Wikipedia:Featured article candidates/Virgo interferometer/archive2

The following is an archived discussion of a featured article nomination. Please do not modify it. Subsequent comments should be made on the article's talk page or in Wikipedia talk:Featured article candidates. No further edits should be made to this page.

The article was promoted by Gog the Mild via FACBot (talk) 19 December 2024 [1].

---

Virgo interferometer

Nominator(s): Thuiop (talk) 21:51, 20 October 2024 (UTC)

This article is about one of the major current gravitational wave detectors. This is the second nomination; during the first one, the article was found lacking in copy editing, so I submitted a request to WP:GOCER, which was completed a few days ago, hence the resubmission. Looking forward to your comments. Thuiop (talk) 21:51, 20 October 2024 (UTC)

@Thuiop, have you considered persuing Good article nomination first? It's not technically required for featured articles to be successfully nominated as good articles first, but it is almost always done and is strongly recommended—especially given that this is your first nomination. Good articles have less strict criteria, and a one-on-one dialog is often more efficient to identify and correct certain common problems, compared to the FAC process. Remsense ‥ 论 21:59, 20 October 2024 (UTC)

Hello @Remsense, I was not aware of that. I did know about Good articles though, but considered it as a second option; I usually contribute to the French Wikipedia, where "FAC" are usually not already "GA" before the nomination. If you think this is a better idea, I am ok with rescinding this nomination and go to GA before. Thuiop (talk) 08:00, 21 October 2024 (UTC)

I would recommend it, but keep in mind that it sometimes takes a prolonged period of time before an editor will pick up your submission for review—often days or weeks, sometimes even months. I think this one wouldn't sit too long though. Remsense ‥ 论 08:48, 21 October 2024 (UTC)

Ok. I will do this if there are no other comment against this idea in the next one or two days. Thanks! Thuiop (talk) 08:55, 21 October 2024 (UTC)

Comments from Graham Beards

I don't think a GA nomination is needed. I have made some edits to the article, which can be found in the history. The images look a little cluttered, at least on my screens, but this is no big deal. In my view this is an excellent, and fairly lay-friendly, introduction to an exciting new field in cosmology. I am interested in what other reviewers have to say, but I am happy to add my tentative support. Graham Beards (talk) 10:05, 21 October 2024 (UTC)

Airship

I have placed {{cn}} tags in a few places; note that image captions do require citations if the information within is not sourced elsewhere in the body. In my opinion, the prose is good but in need of improvement; I cannot comment on the technical and scientific details. ~~ AirshipJungleman29 (talk) 10:14, 21 October 2024 (UTC)

I added the missing citations. Thuiop (talk) 12:19, 21 October 2024 (UTC)

Image review

• How does the gallery here align with WP:GALLERY?

• File:Logo-virgo.png: source link is dead. Ditto File:GW170814.png

• File:GW170814_signal.png: where is this licensing coming from? The source site has an all rights reserved notice

• File:Virgo3_1.jpg: is a more specific source available? Ditto File:BestVirgoSensitivityCurveVSR4.png

• File:VirgoDetectionBench2015.jpg is tagged as lacking source information. Nikkimaria (talk) 04:04, 27 October 2024 (UTC)

• Indeed, it seems it does not. Do you think it would make sense to move it at the beginning of the instrument section, replacing the already present File:Virgo aerial view 01.jpg ?
• Fixed.
• I added the original paper which is indeed under CC.
• I added extra sources in the caption. Did you mean to add the sources in Commons? These files were directly uploaded by the collaboration, but I can link articles where they were used, although those articles are not necessarily under the correct license.
• Fixed.

Thanks for the comments! Thuiop (talk) 11:43, 27 October 2024 (UTC)

• The Commons page for each image should include sourcing that confirms that the image is available under the licensing given. Do you mean that the licensing given is not correct, or that the articles where they are used don't credit them properly? Nikkimaria (talk) 04:32, 28 October 2024 (UTC)

  Ah, no, I meant that these two files were produced by the Virgo collaboration and upload by someone from the collaboration in its name, falling under the "own work" category. It was also used by the collaboration in other places (including a journal paper), but these do not fall under the same licence as far as I know. If you think this is important, I can contact the person who uploaded it and have them confirm this officially. Thuiop (talk) 07:44, 28 October 2024 (UTC)

• Yes please - this should go through VRT. Nikkimaria (talk) 04:25, 29 October 2024 (UTC)https://wiki.riteme.site/wiki/Help:Contents

  Understood, I will get this done in the next few days. Thuiop (talk) 12:45, 29 October 2024 (UTC)

  Took care of it ! Thuiop (talk) 13:20, 6 November 2024 (UTC)

Coordinator comment

Three weeks in and just the single general support. Unless this nomination makes significant further progress towards a consensus to promote over the next four or five days I am afraid that it is liable to be archived. Gog the Mild (talk) 18:53, 10 November 2024 (UTC)

HF

I'll try to start a review within the next day or two. Please ping me if I haven't started by Wednesday. Hog Farm _Talk 16:17, 11 November 2024 (UTC)

@Hog Farm here is the reminder. Thanks for your interest! Thuiop (talk) 08:45, 14 November 2024 (UTC)

My work schedule has gotten crazy this week - I am hoping to get to this Friday or Saturday. Hog Farm _Talk 12:25, 14 November 2024 (UTC)

Apologies for the delay on this; I should be considered to be a strictly nonexpert reviewer here. Hog Farm _Talk 02:33, 18 November 2024 (UTC)

• Generally, information should be found in the body, and not only in the lead. Some examples here include the fact that KAGRA is in the Kamioka mine (which probably isn't relevant enough for this article in general), and the information about the naming of the Virgo Cluster and the details about the Virgo Cluster. This isn't a comprehensive list though.

Ok. I am not sure where to put the information about the naming though, I am a bit iffy about making an extra section just for that but will think about it.

• "The budget of EGO is around 10 million euros per year," - I'm not quite a fan of this phrasing. This appears to be coming from the range of commitments on p. 5 of the source, which shows it ranging from barely 9 million to over 11.5 million. This also needs an as of date, as this is probalby to change in the future given that the source is talking about how the budget needs to increase

This is precisely why I put a coarse estimate, as it fluctuates quite a bit annually, but I can put a range instead (+ date)

• " its final configuration is planned to combine the light of two lasers to reach the required power" - is this a final configuration of the Advanced Virgo, or a planned future upgrade of the Advanced Virgo into something different?

Complicated as there were some issues with the laser before O4, but this is going to be hard to source, which is why I left it in the future tense for now.

• "This laser is sent into the interferometer after passing through the injection system, " - the laser itself, or the beam of the laser?

The beam, I changed it.

• "made from the purest glass obtainable." - can you point me to where this is found in the source? I'm not seeing any references to "purest" or "glass" in the source (a slideshow presentation), and the only references to VIRGO are in the image credits

Ah, fused silica is a type of glass. Changed to "extremely pure" to avoid issues; this matches slide 4 from the presentation. I had not realized that Virgo is barely mentioned in the presentation, but it was made by a Virgo researcher, and all the pictures are of Virgo mirrors (the LMA is the main lab working on the mirrors).

• "A reflective coating (a Bragg reflector made with ion-beam sputtering) is then added. " - I'm struggling to find where the source references a Bragg reflector?

Good catch, I added the source

• " This superattenuator, nearly 8 metres (26 ft) high, is in a vacuum" - is this still the case? The source is from before the Advanced Virgo updates, which I'm told in the article "kept the same vaccum infrastructure" but changed basically everything else? Is this part of the vaccum infrastructure - I'm not sure

Yes, this has not changed.

• "A fraction of this light is reflected back by the signal-recycling mirror, and the rest is collected by the detection system" - can light really be "collected", strictly speaking?

I think this is the correct term here. Could be changed to something like "continues towards" if you feel this is confusing.

• "With the O3 run, a squeezed vacuum source was introduced to reduce the quantum noise which is one of the main limitations to sensitivity." - the ref placement is clearly off here; the next reference in the paragraph is the 1981 paper proposing squeezed vacuums.

Fixed.

Ready for the history section; hopefully I should be able to finish in the next couple days if my work schedule cooperates. Hog Farm _Talk 02:33, 18 November 2024 (UTC)

Thanks a lot for the comments! As for the other commenter, I made individual responses and corrected most of it. Thuiop (talk) 09:00, 18 November 2024 (UTC)

@Thuiop: - Apologies for not having a chance to get back to this yet. As to the naming, I'd personally stick a brief sentence about it in the first paragraph of the history section where you are talking about the formation of the entity. That's where I'd have it if I were writing the article - including the naming with the history of how it was formed. Hog Farm _Talk 14:23, 20 November 2024 (UTC)

Ok, thanks! I added a phrase for that. Thuiop (talk) 00:31, 21 November 2024 (UTC)

Unfortunately, I'm going to have to back out of the rest of this. I've been run into the ground figuratively at work and I need to take a break and catch my breath. Hog Farm _Talk 14:34, 22 November 2024 (UTC)

Fair, thanks for the comments you already made. Take care! Thuiop (talk) 20:32, 22 November 2024 (UTC)

Things have calmed down for me a bit; I hope to be able to finish this review by the end of the week. Hog Farm _Talk 14:28, 4 December 2024 (UTC)

• "serious projects for detecting them only began during the 1970s. The first were the Weber bars, invented by Joseph Weber;" - ref placement issue? The following source is from 1968
• Is it known how much this thing cost to build?

I think that's all from me. I struggled to get through some of the harder science and the description of the instrumentation, but that's not an indictment of this article, rather my scientific knowledge and the Missouri public education system. Hog Farm _Talk 02:31, 6 December 2024 (UTC)

Thanks for the review! Regarding your first point, it was more like Weber made its announcement in 1968, which sparked more projects in the 1970s. But I changed it to "late 1960s" and threw in an extra reference for good measure. As for the cost, I will look into it; I know it is in the order of 10s of millions, but I can check that.
Also, this is a highly technical and niche subject, so it is not surprising that people may struggle with some of the points (there is a lot I do not understand about the finer details of the interferometer either!); if there are parts that you feel are really unclear I am happy to take a look. Thuiop (talk) 09:49, 6 December 2024 (UTC)

I think I'm going to support now. The concerns I had have been addressed, and there are supports for two science-focused editors here who judgment I trust (Graham Bears and Ajpolino), so I feel comfortable with the technical aspects. Hog Farm _Talk 14:08, 6 December 2024 (UTC)

Comments from Mike Christie

• "The Virgo interferometer operates with similar detectors ...": it took me a few seconds to parse this. I took "similar" to mean "similar to detectors mentioned earlier". I understood the point by the end of the paragraph, but how about changing this to "The Virgo interferometer shares data with other similar detectors, including ..."?

  I see what you mean. However, the point was also that observations are jointly planned with other detectors. I modified the formulation to make it clearer and still reflect that.

• "Developed when gravitational waves were only a prediction of general relativity, it has now detected several of them. Its first detection was in 2017 (together with the two LIGO detectors)" This doesn't make it clear that the Virgo was not involved in the first such detection. Could we rephrase, maybe like so: "Gravitational waves, once only a prediction of general relativity, were first detected by the LIGO interferometers in 2015. The first event detected by Virgo as well as LIGO was in 2017; this was quickly followed by ..."?

  This is the only one I did not address yet; I wanted to also make clear that the instrument was developed at a time were no GW had been detected, and operated for a long time before the first detection. Your reformulation, although technically correct, makes it look like Virgo "came late to the party". I will try to think of a better formulation, perhaps extending what is in the parentheses in the current version. Edit: I ended up adding a bit more info on the history in the lead as suggested by the other commenter.

• "The Virgo Collaboration consolidates all the researchers": suggest "consists of" as simpler.

  Done.

• "which gathers scientists from the other major gravitational-waves experiments to jointly analyze the data; this is crucial for gravitational-wave detection": the source doesn't say that this collaboration is crucial for gravitational-wave detection -- I think it's a point worth making but we need another source that says it.

  Done.

• "Many believed at the time that this was not possible; only France and Italy began work on the project, which was first presented in 1987." It's not really clear what "this was not possible" refers to -- I think it must be the detection of low-frequencies, but it might mean, more specifically, that using an interferometer to detect low frequencies was considered impossible.

  Indeed, I made that more explicit.

• And "which was first presented" is vague: if I understand the source, "proposed" would be clearer.

  Done.

• "Virgo's first goal was to directly observe gravitational waves, of which the three-decade study of the binary pulsar 1913+16 presented indirect evidence." Meaning that the first goal was to observe these specific waves? The first part of the sentence reads oddly because detecting these waves is Virgo's only goal. To avoid that reading, how about "Virgo's first goal was to directly observe gravitational waves from the binary pulsar 1913+16, for which there was indirect evidence from three decades of study"?

  Maybe this was confusing; the goal was not to observe those in particular, rather it was somewhat clear at the time that they existed, but not whether it was feasible to detect them. I changed it to make that clearer.

• The article says both that initial Virgo "reached its expected sensitivity" and that "the original Virgo detector was not sensitive enough". Are these two statements are in conflict? The project did not intend to build an instrument that was not sensitive enough. If these aren't in conflict, then presumably that means the designed sensitivity turned out to be insufficient; if so I think we should say so.

  Your last sentence is correct. I removed the "not sensitive enough" part, to instead say that there were no observations.

• The first mention of "mirror towers" had me going down to the "Instrument" section to understand what these were, and I think it might be better to reverse the order of "History" and "Instrument". Putting the instrument description first gives the reader the vocabulary to understand the history section. That would also avoid issues such as saying "The new mirrors were larger (350 mm in diameter, with a weight of 40 kg)" when we don't know how big the old mirrors were.

  I did that, but I am actually now wondering whether this was a good idea, since the Instrument section also mentions the initial and Advanced Virgo periods.

• There's a mixture of tenses in the second paragraph of "Advanced Virgo detector": past tense ("the new mirrors were larger"); present tense ("The optical elements ... are under vacuum"); and subjunctive ("A system of adaptive optics would be installed"). I suggest sticking with past tense throughout.

  Done.

• "In the original plan, the laser power was expected to reach 200 W in its final configuration." Is this phrasing because we don't have a source that gives the laser power as built? Does "final configuration" refer to advanced Virgo, or does "original" mean this is a spec from initial Virgo?

  I left it like this; it is indeed complicated to source the exact laser power, as it was expected to ramp up and has changed many times throughout the detector's life.

• You introduce the abbreviation "aLIGO" and then don't use it anywhere. I think it can be dropped, but what is the difference between LIGO and aLIGO? Is it something the reader needs to understand?

  The abbreviation itself is not really useful indeed, but there was an important point, which is that the LIGO detectors also had their "Advanced LIGO" program. I reflected that.

• "during the O2 observation period": this is not explained until further below. I think an overview of the observational program, as outlined in the box, would be helpful to give the reader the O1, O2, ... vocabulary and some context, before we give the results of the runs. From the box it's not clear that O1 even applies to Virgo, in which case perhaps it's terminology from the LVK collaboration rather than just Virgo? If so I think we should say so. And looking at sentences like "Virgo announced that it would not join the beginning of O4" I see that must be right. I assume this planning of collaborative observations is in order to have the data to cross-check or reinforce the interpretation of detection events? That's implied but not stated.

  This is LVK terminology, I added a phrase to explain that.

• The post-O3 upgrades have an understandable difficulty with tenses since some are in the past and some in the future. I think the present tense ("the first precedes the O4 run") is not a good choice, though; the paragraph is written without making it clear what's been done and what remains to do, and I think doing that, with past tense and then future tense, would read more naturally.

  Good idea, I did that.

That takes me down to the end of the history section. I'll pause there, since I've suggested moving sections around; let me know what you think and I can continue when these points are resolved. Mike Christie (talk - contribs - library) 22:20, 11 November 2024 (UTC)

Thanks for your comments! I have addressed most of them, and will put individual answers to make it easier to read. Thuiop (talk) 12:35, 12 November 2024 (UTC)

I think that makes it much easier to see what's addressed and what isn't. I've struck most points above; I will read through again, though probably not tonight, and bear in mind what you say about the reversal of the sections perhaps causing other issues. Mike Christie (talk - contribs - library) 00:17, 14 November 2024 (UTC)

HiMike, any further thoughts. Gog the Mild (talk) 12:32, 18 December 2024 (UTC)

I don't think I'll comment further -- I got busy in real life shortly after posting these comments and couldn't follow up, and since then there have been plenty of other reviews so I don't think I need to return to this. I haven't spent enough time reading the article to be able to support, I'm afraid. Mike Christie (talk - contribs - library) 12:36, 18 December 2024 (UTC)

Hurricanehink

Support. Seeing as I have an active FAC, I figured I'd review another science article here.

• "The Virgo interferometer is a large Michelson interferometer designed to detect the gravitational waves predicted by general relativity. " - this is a lot for the first sentence, and I'm still not even sure what it is. I clicked on "Michelson interferometer" and it linked to "Interferometry", and I'm already on a bit of a wikihole. Is there a way to make the first sentence even simpler? I realize there's a link on Michelson interferometer, and Michelson stellar interferometer, and I think they're both similar. Also, the part of "predicted by general relativity" seems more like a description of gravitational waves. Mostly, could you expand on this and be broader?

I am not sure how it could be simplified without omitting the interferometric part, which is in my opinion pretty important. Regarding the link, I think that Interferometry is a bit clearer but it could go to Michelson interferometer to avoid surprise (Michelson stellar interferometer is however unrelated). The "general relativity" does apply to gravitational waves but it does not seem too out of place to me, although I am fine if you wish to remove it.

This is on the right track, but I still think just linking Interferometry doesn't help much if someone stumbles across this article, and they're reading it from the beginning. You should link Scientific instrument when you mention "instrument". I'm also not a fan of "huge". Could you reword that a bit? ♫ Hurricanehink (talk) 22:36, 16 November 2024 (UTC)

Follow up, is it an experiment, or is it an instrument? It seems to me that it is an instrument at this point, which is why I thought it should be linked to scientific instrument. ♫ Hurricanehink (talk) 17:59, 18 November 2024 (UTC)

I think both work at this point. I like experiment better, and I am not sure the link to scientific instrument would make it much clearer.

Makes sense. ♫ Hurricanehink (talk) 04:40, 19 November 2024 (UTC)

• "three kilometres" - please convert this and all units to imperial in parenthesis.

Will do. Edit: Done.

This was only done in the lead. Every instance of km in the body of the article has no mile equivalent. ♫ Hurricanehink (talk) 22:36, 16 November 2024 (UTC)

Ah, I was not sure if it was to be repeated when a measure is repeated several times. I will do it tomorrow. Thuiop (talk) 23:52, 16 November 2024 (UTC)

• "The instrument has two arms that are three kilometres long and contain its mirrors and instrumentation in an ultra-high vacuum." - is there any more about the instrument? This is the only sentence in the lead about the actual device itself. All I know is that it's 3 kilometres long. But unfortunately, that's not sourced anywhere.

I can add more details but I think this would be more confusing than anything if you are not familiar with how the instrument works. For the source, I can add one but this is an extremely basic fact which you can find in basically every source from the article.

Again, all material in the lead should be mentioned somewhere in the article, and should have a citation. There doesn't need to be a citation in the lead, but as the lead summarizes everything, the article is incomplete for not covering this bit of detail. ♫ Hurricanehink (talk) 22:36, 16 November 2024 (UTC)

• Should the infobox list the "formation" as 1993 if it was completed in 2003?

Interesting question, I think 1993 is fine since it is the start of the project. I was also thinking about having a small "timeline", but unfortunately this infobox template does not allow for one.

That makes sense, but then why isn't it 1992? Also, since the focus is on the project, is there a way to get an updated map? It's a shame to only have it as of 2017 when that's already seven years out of date. Also, since the map is outdated, I would much rather have an image of the building hosting Virgo, maybe the aerial view of the detector? That is a much better idea for what it is, not some outdated map. ♫ Hurricanehink(talk) 22:36, 16 November 2024 (UTC) ♫ Hurricanehink (talk) 22:36, 16 November 2024 (UTC)

I think I forgot to answer this but I moved the map outside the infobox. Turns out the info is also more recent than I thought as it dates from 2021, although this is still somewhat outdated.

Has there been any attempt for an updated map? ♫ Hurricanehink(talk) 04:40, 19 November 2024 (UTC)

Well, it seems the original was updated until 2021. It will however be hard to maintain it, as although most activity is in Europe, there are now people from other parts of the globe (notably Brazil has joined recently with a few different groups, and there are also people in Asia and Africa scattered around). I will however update the map to include Switzerland, and specify that the map is about European countries only.

Well since the group is such an important part of the topic, it would be nice if the map had everyone. I'm not going to oppose over it, but an up to date map would be appreciate. Also, is there a reason the infobox says 1993 when it was approved in 1992? ♫ Hurricanehink (talk) 18:19, 19 November 2024 (UTC)

Only the CNRS approved it in 1992, it was in 1993 for the INFN (as is written in the first phrase of the history section); the collaboration was therefore established in 1993. As for the map, I agree that it would be nice in principle but in practice I think the hassle is not worth it, especially since the project is in its large majority European; the extra countries are still mentioned in the text. Thuiop (talk) 22:35, 19 November 2024 (UTC)

OK, but the article isn't about the Virgo collaboration. The article is about the interferometer, so either it started in 1992 when it was approved, or 2007 when it first started its science runs, but 1993 doesn't make sense IMO. ♫ Hurricanehink (talk) 17:44, 20 November 2024 (UTC)

The INFN did not approve it before 1993; without the INFN approval the project would have either not seen the light of day or taken a very different form. So 1993 seems right to me.

• Could there be more about the history in the lead?

Hm, sure. I will whip up something but let me know if there are specific elements you want to see. Edit: Done.

• " including the two LIGO interferometers in the United States (at the Hanford Site and in Livingston, Louisiana) " - I'm not sure, but I don't see the Livingston part cited anywhere in the article. I wanted to a random spotcheck, and I didn't see the Hanford part even mentioned at all in the article other than an image caption.

Again, I can add a source but this is very basic information about the LIGO detectors which you would find anywhere LIGO is mentioned.

Any information in the lead needs to be somewhere in the article though. If it's important enough to get a mention in the lead, then that information should also appear in the body of the article. If it's not important enough to be in the lead, then it should be moved to later in the article when you mention LIGO. ♫ Hurricanehink (talk) 22:36, 16 November 2024 (UTC)

• Where is the budget that's in the infobox sourced in the article? "About ten million euros per year"

Good catch, I added a reference. I think the information is only in the infobox currently but could be introduced in the text if needed.

Ideally, it would be in the text of the article. In 2022, it was 11 million euros, for example, but that also mentions the staff, and the electricity, and some other details that aren't in the article at all. It says there are 62 people on the staff as part of the budget, for example. Stuff like that could be included under "Organization". ♫ Hurricanehink (talk) 22:36, 16 November 2024 (UTC)

• Is there a reason the "Organization" section is first? It wasn't formed til 2000, but since it was started before then, it seems like "Instrument" or "History" would make more sense being first.

The reason for this is what "the Virgo Collaboration" and "the LVK Collaboration" are constantly referred to in the sources, and also in a few places in the article, and I wanted these terms to be defined from the start to make sure it is less confusing. Also see the comments from Mike over the order of Instrument and History.

Makes sense. ♫ Hurricanehink (talk) 22:36, 16 November 2024 (UTC)

I've only gotten through the lead and a little bit of the article, but there are some pretty big problems just in the lead. I'll wait to hear back from you before continuing my review, thanks. ♫ Hurricanehink (talk) 03:20, 15 November 2024 (UTC)

Thanks for the comments! I added individual answers to each of them. I have been meaning to check out other FAC but have been pretty busy with work these past weeks, I will try to see if I can drop a few comments on yours in the next few days. Thuiop (talk) 09:07, 15 November 2024 (UTC)

More

• Is there a reference for Virgo being located in Santo Stefano a Macerata? All material in the lead needs to be mentioned in the article somewhere. The Virgo history reference (ref 72) only says it is near Pisa.

Added.

• I guess I need clarification, but since the headquarters are the European Gravitational Observatory, is that an actual building? Like, I'm trying to imagine the actual physical structure, but there isn't a mention of any building anywhere in the article, and the European Gravitational Observatory article says in the first sentence that it's also the Virgo Collaboration, but that seems to be the topic of this article, right? Why does that separate article exist if it's the same thing? That article also says "EGO has an annual budget of €9 million split evenly between the French CNRS and Italian INFN." But sadly the link that says that is broken. Either way, just trying to figure out clarification for what this thing is, and where it's housed. One image mentions the "Mode-Cleaner Building" - is that it? Shouldn't that building be mentioned somewhere?

Hmm, this is a tricky one. EGO is an entity, but it is also used to refer as its physical headquarters, e.g. "at EGO" means the actual site where the detector is. It seems someone messed with the EGO page somewhat recently, I should have put it in my follow list earlier; EGO is a separate entity from the Virgo collaboration. Also, as to why there is a separate article: EGO could in principle have activities beyond Virgo, such as managing another detector. In practice, it only manages Virgo, so the extra page is a bit superfluous.

I think I understand. But shouldn't the building that houses Virgo, the Mode-Cleaner Building, get more of a mention than appearing in image text? ♫ Hurricanehink (talk) 17:59, 18 November 2024 (UTC)

Hm, I forgot to address that part, but the mode-cleaner building does not have much to do with it, it is just the building housing the input mode cleaner. The building hosting the Virgo headquarters is one of the "other buildings including offices...".

Could that be put in prose somewhere? ♫ Hurricanehink (talk) 04:40, 19 November 2024 (UTC)

I added something to the Organization section.

I appreciate the addition, but it added a new problem:

"EGO is responsible for the Virgo site (which represents its headquarters; by metonymy, the Virgo site is sometimes referred to as EGO) and is in charge of the construction, maintenance, and operation of the detector and its upgrades."

This is a lot to put in parenthesis. The metonymy part should probably be its own sentence, considering my own confusion with EGO vs Virgo. But also, there should be something about the building that hosts Virgo. There's still very little. I'd expect something in "history", or "organization". Stuff like the "Mode-Cleaner" building shouldn't only get a mention in an image caption. ♫ Hurricanehink ng(talk) 18:19, 19 November 2024 (UTC)

Hm, I will think about something I can add to the Infrasturcture section. Edit: I had started writing something, but unfortunately this is unsourceable; I have not been able to find an annotated map, aerial view or description of the buildings on the internet.

Nothing about the building? This document talks about the various buildings, at quick search. ♫ Hurricanehink (talk) 17:44, 20 November 2024 (UTC)

Thanks, I missed that one even though I spent quite a bit of time searching. It is pretty out dated but I guess I can use it. I wonder if I should move the gallery to the new paragraph? It probably would be more useful than at the bottom of the page.

Yea it would be better if it wasn't tucked at the end. ♫ Hurricanehink (talk) 20:23, 20 November 2024 (UTC)

I put it in the Infrastructure subsection. Thuiop (talk) 00:32, 21 November 2024 (UTC)

• "Virgo is designed to look for gravitational waves emitted by astrophysical sources across the universe which can be classified into three types" - just to be nitpicky, but you format the three types differently. The first - Transient sources: - has a colon, but the other two has a comma.

Fixed

• " It slightly curves spacetime (changing the light path) and can be detected with a Michelson interferometer in which a laser is divided into two beams travelling in orthogonal directions, bouncing on a mirror at the end of each arm. " - too much for one sentence. Something like "It slightly curves spacetime, changing the light path, which can be detected with a Michelson interferometer. In such a device, a laser is divided into two beams travelling in orthogonal directions, bouncing on a mirror at the end of each arm." - something like that says the same thing, but it takes a bit more time so it doesn't overwhelm the reader. I sometimes have to think when I'm writing a hurricane article, what if the reader doesn't know about something specific, so I'll try writing it on the simpler side.

Split it in different phrases

• "A 50 W output power " - per WP:MOS - all units need to be spelled out before they are abbreviated. I'm assuming this is watt?

Indeed. Done.

• "Key components of the injection system include the input mode cleaner (a 140-metre-long (460 ft) cavity to improve beam quality by stabilizing the frequency, removing unwanted light propagation and reducing the effect of laser misalignment), a Faraday isolator preventing light from returning to the laser, and a mode-matching telescope which adapts the size and position of the beam before it enters the interferometer." - I hate parenthesis within parenthesis! And by the time I got to the word "misalignment" I completely forgot I was in the first set of parenthesis. I suggest starting by descripting the input mode cleaner, so you don't need the one set of parenthesis. And then mention the other two things.

I adjusted the wording to avoid the parentheses.

• "The mirrors are polished to the atomic level to avoid diffusing (and losing) any light." - how often?

Only one time, when they are manufactured. Do you want me to specify it?

Well it's confusing by having present tense, that implies they are polished regularly. ♫ Hurricanehink (talk) 17:59, 18 November 2024 (UTC)

Got it, made it clearer.

• "It is planned to use a wideband configuration, decreasing noise at high and low frequencies and increasing it at intermediate frequencies. " - was it planned, or did it actually use this?

This is a bit of a complicated matter due to some issues with the instrument; I think for now it is more representative to leave it like this as this is how it will be used in the long term.

Sorry, I don't think I get this. Why is it present tense? ♫ Hurricanehink (talk) 17:59, 18 November 2024 (UTC)

Well, this is touchy and I am not sure how much of this is actually public. Basically, there is some mystery source of noise in the detector, and it hase been found that placing the SR mirror in a "misaligned" state helps with reducing that noise (at the cost of not using the SR mirror for its intended purpose). This is supposed to be temporary (probably lasting until the end of O4 next year), and will be complicated to source as most of the investigations are internal to the collaboration. This is why I think it is better to leave it as a "currently planned" thing, which is factual as this is how the SR mirror should be used in the future according to current plans.

Got it, thanks. ♫ Hurricanehink (talk) 04:40, 19 November 2024 (UTC)

• "nearly eight meters high" - I wish every metric unit had unit conversions for Americans like me to be able to understand. Ditto "6,800 cubic meters"

Damn, missed it as it was not in unit form. About the cubic meters, should I convert to gallons? I do not think there is a large enough imperial unit to match the cubic meter, this will amount to millions of gallons.

Yes, gallons is how we usually measure liquids over here. There are larger unofficial units, like "Olympic-sized swimming pools", or "Giraffe-sized", but neither would be very appropriate here. ♫ Hurricanehink (talk) 17:59, 18 November 2024 (UTC)

Ok, done.

• "After further upgrades, Virgo began its third observation run (O3)" - I was wondering where in the article you explained what "O3" was, because the first few times it popped up I had no idea what it was.

This is what I was discussing before with the previous commenter, regarding the placement of the History section. I now think putting it before Instrument makes more sense.

Yea that's a problem. ♫ Hurricanehink (talk) 17:59, 18 November 2024 (UTC)

Any thoughts? ♫ Hurricanehink (talk) 04:40, 19 November 2024 (UTC)

Yes, I think I will move it back to before the Instrument section; I was waiting to see if anyone had a different opinion.

Thoughts on this? ♫ Hurricanehink (talk) 20:23, 20 November 2024 (UTC)

Yes, I ended up moving it back up in the end, it is probably better this way. Thuiop (talk) 00:32, 21 November 2024 (UTC)

• (improving from the original Virgo level by a factor of 100). - what does this mean?

The pressure is 100 times less. Does it need to be clearer?

Yea, I didn't know that "pressure" what was improved. Clearer would be appreciated. ♫ Hurricanehink (talk) 17:59, 18 November 2024 (UTC)

• "with a mass of 1.4 M☉–1.4 M☉ " - 1.4 to 1.4? Am I missing something?

This is a binary system, hence there are two masses. Changed to plural to make that clearer.

I still don't think that makes the sentence clearer. I'm still overwhelmed at the info contained in the following, and would appreciate if it was simpler:

"The most common measure of gravitational-wave-detector sensitivity is the horizon distance, defined as the distance at which a binary neutron star with masses 1.4 M☉–1.4 M☉ (where M☉ is the solar mass) produces a signal-to-noise ratio of 8 in the detector."

I tried improving it a bit more by segregating the information.

Hmm, I guess my biggest question as a layman is why not say "both with 1.4 solar mass (M☉)"? I am still confused why it's written as 1.4 M☉–1.4 M☉ when as far as I can tell, they're both the same size, and that would be a whole lot simpler to read. ♫ Hurricanehink (talk) 04:40, 19 November 2024 (UTC)

Well, this is the standard way to write it, and this is how you will find it in the literature (including the reference I used). I can see how it might be confusing so I will change it.

This now made the sentence a lot longer and more complicated. Could you make this simpler, grammatically speaking? The "typically" part referring to the solar mass could be its own sentence. ♫ Hurricanehink (talk) 18:19, 19 November 2024 (UTC)

"The most common measure of gravitational-wave-detector sensitivity is the horizon distance, defined as the distance at which a reference target (typically a binary neutron star with both components having a mass of 1.4 M☉, where M☉ is the solar mass) produces a signal-to-noise ratio of 8 in the detector."

Better now?

A bit, but is there a reason there isn't a space between 1.4 and solar masses? ♫ Hurricanehink (talk) 06:25, 20 November 2024 (UTC)

Late night editing is why (+ in the editor it rendered the "solar masses" on the next line, so I missed it). Thuiop (talk) 09:11, 20 November 2024 (UTC)

• "Construction of the initial Virgo detector was completed in June 2003,[26] and several data collection periods ("science runs") followed between 2007 and 2011" - why the long wait from 2003 to 2007?

Although they finished building it in 2003, it was not operational before 2007. I added a phrase to reflect that.

• Why the extra spacing in the "Advanced Virgo detector" section?

I am not sure what you mean.

There is an extra space after the fourth paragraph. ♫ Hurricanehink (talk) 17:59, 18 November 2024 (UTC)

I apologize but I really am not seeing it from the editing interface. Is it perhaps because of the image placement for the timeline?

Yup, I get it, no worries. ♫ Hurricanehink (talk) 04:40, 19 November 2024 (UTC)

• The new mirrors were larger (35 cm (14 in) in diameter, with a weight of 40 kg (88 lb)), and their optical performance was improved. - again I hate parenthesis within parenthesis, but that's just me

Removed the parentheses.

• "Observation "runs" for the Advanced detector era are planned by the LVK collaboration with the goal to maximize the observing time with several detectors, and are labelled O1 to O5;" - why the present tense "are planned"?

They are still planned? We are currently during the O4 run, and the O5 plans are susceptible to change still.

But the labeling was done in the past, and decided a while ago, so my big question is, why the present tense? ♫ Hurricanehink(talk) 17:59, 18 November 2024 (UTC)

Well, this is still in flux. The names were decided from the start but the running periods have changed numerous times and are still decided today (in fact it is highly possible that O5 will not start at the current planned date, and the O4 run was extended this year). Hence I think the present is appropriate here.

Got it, appreciate the explanation. ♫ Hurricanehink (talk) 04:40, 19 November 2024 (UTC)

• It was soon followed by the better-known GW170817, the first merger of two neutron stars detected by the gravitational-wave network and (by October 2024), the only event with a confirmed detection of an electromagnetic counterpart in gamma rays, optical telescopes, radio and x-ray domains. - seeing as this reference is from 2017, either it should be "by 2017", or use the template that lists the current month.

Hm, I can change it to current month, but aren't we supposed to put the month this was last checked?

Is this figure regularly updated? I'm mostly just going by the reference, which is as of 2017. ♫ Hurricanehink (talk) 17:59, 18 November 2024 (UTC)

I can update it regularly if needed, but a second event like this would be a big enough thing to make the news, so this will definitely be updated when it happens. I think it is important to note that there were no other similar events observed for the time being, but providing a "negative source" will be hard.

So then you see that it will quickly become out of date. Since the next thing would be news (as I wondered would've been the case), it should be "as of December 2024". ♫ Hurricanehink (talk) 04:40, 19 November 2024 (UTC)

Ok, done.

And perhaps the same thing when you mention "as of 2024" in the lead? That should be {{currentyear}}. ♫ Hurricanehink (talk) 18:19, 19 November 2024 (UTC)

Done.

• "No signal was observed in Virgo, but this absence was crucial to more tightly constrain the event's localization." - this could use a bit more explanation, since I'm not sure why it wasn't detected.

I completed the phrase.

That's my review. There is a lot of good information in the article, so I appreciate your work so far. Please let me know if you have any questions. ♫ Hurricanehink (talk) 22:36, 16 November 2024 (UTC)

Thanks a lot for the review! I put in answers to your various comments and made some changes, including adding references to the stuff from the lead. Thuiop (talk) 00:06, 18 November 2024 (UTC)

Added a few replies, thanks for getting back, Thuiop (talk · contribs). ♫ Hurricanehink (talk) 17:59, 18 November 2024 (UTC)

Thanks, answered those. Thuiop (talk) 22:09, 18 November 2024 (UTC)

Thanks, just a few small things to double check. ♫ Hurricanehink (talk) 04:40, 19 November 2024 (UTC)

Ok, thanks again for all the comments! Thuiop (talk) 13:25, 19 November 2024 (UTC)

Just a few more points for clarification. Some of the edits you made might've introduced some new problems. ♫ Hurricanehink (talk) 18:19, 19 November 2024 (UTC)

Many thanks for all of the edits and tweaks on my account. Happy to give the thumbs up now. ♫ Hurricanehink (talk) 03:30, 21 November 2024 (UTC)

Ajpolino

Happy to take a readthrough and do the source review once you've responded to Hurricanehink's comments above. Ajpolino (talk) 14:11, 17 November 2024 (UTC)

Alright, got through the first couple sections over breakfast. It's a lovely article so far, clear even to a biologist. Small notes as I read through:

• Lead - "The Virgo interferometer is a large-scale experiment... The instrument..." Is the Virgo interferometer an experiment or an instrument? I gather the simple answer is probably "both" but we should at least be consistent in how we conceptualize it in the first few sentences.

Yes, this was also discussed in previous comments. I will settle for "instrument" in the lead, although both would be correct.

• Lead - "The instrument... instrumentation" an instrument's instrumentation seems redundant. Would it be appropriate to say "mirrors and detectors"? Or with the above you could rephrase to something like "the experiment centers on an enormous Michelson interferometer... mirrors and instrumentation...".

Conversely, I changed "instrument" by "detector" to avoid the redundancy.

• Lead - "The collaboration" should "Collaboration" be uppercase since it's referring to the Virgo Collaboration in particular?

I changed it, although it probably was also correct without the uppercase since collaboration is a common noun.

• Organization - "research on, and studies of" are these two different things, or is this redundant?

Yes, it is a bit redundant. It seems like the phrase was initially "research and studies on gravitation" but gradually became distorted; I removed the redundancy.

• Science case - Is there anything that can be done to make "instabilities in compact systems" slightly clearer? I think to my ear "systems" is a generic word (like "things"), but it's probably meant here in a specific sense?

Changed to "astrophysical objects", still somewhat generic, but the point of that specific bit was to be a bit generic.

• Instrument#Laser - O3 and O4 run are mentioned before we know what they are. I see there's been some discussion above on section order. I don't have an opinion on that (yet) but you can get around it here by referring to the date of the run or upgrades (e.g. "reaching 100 W during its 2019–2020 run" or "after 2018 upgrades...").

Yes. I moved the History section following one of the commenters, but I now think this was a mistake; I moved it back.

• Instrument#Laser - "The solution for Advanced Virgo" odd phrasing. Is "Advanced Virgo" used to refer to the upgrades, or to the instrument after it was upgraded? If the former (as the term is used earlier in the article) you could say "The Advanced Virgo upgrades replaced these lasers with..." instead.

I changed it to "Advanced Virgo design"; I myself are not 100% sure which laser is being used right now as there were some issues with the fibre laser early in O4.

• Instrument#Mirrors - "extremely pure glass obtainable" typo?

This was originally "the purest glass obtainable", I forgot to remove the second part when I changed it.

At Instrument#Mirrors. Still very clear. Will get through the rest asap. Ajpolino (talk) 13:24, 20 November 2024 (UTC)

Thanks a lot for the comments! I addressed them; please note that I ended up moving the History section back up, so be sure not to miss it. Thuiop (talk) 20:23, 20 November 2024 (UTC)

• Instrument#Superattenuators - Just to make sure I understand, when you say "benches" do you mean tables that equipment goes on? Or does it have some specific meaning here that I'm not familiar with?

Yes. I clarified the first occurence and added a link to optical table.

• Instrument#Infrastructure - Is it important we learn the abbreviation HWS? It's not used again in the article.

No indeed, although it is widely used in the litterature.

• Instrument#Infrastructure - PCal or Pcal? Either is fine, just be consistent throughout.

Corrected

• Instrument#Infrastructure - Should the paragraph "Due to the interferometer's high power..." be up in the Instrument#Mirrors subsection? The two paragraphs after it also don't seem to quite fit with the first half of the infrastructure section. Maybe they'd go better with Detection system or Noise and sensitivity (or maybe I should just broaden my mental image of "infrastructure")?

No, I wanted the Infrastructure section to regroup all the peripheral subsystems which, although very important, are not as critical as the laser or the mirrors. I feel here that the TCS, the stray light control and the calibration fit in this category. I guess the section could be split in two, but I do not feel it is overly long; happy to hear your opinion.

• Instrument#Infrastructure - Does "additional precautions are needed" mean "additional precautions" are currently being used? Or does it mean they're needed for the future?

Currently. I replaced "needed" by "taken".

• Instrument#Infrastructure - "Dedicated hardware... have been developed for Virgo" Seems silly to say just after we spent 14 paragraphs reading about it. Maybe changing the end of the sentence to "for storing and analyzing Virgo data"? or whatever exactly you want to get across.

I meant specifically electronics, not the things mentioned above. I made it clearer

• Instrument#Detector sens - "a 2011 Virgo sensitivity curve is plotted with a log-log scale." we don't typically refer explicitly to figures in-text, so this can be cut. That said, I don't think there's any prohibition of it, and if your preference is to keep it as-is, I'm not complaining.

Yes, I thought about that when writing (the phrase was already there). I feel it is not too out of place as the juicy stuff is really in the figure, and explaining it without the figure barely makes sense.

• Instrument#Detector sens - On my screen there's a reference (currently 95) floating below this section. Not sure where it's intended to go, so just flagging it for your consideration.

I think it did not get moved properly when I moved the History section, thanks.

• Scientific results - "and putting tight" is the grammar wrong here or am I misunderstanding the sentence?

The grammar was wrong.

Done! Very clear and enjoyable read. Will commence the source review tomorrow. Ajpolino (talk) 03:07, 21 November 2024 (UTC)

Thanks again for the comments Thuiop (talk) 09:31, 21 November 2024 (UTC)

Support on prose. Source review below. Ajpolino (talk) 02:50, 22 November 2024 (UTC)

Source Review

Opening as another section for ease of navigation. The article is cited to reliable sources for the topic: relevant scholarly work as well as explanatory webpages hosted by Virgo and its partners. There are a couple papers from publishers with chequered reputations (MDPI, [2] and [3]) but both are written by authors who would be in a position to speak with authority on the topics at hand.

The reference section needs a bit of sprucing up to meet the FA criteria. All small things:

• The webpage "The Virgo Collaboration" (currently ref 2) is dead and I don't see it on archive.org. Any chance you can find that page elsewhere?
• Can we get a date on the LIGO-Virgo MoU? Ditto [4]. And [5]. I'll stop posting each, but for anything dated (news articles, press releases, etc.) a date would be a nice addition to the reference. Makes it much easier to find the reference if it goes dark.
• "Consistent citations" is one of the FA criteria. Sometimes your source titles are in title case, sometimes sentence case (I gather you're following each referenced publication's style). It doesn't matter what style you pick here, but your reference section should be internally consistent.
• Can we get more reference info on What is Ligo??
• "Many authors of the Virgo Collaboration" reads informal. Perhaps just "The Virgo Collaboration" (as the document first notes) or the classic list a few authors followed by "et al."?
• The Virgo Physics Book - should the date be 2020? Not sure if 2006 is a typo or if I'm missing something.
• Is there any other bibliographic info we can find on the Virgo Final Design document?
• Reference 64 "Instruments_Laser&optics" doesn't seem to be working. It just takes me to Virgo's homepage.
• Can we get some formatting for the "VIRGO Vacuum System Overview" reference? You can plop it into {{cite web}} or just make it match the other official documents you cite.
• It looks like the "The Virgo Newtonian calibration system for the O4 observing run" manuscript has now been published in a journal. Flagging it in case you'd like to update your reference.
• Is "Analysis of sensitivity and noise sources for the Virgo gravitational wave interferometer" a PhD thesis? If so, you should format it like you do the other thesis (Li-Wei Wei).
• I think the paper "Distance measures in gravitational-wave astrophysics and cosmology" is cited twice in separate references (currently 93 and 94)

Once you get through those, I'll take a second look and then I think we can wrap this up. Ajpolino (talk) 02:50, 22 November 2024 (UTC)

Hi, thank you for the comments. I am quite busy this weekend so it will take a bit of time to address them all, but they are duly noted. Thuiop (talk) 09:21, 22 November 2024 (UTC)

I have addressed all the specific comments, I will handle the broader ones later today or tomorrow. Thuiop (talk) 09:58, 26 November 2024 (UTC)

@Ajpolino I added the missing dates and corrected the citation style. Let me know if there is anything I missed. Thuiop (talk) 23:36, 26 November 2024 (UTC)

Super! Traveling for the American holiday, so it may take me a few days to return to this, but I will get to it as soon as possible. Ajpolino (talk) 13:55, 27 November 2024 (UTC)

Thuiop, I've taken the liberty of tweaking some references to make them visually consistent (slightly silly perhaps, but an FAC requirement). Please check to make sure I didn't mess anything up. I tried to match what I assumed was your preference based on the other references. With that, and my comments above, happy to Pass this source review. Thanks for the interesting read. Ajpolino (talk) 03:25, 3 December 2024 (UTC)

Thank you, these look good to me. And thank you again for all the review work! Thuiop (talk) 09:29, 3 December 2024 (UTC)

Sgubaldo

Will take a look. Ping if I haven't said anything by next week. Sgubaldo (talk) 15:00, 19 November 2024 (UTC)

Hi, here is the requested ping @Sgubaldo Thuiop (talk) 09:57, 26 November 2024 (UTC)

Sorry for the delay, will try to have a look before Thursday Sgubaldo (talk) 13:20, 26 November 2024 (UTC)

Apologies again, I've been ill. I'll have this done by the end of the weekend. Sgubaldo (talk) 14:16, 29 November 2024 (UTC)

Thanks for still taking the time to notify me; I hope you will get better! Thuiop (talk) 17:39, 29 November 2024 (UTC)

Infobox

• Could we have a more specific value for the budget (perhaps the 2024 value)?

Done.

• |fields= feels redundant when you’ve already got Gravitational Wave detection under |purpose=::

Done.

• Instead of having Italy under |region=, why not include it after Cascina in |Location= (i.e. Santo Stefano a Macerata, Cascina, Italy)

Done.

• Do we have a more specific number of staff? If not, then just have ≈880, no need for the whole sentence

The exact count changes very often which is why I went for an approximate amount. I feel the sentence is necessary as I would like to stress that these are the people forming the collaboration and not e.g. the people employed by EGO.

• The title above the inbox is ‘The Virgo experiment’, but this isn’t used anywhere else in the text?

Changed to "Virgo".

Lead

• I feel like the first two sentences could be merged. Why not "The Virgo interferometer is a large-scale instrument for detecting gravitational waves located in Santo Stefano a Macerata, near the city of Pisa, Italy."

Done.

• "....was first approved in 1992 and the construction was completed in 2003." – no need for the 'the'

Done.

Organization

• Shouldn't the title be Organisation if you're using British English?

Done.

• ”The Virgo project is managed by…” ==> As this is the very first sentence after the lead, I’d use ‘interferometer’ rather than ‘project.’

Done.

• ”By metonymy, the site itself is sometimes referred to as EGO, as it represents its headquarter” ==> I presume this is trying to say “By metonymy, the site is sometimes referred to as EGO, as the consortium is headquartered there.” It would also be good if you could have a source after this sentence.

Done; I will see if I can find a source but it may be a bit complicated since this is mostly implicit.

• ”EGO is responsible for the Virgo site and is in charge of the commissioning, maintenance, and operation of the detector and its upgrades.” ==> “EGO is responsible for the Virgo site and is in charge of the detector’s commissioning, maintenance, operation, and upgrades.”

Done.

• ”he budget of EGO fluctuates between 9 and 11.5 million euros per year (2018-2024 period), employing around 60 people” ==> “Between 2018 and 2024, the budget of EGO fluctuated between €9 and €11.5 million, employing around 60 people.”

Done.

• ”The Virgo Collaboration consists of all the researchers working on various aspects of the detector.” ==> Is ‘all the’ necessary here?
• ”…Collaboration in October 2024.” => Probably ‘as of’ would work better rather than ‘in’

Done.

Science Case

• I think ‘coalescenses’ is spelt wrong?

Indeed, rectified.

• ”Detection of these sources is a new way to observe them (often with different information than classical methods such as telescopes)….” ==> Do you mean “Detection of gravitational waves from these sources….”

Done.

History

• ”It began making observations again in 2017, quickly making its first detections with the LIGO detectors.” ==> “It began observations again in 2017, and made its first two detections soon after, together with the LIGO detectors.”

Done.

• ”….Weber; although they could detect gravitational waves in theory, none of the experiments succeeded.” ==> True, but I don’t think it tells the full story. Perhaps in place of “although they could detect gravitational waves in theory, none of the experiments succeeded.”, I would specify that he claimed to have detected waves but no one could replicate his findings. Consider adding some information from this source

This is indeed not the full story, but I did not want to go into too much details since this is not a page about Weber bars. However if you think that this is important I can think of something to add.

• Ref. 26 is 118 pages long, could you specify the particular pages for when it’s used?

This one is tricky. I would love to do it but I only have access to the ebook version, which does not have page numbers, and whose pages in the PDF seemingly do not match the physical edition. Is there a way to cite the relevant chapters instead?

• Move Ref. 37 after the bracket and full stop

Done.

• Ref. 41 is over 700 pages long, please specify page numbers

Done.

• ”Observation "runs" for the Advanced detector era are planned by the LVK collaboration with the goal to maximise the observing time with several detectors, and are labelled O1 to O5; Virgo began participating in these near the end of the O2 run.” ==> Should it be ‘were’ instead of ‘are’?

It was discussed above; my opinion is that the runs are still being planned, with the dates of the O5 run not being finalized yet, and the present is therefore correct.

• ”A system of adaptive optics were installed to correct the mirror aberrations in situ…..” ==> “A system of adaptive optics was installed to correct the mirror aberrations in situ.”

Done.

• ”After further upgrades, Virgo began its third observation run…” ==> There’s an extraneous space before this line

Removed it.

• ”The upgrades following O3 are part of the Advanced Virgo + program…” ==> is there an extraneous space before the plus?

Yes, removed.

• ”Plans to enter the O5 run are expected to be known before the end of 2024” ==> Since we’re getting to the end of 2024, is there more info that can be added to this?

It seems it was delayed to early 2025, I reflected that.

• ”The signal, produced by the final minutes of two neutron stars spiralling closer to each other and merging…” ==> There’s a MOS:SEAOFBLUE for ‘neutron stars spiralling closer

I removed the link on "spiralling closer" which was less useful.

Scientific Results

• ”in particular, it was found that the deviation from perfect spinning balls for close known pulsars is (at most)” ==> ‘spheres’ instead of ‘balls’, and no need for the brackets between ‘at most’

Done.

• ”and put tight constraints on the speed of gravity….” ==> Could you add some detail as to what the constraints were?

Done.

• ”the first merger of two neutron stars detected by the gravitational-wave network and (by November 2024) the only event with a confirmed detection of…” ==> ‘as of’ instead of ‘by’

Done.

Outreach

• "The Virgo collaboration participates in..." – capitalise collaboration?

Done.

• "The collaboration is involved in several artistic projects,...." - ditto as above.

Done.

• ”One important activity is the organisation of guided tours of the Virgo facilities for schools, universities, and the public” ==> reads a little puffery. “One example of an activity is guided tours of the Virgo facilities for schools, universities and the public.”

Done.

• ”….which develops methods and devices for the public understanding of gravitational waves and related topics” ==> I don’t understand what this sentence is saying

Rectified.

Other Comments

• Remove ‘as of 2021’ In the image of the countries with institutions contributing to EGO/Virgo since checking Commons shows the image was updated this year

Done, I forgot to upload the legend after having the image updated.

• I realise that the very first detection of gravitational waves was done by LIGO, but Virgo was part of the announcement if I remember correctly. I see it's mentioned in the lead but not the body

I added a mention of it in the body.

• Most non-journal sources are not archived. Perhaps run IAbot on the page

Will do.

Comments above. Feel free to refuse with justification. Sgubaldo (talk) 14:48, 1 December 2024 (UTC)

Thanks a lot for your comments! I haved addressed most of them and put answers above, as with the other commenters.Thuiop (talk) 20:35, 1 December 2024 (UTC)

Hi Sgubaldo, I was wondering if you felt in a position to either support or oppose this nomination? Obviously, neither is obligatory. Thanks. Gog the Mild (talk) 15:07, 16 December 2024 (UTC)

I haven't gone over the Instrument section in enough detail to outright support, but my other comments have been addressed and I think the lead improvements below are great. Sgubaldo (talk) 15:32, 16 December 2024 (UTC)

Comments by RoySmith

My apologies for jumping in at the last minute (and my false start yesterday). I've looked at this a few times but was finally prodded into action by WT:FAC#Science articles are underrepresented. I'm not going to do an in-depth review, but do want to convey my general impression of the article.

My basic concern is the overall structure of the article. This is about a scientific instrument. I think it should put more emphasis on description of the equipment and the experiment it was designed to perform. And, per WP:TECHNICAL, it should make this approachable to a typical reader. I recognize that this is a highly technical topic which can't truly be understood by a reader who doesn't have a grounding in university-level physics, but I think a better job can be done.

The lead section starts with a short paragraph that does indeed talk about the instrument itself, but the majority of the lead is about the international consortium that runs it and the history of its construction. By the end of the lead, the reader still knows almost nothing about with it is, unless they already know what a Gravitational wave or a Michelson interferometer are. The body of the article follows the same pattern. The first section is "Organisation", which goes into detail about who manages is, how it got named, who analyzes the data, etc. The next two major sections (Science case and History) continue to describe things which do not answer the question, "What is this thing?" It's not until we get down to "Instrument" that this question begins to be addressed.

I get the impression that this article shies away from a technical discussion by concentrating too much on the political aspects of how large-scale scientific projects work. Compare with Large Hadron Collider, which is another mega-project run by an international consortium. There, the lead certainly talks about the political aspects, but mostly talks about the instrument itself: what it does, how it works, and the experiments it has performed. The article has a similar structure; it starts out with "Background", which immediately dives into the science. International Space Station is another good example. The lead presents a much more balanced mix of describing the station itself and the international cooperation that went into building and operating it. The body certainly starts out with the organizational stuff ("Conception"), but quickly gets into the science and technology, and spends more time there. I'd like to see this article follow more of that pattern.

Hello Roy, and thanks for your comments.

I think this is mostly a section order question. I do not feel there is too much imbalance into the content; the Organization section is pretty short, and apart from the regular "History" section, the only other non-technical section is the Outreach one which is also very short. Now, as to why the order is that way, it was already partly discussed in the above comments. Basically, it boils down to two things

• I wanted the Organization section to be at the beginning to be able to use terms such as "LVK Collaboration", "EGO" or "Virgo Collaboration", especially in the History section, which requires the reader to understand what these things are.
• It was discussed moving the History section after Instrument, but this ended being confusing to the following commenters. This is because Advanced Virgo is mentioned in the Instrument section, but is introduced in the History section.

So that is the explanation for the article body. For the lead, I do get what you mean, but I am unsure what the alternative is. It is pretty complicated to describe what a Michelson interferometer is, what a gravitational wave is, how the interferometer can detect them and why it is interesting in a sufficiently short manner to fit in the lead. I would like to point out that it is also pretty difficult to understand what the Large Hadron Collider does from reading the lead, unless you already know what a particle accelerator is (although it is later explained in the Background section). Would you be advocating to introduce a Background section? I can try to write something of the sort if you want. Otherwise, I could add a bit more details to the first paragraph of the lead, although I think it would still be cryptic to people. What do you think of the following proposition?

"The Virgo interferometer is a large-scale instrument for detecting gravitational waves in Santo Stefano a Macerata, near the city of Pisa, Italy. The detector is a Michelson interferometer, which can detect the minuscule length variations in its two 3-km (1.9 mi) arms induced by the passage of gravitational waves. The required precision is achieved using many systems to isolate it from the outside world, including keeping its mirrors and instrumentation in an ultra-high vacuum." (with
the correct wiki formatting)

In any case, I am happy to hear your thoughts, either on the body structure or the lead, with these explanations in mind. Thuiop (talk) 16:16, 2 December 2024 (UTC)

I think restructuring might address some of Roy's concerns. A start would be to switch paragraphs two and three of the Lead around. In the body perhaps bring Instrument and to the top. Perhaps History could go at the bottom? Graham Beards (talk) 17:21, 2 December 2024 (UTC)

The issue with History at the bottom is the mentions to Advanced Virgo, which I think are important since the changes were very significant. The Organisation one is a bit more flexible but I would still put it before History. In that sense, the Background section would make sense. As for the lead, this may work. Thuiop (talk) 21:15, 2 December 2024 (UTC)

I'll take a shot the lead. This draws from a few other articles and may not be a strict summary of what's in this article, so further edits to the body might be required if this is used. The three paragraphs talk about, in turn, the history and scientific background, a technical description of the instrument, and finally the organizations that run the experiments.

possible lead replacement

The Virgo interferometer is a large scientific instrument which detects gravitational waves. These waves, produced by massive objects in space such as pulsars and binary stars, radiate outward from their sources at the speed of light. Their existence was theorized in the late 19th and early 20th centuries and predicted by the theory of general relativity. The first attempts in the 1970s to detect the waves failed but led in the early 1980s to the idea of using a large interferometer as a detector. An instrument design, proposed in 1987 by Adalberto Giazotto and Alain Brillet, was approved by the Italian Istituto Nazionale di Fisica Nucleare (INFN) and the French Centre national de la recherche scientifique (CNRS) with construction beginning in 1996 and the first observations made in 2000. The instrument is a large Michelson interferometer; this is an optical device which splits a laser beam into two parts, sending each on a different path and measuring extremely small differences in how long it takes for the beams to traverse the two paths. In Virgo, the two paths are 3 km long steel tubes maintained under an ultra-high vacuum. One path is oriented east-west and the other north-south, and thus react differently to gravitational waves impinging on the system. A set of mirrors at the ends of the tubes cause the beam to bounce back and forth thousands of times through the tubes, increasing the sensitivity of the instrument. The Virgo facility is located in Santo Stefano a Macerata, Italy and operated by the European Gravitational Observatory (EGO), an international consortium of over 800 researchers in 21 countries. Activities are coordinated with the Laser Interferometer Gravitational-Wave Observatory (LIGO) the United States and the Kamioka Gravitational Wave Detector (KAGRA) in Japan, with joint observation runs lasting months or years interspersed with periods used for maintenance and upgrades. The device is named after the Virgo Cluster, which includes about 1,500 galaxies in the constellation Virgo.

RoySmith (talk) 19:30, 3 December 2024 (UTC)

Hi Roy, while we await our expert, the nominator's comments, may I suggest "located" is redundant and "be reflected" is better than "bounce back"? Graham Beards (talk) 20:47, 3 December 2024 (UTC)

Both of those suggestions sound good to me. RoySmith (talk) 22:08, 3 December 2024 (UTC)

Hm, I am not too fond of it. I find it strange to have historical information in the first paragraph, instead of basic information about the instrument such as its location and what it is. Overall, I feel like the focus is not on the correct information: for instance, in the historical part you describe the genesis of gravitational waves and interferometers, but nothing about the history after the year 2000, which is where the interesting stuff happens. I am also not sure about describing what gravitational waves are. For the instrument part, the exact orientation of the arms does not seem relevant to me; the fact that the light bounces thousands of times is also a "technicality"; it is more important to note that a lot of precautions are taken to isolate the instrument from the outside world. Finally, the organisation part does not make the difference between EGO and Virgo Collaboration which is very important. It also does not explain why joint observation is important, while it is a crucial point of operating a gravitational wave detector. Thuiop (talk) 00:37, 4 December 2024 (UTC)

I agree. I still think swapping the second and third paragraphs is worth considering, (and massive objects alone don't cause waves). Also, we need to agree that the focus of the article is as much on the project as it is the interferometer. Graham Beards (talk) 15:26, 4 December 2024 (UTC)

I'm eager to see your improved version. RoySmith (talk) 15:39, 4 December 2024 (UTC)

Ok, let me try something:

New lead proposition

The Virgo interferometer is a large-scale instrument for detecting gravitational waves in Santo Stefano a Macerata, near the city of Pisa, Italy. The detector is a Michelson interferometer, which can detect the minuscule length variations in its two 3-km (1.9 mi) arms induced by the passage of gravitational waves. The required precision is achieved using many systems to isolate it from the outside world, including keeping its mirrors and instrumentation in an ultra-high vacuum and suspending them using complex systems of pendula. Its observations are concentrated on specific periods, between which the detector is upgraded to increase its sensitivity. These "observation runs" are planned in collaboration with other similar detectors, including the two LIGO in the United States and the Japanese KAGRA, as cooperation between several detectors is crucial for detecting gravitational waves and pinpointing their origin. It was conceived and built when gravitational waves were only a prediction of general relativity. The project, named after the Virgo galaxy cluster[4], was first approved in 1992 and construction was completed in 2003. After several years of improvements without detection, it was shut down in 2011 for the "Advanced Virgo" upgrades. In 2015, the first observation of gravitational waves was made by the two LIGO detectors, while Virgo was still being upgraded. It resumed observations in early August 2017, making its first detection on 14 August (together with the LIGO detectors); this was quickly followed by the detection of the GW170817 gravitational wave, the only one observed with classical methods (optical, gamma-ray, X-ray and radio telescopes) as of 2024.[5] Virgo is hosted by the European Gravitational Observatory (EGO), a consortium founded by the French Centre National de la Recherche Scientifique (CNRS) and the Italian Istituto Nazionale di Fisica Nucleare (INFN).[1] The broader Virgo Collaboration, gathering 880 members in 21 countries,[2] operates the detector, and defines the strategy and policy for its use and upgrades. The LIGO and Virgo collaborations have shared their data since 2007, and with KAGRA since 2019, forming the LIGO-Virgo-KAGRA (LVK) collaboration.[3]

Thuiop (talk) 23:03, 4 December 2024 (UTC)

• Two comments.
  • In the first sentence it is ambiguous as to whether it is the waves or the detector which are in Santo Stefano a Macerata. It needs rearranging to something like. "The Virgo interferometer is a large-scale instrument in Santo Stefano a Macerata, near the city of Pisa, Italy for detecting gravitational waves.
  • And this is a little awkward "Its observations are concentrated on specific periods, between which the detector is upgraded to increase its sensitivity." How about "Between its periodical observations the detector is upgraded to increase its sensitivity." ? Graham Beards (talk) 11:42, 5 December 2024 (UTC)

    Ah, I had missed this comment. I am happy to implement these suggestions, depending on @RoySmith opinion. Thuiop (talk) 14:31, 6 December 2024 (UTC)

    I don't think we need to have "in Santo Stefano a Macerata, near the city of Pisa" in the first sentence. That's just not the most important thing about it. Imagine you were in an elevator taking a ride up to your office and had 30 seconds to tell a colleague about this instrument. How much of that precious time would you spend explaining that it was in that specific town, and that the town was near Pisa? Wouldn't it be enough to just say that it is "in Italy"?

    My understanding of the physics here is that while it's not essential that the arms are oriented east-west and north-south, it is essential that they are at right angles to each other as that lets you decompose the signal into two orthogonal components, maximizing the directional sensitivity. RoySmith (talk) 14:47, 6 December 2024 (UTC)

    I can replace by "near Pisa, Italy".
    I can also mention the perpendicularity of the arms, but Michelson interferometers typically have perpendicular arms already so this does not seem to be an important information to me. Also, the picture in the infobox shows them to be perpendicular. Thuiop (talk) 16:26, 6 December 2024 (UTC)

    I think it's already there: "From the air, the Virgo detector has an "L" shape with its two 3-km-long (1.9 mi) perpendicular arms." Graham Beards (talk) 16:40, 6 December 2024 (UTC)

    In the body, sure; I think he was talking about the lead in particular. Thuiop (talk) 16:42, 6 December 2024 (UTC)

    I am not convinced that is needed. As you say, it is shown in the Lead image. Graham Beards (talk) 18:49, 6 December 2024 (UTC)

    Ok, in any case, I changed the lead to this new proposition. Thuiop (talk) 09:08, 9 December 2024 (UTC)

@FAC coordinators: I think we are all done here. Graham Beards (talk) 13:08, 14 December 2024 (UTC)

• Hi Roy, in the light of Graham's comment was wondering if you felt in a position to either support or oppose this nomination, or make any other comment regarding its suitability for promotion? Obviously, none of this is obligatory. Thanks. Gog the Mild (talk) 13:51, 14 December 2024 (UTC)

  The lead section as it stands now is an improvement over what it was before, but beyond that I haven't read the article in enough detail to either support or oppose. RoySmith (talk) 14:26, 14 December 2024 (UTC)

Drive-by comments

• Vinet 2020: the title on the title page differs from the one you give. Suggest using the |volume= parameter.
• "The Virgo interferometer is a large-scale instrument near Pisa, Italy". Suggestion: insert 'scientific'.
• "including the two LIGO in the United States and the Japanese KAGRA". Acronyms in full at first mention please.
• "the only one observed with classical methods". Perhaps 'the only one also observed with classical methods'.

Gog the Mild (talk) 12:27, 19 December 2024 (UTC)

Hi Gog, I have taken the liberty of including all bar the first point. Graham Beards (talk) 12:47, 19 December 2024 (UTC)

Hi Gog, Graham,

Thanks for the comments and their implementation. I agree with 2. and 4. (I think I had initially included the "also" but it was removed through some copy-editing). Regarding 3., I am fine with mentioning the acronyms in full, although I have never seen someone referring to either of them with something else than the acronym.

I also changed the title for Vinet 2020 to the one from the title page. Note that it used to be called "Vol II" (see e.g https://labcit.ligo.caltech.edu/~hiro/docs/vpb2.pdf), but it seems they dropped the denomination at some point. Thuiop (talk) 13:10, 19 December 2024 (UTC)

• Closing note: This candidate has been promoted, but there may be a delay in bot processing of the close. Please see WP:FAC/ar, and leave the {{featured article candidates}} template in place on the talk page until the bot goes through. Gog the Mild (talk) 13:12, 19 December 2024 (UTC)

The above discussion is preserved as an archive. Please do not modify it. No further edits should be made to this page.