changes in an interference pattern? It would...

The recent LIGO result seems likely to lead to a lot of rewriting of textbooks. Some topics that occur to me: (1) Obviously it needs to be discussed in any GR textbook's discussion of gravitational waves. (2) The fact that the waveform matches so well with GR calculations seems to be extremely...

The news out of LIGO is being heralded as one of the most important experimental verifications of physics in decades, as it provides experimental support to the General Theory. The news makes it seem as though it were like the Higgs Boson was; theoretically concrete, but up in the air until...

I didn't see these areas addressed, my apologies if I missed them. If there was no delay in the detection of the signals at the two sites, would that mean that the location of the event was 'directly overhead' or 'directly below'? Was the delay, compared to the speed of light and distance...

http://xkcd.com/1642/ I've made a suggestion like this before. The LIGO results are wonderful, but the questions from "out there" sometimes display a level of understanding best dealt with the xkcd.com comic linked above. My opinion only. I've made this suggestion before. With regard to...

Would it be possible to duplicate the Michealson & Morely experiment using LIGO data? Essentially the geometry seems to be the same , so I was wondering whether it would be possible verify the M&M result at a much higher resolution using existing LIGO data or is the stability not designed to...

As the discovery matches templates based on GR, and the regime is of very strong gravitational fields and very high speeds (relativistic speeds), and there is a 90% match between model and measured data, this does rule out linear or quasi linear alternative theories of gravity?

I am trying to understand how the photons in the LIGO beams behave when going along the "slopes" of the gravitational waves, in particular how the Shapiro delay gets factored into the resulting interference. To simplify the situation, suppose that a LIGO photon starts orthogonally to a wave...

Before the recent LIGO result, there was already not much doubt that gravitational effects propagated at c, but the evidence was indirect. To what extent does the LIGO result test this directly, and how will this be improved in the future? The H1 and L1 instruments are separated by 3002 km...

I'm trying to reconcile yesterday's announcements with the rumors that have been reported. I and others have heard rumors of three events. Yesterday they reported on the event from 14-Sep-2015, and the paper LIGO-P1500217 titled "The Rate of Binary Black Hole Mergers Inferred from Advanced...

Could someone please describe the recent LIGO project, gravitational waves and their detection in simple terms. PLEASE.

The LIGO paper https://dcc.ligo.org/LIGO-P150914/public puts limits on the dispersion of gravitational waves, which can be interpreted as an upper limit of 10^-22 eV on the mass of the graviton. We all know that low-amplitude gravitational waves are supposed to propagate at c according to the...

https://losc.ligo.org/events/GW150914/']The[/PLAIN] LIGO Open Science Center has released data from the gravitational wave detection along with a tutorial going through some typical signal processing tasks on strain time-series data associated with it. GW150914 Data Release From the tutorial...

Does anyone know where we can watch the live stream of the conference held at Washington DC on 11 feb 2016 10:00 am

LIGO will apparently announce on February 11, the detection at five plus sigma of gravity waves (3 solar masses of energy worth in about 100 seconds) emitted as two medium sized black holes of about 65 solar masses combined spiral into each other and merge into a single Kerr (i.e. spinning)...

There are rumours that scientists at Advanced LIGO have detected gravitational waves ... it is about 100 years after Einstein predicted they were there in his mathematical theory of general relativity ... Anyone know more about this rumour ...? Peter

There is a rumor going around that a gravitational wave inspiral has been seen at advanced LIGO. The web sites say it went on line in Sept, 2015, so I guess this is possible. Has anyone here heard anything?

Here, you can find the paragraph below: But I don't understand how a non-detection can mean the detection pf gravitational waves! Anyone knows what's the point? Thanks

From WIKI, In February 2007, GRB 070201, a short gamma-ray burst, arrived at Earth from the direction of the Andromeda Galaxy, a nearby galaxy. The prevailing explanation of most short gamma-ray bursts is the merger of a neutron star with either a neutron star or black hole. LIGO reported a...

I had a quick Google and there was nothing very interesting with a recent date. It seems that the management introduced some 'test' data. a while ago, to see of the system worked and it was detected. I'm sure someone here must be a bit 'in the know' about what's going on.?

Can anyone explain what the purples and signs are in this picture?

Advanced LIGO, scheduled to start in 2014, is believed to be able to detect gravitational waves from stellar sources. According to our best current models, does Advanced LIGO stand any chances of detecting the stochastic GW wave background? And even measure its temperature? (No more than 0.9K...

Hello, I was recently accepted into the LIGO REU at Caltech and was wondering if anyone here had any experience with the program? If so, could you provide a brief rundown of your summer experience? Thanks so much!

This observatory is designed to detect gravitational waves, however, I feel that it won't work. I am sure I am wrong in my assumption, but I would like someone to explain to me why I am wrong. I feel that this machine will not work because the gravitational waves passing over the machine will...

arXiv:0804.1747 [pdf, other] Title: The Einstein@Home search for periodic gravitational waves in LIGO S4 data Authors: LIGO Scientific Collaboration: B. Abbott, et al Comments: 29 pages, 19 figures Subjects: General Relativity and Quantum Cosmology (gr-qc) A search for periodic...

On February 1, 2007, the Konus-Wind, Integral, Messenger, and Swift gamma-ray satellites measured a short but intense outburst of energetic gamma rays originating in the direction of M31, the Andromeda galaxy, located 2.5 million light-years away. The majority of such short (less than two...

ok guys maybe I missed something but this project looks more and more like a Hi Fi enthusiast tuning his kit with excited enthusiasm. But no music is heard. :devil: Ok so a few years or so I said this would fail through an error of priciple. LOL I no nothing compared to these guys... so why...

Just a few questions for anyone. I am trying to buffer photons for a long delay quantum eraser. Is there anyway to convert one arm of a 4km LIGO interferometer into a high-fidelity photon buffer? If a beam is merely reflected once down the length of the tube, it is stored for ~13 µs with...

Posted 6 May 2005 http://arxiv.org/abs/gr-qc/0505029 Upper limits on gravitational wave bursts in LIGO's second science run Authors: LIGO Scientific Collaboration 23 pages, 14 figures, to be submitted to Phys Rev D "We perform a search for gravitational wave bursts using data from...

LIGO may have failed to detect gravity waves because they move faster than light and so have a greater wavelength than expected and probably a lower amplitude too.

LIGO may have failed to detect gravity waves because they move faster than light and so have a greater wavelength than expected and probably a lower amplitude too.

What is the wavelength and amplitude of the gravitational waves that LIGO is trying to detect? Are these waves made of gravitons (as light waves can be made of photons) and how much energy do they carry?

Have you heard about the LISA project? It is an oversized version of LIGO (Laser Interferometer Gravitational Wave Observatory). LIGO is being built now, and it is basically two L shaped interferometers (one in Louisiana and one in Washington); each 4 km long. LISA will be a much bigger...