Wikipedia:Reference desk/Archives/Science/2014 December 24

= December 24 =

What is the reason for the red color of SEDURAL that appears in the urine of the patient?
What is the reason for the red color of SEDURAL that appear in the urine of the patient? The pharmacy companies couldn't create it without this color? Is there any purpose for this color? — Preceding unsigned comment added by 5.28.174.110 (talk) 01:32, 24 December 2014 (UTC)


 * I'm only answering quickly here and so some of this is a guess, but note that Phenazopyridine is an azo dye that was invented by Bernhard Joos in 1932, after which he founded Cilag. I presume that this was a part of the general realization that "vital dyes" could have specific pharmacological effects -- scientists had noted that the dyes they developed might stain different kinds of organic molecules, and deduced that a dye that stained one part of a cell but not another, or better yet stained a bacterium more than it stained the host cell, might have a medicinal effect.  This is closely akin to the notion of binding affinity (which may or may not imply IC50), and soon the scientists realized they didn't have to actually see the compound bind to a specific structure for it to have the potential to do so.  Still, seeing a dye light up unwanted bacteria must have quickened many a pulse in the old days as people wondered if they might use them as "magic bullets" to kill the disease without touching the host.  Now this compound isn't anti-infectious but analgesic, which can be compared to some other small aromatic molecules like aspirin, but of course it is still useful.  Many other compounds with similar effects have been identified, but redesigning this one would be hard because the whole point of an azo structure is to create color, by linking two aromatic rings with the nitrogen bridge; to make it colorless implies a total chemical redesign, almost from end to end of the molecule. Wnt (talk) 01:45, 24 December 2014 (UTC)
 * Thank you for the explanation, but I didn't understand the reason about the color. 5.28.175.146 (talk) 02:54, 24 December 2014 (UTC)
 * Well, there are two ways to look at it. Historically, scientists started out trying their best to make dyes, came up with a bunch of them, then started to examine their effects, which is why an old medicine turned out to be a dye.  Scientifically, the reason why this chemical is a dye is that it has a long system of conjugated double bonds.  To give you an idea (I'm glossing over a lot, like Hückel's rule...) if you have something that is N-C=C-N=N-C=C, it could also be N+=C-C=N-N=C-C-.  That means that the longer the conjugated double bond set, the further the molecule can conduct an electron from one end to the other like a little wire.  And like a simple antenna of a certain length that picks up a certain radio station, these molecules pick up light of a certain frequency.  (It's not really that simple, in that the molecule is much, much shorter than the wavelength of the light it absorbs; you can use Woodward's rules and see that adding a bit under 3 angstroms to the molecule length means adding 300 angstroms to the wavelength.  The absorption goes by the energy of the photon in the molecular orbital - I'm not sure, but I think ultimately you can work out the math as somehow equivalent to the classical picture of an electron oscillating back and forth with the same frequency as the light, in a constrained environment, but honestly I don't think I ever was particularly clear on whether that's really true or not!) Wnt (talk) 04:20, 24 December 2014 (UTC)

Dealing with a difficult “educator”
Hello everyone.

I am posting here for advice regarding professionally handling an “educator’s” conduct which I’m questioning. To remain within the guidelines, I won’t mention any names, nor will I ask for any opinions [even if it sounds at times that my post may invite such], but will write, in good faith, whatever I believe is allowed here for the purpose of obtaining information about standard professional guidelines within the intellectual community including professional conduct guidelines. This post is only intended to address the claims and the conduct in itself in reference to professional standards and guidelines, with no identities mentioned to avoid WP:BATTLE.

To avoid giving any personal information, I will keep things as general as possible.

I had recently struck up a conversation regarding various scientific disciplines with somebody who works for an organization. He claimed to have training in meteorology, biology, social science, and some medical science. He began making claims and claimed that he “enjoyed speaking”, but completely refused to provide any sources when I asked, even smirking with an “elementary school” smirk, demanding that I accept the claims he makes, stating “No! I don’t need to [cite sources]!”

A few true examples of claims he has made which I can recall off the top of my head:


 * “Soap makes water wetter”
 * It would be significantly harder for the average person to breathe in Denver, Colorado than in most other U.S. cities, following it with commentary, “I don’t care what else you say”, unless acclimated over a period of time.
 * A cold front, when travelling south from the arctic, descends in altitude, and travels (word for word) “like syrup poured onto a plate”, claiming that cold air is literally “piled up high” in the arctic, then loses altitude as it spreads horizontally to lower latitudes.
 * [In response to my own comment that the dewpoint is how meteorologists measure absolute atmospheric moisture content], he stated “No! The dewpoint is not a measure of absolute moisture. It is only the effect of the absolute moisture. The absolute moisture is measured using various other scientific measurements”, such as grams per milliliter if I remember correctly.
 * [Also some claims regarding sexuality which I don’t feel comfortable posting without being given the “OK”, and may or may not even want to post at all].

He also said, based on some beliefs that I have expressed in regards to the eugenics movement (will not go into detail), that “I think your ideas have some similarities to the fascist regime”. When I later complained about his statement, in that I felt that he referred to me as a fascist he then returned, stating that I made a false complaint, commenting to me, “the way you perceive things is [erroneous]”, arguing “I did not call you a fascist; I said that your ideas had some similarities, which is different!” But nevertheless, I still stand behind my view (references regarding usage of the word fascist in this regard would be useful just for the sake of it).

Furthermore, in regards to some views that I have expressed, in fact, with stress, about morality in our society (sensitive, so will not go into detail), he stated, word for word, with the “elementary school” smirk again, “See how you have that RAISED tone of voice? That means you are predicating your happiness on other peoples’ actions, and that is by definition control!”, also raising his voice slightly, and claiming that it was an analysis of my behavior based on his psychology training. Since he did claim to be a “counselor” on top of all of the other educational qualifications he claimed to have, I was in fact open to a certain extent for discussions regarding morality, but later wasn’t sure if that was a good choice to make. On a future occasion, he later gave a slightly reworded variant, stating “You are predicating your happiness on the thoughts, feelings, and actions of others”.

Given that a definition is easy to lookup, I found no formal definition even close to this statement, but would be interested in any sources which may even be remotely close to this “definition”, and additionally, would be interested in knowing the formal terminology and guidelines that describe “making up definitions” from an intellectual community perspective.

Sources consisting of the subject matters discussed as well as any covering standard professional guidelines are requested. Thanks in advance. 2602:304:59B8:4149:207E:1B06:3FB7:5FEA (talk) 01:55, 24 December 2014 (UTC) (Last edited by 2602:304:59B8:4149:207E:1B06:3FB7:5FEA (talk) 01:59, 24 December 2014 (UTC), reason: Punctuation)


 * Well, for starters, soap does indeed "make water wetter", by cutting back on its Surface tension. This explains in more depth.
 * The Denver Post has a writeup on how to deal with altitude sickness, which is apparently not a small problem in Denver. ←Baseball Bugs What's up, Doc? carrots→ 02:05, 24 December 2014 (UTC)


 * Soap can form a micelle or layer that makes a firm contact between a hydrophobic substance and water, and so (to such molecules) maybe it makes water wetter (though obviously that can be defined to be meaningless)
 * There is less air in Denver relative to other U.S. cities. I remember flying there and it was like they never let the air back into the plane.  Of course, that means you can actually puff more of the thin air than you could of thick sea level air, but I kind of like the latter anyway. :)
 * A cold front does approach with the cold air fanned out in a wedge in front of it, close to the ground, like syrup on a plate. They often are described as "arctic air" in provenance, though of course they can approach from non north directions.
 * The dew point is indeed related to one way to measure humidity with a wet bulb thermometer; many other methods exist including calibrating the shrinkage of a hair from your head. I think he has a point that at some point somebody had to measure how much water was actually in a sample of air to know what it meant.

Based on these things, I would say that he is trying to make approachable generalities to describe scientific concepts, but they may confuse some people rather than enlighten them. Your differences may be more personal than scientific in nature, with neither of you giving the other a full chance to be understood. Wnt (talk) 02:09, 24 December 2014 (UTC)


 * Thanks for responding. The ultimate concern that I had was the issue regarding proper procedure in the intellectual community, and how I should respond (from a scientist's perspective) to somebody who literally becomes rude to avoid citing sources, which I politely requested, and who also uses questionable definitions to make personal attacks, for which, just out of curiosity, I wanted to know if there even was any validity behind that "control definition", and ultimately wanted to improve my professional skills in dealing with "educators" like this in the future to avoid being in an awkward position, besides the fact that I questioned the validity of the content given the other party's response to my request for sources. There were also other profane remarks which I didn't feel comfortable posting which also undermined his credibility in my mind. Ultimately after finding myself in this difficult and awkward position I would like to feel that I would be able to respond to it more professionally if it ever arose in the future. 2602:304:59B8:4149:207E:1B06:3FB7:5FEA (talk) 02:30, 24 December 2014 (UTC)


 * Well, for one thing, if he ever repeats any of these truisms, you could say, "Yes, I know, I was just reading about it." ←Baseball Bugs What's up, Doc? carrots→ 03:46, 24 December 2014 (UTC)


 * Well, professionally, you know how it is: there's nothing to be gained from a 'political' struggle (in the petty sense). If you get into a fistfight with a whore it doesn't matter if she started it, it still looks bad for you.  Now in this case my gut sympathy is with the other guy; I have a feeling I'd like him ... all the more reason not to try to bring things to a head. Wnt (talk) 04:24, 24 December 2014 (UTC)


 * Not fighting. On the contrary, this would be kind of kissing up. Stroking his ego, as it were. ←Baseball Bugs What's up, Doc? carrots→ 04:27, 24 December 2014 (UTC)


 * It is true that Denver is the highest altitude major city in the United States, and it is the "mile high city" at over 5,200 feet elevation. So, yes, if you fly from sea level to Denver, you may notice some minor breathlessness at first. Most people will adapt quickly. Mexico City is about 2000 feet higher, and there was concern about altitude sickness before the 1968 Olympics, but the concerns were pretty much unfounded. True altitude sickness is rare below 8000 feet elevation, and there are towns in Colorado such as Leadville at elevations above 10,000 feet. Personally, I have spent many weeks camping in California at altitudes above 10,000 feet, and really have difficulties only when climbing well above 13,000 feet. But I have climbed two 14,000'+ peaks in my 50s, namely Mount Shasta and Mount Whitney. Skilled Himalayan mountaineers can function, briefly, at altitudes twice that high. Careful acclimatization is essential at very high altitudes. Cullen328  Let's discuss it  07:02, 24 December 2014 (UTC)


 * Depending on where you live, and what the eugenic views you were expressing were, commenting that your views were similar to those espoused in the fascist regime might be considered helpful, since you were presumably unaware of the history and connotations of your views. That you took that as them calling you a facist, and took offense, indicates that the problem is not simply with them not citing sources. 86.156.148.98 (talk) 10:04, 24 December 2014 (UTC)


 * Anyone who espouses eugenics stands a good chance of being labeled a Nazi. ←Baseball Bugs What's up, Doc? carrots→ 15:05, 24 December 2014 (UTC)`


 * Interestingly enough, he took it back when I complained, then mentioning "[my] perception", besides the fact that I expressed belief in the strictly voluntary form of "eugenics" if that would even be a good word for me to use in that case. 2602:304:59B8:6849:C420:9184:83F7:2AA9 (talk) 20:30, 24 December 2014 (UTC)


 * You say it was a "conversation", so I assume you were actually talking, and not via email or online chat. Asking someone to "cite sources" in an actual real-time conversation is a little awkward. What are you expecting him to do? Pull some journal articles out of a backpack? Just because I'm extremely familiar with a subject doesn't mean I could produce a reference to a reliable source on-demand for any given topic. I would be taken aback and probably a little annoyed if someone asked me to cite sources in a casual conversation. Scientists and educators are normal people, they're not always in conference/teaching-mode where they expect to have to be able to rigorously defend everything they say. Mr.Z-man 14:19, 24 December 2014 (UTC)


 * My 9th grade Earth science and astronomy teacher absolutely could not be convinced that an egg can stand on end when it's not an equinox. Then I finally got the egg to stand after a few minutes (the surface was polished or semi-polished & rigid, unlike wood) so I said I could do it again on the solstice and she forgot about it (maybe) and didn't bring an egg.


 * Also, all cruising altitude air is at 8,000 feet. Only the Boeing 787 is at 6,500 ft. If you've flown at cruise you were breathing thinner than Denver air (and much drier) quicker than you could've possibly gotten to Denver from low altitude (as the W. Great Plains are still very high). I didn't notice a thing about mile high air (though I had a half day to adapt (4,000' @ 100 m/hr) and forgot to see if running was harder). Sagittarian Milky Way (talk) 20:12, 24 December 2014 (UTC)


 * Cold air does sink, and it also stands to reason that there would be nothing but cold air at the poles, with more of a mix of temperatures in more temperate areas. Of course, you can't normally see cold air sinking, but you can when it contains fog, as in this video: .  Describing this as syrup seems about right.  A complicating factor is that air also becomes thinner at altitude, and this causes it to contain less heat per unit volume, as does radiating heat into space, while air near the ground tends to be warmed by the (solar heated) ground or ocean.  So, even though cold air sinks, that doesn't mean the air on the ground will remain cold.  See temperature inversion for details.  StuRat (talk) 21:08, 24 December 2014 (UTC)
 * Eugenics unfortunately were misused by Nazis to justify murdering everyone but themselves, and thus acquired a very bad name. Thankfully, it seems it will soon no longer be necessary to control who can breed to improve the gene pool, as soon we will be able to eliminate bad genes, like those which cause cancer, by genetic engineering.  (Of course, this might lead to it's own Gattaca type problems.) StuRat (talk) 20:47, 24 December 2014 (UTC)


 * Sources can be requested if you have a real need for them, like you are writing an academic paper and want sources to back up whatever is claimed. However, in common conversation, demanding sources is a bit rude.  Consider if you said "I had spaghetti for lunch" and he aid "Prove it !  Let's see a receipt from the restaurant !".  The same is true of casual scientific claims, made in conversation.  Now, if a particular claim is utterly unbelievable, that's a bit different, just like if you claimed to be abducted by aliens, people would expect some proof, or think you were a nut.  Since most of this person's claims seem to be correct, I suggest you go online and look them up yourself, before challenging him to provide sources.  If you find sources to disprove his claims, you can provide those and then challenge him to provide sources to back up his claims.  BTW, we have the same issue here on the Ref Desk, where some individuals constantly ask for sources for really obvious things, apparently just to be annoying.  StuRat (talk) 20:47, 24 December 2014 (UTC)


 * and Reasonable enough. The ultimate intention I had by posting was to learn better professional skills. Maybe I shouldn't have asked for sources in regards to the meteorological claims. It's good to know that those were valid, but was my "educator" right in his other claims such as the assertion that the dictionary proved that I was a control freak? 2602:304:59B8:6849:C420:9184:83F7:2AA9 (talk) 21:35, 24 December 2014 (UTC)


 * There you're getting into the soft "sciences", where it's mostly just opinion. That bit about deriving happiness from how other perceive you is undoubtedly true of most people.  Freud called that the ego, and we all are supposed to have one, but should work more to derive satisfaction from our super-ego.  Of course, to not care at all for what other's think can also cause problems, so nobody should be 100% super-ego driven.


 * One other hint, when you do doubt one of his claims, and find reason to doubt it through your own sources, there's a way to ask for his sources without implying that you don't believe him. Present it a if you are interested in the topic and wish to read more about it, and are asking if he could recommend a good place to do so.  Then, even if you have absolute proof that he was wrong, you don't always have to tell him that.  If he's the kind of person that would appreciate the correction, then fine.  If he would get all upset, then you might just let him continue believing it to be true.  This might be good to practice around the Christmas table, too, if a relative makes an unlikely claim.  StuRat (talk) 21:56, 24 December 2014 (UTC)

When cheeking blood for glucose- how many types of molecules of glucose does it cheeks?
When cheeking blood test it cheek only one types of molecules (of glucose) or only one? 5.28.175.146 (talk) 02:17, 24 December 2014 (UTC)


 * Have you read our article on glucose? μηδείς (talk) 02:32, 24 December 2014 (UTC)


 * Yes, I have. Maybe I didn't understand something? I know the famous form of glucose (C6H12O6) but it's not clear to me what are the types of glucose that cheeked in the laboratory or in the glucometers. I didn't see something about on the article. 5.28.175.146 (talk) 03:07, 24 December 2014 (UTC)


 * Are you, perhaps, asking if all of the isomers of glucose are checked equally by a glucometer? Perhaps one of our chemical-minded editors will be able to answer. -- ToE 03:21, 24 December 2014 (UTC)


 * Yes, I am. Thank you. 5.28.175.146 (talk) 03:56, 24 December 2014 (UTC)


 * Among the isomers of glucose, several are different transient states of the same thing. For any single stereoisomer (there are two enantiomers), the straight-chain form and the various closed-ring pyranose and furanose forms can easily and rapidly interconvert when dissolved in water. They are therefore not distinguishably "different chemicals" in many testing scenarios with biological samples--a test for any one of them would suffice. But only one of the two enantiomers is noticeably present in...well, much of anything at all in nature, let alone commonly encountered as a nutrient or blood component. Therefore the test only needs to detect that one ( D ), but it would not be a problem if the test were not able to distinguish or detect specifically that one between the two because the "other one" ( L ) is not present. The other aldohexose steroisomers are not glucose at all. I don't know if they have noticeable and noticeably-variable presence in blood, the details that would determine whether a "glucose" test would need to avoid detecting them. DMacks (talk) 05:00, 24 December 2014 (UTC)


 * The different enantiomers of glucose convert rapidly among one another in solution, and as the standard glucose meter oxidizes glucose to gluconolactone catalyzed by glucose oxidase (sometimes known as GOx) the remaining enantiomers will spontaneously convert to D-Glucose. So, directly or indirectly the meter will detect the four standard D- enantiomers of glucose present. μηδείς (talk) 05:27, 24 December 2014 (UTC)


 * Glucometer mentions some specific enzymes that are used in some of the common test equipment. They seem to be specific to glucose rather than other aldohexose isomers of it. The article about glucose oxidase even discusses how the various forms of the relevant enantiomer of glucose interconvert easily enough to be all detected together. Medeis is not correct that enantiomers convert between each other. Within one enantiomeric form, certain structural and epimeric forms interconvert. The other enantiomeric form would have its own equivalent set of forms, but there is no crossover betwen one enantiomer and the other. The enzyme is specific for one enantiomeric form, but, being a biologically derived material, it is already tuned for the biologically relevant enantiomer of glucose (the un-natural enantiomer of the enzyme, if one were to make it, would be specific for the un-natural enantiomer of glucose). DMacks (talk) 05:32, 24 December 2014 (UTC)


 * I hope you won't find me cheeky if I point out the words you want are "checking" and "checks". StuRat (talk) 05:15, 24 December 2014 (UTC)


 * They may have confused "glucose" and "gluteus". ←Baseball Bugs What's up, Doc? carrots→ 15:03, 24 December 2014 (UTC)


 * You just had to butt in... StuRat (talk) 18:59, 24 December 2014 (UTC)


 * The bottom line here is calibration. The activity of glucose oxidase creates a cascade of electrons in proportion to the amount of glucose reacted.  In theory, you ought to be able to figure out how many electrons to react how much of a particular form that the enzyme can work on, what proportion of the pool that form is, etc...  but in practice it will be far more accurate to simply measure a curve of electrode values from various known concentrations of glucose from a chemical reagent container.  Often this changes from lot to lot of the strips, hence the need for "coding" in many of the test devices (which is basically uploading the right calibration curve to them as far as I would guess) Wnt (talk) 17:59, 26 December 2014 (UTC)

Insulin and other hormones
I read in our article Insulin that "Unlike many medicines, insulin currently cannot be taken orally because, like nearly all other proteins introduced into the gastrointestinal tract, it is reduced to fragments". Is it not wonder to say that Insulin can not administrated by oral way because "it is reduced to fragments", while many hormones administrated by oral way? 5.28.175.146 (talk) 04:08, 24 December 2014 (UTC)


 * Insulin is a protein. We eat organisms made of many proteins with many different purposes and if we let them into our bodies it would be chaos (then death).  So the digestive system chops them up in little bits, and doesn't let anything of them in except what has been chopped up into little bits.  With... lots of clever little exceptions (if your intestine isn't virus-proof or even roundworm-proof, it's not protein-proof!), but so far, nothing really good enough to let people take insulin orally.  It is, however, not actually impossible to come up with a way, and that might happen fairly soon. Wnt (talk) 04:28, 24 December 2014 (UTC)
 * Didn't someone ask this same question just a day or two ago? ←Baseball Bugs What's up, Doc? carrots→ 15:03, 24 December 2014 (UTC)


 * This is a reasonable follow-up to the previous question, though best form would have been following up in that section itself. To the questioner, I would say that while our hormone article does indicate that some hormones are proteins, most are not, and that the estrogen (specifically estradiol) and a progestogen (specifically progestin) in combined oral contraceptive pills are steroids.  Perhaps someone more chemically minded can explain why steroids stand up to the digestive process better than proteins.  Wnt's point is that our digestive system has evolved to process proteins for food. -- ToE 15:48, 24 December 2014 (UTC)
 * Yes, it's interesting. 194.114.146.227 (talk) 02:07, 25 December 2014 (UTC)

Main Battle Tank
Why some armies prefer manual-loaded tanks than Auto-loaded ones, specially that some auto-loaded tanks like French Leclerc , South Korean XK2 and Japanese Type 90 are safe ? ( this isn`t a criticize ) anything else except more ready to use ammunition ? 86.108.50.148 (talk) 12:53, 24 December 2014 (UTC)


 * Reasons not to use an automated loading system:


 * 1) More automation means more potential for breakdowns. Allowing for a manual override can address this, unless the automated system can somehow jam the turret.


 * 2) There's also the weight and space taken up by the automated system, where those are at a premium.


 * 3) The heat and noise produced by the automated system must also be considered, potentially making it rather unpleasant inside the tank.


 * 4) Cost could also be a factor. I imagine such a system, if only used on a small number of tanks, is very expensive per unit.  There may be better places to spend that money.


 * 5) There could also be some human factor reasons. For example, having something to do for a crew member who normally just waits for his turn to do something (like fire suppression or repairs) might make him less stressed.  StuRat (talk) 18:52, 24 December 2014 (UTC)


 * StuRat pretty much nailed it, but the main reason is because of reliability. Less complexity is currently favored in that regard in U.S tank operations.  In addition, losing the loader would mean one less man to perform maintenance, etc.  Also, autoloaders are NOT faster than a human loader.  Lastly, the autoloading carousel type system actually creates a dangerous situation if the tank is hit because there are a bunch of live shells all over the turret, rather than in a blastproof box that the Abrams currently uses. Justin15w (talk) 21:23, 24 December 2014 (UTC)

Thank you all, but I remembered a point , are there blow out panels above the ammo of the auto-loader in French , South Korean and Japanese tanks ?86.108.123.251 (talk) 04:47, 25 December 2014 (UTC).

Does having many dream-wake cycles in a few hours have an effect on content?
Like at least 10 in 3 hours? Possibly making them more random? The weird content is from defragmenting you're brain's hard drive while you're still using it, transferring some to long term memory and discarding the least important right so what happens after that's finished? (probably before 8 hours) Sagittarian Milky Way (talk) 15:41, 24 December 2014 (UTC)
 * Are there any studies indicating whether anyone can remember dreams that did not occur just before waking? ←Baseball Bugs What's up, Doc? carrots→ 15:48, 24 December 2014 (UTC)
 * So you find it impossible for a human to wake up 10 times in 3 hours for any reason (including being woken up by injuries, infections, bladder, enlarged prostate, nightmares, sounds, cats, forcing sleep for time killing, lucid dreams, jet lag, zzz's banking, bedtime latening)? Sagittarian Milky Way (talk) 21:36, 24 December 2014 (UTC)
 * "Just before waking", be it once to ten times, or even every few minutes if you suffer sleep apnea, for example. ←Baseball Bugs What's up, Doc? carrots→ 22:28, 24 December 2014 (UTC)
 * Ah, I thought you were wondering if many dreams were false memories. Now I see you were asking about sleep causing amnesia. But yes, they woke people up 10 minutes after their eyeballs stopped moving rapidly and they didn't remember a thing. Even 5 minutes was vague. Which is why you have 5 dreams (average) of increasing frequency and duration and don't remember them all. Sagittarian Milky Way (talk) 09:36, 25 December 2014 (UTC)

The train-and-platform thought experiment:
Please click on the train for its diagram. Let the backlights and headlights of the shown train (used for thought experiment) are remotely controlled. Remote control (source) is located at midway while targets are located at front and rear end of the train. Lets concentrate on backlights only. Let two pulses (shown in the diagram) are sent simultaneously by a remote control device towards the said targets in order to turn on their respective lights. According to the Einstein’s theory, a stationary observer sees the rear strike (a pulse has reached already at the rear target) before the onboard observers (a pulse yet to arrive at rear target). Imagine, as soon as the stationary observer sees the illumination of backlights; let another onboard observer stops the pulse just before hitting the rear target. Since a pulse didn’t reach the rear target therefore would the backlights of the Einstein’s train be still turned on for stationary observer on platform? I presume that missing information are understandable. Thanks 162.157.210.127 (talk) 18:43, 24 December 2014 (UTC)Eclectic Eccentric Kamikaze
 * I fixed your Relativity of simultaneity wikilink. -- ToE 21:19, 24 December 2014 (UTC)
 * The is a reference desk. It is here to answer questions. It is not here to engage in speculation about incomprehensible thought experiments. If you do not find Wikipedia's material on relativity sufficient for your understanding, I suggest you look elsewhere rather than wasting everyone's time with this repetitive nonsense. AndyTheGrump (talk) 19:04, 24 December 2014 (UTC)


 * Either the signal to turn on the lights reaches the back or it doesn't. The intersection of two real entities, in the case the pulse reaching the light, is an event that must equally happen (or not) for all observers.  They can disagree on when it occurs or the order in which it occurs with respect other events, but there is no construction of special relativity that would allow some observers to think that the pulse reached the lights and other observers to think that the pulse never reaches the light.  Dragons flight (talk) 20:28, 24 December 2014 (UTC)

Thank you ToE for fixing the link.

Dragon Flights: All observers agreed before the start of journey that a light signal would be stopped just before the rear target such that the distance covered by pulse is greater than pre calculated (Ct-Vt). Where V is velocity of train. All observers can then discuss their disagreement (on/ off backlights) after the completion of journey.

I post my question in very polite and respectful manners therefore I believe that I didn’t break the Wikipedia rules. It doesn’t show any challenge or disrespect for the current valid theory. I believe there are lots of pundits out there who would be happy to respond voluntarily on Wikipedia. Please don’t respond if it’s offensive for some grumpy volunteers. Although I am ignoring this time but this is very rude to tell someone that your question is nonsense. I still respect you “AndyTheGrump” for your free time that you are dedicating to Wikipedia but if you are still thinking that I am troll then tell your supervisor that I reported you for your grumpiness. Wikipedia is not for ill-temper volunteers either. 162.157.210.127 (talk) 00:18, 25 December 2014 (UTC)Eclectic Eccentric Kamikaze


 * The problem is that it's very easy to formulate such complex "puzzles" - and sometimes it's quite hard to solve them. Generally, it's enough to know that relativity is 'real' and it works, and everything comes out right in the end...and there is really no need to chase down every one of them.  Inventing complex problems and asking us to solve them for you is unnecessary and redundant - and your description is kinda complicated and confusing - so it's not surprising that you'll find it hard to get anyone here to go to all that trouble.  The best answer is "Nothing weird happens...but I can't be bothered to figure out why."  That said, AndyTheGrump is well named - and his grumpy response is really unacceptable here.  You deserve an apology. SteveBaker (talk) 17:46, 25 December 2014 (UTC)


 * We should all strive to be WP:CIVIL here, but, in partial defense of Andy, your questions are rather hard to understand, and they can leave the impression that we have to invest much more time deciphering what you are trying to ask than you took in posing the question. For this particular question, Relativity of simultaneity discusses one classic Gedankenexperiment while Relativity of simultaneity discusses another.  Both are accompanied by their own illustrations, but neither include the backlights, headlights, and remote control you mention.  Perhaps if I look back through the archives at your previous questions I would be able to infer what you are trying to ask and then reconstruct your question in terms that can be answered, but that is significant investment just to understand the question.  As User:Eclectic Eccentric Kamikaze is available, I suggest that you register your moniker so that meta-discussions like this can be done off the reference desk on your personal talk page.
 * From the best that I can understand of your question, you have modified the first of the Gedankenexperiments mentioned above by the addition of remotely activated lights at either end of the traincar, each of which will be turned on when struck by the light pulse emitted from the center of the car, giving a signal for observers to witness, and allowing them to conclude when the event occurred.
 * I think that your problem comes in saying, "According to the Einstein’s theory, a stationary observer sees the rear strike (a pulse has reached already at the rear target) before the onboard observers (a pulse yet to arrive at rear target)." Nothing in the relativity of simultaneity should suggest that a single event in spacetime occurs earlier (in any absolute sense) in one reference frame than in another.  What it does tell us is that you can have two distinct spatially separated events whose order of occurrence depends on the reference frame in which they are considered, and thus no absolute order for them exists.  (Note that two events which are temporally separated (the distance between the events is less than the distance light would travel during the time between the events -- as measured in any reference frame) then the order will be the same in all reference frames, preserving causality.  See space-like vs. time-like.) -- ToE 19:03, 25 December 2014 (UTC)
 * It should be noted that 'Eclectic Eccentric Kamikaze' has a habit of posting obscure comments and unintelligible questions on ref desks - and on article talk pages. See for example this ridiculous comment at Talk:Gravitational acceleration : "The simultaneous abruptness of motion starts equally on either side of "c" right at the inception of "g" of each M which sent the aforementioned masses “M” swiftly into different types of motion such as gravitational jerk, jounce, crackle, pop, lock, drop etc, wherefore, should the propinquity of higher derivatives of position as such be included in the topic if yes then what would be their falling equations and order of the derivatives?" I see no reason not to assume that 'Eclectic Eccentric Kamikaze' is a troll, intent on causing disruption. AndyTheGrump (talk) 19:50, 25 December 2014 (UTC)

Since I posted a question therefore I am responsible for the creation of mess. So I apologies you all for the inconveniences that I caused. I thought any volunteer (around the world) could answer on Wikipedia Science reference Desk. I didn’t know Wikipedia Science Reference Desk is taking full responsibility for the posted question. It might be crackpot question/idea for some whiz but not for ordinary person therefore I asked here. I apologies again before leaving on my accord from this desk only. I thank you all for your precious time. 162.157.210.127 (talk) 04:49, 26 December 2014 (UTC)EEK


 * The problem with the question is that you say "a stationary observer sees the rear strike... before the onboard observers". A stationary observer where?  Actually, the frame of reference of the observer doesn't affect whether he sees the strike first - only the relative distance along the light cone from the strike to him vs. another observer.  The path outward that a hypothetical burst of X-rays would take from the moment of strike is the same in all frames of reference, i.e. it moves outward at c in a spherical shell.  Note that if anyone sees "strike", then there is a path backward in time at speed c back to the strike event, and so it is not normally (and by normally I mean in any generally accepted way, Tipler cylinders aside) possible to undo the spread of the news of that event to any other observer who will ever be hit by the light cone. Wnt (talk) 12:18 pm, Today (UTC−5)