Talk:LIGO

message: We need to add a subsection with a description of the interferometers and how
its possible for them to measure such small distances.
Two things strike me about this summary.  First, how do the detection facilities account for the overwhelmingly powerful effects of even very minor earthquakes that occur every day at multiple locations around the earth?  
: Multiple detectors in several locations of same cosmic event. Allows one to subtract local noise. (Not just earthquakes, this experiment detects slamming doors.) Someone who knows more, add more. GangofOne 07:00, 7 August 2005 (UTC)
thread_title: Untitled

message: * Should the two GW observations be mentioned in the summary?
The article contains the statement "But if and when even one verified gravitational wave event is observed by any of the worldwide detectors, it will be a truly exciting moment for all astronomers and astrophysicists worldwide who have waited so long for such an event to be seen." If this is true, then the newly added statement "In February 2007 a short gamma ray burst, GRB070201 which came from the direction of the Andromeda Galaxy, failed to be observed by LIGO. This was significant as it ruled out the Andromeda Galaxy as the location of the event." is not correct. since LIGO has not been able able to demonstrate detection of any verifyable gravity waves. So I have modified the sentense to reflect this.
Blufox (talk) 12:29, 23 January 2008 (UTC)
thread_title:  observations 

message: This does not pertain to this article, but the article on 1 attometre references LIGO, and I want to make sure it has its facts straight. Has LIGO actually reached 1 attometre sensitivity, or is that its target? Could someone who knows this please check the article. Pulu (talk) 06:58, 12 November 2008 (UTC)
thread_title: 1 attometre

message: The home-computer discovery with references 7 and 8 is not really relevant because it is a discovery of a pulsar using radio data, not gravitational waves. 99.38.163.5 (talk) 02:45, 9 September 2010 (UTC)
thread_title:  Einstein@home 

message: Apparently Australia was unable to raise the funds, much less than by the October 1 deadline.
However, there was interest from India, and apparently there is the potential to locate a third interferometer there:
* U.S. gravitational wave detection experiment looking at India as a possible site
* 2011 NSF Review of LIGO-India Effort
* Boost for India's hopes to host gravity wave detector
I don't have time to properly wikify this information, so I'm dumping it here for use by anyone who does.
71.41.210.146 (talk) 21:33, 28 October 2011 (UTC)
thread_title:  LIGO Australia dead, LIGO India under consideration 

message: In the Notes section
^ "LIGO Sheds Light on Cosmic Event". 2007-12-20. Retrieved 2007-12-21.
points to http://mr.caltech.edu/media/Press_Releases/PR13084.html which redirects to the useless http://www.caltech.edu/content/press
From the text it is unclear what exactly the non-detection demonstrates.
Is there some working link to the referenced article or to some other explanation of the event somehow related to the detector?--Dobrichev (talk) 13:40, 11 January 2013 (UTC)
thread_title:  dead link 

message: The statement "... gravitational waves that originate tens of millions of light years from Earth are expected to distort the 4 kilometer mirror spacing by about 10−18 m ..." does not mention what the magnitude of the gravitational waves are at their origin -- i.e., whether they are created due to two blackholes colliding or two asteroids colliding. -  Subh83 (talk | contribs) 10:40, 23 June 2013 (UTC)
thread_title:  incomplete statement 

message: Detecting gravity waves through analysis of the earth's seismic data is apparently nine orders of magnitide more sensitive than LIGO.  So why bother building Advanced LIGO (which will be only one order of magnitude more sensitive)? 199.46.199.232 (talk) 23:34, 14 March 2014 (UTC)
thread_title:  Does the "Dyson approach" obviate the need for "Advanced LIGO"? 

message: From the article: "A decision by ESA on the proposal is expected for November 2013"
So, what's the decision? Shouldn't the article be updated? 96.32.186.207 (talk) 06:42, 2 April 2014 (UTC)
thread_title:  What's the ESA decision on NGO? 

message: am i the only kid who would like a section like ligo can detect teh equivalent of 1/1000 of  human hair distance change between earth and sun..or
the sensitivity of ligo is great, ordianry metaphors fail  — Preceding unsigned comment added by 50.49.131.230 (talk) 03:06, 3 January 2015 (UTC)
thread_title: geez where is the excitement about engineering

message: Since there seems to be some confusion on the part of an IP user, let me point out MOS:BOLD, specifically the guideline
:"Do not use boldface for emphasis in article text."
However, this stylistic issue is perhaps secondary to a more substantial apparent misunderstanding of science in general and LIGO in particular.  The stylistically inappropriate boldface is being used to emphasize that LIGO has not yet detected gravitational waves.  I believe this emphasis is intended to imply that LIGO has therefore failed in its mission, but such an implication would be incorrect.  My understanding, as a non-expert, is that LIGO has met or exceeded its design goals.  Therefore either observation or non-observation of gravitational wave signals provides new and valuable information about the frequency of astrophysical events predicted to generate such signals, precisely what LIGO is supposed to produce.
Finally, I would request that the IP user refrain from accusing me of vandalism per WP:GOODFAITH.  Cheers, David Schaich Talk/Cont 19:54, 6 September 2015 (UTC)
thread_title: Matters of style and substance

message: LIGO-India's section is unclear to me. The first paragraph claims the "designs and hardware" for one of the two "Advanced LIGO detectors" will be installed in India. The second paragraph mentions the network of three detectors formed by linking LIGO and Virgo observatories, and discusses the benefit of adding a fourth site.
But the third paragraph begins with "The NSF was willing to permit this relocation". What is being relocated where? The hardware for one of the two advanced US-based LIGO detectors? The original Australian plans? The fourth paragraph appears to clarify that one of the US detectors will be relocated - is that it? It's as if there's something missing or mis-ordered in the four paragraphs that could help avoid confusing the reader. -84user (talk) 04:54, 27 September 2015 (UTC)
replies: text: It may be a problem with chronology and/or need to update.  Cheers, BatteryIncluded (talk) 20:45, 27 September 2015 (UTC)
replies: text:  i find it quite painful to read this article because of mixed up chronological order, mixing current state with past and future in the same paragraphs. even the introduction is following this mixed up pattern. can we change the structure a little bit to fix this? --ThurnerRupert (talk) 03:44, 15 February 2016 (UTC)
thread_title: Future unclear

message: User:BatteryIncluded, thanks for your hint, i did not clue into really looking at this long list of authors before. but at the same time i'd love to make the story a little less abstract, and include information that a real person needs to do work to spot something, and marco drago was lucky to see it. to somehow describe that there are data feeds, alerts, checking happens around the world, around the clock. also missing is that parts of ligo come from different areas of the world, this is a truely international effort, besides of course the fact that every american taxpayer contributed one or two dollars to it at least. --ThurnerRupert (talk) 05:36, 13 February 2016 (UTC)
replies: text: My concern is that he is being promoted in Wikipedia to the degree that to the casual reader he looks like the "discoverer".  In fact it is a factoid, and it is so, that his Biography/article was labeled as non-notable and proposed for deletion. I have no problem with his single mention in the proper article subsection, but spamming other Wikipedia articles is another.  Keep the perspective. Cheers, BatteryIncluded (talk) 05:48, 13 February 2016 (UTC)
thread_title:  credits, credits 

message: According to this official source, laser power on entering interferometer is 200 Watts, not 20 Watts as shown on the image in the article and written in the text of the article. I think, this should be corrected. Illustr (talk) 21:02, 18 April 2016 (UTC)
replies: text: I was talking with Sheila Rowan earlier this week, and she mentioned that in 2015 Advanced LIGO used only a small fraction of their total possible input laser power.  Increasing the amount of power coming in from the laser is one of the ways they expect to become more sensitive this year and in the near future.  Checking arXiv:1602.03837, I see (at the bottom of page 3) "20 W of laser input".  So I think 20W is the correct number currently being used, even though 200W may be the theoretical peak that they'll try to reach in the future. David Schaich Talk/Cont 17:11, 23 April 2016 (UTC)
replies: text: Thank you, this makes it clear. Illustr (talk) 12:29, 24 April 2016 (UTC)
thread_title:  Laser power 

message: United States of America, not even mentioned. Stop the European jealously and censorship.
:Hm.  The locations are in Benton County, Washington and Livingston Parish, Louisiana, where 99.9% of United States citizens do NOT live, so the statement above could be considered 99.9% misleading.   
:LIGO is a truly international scientific consortium, financed and staffed globally.  The VIRGO detector in Italy increases the effective angular sensitivity by approximately a factor of 10.  A third LIGO, in India real soon now , will increase sensitivity further.  The idea was championed and developed by German physicist Rainier Weiss and Scottish physicist Ron Drevers, and was implemented by thousands of geniuses worldwide.  
:I'm proud to live in the USA that welcomes and enables genius from the entire planet, and collaborates with all nations in the exploration of the universe.  And I'm proud to personally contribute to similar international collaborations.  It is sad that many of my fellow citizens never accomplished anything more significant than being born here, but it is never too late to learn a practical skill and improve the world (or at least your county, state, or nation) with it.
:BTW, it is amusing that the location given in the sidebar is accurate to 30 centimeters; this appears to be the center of the beam crossings at each site. Thanks to TobinFricke  for the exacting detail, a personal example of the global collaboration that makes LIGO so spectacular! KeithLofstrom (talk) 19:20, 27 September 2018 (UTC)
thread_title:  Location 

message: The second paragraph under the "History" section:
"Prototype interferometric gravitational wave detectors (interferometers) were built in the late 1960s by Robert L. Forward and colleagues at Hughes Research Laboratories (with mirrors mounted on a vibration isolated plate rather than free swinging), and in the 1970s (with free swinging mirrors between which light bounced many times) by Weiss at MIT, and then by Heinz Billing and colleagues in Garching Germany, and then by Ronald Drever, James Hough and colleagues in Glasgow, Scotland."
seems way too close to the following paragraph in its cite:
"Prototype interferometric gravitational wave detectors (“interferometers”) were built in the late 1960s by Robert Forward and colleagues at Hughes Research Laboratories (with mirrors mounted on a vibration isolated plate rather than free swinging), and in the 1970s (with free swinging mirrors between which light bounced many times) by Weiss at MIT, and then by Hans Billing and colleagues in Garching Germany, and then by Ronald Drever, James Hough and colleagues in Glasgow Scotland."  — Preceding unsigned comment added by 82.45.253.129 (talk) 14:50, 19 July 2016 (UTC)
thread_title:  Plagiarism 

message: Do any of the references talk about the blind spots of the detectors?  Tayste (edits) 03:49, 18 October 2017 (UTC)
replies: text: The reference I added two sections above includes full polar diagrams. That's probably more detailed than most people would want though. George Dishman (talk) 13:23, 8 November 2017 (UTC)
thread_title:  Blind spots 

message: The article mentions briefly that LIGO uses the Fabry-Perot type of interferometer and provides a link to Wikipedia's page on that topology, but although that page gives a comprehensive analysis of their behaviour for a fixed structure and variable wavelength, it doesn't address the way LIGO works with fixed monochromatic illumination and variable arm length. This thesis gives a comprehensive analysis of the way the cavities perform in LIGO. I would suggest including at least Figure 1 would be of benefit (if this is an acceptable source) and it would make clearer how the shorter arms  mention in the penultimate sentence in the section on observatories produce the same response at frequencies above around 200Hz but half the response below that. [p.s. On trying to make the Fabry-Perot link internal, I got an error message saying %E2 was illegal, but the link was copied from the address bar of the page, is WP breaking its own rules?] George Dishman (talk) 13:22, 8 November 2017 (UTC)
thread_title:  Fabry-Perot interferometer performance 

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thread_title:  External links modified 

message: On Nov. 15, 2017, LIGO detected its 6th gravitational wave, GW170608. 
https://www.ligo.org/detections.php
This wiki only mentions the 5 gravitational waves found. Please update!  Whisperjunkie (talk) 06:16, 28 February 2018 (UTC)
thread_title:  6th gravitational wave detected 

message: By mid-September 2015 "the world's largest gravitational-wave facility" completed a 5-year US $200-million overhaul at a total cost of $620 million.
So I'm guessing that supplementary Girl Guide cookies sold like hot cakes over the specified time period? — MaxEnt 22:17, 17 July 2018 (UTC)
thread_title:  What's $420m between friends? 

message: The article seems to be missing that LIGO was for a while in the budgeting stage going to be in outer space! Because it was thought that they would need to be away from noise sources, and that the lasers would have to be very very long. It would have been massively expensive, and tediously hard to get set up. Someone came along and figured out that LIGO done on terra firma was possible, as long as all the noise could be budgeded properly, detected and then cancelled out. The success of LIGO is mainly because of sensing noise sources and cancelling them out. -Inowen (nlfte) 09:04, 7 September 2018 (UTC)
replies: text:  LIGO was never intended to be in space, you are probably thinking of LISA. That was cancelled but is now being worked on as eLISA. George Dishman (talk) 21:48, 17 September 2018 (UTC)
thread_title:  Outer space 

message: The article still thinks the O3 run is in the future... I would update it but I don't find clear dates. They stopped publishing candidate events at a rapid rate early June (source), but such a short observation run sounds implausible. The same issue applies to Virgo interferometer which doesn't even know about that observation run. --mfb (talk) 13:13, 28 June 2019 (UTC)
replies: text: It started on 1 April, I've updated the article. Absolutelypuremilk (talk) 14:25, 28 June 2019 (UTC)

text: They started publishing new candidates again! I wonder what caused the gap. --mfb (talk) 02:04, 13 July 2019 (UTC)
thread_title:  O3 run: dates 

message: The text says that (a) it will use a silicon mirror and (b) that silicon will be transparent to the light. A bulk transparent material can't work as mirror. The reference discusses a silicon mirror, but says nothing about transparency. Pure silicon does have a high transmission rate for 1500 nm if it is not too thick. Will it get a mirror coating? Why would the transparency be relevant then? --mfb (talk) 11:11, 7 September 2019 (UTC)
thread_title:  LIGO Voyager mirror: Error in text? 

message: Does anyone know when the LIGO building was completed?  That is, not necessarily the stuff inside, but just the empty building. Gah4 (talk) 20:19, 25 June 2020 (UTC)
thread_title:  building 

message: Approximately 1000 members of the LIGO Scientific Collaboration shared the following prizes in common for significant contributions to astrophysics:
*2017:  Princess of Asturias Award In Technical and Scientific Research
*2017:  Einstein Prize
*2016:  Gruber Cosmology Prize
*2016:  Breakthrough Prize in Fundamental Physics  — Preceding unsigned comment added by 50.1.214.5 (talk) 02:45, 22 February 2021 (UTC)
thread_title:  Awards 

message: This line references a future time that has now passed. This should be updated based on the actual progress at LIGO.
"Its sensitivity will be further enhanced until it reaches design sensitivity around 2021."
--Chowlab92 (talk) 02:09, 24 January 2022 (UTC)
thread_title:  Update needed on sensitivity improvements 

message: This one gives some explanation on the quadrupole source of gravitational waves, and especially on their polarization. This one a little more detail, and more equations. Gah4 (talk) 06:31, 6 April 2022 (UTC)
thread_title:  polarization