Talk:Cherenkov radiation

message: This article states that "even very radioactive substances do not glow in air"; on the other hand. polonium claims, supported by LANL , that polonium does glow blue in air "by excitation of the surrounding air". Is this a different glow, or is this article wrong? --Andrew 18:07, Dec 16, 2004 (UTC)
Upon further research, a number of radioactive substances definitely glow (see the CRC handbook; eg. polonium, promethium, and radium).  So I took out the claim:
:The Cherenkov effect is used as a visual cue in Hollywood movies to announce radioactive materials.  However, it should be noted that even very radioactive materials do not glow in air - the particles are simply too slow - and that even in water a source may be producing a dose of radiation lethal in seconds without easily visible Cherenkov radiation. A source itself would only glow if it was very strong, transparent, and an insulator.
:I wrote that working from the basis that a particle would only produce a Cherenkov effect in air if it was faster than the speed of light in air (meaning it'd have to be at a highly relatavistic speed).  This may be a misunderstanding of the physics involved on my part, however.  In any case, we should probably note that the glow cannot be counted on to identify a (perhaps dangerously) radioactive object.  I'd also note that "excitation of the surrounding air" could refer to excitation of electrons in air, by passing particles, which then produces light when the electrons return to the ground state.  This is different from Cherenkov radiation.  Pakaran 00:18, 29 Apr 2005 (UTC)
thread_title: Glow

message: Should we mention that Cherenkov radiation was predicted by Oliver Heaviside in 1888-1889?
Absolutely: in standard practice (calling an effect after the one who predicted it, starting with Halley) it would even be called Heaviside radiation. Thus it should be mentioned in the leading paragraph. Harald88 17:02, 22 March 2006 (UTC)
replies: text: Except that Heaviside's "prediction" concerned an hypothetical charged particle moving faster than light in the VACUUM. 79.32.63.99 (talk) 13:18, 14 October 2011 (UTC)
replies: text: If I am not mistaken, he only considered this (in vacuum) as a hypothetical possibility. What would happen if...? There was nothing wrong with this. My very best wishes (talk) 14:47, 24 August 2013 (UTC)

text: I also referenced a similar predictive work by Arnold Sommerfeld - it seems that due to the newly found restriction of Einsteins relativity in the early 1900s, any intellectual games with super-c particles were also quickly forgotten. --Gunnar (talk) 20:07, 16 January 2019 (UTC)
thread_title:  Heaviside's prediction 

message: This may seem like an obvious question to those who are technically acquainted...
You say that the absence of Cherenkov radiation is not a sure sign of the absence of dangerous levels of radioactivity,
but could it be said that the presence of Cherenkov radiation is a sure sign of the presence of dangerous radioactivity?
--68.107.141.30 00:52, 25 December 2005 (UTC)
replies: text: Yes, it's true that the presence of the Cherenkov's Radiation means that -to put things simply- you're in big trouble. But only if you are in the same medium as the one in which the radiation occurrs or and similiar and close to the source. If you're in a medium which stops the radiation then it's, of course, stopped. For example: imagine Cherenkov's Radiation occurring in a place fully isolated from the outside -- you're safe outside as long as the isolation is not destroyed. Isolation can anyting that doesn't meet the requirements for the radiation to take place. Another example: It's much harder to produce the radiation in the air than it is in water. If you produce weak radiation in water then you can make it powerful enough for it to visible in water, but at the same time weak enough for it to be harmful in air. Then, you'll be able to actually watch it, standing next to the water pool.  —Preceding unsigned comment added by 83.142.107.30 (talk) 23:14, 6 April 2008 (UTC)
thread_title:  Explicit definition 

message: In the Science and technology in the Soviet Union article, the name is spelled as Tscherenkov (assuming it's the same person). Should there be a redirect from Tscherenkov radiation to Cherenkov radiation? Googling suggests this is the german spelling of the name.
--129.240.122.183 22:35, 26 January 2006 (UTC)
replies: text: Sure, why not? Done. -- Xerxes 04:17, 27 January 2006 (UTC)
replies: text: This is a small point but it's noteworthy: while the man's name is Cherenkov, the phenomenon is called Cerenkov Radiation (without the 'h').  I've never seen it spelled with an 'h' in any physics text.  But this is a small point. Astrobayes 22:23, 29 June 2006 (UTC)
replies: text: The spelling Cerenkov was frequently used in scientific papers in the past. (I have no idea why). According to Google ngrams, since about 1995 the majority of English-language works use "Cherenkov". --ABehrens (talk) 06:11, 12 January 2018 (UTC)

text: See Pavel Alekseyevich Cherenkov for further discussion. The guy's name was "Черенков", not any of the above. The current standard transliteration would seem to be "Cherenkov", but transliterations have been known to change over the years. "Čerenkov" does appear to dominate in science, but what that indicates is questionable. Probably it means that it was the favored spelling of someone who wrote a notable book. If someone is interested and has a lot more free time than I do, it would be a nice thing to track down. :) Andrew Rodland 22:28, 17 July 2007 (UTC)
replies: text: There are at least a dozen standards for the Romanization of Russian. The Scholarly/Scientific system, which uses single characters to represent single Russian letters, would write "Čerenkov". So does the ISO-9 standard, and the Russian GOST 7.79(System A). Other standards would use "Cherenkov". --ABehrens (talk) 06:11, 12 January 2018 (UTC)

text: See V.P. Zrelov,Cherenkov Radiation in High Energy Physics, 1970, widely referred to physics text... —The preceding unsigned comment was added by Stuart Ponder 63.199.162.164 (talk) 08:54, 5 December 2006 (UTC)

text: There are several official Russian standards for transcribing Cyrillic using the Roman alphabet. (You can see them at ru:Транслитерация русского_алфавита латиницей). In one of those systems, "Ч" is transcribed as "Č". "Tch" is the French way of representing the "ch" sound. Since French was the international language of diplomacy, the "tch" Romanization was formerly (until about 20 years ago) used on Russian passports. --ABehrens (talk) 06:11, 12 January 2018 (UTC)
thread_title:  Tscherenkov / Cherenkov 

message: Could someone explain in the article what's meant by "faster than the speed of light in the medium"? I thought the speed of light was a constant, and nothing could go faster than it?
:Nothing can go fater than Light in vacuum, however, you can go faster than light in a medium (like water or glass) because light is slowed down. --Falcorian (talk) 03:42, 25 March 2006 (UTC)
replies: text: If you want a straightforward answer, consider this: The speed of any electromagnetic wave is, to first order, v = c/n, where n is the medium's index of refraction, c = 3*10^8 meters/sec.squared.  For vacuum, n=1 so the speed of light (which is an electromagnetic wave) is v=c.  Nothing can exceed that speed.  But, for many material media n>1 so then v<c and light in that medium travels slower than light in vacuum.  It is therefore possible for something traveling faster than this speed to exceed the speed of light in that medium. Astrobayes 22:27, 29 June 2006 (UTC)

text: That, sir, is a terrible redefinition of "straight-forward" and you should be ashamed of yourself.--Healyhatman (talk) 02:10, 25 June 2008 (UTC)

text: That struck me as a very straight-forward explanation and I also consider the analogy of 'why' (in the article itself) to be a great one.96.52.176.113 (talk) 03:52, 17 September 2008 (UTC)
thread_title:  Superluminal? 

message: Should I add "sometimes this is refered to as a "luminal boom" - because I've heard that before. 68.6.112.70 08:16, 17 April 2006 (UTC)
replies: text: Generally, made-up words and phrases should not be added to articles. The analogy to sonic booms is already in the article. -- Xerxes 15:54, 17 April 2006 (UTC)

text: Where have you "heard that before?"  If you cite a verifiable source, then what you're saying would carry some weight behind an edit or addition.  If not, then it's probably best to leave this phrase out as it would be more likely to garner a revert. Astrobayes 22:30, 29 June 2006 (UTC)
thread_title: Luminal boom

message: The definition mentions that this effect is when a "charged particle" goes through an "insulator". However, I would think that this effect should occur when ANY particle (charged or not) passes through ANY medium (inulator or not) at faster than the propogation speed of photons in that medium. 68.6.112.70 08:18, 17 April 2006 (UTC)
replies: text: You're wrong about charged particles; a neutral particle has no impact on the electromagnetic fields inside the medium, so it cannot produce radiation. The bit about conductors is already explained in the article: no light is produced. -- Xerxes 15:54, 17 April 2006 (UTC)
replies: text: In that case something else must be used to detect neutrinos since they do not carry a charge. I read that Cherenkov Radiation was used in the IceCube neutrino detector. Something must be contradicting.  — Preceding unsigned comment added by 138.226.68.10 (talk) 15:05, 19 April 2012 (UTC)
replies: text: IceCube and other Cherenkov-based neutrino telescopes measure the reaction products of a neutrino interaction, such as electrons, muons, and tau's, which are charged particles and emit Cherenkov radiation. --  Questgame (talk) 10:35, 2 July 2019 (UTC)
thread_title: Definition

message: "Colloquially and in chemistry, matter is easy to define because it is directly associated with mass." []
I think the use of the term 'matter' in the following sentence in this article on Cherenkov radiation is misleading:
"Matter can be accelerated beyond this speed [the speed of light] during nuclear reactions and in particle accelerators."
The problem is that 'real', 'physical' matter can NOT be accelerated beyond the speed of light. Only theoretical particles like Tachyons (which do not have any mass) can go beyond the speed of light. 'Matter' suggests real particles with real mass, hence it is misleading. 
The problem of course is the loose definition of matter, but in this instance i think it pays to be pedantic since not going beyond the speed of light is a fundamental rule we all learn in physics class! 
Instead i would suggest something like the following:
"Certain special particles can be accelerated beyond this speed during nuclear reactions and in particle accelerators."
--Kavrod 14:46, 8 January 2007 (UTC)
replies: text: I disagree. It says: "For example, the speed of light in water is only 0.75c. Matter can be accelerated beyond this speed during nuclear reactions and in particle accelerators." which is true. Matter can be accelerated to faster then 0.75c in water. Further, it says right after that "Cherenkov radiation results when a charged particle, most commonly an electron, exceeds the speed of light in a dielectric (electrically insulating) medium through which it passes." Matter can't break 1c, but it can certainly go faster than the speed of light in certain mediums. --Falcorian (talk) 18:05, 8 January 2007 (UTC)
replies: text: As far as I have read here it has not been mentioned that while the index of refraction for visible light is approx 1.5 in water it may be close to one and even below one for high energy photons (X-rays/gamma) or short wavelength (de Broigl)/high energy particles. To be clear; I am referring to the real part of the index of refraction that is related to phase-shift, not the imaginary part that is related to absorption. Also, it is the average speed of light that is below c in a medium with n>1, between hand shakes/interactions the re-emitted photon always propagate at c. While Im at it, the closer to resonance the longer it takes before re-emitting the photon.
85.230.24.89 (talk) 20:34, 23 April 2009 (UTC)
thread_title:  Accelerating 'matter' beyond speed of light. 

message: The figure shows an 90 degree angle between wavefront and emission angle. Note that the pysical
light front of photons are not in 90 degree angle with the emitted light. This is due to the difference between group and phase velocity. Read for example http://arxiv.org/abs/hep-ex/0008001  —Preceding unsigned comment added by 130.237.208.86 (talk) 13:28, 4 November 2007 (UTC)
replies: text: Correct for the usual case of a dispersive medium. Maybe one should note that right angle the image is true for the ideal case of a non-dispersive medium (where phase and group velocity are the same). Maybe I come round to do this at some point. -- KlausFoehl (talk) 11:58, 23 July 2009 (UTC)
thread_title:  the angle is not 90 degrees. 

message: Copied from Wikipedia talk:WikiProject Physics/Archive May 2009. -- Crowsnest (talk) 09:41, 8 July 2009 (UTC)
replies: text: A Google Scholar and Google Books search gives that "Cerenkov radiation" and "Cherenkov radiation" are far more common than "Čerenkov radiation". I will change it to  "Cherenkov radiation", in agreement with Pavel Alekseyevich Cherenkov. See also WP:COMMONNAME. -- Crowsnest (talk) 09:13, 25 May 2009 (UTC)
replies: text: While Cherenkov is most frequent, I say that Čerenkov as per Scientific transliteration of Cyrillic should remain being mentioned. -- KlausFoehl (talk) 14:08, 19 April 2013 (UTC)
thread_title:  Čerenkov / Cherenkov 

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thread_title: File:Advanced Test Reactor.jpg Nominated for Deletion

message: As there isn't an article on gravitational cherenkov radiation as far as I can tell I thought I should propose the creation of a section on it in this article. BarryFFFFFF (talk) 20:08, 4 January 2012 (UTC)
thread_title:  Gravitational Cherenkov Radiation 

message: There are articles Cherenkov detector and Cherenkov radiation.
I think that an overlap in contents is unavoidable, but I wonder: should some content in Cherenkov radiation be better placed in the Cherenkov detector article?
I do not think that the two articles should be merged.
Waiting for other opinions. And I suggest Talk:Cherenkov detector for discussion. -- KlausFoehl (talk) 16:05, 19 April 2013 (UTC)
thread_title:  articles [[Cherenkov detector]] and [[Cherenkov radiation]] 

message: I propose the deletion of this section, "Vacuum Cherenkov Radiation," because
it describes an unobserved phenomenon supported by various unobserved
phenomenon. Currently, "Vacuum Cherenkov radiation" is a pseudo-scientific
supposition describing a yet unobserved phenomenon with no supporting empirical
or solid theoretical evidence.
"Vacuum Cherenkov radiation is the conjectured phenomenon which refers to the
Cherenkov radiation of a charged particle propagating in the physical vacuum."
This wouldn't be Cherenkov radiation, as Cherenkov radiation is caused by
emission from the medium itself. The proposed "vacuum Cherenkov" radiation
would be a different phenomenon entirely, one that has not been observed and
according to special relativity and the Standard Model should not be observed
in the foreseeable future, at least not by the mechanisms describing Cherenkov
radiation in the main article.
The section goes on to explain the possible mechanics of the proposed effect.
These explanations rely on altering fundamental physical constants, ignoring
various rules of the Standard Model, ignoring special relativity, modifying the
topology of space-time itself, discovered non-existent (thus far) superliminal
particles, or discovering energy dependent velocities of those particles (again
no evidence of that so far) ... it describes an unobserved phenomenon
backed by unobserved phenomenon and unsupported theoretical models.
In short, this section is not science. Interesting perhaps, but not science and
because of this I do not feel it belongs in this article. If there are no major
objections, I would like to delete this section but thought I would discuss it
first.
Vcfahrenbruck (talk) 22:00, 29 September 2013 (UTC)
thread_title:  Vacuum Cherenkov radiation - Proposed Deletion 

message: I can't find any mention here of gamma rays inducing Cherenkov radiation, even though that was how the original discovery was made. The original research paper of 1934 was entitled, "Visible Emission of Clean Liquids by Action of γ Radiation." http://web.ihep.su/owa/dbserv/hw.part2?s_c=CERENKOV+1934 http://web.ihep.su/dbserv/compas/src/cerenkov37/eng.pdf Zyxwv99 (talk) 00:31, 12 September 2014 (UTC)
thread_title:  Gamma rays 

message: I'm dubious about some of these claims, and the cited sources don't back them up:
:In popular culture[edit]The typical association of Cherenkov radiation with accelerated particles from radioactive materials and processes, as well as its perceived other-worldly glow, have made it a common popular-culture hallmark of radioactivity. It determined the colour of Doctor Manhattan in Watchmen,[10][11] as well as the radioactive glow of products from the nuclear power plant in The Simpsons (where it was inaccurately portrayed as green[12]). The classic blue glow that is usually given off by Godzilla's spines before he fires his Atomic Breath, and the normally-blue colour of the beam itself, can also be attributed to Cherenkov radiation.
Source [10] talks about Cherenkov radiation, but doesn't say anything about doesn't say any thing about Dr Manhatten, or pop-culture depictions of radiation in general.  ([11] does say that his colour was inspired by Cherenkov radiation).  [12] says that the typical depiction of radioactive materials as glowing green (e.g. in the Simpsons) is based on the commonest colour of radium paint.  I'll have a go at rewriting the section to better reflect the sources.  Iapetus (talk) 09:37, 21 August 2015 (UTC)
thread_title:  "In Popular Culture" section 

message: Cherenkov: add phonetic characters please!  — Preceding unsigned comment added by 2A02:587:4109:3E00:1CA5:C59E:60BC:4528 (talk) 07:35, 23 October 2016 (UTC)
thread_title:  Cherenkov: add pronunciation 

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thread_title:  External links modified 

message: Hello all
I have made a recent change to the article by editing one of the sections to explain the speed at which light propagates and why it is slower than the actual speed of light. Please comment on my changes 
Shadowstone1 (talk) 09:05, 22 August 2019 (UTC)
thread_title:  Speed at which light propagates 

message: The article says "There are some misconceptions about Cherenkov radiation. For example, it is believed that the medium becomes electrically polarized by the particle's electric field. If the particle travels slowly, then the disturbance elastically relaxes back to mechanical equilibrium as the particle passes. But when the particle travels, the limited response speed of the medium means that a disturbance is left in the wake of the particle, and the energy contained in this disturbance radiates as a coherent shock-wave. Such conceptions do not have any analytical foundation, as electromagnetic radiation is emitted when charged particles move in a dielectric medium at subluminal velocities which are not considered Cherenkov radiation."
I've had three or four shots of vodka, so I could be wrong, but as far as I can tell, the third and fourth sentences combined with the last sentence don't seem to connect to the first two? If they do, I suspect there needs to be more explanation.  — Preceding unsigned comment added by Dstar3k (talk • contribs) 23:08, 21 August 2020 (UTC)
thread_title:  Misconceptions 

message: From Quora:
The first person to see it was Marie Curie in 1910. Since she didn’t pursue the observation, so she clearly didn’t think much about it. Heaviside and Sommerfeld predicted it independently in 1888 and 1904 respectively
This is not any of it in our current article and should be. I have asked there for sources. Or can someone here provide them? Andrewa (talk) 00:17, 7 July 2021 (UTC)
replies: text: Forget the above, it's there and I missed it somehow. Andrewa (talk) 06:42, 8 July 2021 (UTC)
thread_title:  Curie, Heaviside, Sommerfield