Article snapshot taken from Wikipedia with creative commons attribution-sharealike license.
Give it a read and then ask your questions in the chat.
We can research this topic together.
<!--- Please DO NOT enter your question at the top here. Put it at the bottom of the page. An easy way to do this is by clicking the "new section" tab ---><noinclude>{{Misplaced Pages:Reference desk/header|WP:RD/S}}
{{bots|deny=ClueBot NG}}
<noinclude>
{{pp-move-indef}}
{{Misplaced Pages:Reference desk/header|WP:RD/S}}
]
]
]
]
]
]
]
]
]
</noinclude>
] </noinclude>
{{Misplaced Pages:Reference_desk/Archives/Science/2011 August 11}}
{{Misplaced Pages:Reference_desk/Archives/Science/2011 August 12}}
==='Av a go at interpreting this ]===
= December 24 =
{{hat|Medical advice question collapsed}}
Strictly hypothetical of course. I really shouldn't have to point out that it's not a request for medical advice for a real case because that would be nuts... but I do anyway, just so we're all on the same page {{=)|grin}}
== Unknown species of insect ==
'''Results''':
Am I correct in inferring that ] this guy is an ]? I was off-put by the green head at first, but the antennae seem to match. ''']]''' 03:00, 24 December 2024 (UTC)
* ] total ] level: 7 umol/L (normal range 1-17)
* Serum total ]: 72 g/L (normal range 64-83)
* Serum ]: 48 g/L (normal range 35-50)
* Serum ]: 24 g/L (normal range 18-36)
* ]: 94 u/L (normal range 40-129)
* Serum ]: 96 u/l (normal range 0-40) '''high'''
* Serum ] level: 179 u/L (normal range 5-60) '''high'''
(Serum electrolytes, glomerular filtration rate, and blood glucose level avaliable on request)
:<s>It looks like one of the invasive ]s that happens to like my blackberries in the summer.</s> ] (]) 13:11, 24 December 2024 (UTC)
Please indicate your level of expertise! Even I'm capable of clicking on each individual article and considering an indicator in isolation - although not necessarily of coming to a conclusion... other than the hypothetical patient really ought to drink less!
::I would say not necessarily a Japanese beetle, but almost certainly one of the other ] beetles, though with 35,000 species that doesn't help a lot. Looking at the infobox illustration in that article, 16. & 17., "]" looks very similar, but evidently we either don't have an article or (if our ] article is a complete list) it's been renamed. {The poster formerly known as 87.81.230.195} ] (]) 14:18, 24 December 2024 (UTC)
<span style="background-color:silver;color:black;">] ]</span> 00:42, 13 August 2011 (UTC)
:P.S. I just looked at this and it really does look like I'm soliciting medical advice and/or some kind of homework. I absolutely promise that I am not. I can't think how to rephrase the question, without utterly altering it. And I am not a medical student, nor have I ever been one. I knew some medical students at university but they are doctors now. Not sure what else I can say! <span style="background-color:silver;color:black;">] ]</span> 00:49, 13 August 2011 (UTC)
::P.P.S. There is a very good reason I am using those specific numbers, but it's a long story that's a bit silly. Suffice to say it is certainly not from any real liver test. <span style="background-color:silver;color:black;">] ]</span> 00:51, 13 August 2011 (UTC)
:::Yes, it's not the Japanese beetle for this beetle appears to lack its white-dotted fringe although its condition is deteriorated. Its shape is also more or less more slender; and not as round. ] (]) 15:02, 24 December 2024 (UTC)
:You can say that you are not requesting medical "avice" all you want, but what you are asking for is an interpretation of a medical test, which requires additional information in order to provide accurately. It would be irresponsible for us to speculate about possible explanations for the values you have given, since it would be impossible for us to know all of the relevant details. In any event, you have already linked to several articles that discuss the possible explanations for different elevated levels. That's about the best you can ask of an encyclopedia; we should not provide a more detailed discussion of this specific scenario. --- ] (]) 10:32, 13 August 2011 (UTC)
:Perhaps it is the ] ]. Shown . ] (]) 16:09, 24 December 2024 (UTC)
::Just as a matter of basic bandwidth, you're not likely to get a diagnosis out of these numbers - you're looking at two abnormal results and trying to assess the likelihood of a vast number of possible genetic diseases, infections, injuries, toxins, blockages, and tumors. A ] is doubtless important to make a guess, and any guess might mean more tests to confirm it.
::That looks like easily the best match I've seen so far, and likely correct. {The poster formerly known as 87.81.230.195} ] (]) 17:09, 24 December 2024 (UTC)
::But as a matter of personal understanding, which should encourage such a patient to obtain appropriate medical attention, the first thing to understand is that ] (ALT) is an ] protein.<sup></sup> So when it turns up in high levels in the blood, it means that somewhere in the liver, cells are getting physically busted open and releasing their contents. The same source indicates that GGT is a confirmatory, nonspecific test for liver troubles. Note that serum ] can give an indication when the bile duct is blocked, and ] gives some indication of the overall function of the liver when chronic disease is present. ] (]) 12:09, 13 August 2011 (UTC)
{{hab}}
= December 25 =
{{Misplaced Pages:Reference_desk/Archives/Science/2011 August 13}}
== Mass of oscillating neutrino ==
= August 14 =
From the ] it follows that a particle that is not subject to external forces must have constancy of mass.
== Brownian ratchet (again) ==
If I am right, this means that the mass of the neutrino cannot change during the ], although its flavoring may. Is this written down somewhere? Thank you. ] (]) 19:24, 25 December 2024 (UTC)
Hi, looking at the article ], it seems to me that if the cog wheel and pawl, as well as the structures fixing them in place, were made out of a hypothetical material that was completely rigid on an atomic scale in the face of thermal noise, then the device would work as advertised in violation of the laws of thermodynamics. Is that true? Do the laws of thermodynamics in themselves make the existence of such a material impossible then? ] (]) 01:24, 14 August 2011 (UTC)
:Any (flavored) neutrino that is really observed is a superposition of two or three mass eigenstates. This is actually the cause of ]. So, the answer to your question is complicated. ]_] 19:40, 25 December 2024 (UTC)
:Important note: particle physicists today generally only ever use "mass" to mean "]" and never anything else: . Like the term says, invariant mass is well, invariant, it never changes ever, no matter what "external forces" may or may not be involved. Being proper particle-icans and following the standard practice in the field, then, the three neutrino masses are constant values. ..."Wait, three?" Yeah sure, turns out ]. As mentioned, due to Quantum Weirdness we aren't able to get these different states "alone by themselves" to measure each by itself, so we only know the differences of the squares of the masses. Yeah welcome to quantum mechanics.
:]: "Quantum mechanics describes nature as absurd from the point of view of common sense. And yet it fully agrees with experiment. So I hope you can accept nature as She is {{snd}} absurd." --] (]) 06:06, 26 December 2024 (UTC)
::The equation <math>E^2 = (p c)^2 + \left(m_0 c^2\right)^2</math> uses invariant mass {{math|''m''<sub>0</sub>}} which is constant if {{math|''E''}} and {{math|''p''}} are constant. The traveling neutrino has a varying mass mixture of different flavors with different masses. If a mixture of different masses changes, you would expect the resulting mass to change with it. But somehow this does not happen as the neutrino mass mixture changes. These mixture changes cannot be any changes. The changes must be such that the resulting mass of the traveling neutrino remains constant. My question is whether this is described somewhere. ] (]) 11:16, 26 December 2024 (UTC)
:::I freely confess I'm uncertain exactly what's being "asked for" or "gotten at" here. Have you looked at the ] article? From it: {{tpq|That is, the three neutrino states that interact with the charged leptons in ]s are each a different ] of the three (propagating) neutrino states of definite mass. Neutrinos are emitted and absorbed in weak processes in flavor ]s '''but travel as mass eigenstates.'''}}
:::What is it that we're "doing" with the ] here? For the neutrino, we don't have a single value of "mass" to plug in for <math>m_0</math>, because we can't "see" the individual mass eigenstates, only some ] of them. What you want for describing neutrino interactions is ], which is special relativity + QM. (Remember, relativity is a "classical" theory, which presumes everything always has single well-defined values of everything. Which isn't true in quantum-world.) --] (]) 18:41, 26 December 2024 (UTC)
::::Not all potential evolutions of a linear combination of unequal values produce constant results. Constancy can only be guaranteed by a constraint on the evolutions. Does the fact that this constraint is satisfied in the case of neutrino oscillation follow from the ], or does this formulation allow evolutions of the mass mixture for which the combination is not constant? If the unequal values are unknown, I have no idea of how such a constraint might be formulated. I think the OP is asking whether this constraint is described somewhere. --] 00:51, 27 December 2024 (UTC)
:No, it would not work in that case. Since thermodynamics is nothing more than information theory applied to Nature, the best way to see through paradoxes like this one, is to translate it in terms of information. Although it may not always allow you to actually do detailed computations, for that you may need to consider the detailed dynamics (which in this case involves rather complicated non-equilibrium thermodynamics).
= December 27 =
:So, if a molecule strikes the wheel in the right way, it will move, pushing the pawl. But the pawl (assumed to be rigid) will then oscillate. This motion can cause the wheel to move backward. This motion, being a consequence of the molecule striking it, contains the information that a molecule made the wheel move earlier. For the device to work as advertised, you need to get rid of this information. But the fundamental laws of physics forbid you to erase information completely from the universe. The best you can do is dump the information from the unwanted place (the pawl) to somewhere else. For this to happen by itself requires dissipation of the energy, but that won't happen in thermal equilibrium. ] (]) 15:29, 14 August 2011 (UTC)
== Low-intensity exercise ==
:A closely related way to see through this, is to consider time reversal symmetry. Under time reversal a final state will evolve back to an initial state, which implies that the final state contains the information present in the initial state. If you consider the process that moves the wheel in the right directon, then you can see how the wheel would move in the wrong direction by applying time reversal to that process. In thermal equilibrium, both processes occur with equal probability. ] (]) 15:47, 14 August 2011 (UTC)
If you exercise at a low intensity for an extended period of time, does the ] still occur if you do it for long enough? Or does it only occur above a certain threshold intensity of exercise? ] (]) 20:13, 27 December 2024 (UTC)
::The "Why it fails" section of the article explains that the machine fails because "a ratchet and pawl small enough to move in response to individual molecular collisions also would be small enough to undergo Brownian motion as well. The pawl therefore will intermittently fail by allowing the ratchet to slip backward or fail by not allowing the ratchet to slip forward." Is this explanation incorrect or incomplete? If it is correct and complete then why would my magic material not eliminate the (relative) Brownian motion of the pawl and the cog, thereby preventing the ratchet from slipping? ] (]) 20:50, 14 August 2011 (UTC)
:Hows about you try it and report back? :) ←] <sup>'']''</sup> ]→ 21:31, 27 December 2024 (UTC)
:::If you assume that the pawl doesn't dissipate energy, then it will flutter hence and forth and that will make the set up to fail to work. So, te given explanation is incomplete. It's similar to the old arguments puporting to show why Maxwells Demon fails. While these analyses are technically correct, they are sort of "Straw Man arguments", i.e. they make assumptions and then one shows that the set up fails, but that is then due to the assumptions that are made. Then, if you make a different assumption, like you did here, it seems that the thing really can work.
::I wanted to try it just today, but I had to exchange the under-desk ] I got for Christmas for a different model with more inclined treadles because with the one I got, my knees would hit the desk at the top of every cycle. Anyway, I was hoping someone else tried it first (preferably as part of a formal scientific study) so I would know if I could control whether I got a runner's high from exercise or not? ] (]) 03:09, 28 December 2024 (UTC)
:::Like in case of Maxwell's Demon, the fundamental reason why this doesn't work was given by Landauer: you can't erase information, at best you can move it, and there is an entropy cost to be paid for that (so that won't happen in thermal equilibrium).] (]) 21:20, 14 August 2011 (UTC)
Also, sorry for adding to my own question, but here's a related one: is it known whether the length of a person's ] (which is inversely correlated with its sensitivity) influences whether said person gets a runner's high from exercise (and especially from low-intensity exercise)? ] (]) 03:14, 28 December 2024 (UTC)
::::Thanks. The need for the pawl to dissipate energy may be a way forward for me to understand why my proposal would not work. Unfortunately the "information" argument is beyond me; I don't even begin to understand how it's relevant. If you think the article's explanation is incomplete and ever have the time and inclination to improve it then I'm sure that would be appreciated by readers. ] (]) 21:53, 14 August 2011 (UTC)
== ] vs ] ==
:::::The article explanation is fine. You seem to think that your rigid material would be immune to Brownian motion. It would not. ] (]) 21:57, 14 August 2011 (UTC)
Hi,
::::::The article said (before I fixed it) "a ratchet and pawl small enough to move in response to individual molecular collisions also would be small enough to undergo Brownian motion as well" . That makes no sense. "Movement in response to individual molecular collisions" ''is'' Brownian motion. I think the OP was misled by that sentence and imagined a device that's immune to one but not the other. -- ] (]) 22:37, 14 August 2011 (UTC)
::::::: My idea was that the rigid material would be immune to "internal" Brownian motion affecting the positions of the pawl and cog <u>relative to one another</u>. I did not imagine the rigidity would prevent the whole assemblage from jiggling about in unison if hit, say, by air molecules. ] (]) 00:21, 15 August 2011 (UTC)
:::::::The latter IS Brownian motion. The first is thermal agitation. Brownian motion is the apparently random jitter of objects due to the action of molecules on them. ] (]) 01:33, 15 August 2011 (UTC)
::::::::Oh, thanks, I think I have been misunderstanding this. I was imagining that the slippage was due to relative motion between the pawl and cog caused by this "thermal agitation", but in fact the whole assemblage jittering about even in unison would jiggle the pawl and allow the ratchet to slip? That seems to make sense; is that right? I guess any spring/gravitational force strong enough to defeat this would also stop the cog rotating in the desired direction? ] (]) 11:46, 15 August 2011 (UTC)
What is the difference between an auxotroph and a fastidious organism? It seems to me the second one would have more requirements than the first one, but the limit between the two definitions is rather unclear to me.
== Are hummingbirds territorial? ==
Thank you ] (]) 23:17, 27 December 2024 (UTC)
We have three or four ruby-throated hummingbirds which frequent our backyard bushes and feeder. Lately, one female seems to be hanging around longer than most. She will spend most of the day perched or resting in a weiglia bush which is aboutr 20 feet from the feeder. When another humingbird attempts to use the feeder, whe will leave her perch and chase off the "intruder". Is this normal behavior? JDBaker] (]) 01:44, 14 August 2011 (UTC)
:I'm not 100% sure, but it seems to me that an auxotroph is a specific type of a fastidious organism. ] (]) 03:02, 28 December 2024 (UTC)
:Symbiosis aside, it would seem that most auxotrophs would be fastidious organisms, but there could be many more fastidious organisms that aren't auxotrophs. Auxotrophs specifically can't produce organic compounds on their own. There are a LOT of organisms that rely on the availability of non-organic nutrients, such as specific elements/minerals. For instance, vertebrates require access to calcium. Calcium is an element; our inability to produce it does not make us auxotrophs.
:But perhaps symbiosis would allow an organism to be an auxotroph without being a fastidious organism? For instance, mammals tend to have bacteria in our guts that can digest nutrients that our bodies can't on their own. Perhaps some of those bacteria also assemble certain nutrients that our bodies can't? -- ] (]) 14:27, 28 December 2024 (UTC)
= December 28 =
:Yes, extremely. Given their high metabolism, food is a very high value localized commodity for hummingbirds. It's half the fun of watching them. ] (]) 01:48, 14 August 2011 (UTC)
== Paper with wrong enantiomer in a figure ==
::We have three feeders, none visible from the others, arranged around the house, and probably at least 6-8 hummingbirds in the neighborhood. They're constantly chasing each other in circles around the house from feeder to feeder. It appears that all get enough food, but the behavior is typical of ]s. Other species seem to be less territorial. '''<font face="Arial">] <small>]</small></font>''' 13:29, 14 August 2011 (UTC)
In the following reference:
:::If they were colonial and had stings like bees they'd be frigging terrifying. (Reminds me of monsters from '']'' and '']''. ] (]) 19:25, 14 August 2011 (UTC)
:{{cite journal |last1=Quack |first1=Martin |last2=Seyfang |first2=Georg |last3=Wichmann |first3=Gunther |title=Perspectives on parity violation in chiral molecules: theory, spectroscopic experiment and biomolecular homochirality |journal=Chemical Science |date=2022 |volume=13 |issue=36 |pages=10598–10643 |doi=10.1039/d2sc01323a |pmid=36320700}}
it is stated in the caption of Fig. 8 that ''S''–] is predicted to be lower in energy due to ], but in the figure the wrong enantiomer is shown on this side. Which enantiomer is more stable, according to the original sources for this data? –] (]]) 08:18, 28 December 2024 (UTC)
== Where can I find data on the circulation and citation rates of these journals? ==
== Using gene therapy to change physical characteristics ==
Hello everyone, To write an article about a scientist, you need to know, where can I find data on circulation and citation rates of journals from ? ] (]) 09:58, 28 December 2024 (UTC)
Is it theoretically possible to use gene therapy to change physical characteristics like... hair or eye color? Something like that? ] (]) 02:16, 14 August 2011 (UTC)
== So-called “Hydrogen water” ==
:It certainly is, but the symptoms of the infection and the reactions that might occur could be like having the symptoms of HIV and the pox or viral meningitis at the same time. A certain percentage of human obeistiy is likely caused by viral infection. Keep in mind that many traits depend on development, so, for instance, once you've reached adulthood and your bones have stopped growing, a gene for a bigger body frame won't do anything. You will not be the one you want to have such methods tried on first. Read ]'s ''Next'' and its afterword. Read the brilliant ''Dark Benediction'' by ].] (]) 02:58, 14 August 2011 (UTC)
I saw an ad promoting a device which presumable splits water into
:Yes. However, note that the characteristics wouldn't change in a few seconds or minutes, like in your average bad sci-fi movie. More likely they would change as the hair or eye pigment is naturally replaced, so over the course of weeks or months. In the case of hair, this might lead to a "bad dye job" period with different colored roots. They eye color might also be somewhat unattractive when midway between the two colors. ] (]) 03:08, 14 August 2011 (UTC)
hydrogen and oxygen and infuses water with extra hydrogen, to
a claimed surplus of perhaps 5 ppm, which doesn’t seem like much. I found a review article which looked at several dozen related studies that found benefits:https://pmc.ncbi.nlm.nih.gov/articles/PMC10816294/ .
I’ve noticed that carbon dioxide or chlorine (chloramine?) dissolved in water work their way out pretty easily, so I wonder if dissolved hydrogen could similarly exit hydrogen enriched water and be burped or farted out, rather than entering the blood stream and having health benefits. is it more than the latest snake oil? ] (]) 23:01, 28 December 2024 (UTC)
== How massive? ==
:Yes, the dissolved hydrogen will exit the water just as quickly (even faster, because of its low ] and complete lack of ] or capability for ]), and even if it does enter the bloodstream, it will likewise get back out in short order before it can actually do anything (which, BTW, is why ]s use it in their breathing mixes -- because it gets out of the bloodstream so much faster and therefore doesn't ]) -- so, I don't think it will do much! ] (]) 01:50, 29 December 2024 (UTC)
::It's conceivable it might take out the chloramine, I guess. I don't think there's very much of it, but it tastes awful, which is why I add a tiny bit of vitamin C when I drink tap water. It seems to take very little. Of course it's hard to tell whether it's just being masked by the taste of the vitamin C. --] (]) 02:12, 29 December 2024 (UTC)
:If you just want to split water into hydrogen and oxygen all you need is ]. You don't say where you saw this ad but if it was on a socia media site forget it. ]|] 11:47, 29 December 2024 (UTC)
::If this so-called hydrogen water was emitting hydrogen bubbles, would it be possible to set it afire? ←] <sup>'']''</sup> ]→ 14:03, 1 January 2025 (UTC)
:We once had an article on this topic, but see ]. ] (]) 22:27, 1 January 2025 (UTC)
::I don't know if it is rubbish or not but a quick look on the web indicates to me it is notable enough for Misplaced Pages. I didn't see anything indicating it definitely did anything useful so such an article should definitely have caveats. I haven't seen any expression of a potential worry either so it isn't like we'd be saying bleach is a good medicine for covid. ] (]) 23:07, 1 January 2025 (UTC)
:'']'' does not sound of exceptionally high quality. ] (]) 01:05, 2 January 2025 (UTC)
= December 29 =
How much mass must an asteroid have to have a large influence on tectonic activities when striking earth?--] (]) 10:32, 14 August 2011 (UTC)
== Potential energy vs. kinetic energy. Why not also "]" vs. "]"? E.g. in the following case: ==
:I wrote a Spanish article a bit related: ] (). ] (]) 10:58, 14 August 2011 (UTC)
In a ], reaching the highest point involves - both a minimal kinetic energy - along with a maximal potential energy, whereas reaching the lowest point involves - both a maximal kinetic energy - along with a minimal potential energy. Thus the mechanical energy becomes the sum of kinetic energy + potential energy, and ''is a conserved quantity''.
::Created a stub: ]. ] (]) 11:13, 14 August 2011 (UTC)
So I wonder if it's reasonable to define also "potential velocity" vs. "kinetic velocity", and claim that in a harmonic oscillator, reaching the highest point involves - both a ''minimal'' "kinetic velocity" (i.e. involves what we usually call ''a rest'') - along with a ''maximal'' "potential velocity", whereas reaching the lowest point involves - both a ''maximal'' "kinetic velocity" (i.e. involves what we usually call ''the actual velocity'') - along with a ''minimal'' "potential velocity". Thus we can also define "mechanical velocity" as the sum of "kinetic velocity" + "potential velocity", and ''claim that the mechanical velocity is a conserved quantity'' - at least as far as a harmonic oscillator is concerned.
thanks... a bit more?:D--] (]) 13:09, 14 August 2011 (UTC)--] (]) 13:09, 14 August 2011 (UTC)--] (]) 13:09, 14 August 2011 (UTC)
Reasonable?
:I can find no sources either at GoogleBooks or GoogleScholar that even mention "crust tsunami" - where have you seen the term used apart from the video? ] (]) 21:03, 14 August 2011 (UTC)
::I think Emijrp mis-heard what was on the video. The announcer says ''crest tsunami'', not ''crust tsunami''. At least I think that's what he says. That term doesn't seem to show up on Google Scholar either; it may have been just a nonce term. --] (]) 08:55, 15 August 2011 (UTC)
Can anyone answer my question...?--] (]) 08:23, 15 August 2011 (UTC)
Note that I could also ask an analogous question - as to the concept of "potential momentum", but this term is already used in the theory of ] for another meaning, so for the time being I'm focusing on velocity.
Well, the Spanish source, taken for what it is, says "centenares de kilometros" which means "hundreds of kilometers", which certainly would splash the crust. Anything that big won't leave witnesses. Leaving aside the reliability of the sources, the Spanish article specifies crust tsunami, whereas crest tsunami simply makes no sense in the context. ] (]) 15:57, 15 August 2011 (UTC)
See '''""''' ] (]) 16:01, 15August2011 (UTC)
] (]) 12:26, 29 December 2024 (UTC)
: 'kinetic velocity' is just 'velocity'. 'potential velocity' has no meaning. ] (]) 13:56, 29 December 2024 (UTC)
:I'm not sure how much support that idea has, but it is interesting that the onset of ] (and thereby plate tectonics) has recently been dated to 3 billion years ago from the observation of inclusions in diamonds . ] (]) 17:14, 15 August 2011 (UTC)
::Per my suggestion, the ratio between distance and time is not called "velocity" but rather "kinetic velocity".
::Further, per my suggestion, if you don't indicate whether the "velocity" you're talking about is a "kinetic velocity" or a "potential velocity" or a "mechanical velocity", the very concept of "velocity" alone has no meaning!
::On the other hand, "potential velocity" is defined as the difference between the "mechanical velocity" and the "kinetic velocity"! Just as, this is the case if we replace "velocity" by "energy". For more details, see the example above, about the harmonic oscillator. ] (]) 15:14, 29 December 2024 (UTC)
:::You could define the ''potential velocity'' of a body at a particular height as the velocity it would hit the ground at if dropped from that height. But the sum of the potential and kinetic velocities would not be conserved; rather <math>v_{\mathrm{tot}} = \sqrt{v_{p}^{2} + v_{k}^{2}}</math> would be constant. ] (]) 18:54, 29 December 2024 (UTC)
::::Thank you. ] (]) 20:07, 29 December 2024 (UTC)
::: 'Potential velocity' has no meaning. You seem to be arguing that in a system where energy is conserved, but is transforming between kinetic and potential energy, (You might also want to compare this to ].) then you can express that instead through a new conservation law based on velocity. But this doesn't work. There's no relation between velocity and potential energy.
::: In a harmonic oscillator, the potential energy is typically coming from some central restoring force with a relationship to ''position'', nothing at all to do with velocity. Where some axiomatic external rule (such as ] applying, because the system is a mass on a spring) ''happens'' to relate the position and velocity through a suitable relation, then the system will then (]) behave as a harmonic oscillator. But a different system (swap the spring for a ]) doesn't have this, thus won't oscillate. ] (]) 00:00, 30 December 2024 (UTC)
::::Let me quote a sentence from my original post: {{tq|Thus we can also...claim that the mechanical velocity is a conserved quantity - '''at least as far as a harmonic oscillator is concerned'''.}}
::::What's wrong in this quotation? ] (]) 07:52, 30 December 2024 (UTC)
:::::It is true, not only for harmonic oscillators, provided that you define {{math|1='''v'''<sub>pot</sub> = − '''v'''<sub>kin</sub>}}. --] 09:07, 30 December 2024 (UTC)
::::* You have defined some arbitrary values for new 'velocities', where their ''only'' definition is that they then demonstrate some new conservation law. Which is really the conservation of energy, but you're refusing to use that term for some reason.
::::: As Catslash pointed out, the conserved quantity here is proportional to the square of velocity, so your conservation equation has to include that. It's simply wrong that any linear function of velocity would be conserved here. Not merely we can't prove that, but we can prove (the sum of the squares diverges from the sum) that it's actually contradicted. For any definition of 'another velocity' which is a linear function of velocity.
::::: Lambiam's definition isn't a conservation law, it's merely a ]. The sum of any value and its ] is always ]. ] (]) 14:04, 30 December 2024 (UTC)
::::::{{small|It is a law of conservation of ''sanity''. Lacking a definition of potential energy, other than by having been informed that kinetic energy + potential energy is a conserved quantity, there is not much better we can do.}} --] 11:20, 31 December 2024 (UTC)
::::::: We have a perfectly viable definition of potential energy. For a pendulum it's based on the change in height of the pendulum bob against gravity. For some other oscillators it would involve the work done against a spring. ] (]) 16:33, 31 December 2024 (UTC)
::::::::Oops, I mistyped. I meant to write:
:::::::::"{{small|Lacking a definition of potential velocity, other than by having been informed that kinetic velocity + potential velocity is a conserved quantity, there is not much better we can do.}}"
:::::::: --] 23:32, 31 December 2024 (UTC)
= December 30 =
== Time it takes solar system to orbit around the galactic centre. ==
== Saltiness comparison ==
I have read a lot of articles that tell me that its 225 million years.
Is there some test one might easily perform in a home ] to compare the ] (due to the concentration of ] ]s) of two liquid preparations, without involving biological ]s? --] 09:22, 30 December 2024 (UTC)
I would like to know how astronomers have measured this, also does this mean that the deep sky objects will "move" into other areas of the sky ?
:Put two equally sized drops, one of each liquid, on a warm surface, wait for them to evaporate, and compare how much salt residue each leaves? Not very precise or measurable, but significant differences should be noticeable. {The poster formerly known as 87.81.230.195} ] (]) 10:21, 30 December 2024 (UTC)
thx :) <span style="font-size: smaller;" class="autosigned">— Preceding ] comment added by ] (]) 12:15, 14 August 2011 (UTC)</span><!-- Template:Unsigned IP --> <!--Autosigned by SineBot-->
:The movement of stars in the night sky relative to each other and very distant objects is called ]. That's caused by the relative motion of the stars and our solar system. The estimate of the length of a ] (and it's a pretty rough estimate) is got by measuring the distance to the centre of the galaxy (see ] for how distances are measured), using that to estimate the length of the Sun's orbit and then measuring the speed of the sun through the galaxy to get how long it will take to complete one orbit. I'm not quite sure how the orbital speed is measured, though... it's easy enough to work out how we're moving relative to nearby stars, but they are also orbiting the centre of the galaxy, so that doesn't help much. See ] for some more details. --] (]) 13:45, 14 August 2011 (UTC)
::One has to identify objects that belong to the halo of the Milky Way, not the disk. The halo shows no net rotation, so one can determine the Sun's velocity relative to the mean of these objects. Candidates are globular clusters and so-called high-velocity stars. If one plots their velocity vectors, they show an asymmetric distribution with a centroid at around −220 km/s (so-called "asymmetric drift"). --] (]) 18:15, 14 August 2011 (UTC)
::The principle is sound, but the residue from one drop won't be measurable using kitchen equipment -- better to put equal amounts of each liquid in two warm pans (use enough liquid to cover the bottom of each pan with a thin layer), wait for them to evaporate and then weigh the residue! Or, if you're not afraid of doing some ], you could also try an indirect method -- bring both liquids to a boil, measure the temperature of both, and then use the formula for ] to calculate the saltiness of each! ] (]) 18:22, 30 December 2024 (UTC)
==Identify (?) bomb==
]
This is from RAF Cowden, an aerial bombing test range, possibly a bomb. But is it actually a bomb or something else? (I didn't take the photograph so I don't know the scale but it must be ~1.5ft long) - looks odd for a bomb.. What is it? Thanks. ] (]) 16:40, 14 August 2011 (UTC)
:It is quite possibly an older ] which has lost its tail fins. I'd watch my step in that area. ] (]) 21:03, 14 August 2011 (UTC)
::Such things are common in former artillery ranges, even those which supposedly have been "cleared." In the U.S. at least one has been turned into a park (] in Pennsylvania) which issues warnings about finding old ordnance to visitors.
:Compare . Possibly the front half of a practise bomb. ] (]) 23:47, 14 August 2011 (UTC)
:::Presumably the ''liquid preparations'' are not simple saline solutions, but contain other solutes - or else one could simply use a hydrometer. It is unlikely that Lambian is afraid of doing some algebra. ] (]) 18:57, 30 December 2024 (UTC)
This is what's called a '']'', which may or may not carry an explosive payload which might be called a bomb. (The mistake would be analogous to showing a picture of an envelope and calling it a letter. An envelope is not a letter and may or may not contain a letter.) What sort of shell this is I haven't a clue. ] (]) 01:34, 15 August 2011 (UTC)
:<s>Assuming the liquid preparations are water-based and don't contain alcohols and/or detergents one can measure their rates of dispersion. Simply add a drop of food dye to each liquid and then time how rapidly droplets of each liquid disperse in distilled water. Materials needed: food dye, eye dropper, distilled water, small clear containers and a timer.</s> ] (]) 21:09, 30 December 2024 (UTC)
:::The ] of a solution will indicate its molarity, but not identify the solute. ''Liquid preparations'' that might be found in a kitchen are likely to contain both salt and sugar. Electrical conductivity is a property that will be greatly affected by the salt but not the sugar (this does not help in distinguishing Na<sup>+</sup> from K<sup>+</sup> ions though). ] (]) 22:23, 30 December 2024 (UTC)
:::Thanks - Nanonic's images of the 'BDU-33' nailed it - looks the same - (though I though the one here looks bigger).] (]) 02:06, 15 August 2011 (UTC)
::::That's what I'm thinking too -- use an ] to measure the ] of the preparation, and compare to that of solutions with known NaCl concentration (using a ]-type method). ] (]) 20:18, 31 December 2024 (UTC)
:Quantitative urine test-strips for sodium seem to be available. They're probably covering the concentration range of tens to hundreds millimolar. ] (]) 00:58, 2 January 2025 (UTC)
{{clear}}
::Thanks, test strips seem more practical in the kitchen setting than an ohmmeter (why not call it a "]meter"?), for which I'd need to devise a way (or so I think) to keep the terminals apart at a steady distance. Test strips require a colour comparison, but I expect that a significant difference in salinity will result in a perceptible colour difference when one strip is placed across the other. Only experiment can tell whether this expectation will come true. Salinity is usually measured in g/L; for kitchen preparations a ballpark figure is 1 g/L. If I'm not mistaken this corresponds to {{nowrap|1=(1 g/L) / (58.443 g/mol) ≈}} {{nowrap|1=0.017 M = 17 ].}} I also see offers for salinity test strips, 0–1000 ppm, for "Science Education". --] 11:40, 2 January 2025 (UTC)
:::Test strips surely come with a printed color-chart. But if all you are trying to do is determine which is more salty, then that's even easier than quantifying each separately. Caveat for what you might find for sale: some "salinity" tests are based on the chloride not the sodium, so a complex matrix that has components other than NaCl could fool it. ] (]) 18:44, 2 January 2025 (UTC)
== The (uncommon?) terms "relativistic length", and "relativistic time". ==
== Fly stickers - do they work? ==
1. In Misplaced Pages, the page ] is automatically redirected to our article ], ''which actually doesn't mention the term "relativistic length" at all''. '''I wonder if there is an accepted term for the concept of relativistic length'''.
Got myself a recurring fly/midge problem in my kitchen bin this summer. Those coloured, flower-shaped window stickers that claim to kill flies (that you can find really cheap on eBay). Do they really work as well as is claimed? --] (]) 20:24, 14 August 2011 (UTC)
2. A similar qusestion arises, at to the concept of relativistic time: The page ], is automatically redirected to our article ], which prefers the abbreviated term "time dilation" (59 times) to the term "relativistic time dilation" (8 times only), and ''nowhere'' mentions the term "relativistic time" alone (i.e. without the third word "dilation") - although it does mention the term "proper time" for the shortest time. Further, this article doesn't even mention the term "dilated time" either. It does mention, though, another term: ], but regardless of time dilation in ''Special'' relativity. '''To sum up, I wonder what's the accepted term used for the dilated time (mainly is Special relativity): Is it "coordinate time"? "Relativistic time"?'''
:Taking out the garbage works ''great''. ] (]) 21:26, 14 August 2011 (UTC)
::Sounds like a cuter version of ], which works fine but is not at all pleasant to look at. ] (]) 21:29, 14August2011 (UTC)
] (]) 09:32, 30 December 2024 (UTC)
:Are you reading these things as "contraction of relativistic length" etc.? It is "relativistic contraction of length" and "relativistic dilation of time". --] (]) 09:37, 30 December 2024 (UTC)
::Naw man, I *do* take out the garbage when the bag is full. However, I have loads of flies in my bin again about a day later when there's very little in there (just some mandarin peel and a couple of apple cores today - opened bin to drop in pizza box and flies erupted). I'm not sure where they're coming in from. They're not regular houseflies - these are much smaller (maybe 4mm long). --] (]) 21:36, 14 August 2011 (UTC)
::When I wrote: {{tq|The page ] is automatically redirected to our article ] which...nowhere mentions the term "relativistic time" alone (i.e. without the third word "dilation")}}, I had already guessed that the term "dilation of relativistic time" (i.e, with the word "dilation" preceding the words "relativistic time") existed nowhere (at least in Misplaced Pages), and that this redirected page actually meant "relativistic dilation of time". The same is true for the redirected page "relativistic length contraction": I had already gussed it didn't mean "contraction of relativistic length", because (as I had already written): {{tq|the article ]...doesn't mention the term "relativistic length" at all}}.
::Anyway, I'm still waiting for an answer to my original question: Are there accepted terms for the concepts, of relativistic length - as opposed to ], and of relativistic time - as opposed to ]? ] (]) 10:12, 30 December 2024 (UTC)
:::A term that will be understood in the context of relativistic length contraction is ''relative length'' – that is, length relative to an observer.<sup></sup> --] 10:55, 31 December 2024 (UTC)
::::Thank you. The middle source uses the term "comparative length", rather than "relative length". I couldn't open the third source. ] (]) 08:04, 1 January 2025 (UTC)
:::::The text under the graph labelled '''Comparative length''' on page 20 of the middle source reads:
::::::Graph of the relative length of a stationary rod on earth, as observed from the reference frame of a traveling rod of 100cm proper length.
:::::A similar use of "relative length" can be seen on the preceding page. --] 10:23, 2 January 2025 (UTC)
== What did Juan Maldacena say after "Geometry of" in this video? ==
:::Almost certainly part of the ] family attracted by, err, mandarin peel and apple cores. Nothing an appropriately sized seagull couldn't sort out, I'll be bound. I've used the window stickers to try to kill other sorts of flies: no joy. --] ] 21:41, 14 August 2011 (UTC)
I was watching this video ] and ] as they explore a wealth of developments connecting black holes, string theory etc, ] said something right after "'''Geometry of'''" Here is the spot: https://www.youtube.com/live/yNNXia9IrZs?si=G7S90UT4C8Bb-OnG&t=4484 What is that? ] (]) 20:46, 30 December 2024 (UTC)
:::::<small>Seagulls, hehe. ] (]) 21:47, 14 August 2011 (UTC)</small>
:]. --] (]) 21:05, 30 December 2024 (UTC)
::Thank you, its the ]'s accent which made me post here. ] (]) 21:18, 30 December 2024 (UTC)
= December 31 =
::::::I wish that was my gull-friend. --] (]) 21:52, 14 August 2011 (UTC)
== Brightest spot of a discharge tube ==
::::There may be something else attracting them, a lingering smell in the bin perhaps? Keeping in mind that many bugs find their food almost entirely by smelling for it, you may want to consider scrubbing the inside of the bin with bleach or something. Even if you can't smell it, they apparently can. ] (]) 21:43, 14 August 2011 (UTC)
]
::::Yes, almost certainly fruit flies, given the examples. If you eat a lot of fruit, you might consider throwing the cores and peels and whatever outside immediately. They're biodegradable anyway :P -- '''<span style="font-family:century gothic">] ]</span>''' 21:46, 14 August 2011 (UTC)
]
What causes the discharge tubes to have their brightest spots at different positions? ] (]) 13:12, 31 December 2024 (UTC)
: See also the pictures at ]. --] (]) 13:26, 31 December 2024 (UTC)
::::I moved to Georgia (US) last summer from parts further north and both this and last summer I've had a similar problem with fruit flies in the trash. Once they take hold it's hard to get rid of them. If there's any sort of food waste in the trash they're back with in a day or two of taking out the garbage. One thing I've found that helps a lot is to scrub out the trash bin. The flies lay eggs on the inside of the lid and inside of the bin itself (outside of the bag). You'll see a lot of fly maggots hanging out here (the eggs themselves are hard to see). Cleaning the bin is not guaranteed to fully eradicate them, depending on how thorough you are, but it will at least keep the numbers in check. I haven't heard of those stickers so I don't know if they work. I did read online that you can make a trap with vinegar and some detergent, and it was completely ineffective. ] (]) 22:13, 14 August 2011 (UTC)
= January 1 =
:::::Keep garbage (kitchen waste, as opposed to trash) in the freezer until you take it to the curb. ] (]) 22:19, 14 August 2011 (UTC)
== Two unit questions ==
::::::Freezer is one option. Garbage disposal is another. Flushing is a third. Putting them in the outside trash is a fourth. A sealable "slop jar", such as an old coffee tin, is a fifth option. There's just no need to leave fruit fly food out in your home where fruit flies can get to it. ] (]) 23:35, 14 August 2011 (UTC)
#Is there any metric unit whose ratio is not power of 10, and is divisible by 3? Is there any common use for things like "{{frac|2|3}} km", "{{frac|5|12}} kg", "{{frac|3|1|6}} m"?
:As for your current population, one method which can work is to leave out plates filled with lemon-scented (hand) dish-washing detergent. The lemon scent attracts them, and the detergent traps and kills them. ] (]) 23:38, 14 August 2011 (UTC)
#Is a one-tenth of nautical mile (185.2 m) used in English-speaking countries? Is there a name for it?
--] (]) 10:41, 1 January 2025 (UTC)
:1 not that I know of (engineer who has worked with SI for 50 years)
Keeping ''everything'' in the fridge or freezer, including grain food from the pantry and food scraps from the garbage (assuming, as in NYC, garbage disposals are illegal or you have a septic tank) will work against mice, rats, house flies, fruit flies, roaches and ]. Flushing helps too but leaves a mess between kitchen and toilet. ] (]) 00:51, 15 August 2011 (UTC)
:2 not that I know of (yacht's navigator for many years on and off)
:] (]) 11:35, 1 January 2025 (UTC)
::In Finland, ''kaapelinmitta'' is 185.2 m. Is there an English equivalent? --] (]) 18:11, 1 January 2025 (UTC)
:::]. --] (]) 18:26, 1 January 2025 (UTC)
::::Good article. I was wrong ] (]) 22:26, 1 January 2025 (UTC)
:Thanks for the tips, guys. I've never ever had this problem before. Sure, I've had insects get in my house (who hasn't?), wasps nests, flying ant day crap, etc. but never an infestation of the little bastards on this scale. --] (]) 00:59, 15 August 2011 (UTC)
:::The answer can be found by looking up '']'' on Wiktionary. --] 00:14, 2 January 2025 (UTC)
== What is more physiological (for a right-hander) left-hand drive or right-hand drive? ==
::I'd guess the core of the problem is that a pregnant female found it's way to your rotting garbage. ] (]) 03:01, 15 August 2011 (UTC)
Has anyone determined whether it is better for a right-hander to have the left hand on the steering wheel and the right hand on the gear shift stick, or the other way round? Are there other tests of whether left-hand drive or right-hand drive is physiologically better (for a right-hander at least)? ] (]) 12:03, 1 January 2025 (UTC)
:I had a problem with fruit flies and those stickers were very helpful (they become more effective once a few flies are stuck to them - that seems to attract other flies more than the smell). The other thing I found useful was a vacuum cleaner. I would use it to literally suck them out of the air. It took several weeks to get rid of them completely, but they're gone now. --] (]) 11:34, 15 August 2011 (UTC)
:<small>Supplementary question: I've only driven right-hand-drive vehicles (being in the UK) where the light stalk is on the left of the steering column and the wiper & washer controls are (usually) on the right. On a l-h-drive vehicle, is this usually the same, or reversed? {The poster formerly known as 87.81.230.195} ] (]) 12:12, 2 January 2025 (UTC)</small>
= August 15 =
::<small>Modern cars are designed for mass production in RH- and LH-drive versions with a minimum difference of parts. Steering columns with attached controls are therefore unchanged between versions. ] (]) 12:29, 2 January 2025 (UTC)
:::In the UK nowadays, are cars still mostly manual transmission, or has automatic become the norm? ←] <sup>'']''</sup> ]→ 12:38, 2 January 2025 (UTC)
::::In the UK, sales of new automatics have just recently overtaken manuals - so probably still more manuals than automatics on the road. ] (]) 14:37, 2 January 2025 (UTC)</small>
:::::<small>This may be tied to the rise of EVs, since they have automatic transmissions by default. {The poster formerly known as 87.81.230.195} ] (]) 05:29, 3 January 2025 (UTC)</small>
:::In Australia, we drive on the left, and the indicator and wiper stalks are the opposite way to the UK. Having moved back from the UK after 30 years, it took me a while to stop indicating with wipers. ] (]) 05:08, 3 January 2025 (UTC)
::::This depends more on where the car came from I think. For European or American cars it tends to be in the UK direction. For Asian cars or I guess those odd Australian made cars which are out there, it tends to be in the other. See e.g. . The UK being a bigger market I think most manufacturers have come to follow the new UK norm for cars they intend to sell there although I suspect to some extent it's still true in the sense that I think most Asian car brands, at least assemble their cars in the EU or maybe the UK if they're destined for the UK (made a lot of sense pre-Brexit) . It sounds like the new UK norm is fairly recent perhaps arising in the 1980s-1990s after European manufacturers stopped bothering changing that part of the production for the reasons mentioned by Philvoids. As mentioned in one of the Reddit threads, the UK direction does make it difficult to adjust indicators while changing gear which seems a disadvantage which is fairly ironic considering the the UK has much more of a preference for manuals than many other RHD places with the other direction. ] (]) 04:31, 6 January 2025 (UTC)
:::::<small><p>For further clarity, AFAICT, LHD vehicles generally have their indicators on the left and wipers on the right. As mentioned, assuming the gear stick is in the middle which AFAIK it is for most cars by now, this seems the better positioning especially on manual cars since you're much more likely to want to need to indicate while changing gear than you are going to want to adjust your wipers even in the rainy UK. The UK being LHT/RHD especially with their own manufactured cars tended to have the indicators on the right and wipers on the left in the more distant past so again the positions that made most sense. </p><p>While I don't have a source for this going by the history and comments, it sounds to me like what happened is European manufacturers who were primarily making LHD vehicles, with the UK and Ireland their main RHD markets but still small compared to the LHD market stopped bothering changing positions for RHD vehicles as a cost saving measure. So they began to put wipers on the right and indicators on the left even in their RHD vehicles no matter the disadvantage. I'm not so sure what the American manufacturers did or when and likewise the British but I think they were a fairly small part of the market by then and potentially even for them LHD was still a big part of their target market. </p><p>Meanwhile Asian manufacturers however still put their indicators on the right and wipers on the left in RHD vehicles, noting that Japan itself is LHT/RHD. I suspect Japanese manufacturers suspected, correctly, that it well worth the cost of making something else once they began to enter the LHD markets like the US, to help gain acceptance. And so they put the indicators on the left and wipers on the right for LHD vehicles even if they did the opposite in their own home market and continued forever more. Noting that the predominance of RHT/LHD means even for Japanese manufacturers it's generally likely to be their main target by now anyway. </p><p>Later I assume South Korea manufacturers and even later Chinese felt it worth any added cost to increase acceptance of their vehicles in LHT/RHD markets in Asia and Australia+NZ competing against Japanese vehicles which were like this. And this has largely continued even if it means they need to make two different versions of the steering column or whatever. It sounds like the European and American brands didn't bother but they were primarily luxury vehicles in such markets so it didn't matter so much. </p><p>This lead to an interesting case for the UK. For the Asian manufacturer, probably many of them were still making stuff which would allow them to keep putting the indicators on the right and wipers on the left for RHD vehicles as they were doing for other RHD markets mostly Asian. And even if they were assembling them in the EU, I suspect the added cost of needing to ship and keep the different components etc and any difference it made to the assembly line wasn't a big deal. </p><p>So some of did what they were doing for the Asian markets for vehicles destined for UK. If they weren't assembling in the EU, it made even more sense since this was likely what their existing RHD assembly line was doing. But overtime the UK basically adopted the opposite direction as the norm no matter the disadvantages to the extent consumers and vehicle enthusiast magazines etc were complaining about the "wrong" positions. So even Asian manufacturers ended up changing to the opposite for vehicles destined to the UK to keep them happy. So the arguably better position was abandoned even in cases where it wasn't much of a cost saving measure or might have been even adding costs. </p><p>] (]) 05:43, 6 January 2025 (UTC)</p></small>
::I've driven different (automatic) left-hand-drive vehicles with the light stalk on each side, but left side has been more common. Perhaps because the right hand is more likely to be busy with the gear shift? (Even in the US, where automatic has been heavily dominant since before I learned to drive.) -- ] (]) 17:32, 2 January 2025 (UTC)
:It's better for a right-hander to have both hands on the steering wheel regardless of where the gear lever is. See . I suspect the same goes for a left-hander. ] (]) 14:39, 2 January 2025 (UTC)
::I suppose that the question is whether right-handers have an easier time operating the gear stick when changing gears in manual-transmission cars designed for left-hand traffic, with the steering wheel on the right (like in the UK) or right-hand traffic, with the steering wheel on the left (like in most of continental Europe). Obviously, drivers will use their hand at the side where the gear stick is, so if it is in the middle and the driver, behind the wheel, sits in the right front seat, they'll use their left hand, regardless of their handedness. But this may be more awkward for a rightie. Or not.
::--] 16:30, 2 January 2025 (UTC)
:::In my personal experience (more than 10 years driving on each side of the road, in all four combinations of car handedness and road handedness) the question which hand to use for shifting gears is fairly insignificant. Switching from one type of car to the other is a bit awkward though. —] (]) 18:33, 2 January 2025 (UTC)
::::My first car, a ], had the gearstick on the left and the handbreak on the right, which was a bit of a juggle in traffic. ] (]) 19:13, 3 January 2025 (UTC)
== Distinguishing a picture of a sunset from the picture of a sunrise? ==
== Why are humans physically weak? ==
Is there a way (if you don't know which way is west and which way is east in a particular location) to distinguish a picture of a sunset from the picture of a sunrise? ] (]) 12:08, 1 January 2025 (UTC)
It seems to me that humans, compared to animals of similar weight and size, are quite weak. Especially taking into account the fact that we live in an advanced civilization were food containing the right amount of nutrients is served on time, we can get enough rest etc. etc., while animals cannot assume that they'll have the optimal amount of food every day.
:Generally, no, but there are a few tricks that sometimes work. In dry sunny weather, there's more dust in the air at sunset (due to thermals) than at sunrise, making the sky around the sun redder at sunset. But in moist weather, mist has the same effect at sunrise. If the picture is good enough to see ], comparing the distribution of sunspots to the known distribution of that day (this is routinely monitored) tells you where the North Pole of the sun is. At sunset, the North Pole points somewhat to the right; at sunrise, to the left. If you see any ] or ] clouds in the picture, it was a sunset, as such clouds form during the day and disappear around sunset, but absence of such clouds doesn't mean the picture was taken at sunrise. A very large cumulonimbus may survive the night. ] clouds are often very large, expanding into ], in the evening, but are much smaller at dawn as there's more air traffic during the day than at night, making the upper troposphere more moist towards the end of the day. Cirrostratus also contributes to red sunsets and (to lesser extend, as there's only natural cirrostratus) red sunrises. ], ], flowers and flocks of birds may also give an indication. And of course human activity: the beach is busier at sunset than at sunrise. ] (]) 13:41, 1 January 2025 (UTC)
Also we need to do quite a lot of exercise to be fit, while e.g. gorillas are much stronger than humans, even though they eat and sleep all day long. ] (]) 00:12, 15 August 2011 (UTC)
::Supposing the photograph has high enough resolution to show ]s it can be helpful to know that the pattern of spots at sunrise is reversed left-right at sunset. ] (]) 13:21, 3 January 2025 (UTC)
:::At the equinox, the disk of the Sun with its pattern of sunspots appears to rotate clockwise from sunrise to sunset by 180 degrees minus twice your latitude (taking north positive). At my place, that's 75 degrees. Other times of the year it's less; at the start and end of polar day and polar night, there's no rotation. Sunset and sunrise merge then.
:::And I forgot to mention: cirrostratus clouds will turn red just after sunset or just before sunrise. At the exact moment of sunrise or sunset, they appear pretty white. ] (]) 17:06, 3 January 2025 (UTC)
::::I differ: the same rotation is involved everywhere on Earth. If you stand on tiptoe at a N. or S. pole to take a picture of the Sun it is you who must pirouette 15 degrees per hour to keep facing the Sun. The Earth rotates you at this rate at all non-polar locations. If you stand within the arctic or antarctic circles, for parts of the year the 24-hour night or 24-hour daylight seem to prevent photographs of sunrise or sunset. However the terms "sunrise" and "sunset" can then be interpreted as times that are related to particular timezones which are generally assigned by longitude. In photographing the 24-hour Sun the equatorial rise and set times for your own longitude are significant elevation maxima worth mentioning even though the minimum elevation remains above the horizon. I maintain that the sunspot pattern observed from any location on Earth rotates 360 degrees per 24 hours and that "night", the darkness from sunset to sunrise, is when the Earth's bulk interrupts one's view of the rotation but not the rotation itself which is continuous.
:::::Taking the Earth as reference frame, the Sun rotates around the Earth's spin axis. The observer rotates around his own vertical axis. The better both axes are aligned, the smaller the wobble of the Sun. In the northern hemisphere, it rotates clockwise from about 6 till 18 by 180 degrees minus twice your latitude and counterclockwise at night, in the southern hemisphere it's the opposite. Try a planetarium program if you want to see it. ] shows some sunspots, does things right and is free and open source. ] (]) 10:27, 5 January 2025 (UTC)
:::::]We deprecate the obselete ] and suggest Misplaced Pages references that are free and just one click away (no extra planetarium software needed). The axes of rotation of the Sun and Earth have never in millions of years aligned: the ] is the orbital plane of Earth around the Sun and Earth currently has an ] of about 23.44° without "wobbling" enough from this to concern us here. ] (]) 14:56, 5 January 2025 (UTC)
::::::This isn't my field but sunspots aside, if you know the location and date, I assume the appearance of other astronomical objects like the moon or rarely another star probably Venus, in the photograph should be enough to work out if it's a sunset or sunrise. That said, to some extent by taking into account other details gathered from elsewhere's I wonder if we're going beyond the question. I mean even if you don't personally know which is east or west at the time, if you can see other stuff and you know the location or the stuff you can see is distinctive enough it can be worked out, you can also work out if it's sunset or sunrise just by working out if it's east or west that way. ] (]) 03:54, 6 January 2025 (UTC)
:::::In my experience (Southern England) they tend to be pinker at dawn and oranger(!) at dusk. {The poster formerly known as 87.81.230.195} ] (]) 03:23, 4 January 2025 (UTC)
::::::Pink clouds must result from blending of reddish clouds with the blue sky behind. There's actually more air between the observer and the clouds than behind the clouds, but for that nearby air the sun is below the horizon. ] (]) 10:27, 5 January 2025 (UTC)
::::The questioner asks for interpretation of a single picture. It is beside the point that more would be revealed by a picture sequence such as of changing cloud colours. ] (]) 12:41, 4 January 2025 (UTC)
:Recalling Leonard Maltin's comment about the ''Green Berets'' movie, which was filmed in the American state of Georgia: "Don't miss the closing scene, where the sun sets in the east!" ←] <sup>'']''</sup> ]→ 22:37, 5 January 2025 (UTC)
::Which you can only tell if you know which way is east in the image. Maltin, or his writer, appears to have assumed that Vietnam has a seacoast only on the east, which is wrong. --] (]) 03:46, 6 January 2025 (UTC)
:::Georgia has only an eastern seacoast. ←] <sup>'']''</sup> ]→ 10:31, 6 January 2025 (UTC)
::::<small>] ] (]) 14:18, 6 January 2025 (UTC)</small>
::::So what. Bugs? The claim is about the setting, not the filming location. --] (]) 07:30, 7 January 2025 (UTC)
:::::But as it was filmed in (The US State of) Georgia, it must actually show a sunrise, regardless of what the story line says – how do you know that wasn't what Maltin actually meant? {The poster formerly known as 87.81.230.195} ] (]) 10:35, 7 January 2025 (UTC)
::::::I assume (not having seen the film) that, <u>in the story line</u> of '']'' , the closing scene takes place in the late afternoon, which means it shows a sunset. The plot section of our article on the film places the closing scene at or near ], which is on the east coast of Vietnam. This means that Maltin did not make an unwarranted assumption; he was just seeking an excuse to bash the film. --] 13:55, 7 January 2025 (UTC)
= January 6 =
:Who needs physical strength when our brains allow us to ? '''Warning - a very violent video''', though it's the best example that I can think of that demonstrates man's (even those men that some would dismiss as 'primitives') utter superiority over far stronger animals. --] (]) 00:33, 15 August 2011 (UTC)
== Does the energy belonging to an electromagnetic field, also belong (or is considered to belong) to the space carrying that field? ==
::<small>(Edit conflict)</small> We don't depend on our strength for survival as a species, our cognitive ability has usurped that position. We used to be stronger not so long ago, you can see a record of decrease in masculinity and bone density only as recently as 1000 years ago. ] (]) 00:37, 15 August 2011 (UTC)
] (]) 18:41, 6 January 2025 (UTC)
::The video isn't particularly good as an example, as the voice over is used to make the sociological points (rather tacky ones at that), rather than the cinematography or contents. As far as I can tell it also shows different people (dress, number of people, hunting styles) hunting different animals in different ways in different terrain. Some of the shots are obviously out of sequence. And it requires more than a little elementary reading to observe the role of mutual aid in hunting here due to its obscuration. Wouldn't Kropotkin's ''Mutual Aid''—despite its methodological problems and age—make this point better? ] (]) 01:49, 15 August 2011 (UTC)
:It would be unusual to express the situation in such terms. Since the notion of energy "belonging to" some entity is not itself a physical concept – any practical approach to energy bookkeeping that satisfies the law of conservation of energy will do – this cannot be said to be wrong. It is, however, (IMO) not helpful. Does an apple belong to the space it occupies? Or does that space belong to the apple? --] 23:37, 6 January 2025 (UTC)
:::Kurt's linked movie incongruously shows hunters with primitive spears and wearing obviously machine-made short trousers. Why in such a large crowd has no one thought of using a bow and arrows which would save a lot of running? These are posed movie scenes using many extras not all of whom own spears or do more than jiggle them. ~~
::First, I let you replace the notion of energy "belonging to" some entity, by the notion of energy "attributed to" some entity, or by the notion of energy "carried by" some entity, and the like. In other words, I'm only asking about the abstract relation (no matter what words we use to express it), between the energy and the ''space'' carrying the electromagnetic field, rather than about the specific term "belong to".
::Second, I'm only asking about ''what the common usage is'', rather than about whether such a usage is wrong or helpful.
::The question is actually as follows: Since it's ''accepted'' to attribute energy to an electromagnetic field, is it also ''accepted'' to attribute energy to the ''space'' carrying that field?
::So, is your first sentence a negative answer, also to my question when put in the clearer way I've just put it? ] (]) 03:28, 7 January 2025 (UTC)
:::The answer remains the same. It would be a highly unusual use of language to "attribute" electromagnetic energy to a volume of space, in quite the same way as it would be strange to "attribute" the mass of an apple to the space the apple occupies. But as long as an author can define what they mean by this (and that meaning is consistent with the laws of physics), it is not wrong. --] 13:21, 7 January 2025 (UTC)
= January 7 =
:Starvation seems to have been rampant in our past, such that we've evolved to use as little energy as possible. Thus we only develop big muscles when our body detects a need for them, that is, when out current muscles are overtaxed. ] (]) 00:41, 15 August 2011 (UTC)
::Exactly. ] (]) 00:47, 15 August 2011 (UTC)
:Let's forget about the big brains for a second, just for the point of argument. In terms of physical fitness (from an evolutionary standpoint), there is a lot more than just "strength". Gazelles are not very strong, compared to a cat of the same size. But that's because they are optimized (by evolution) for speed. Some animals are clearly optimized for raw strength. Humans, taken from a purely physical view, and throwing out the lazy excesses of modern life, are optimized to be somewhat mediocre in strength (not at all "weak" — consider that humans whose lives rely on physical strength, like professional athletes, are actually pretty strong), mediocre in speed (we don't run terribly fast), but we are ''great'' at endurance. Check out the ] for example — even horses, which we think of as being great draft animals (and are only as great as they are because we bred them for thousands of years), are pretty poor compared to humans over long hauls. We're great long distance runners. We have way more endurance than the gazelle like animals who can conjure up huge amounts of speed but not for very long. We fit a specific evolutionary niche, even without the brains (which can't be left out, in the end — your evolutionary niche changes once you can hunt in packs, use weapons, etc.). We are also terribly versatile — our body is great at regulating temperature and dealing with very different climates, which is something that a lot of very strong or very fast animals do not have. Having tons of extra muscle mass would not only require a very different type of diet (more reliably protein rich than we had for most of our evolutionary history) but would reduce that endurance advantage. I don't want to tell a "just so" story, but it seems rather clear that we have long occupied a very different type of evolutionary niche than, say, a gorilla, or even a chimpanzee. The particular primates we have evolved from all look like creatures that survived on endurance, adaptability, and intelligence, none of which are particularly served by gigantic muscles. --] (]) 01:46, 15 August 2011 (UTC)
:::Yes, the points of endurance and human eye-hand and other types of co-ordination (which are also highly important for speech) are quite important. Imagine an orangutan ballet. ] (]) 02:16, 15 August 2011 (UTC)
::::Even more-so than eye-hand coordination is simply the intricacy of control of the hands and fingers in general. Humans are capable of some rather minute and complex hand and finger control. Even ignoring the problem of figuring out music in general, I'm not sure you could teach a chimpanzee to play halfway decent electric guitar, or to stitch a quilt, or anything like that. I'm not sure that any other animal has the motor control that humans do over their fingers. --]''''']''''' 02:53, 15 August 2011 (UTC)
:::::Yes, I was negligently vague in saying just eye-hand co-ordination. We also have amazing coordination of our faces and vocal apparatuses. Speech is essentially a sort gesture transfreed to the mouth. Another thing to consider is that we can transfer learned modules from one organ to another, for instance signing our signatures, which we have only ever practised with our fingers, to a pen held by our lips or our toes. That's actually quite amazing and something no animal can really copy. ] (]) 03:18, 15 August 2011 (UTC)
::::::That's quite a formidable wall of text you people have conjured up, so forgive me if I'm echoing a previously stated point: Who needs strong muscles when you have the knowledge to smith a sword? --<span style="text-shadow:gray 0.2em 0.2em 0.1em" class="texhtml">] <sup><sub>]</sub></sup><small><sub style="margin-left:-3.2ex">]</sub></small></span> 03:37, 15 August 2011 (UTC)
::::::::Because big muscles are required to wield the sword, of course. ] (]) 03:50, 15 August 2011 (UTC)
::::::::Smithing a sword is actually a pretty recent innovation from an evolutionary standpoint. It's not what got us through those thousands of years before civilization really started up. The real human innovations are being able to organize themselves in groups, be extremely adaptable, and have lots of fine motor skills. High tech (which metal smithing counts as) is pretty cool but didn't play any real role in our evolutionary history, except for the fact that it allowed a few groups of humans to kill out a bunch of other groups of humans. --] (]) 15:06, 15 August 2011 (UTC)
:::::::Well, actually you do see heavier musculature in areas like New Guinea and Subsaharan Africa where physical competition between equally armed males is more important for reproductive success. Males in New Guinea tribes that still practice intertribal warfare can have the same chance as male chimps, about 30-35% of dying in violence. To the victors go the ladies. See the well written and researched . ] (]) 03:46, 15 August 2011 (UTC)
::::::::I agree entirely that the strength of humans is really underestimated by most here in this thread. Humans whose life depends on their raw strength (rare in any state of "civilization") are pretty formidable creatures. They couldn't arm wrestle with a full grown chimp, but they are not indefensible weaklings. The fact that all its takes is a spear to hunt lions says something quite profound about the abilities of humans to be pretty dangerous even without a huge amount of technological augmentation. Stone age man was a pretty formidable animal, as the record of megafauna extinction shows. --] (]) 15:06, 15 August 2011 (UTC)
:I feel this thread is going somewhat off track when talking about all the things humans are good at. This would only be relevant if they were somehow mutually exclusive with being strong. I don't see how having dexterity in the fingers precludes strength, for example. We should instead focus on the disadvantages of strength. The two I've seen mentioned so far are the energy requirements and the need to eat meat on a regular basis. ] (]) 03:48, 15 August 2011 (UTC)
::Well, and the fact that hypertrophy in certain areas leads to hypotrophy in others. (There's a ] about that in developmental biology, but I forget who.) Big muscles do compete with big brains and other sorts of costly development. Heavy musculature didn't lead to Neanderthal dominance Given we interbred, and the gracile form succeeded, that likely says alot. You can't look at just musculature and judge its value on its own. Biology doesn't work that way. You have to look at other tradeoffs like long distance stamina and human memory and coordination (which are interrelated) to make any holistic sense. Otherwise, by itself, cost no object, bigger muscles will obviously be beneficial. ] (]) 04:05, 15 August 2011 (UTC)
:The ] is probably the favoured reason for why we are not built for strength. Look at the winners of the marathon event and you'll see what's optimal for ] where one man can hunt down and kill an antelope with a stone. ] are the other main persistence hunters, they have a bit more speed and use teeth instead of stones but have less persistence. ] (]) 12:48, 15 August 2011 (UTC)
So would it be safe to assume that other apes don't have anywhere near the endurance that humans do, and that the distance covered by the ape army in '']'' is pretty unrealistic? <small>(Because otherwise the film is ''very'' plausible!)</small> —''']'''<sup>]</sup> 14:22, 15 August 2011 (UTC)
:It is a fact that other apes do not have the body structure or musculature to endure long distance upright walking, let alone the endurance for long marches. Apes revert to knuckle walking about as quickly as we revert to flat footed from tippy-toe walking.No ape other than ] has ever been documented as adopting an upright stance as a matter of habit, hence speculation as to his unique species status. As for plausibility, that depends more on the ignorance of the audience than the accuracy of the artwork. For example, those who know nothing of physics might accept the notion that there could be such a thing as "red matter" which could in the most recent Star Trek movie be used to create a black hole. But any knowledge of gravity and the types of substances that exist show the idea to be ridiculous, not to mention the idea that a supernova of one star could immediately destroy a planet in another system over as was done to Romulus. I have not seen the new Apes movie (the first remake was dreadful) so maybe I am wrong, but given what I know about the creators I don't find it plausible that it will be plausible. ] (]) 15:47, 15 August 2011 (UTC)
Thanks everyone for the replies so far. Reading all the replies, what is still an issue is more or less what StuRat wrote above about why physical strenght would have to come a the expense of physical strength. Of course, having an extremely muscular body build may not be comaptible to being able to perform well at long distance running, while the latter ability may have been important for us in the past. Now, it seems to me that humans are more susceptible to become "couch potatoes" when they don't exercise a lot while a gorilla can just eat and sleep all day long. As suggested above, that has to do with the human body adapted to deal with famines. ] (]) 17:23, 15 August 2011 (UTC)
== Guinea pigs and motion sickness ==
According to author ] in the book '']'' (2010), guinea pigs do not suffer from motion sickness. Why is this? ] (]) 06:21, 15 August 2011 (UTC)
:Googling "guinea pigs motion sickness" brings up several research papers that suggest this is untrue.--]|] 07:41, 15 August 2011 (UTC)
::I think Roach means to say that guinea pigs don't suffer from motion sickness in zero-g. In any case, I'm not seeing anything showing they suffer from motion sickness like other animals. ] (]) 10:11, 15 August 2011 (UTC)
:::A key point is probably 'what do you mean by motion sickness in zero-g'? If you mean something that really is ] that occurs in zero-g environments, then there's no to think any animal which gets motion sickness won't get it. This ref () supports the conclusion that what you call 'zero-g motion sickness' or is also (and more commonly) called space (motion) sickness or ] is indeed a form of ]. That being the case, there's reason to think animals which get motion sickness aren't going to get zero-g motion sickness. However the ref also suggests it's still something that is poorly understood (in terms of what causes it).
:::While there has been a fair amount of research, I don't find much evidence it's been that well observed in animals in space. A lot of research treats space motion sickness as a form of motion sickness, so use methods to stimulate it. Notably from a few quick searches, I can't find any refs discussion space motion sickness in dogs or guinea pigs or mice. However, it has evidentally been observed in monkeys .
:::BTW mentions guinea pigs and rats are a poor model for ('normal') motion sickness since they don't ] (leading to dogs and monkeys being the most commonly used ones). The earlier ref on space motion sickness also mentions this for rats and rabbits. Evidentally ] can be made to vomit and do get motion sickness including vomitting . Cats have also been suggested as models , including for zero-g maneuvers in parabolic flight, although I presume that's a poor model if you believe space motion sickness is unique, since the maneuvers would generally induce motion sickness ala ] anyway hence ]. (I should mention I didn't read the article as I don't have access to the archives .)
:::From and , I gather ] drugs are one of the targets to try and prevent or reduce space motion sickness, which isn't surprising since it's perhaps one of the worse symptoms. Some experiments relating to space motion sickness have used guinea pigs (admitedly a rather long time ago) and more recently rats which would seem odd if the researchers did not believe they could get space motion sickness.
:::All this leads me to conclude there's no reason to believe guinea pigs don't get space motion sickness. They don't vomit, so are often a poor model for motion sickness, unless you use a more sophisticated system, although this still won't work if one of you specific targets is vomiting. But it seems to be usually accepted (as Shantavira said) they do get ('normal') motion sickness e.g. . As hinted at earlier, other non-emetic species like rats also seem to be considered to show motion sickness (the first ref on space motion sickness also mentions this in general). This old article doesn't entirely agree, but that just seems to relate to the lack of vomitting. If you follow a similar definition then the answer is obviously, no they don't get motion sickness including space motion sickness. (IMO a more logical POV is they do get motion sickness but it isn't as bad as in some other animals due to the lack of vomitting.)
:::BTW one of the key signs of motion sickness in non-emetic animals appears to be ] and immobility (from the first ref but I think I also read it elsewhere) although there are also other symptoms like those relating to food and water intake, urination and defacation.
:::Also I would point out from what I've seen (and as is hardly surprising), that at the current time most research on space motion sickness is targetted at ways to reduce and prevent it, as well as trying to understand it, ultimately for humans. The well-being of pet or research guinea pigs in space may be a minor concern but isn't the biggest concern (by which I mean researchers probably aren't going to spend great amounts of time studying space motion sickness in guinea pigs so they can work out what harm it is doing except to study the effects in general or to prevent their experiments being screwed up by sick guinea pigs).
:::P.S. I just found which does mention space motion sickness in rats.
:::] (]) 14:55, 15 August 2011 (UTC)
== What leaf is this? ==
] (]) 06:39, 15 August 2011 (UTC)
: It look quite a lot like ] (''Ocimium basilicum''). ] (]) 07:07, 15 August 2011 (UTC)
:(e/c) Most probably ] (possibly an '']'' cultivar).
:But we can't really know for sure without other info. Where is it from? Can you describe the odor? Do you have pictures of other parts of the plant? Can you describe the flowers? How large is it?-- '''<span style="font-family:century gothic">] ]</span>''' 07:18, 15 August 2011 (UTC)
== Quantum mechanics/many-worlds ==
If I understand correctly, then the ] of quantum mechanics implies (among other things) that for every quantum mechanics experiment performed, there is a universe created that observes every possible result, e.g. if an experiment is performed, and a particle is measured that can be in state A or state B, then there will be a universe in which the outcome is A, and a universe in which the outcome is B. Does this mean that there would be a universe in which the results of every single quantum physics experiment ever would be consistent with a wholly deterministic (i.e. not probabilistic) theory of quantum mechanics? Like, as in, all the scientists in that universe (justifiably) think if you set up ''x'' equipment in ''y'' configuration and perform a measurement, then you will always get ''z'' result without fail, and they all have no idea what 'superposition of states' means? --] <sup>(])</sup> 11:33, 15 August 2011 (UTC)
:Yes. When scientists do experiments they usually look at what the probability of such an outcome is given the theory they are testing (eg. classical mechanics) and if that probability is very low (less than 5% is common, although some fields use much lower values) then they reject the theory and try and come up with something else. Just because there is a less than 5% chance of something happening obviously doesn't mean it can't happen, so there is always a possibility of incorrectly rejecting a correct theory. Since it's possible for that to happen once, it is also possible for it to happen every time. Under many-worlds, anything that is possible happens in some universe, so if many-worlds is correct there must be universes where no-one has ever noticed a quantum effect. The "density" of such universes in the multi-verse would be extremely low, though. --] (]) 11:40, 15 August 2011 (UTC)
::No. When repeating the experiment, the longer the uninterrupted run of outcomes A (or B) the rarer the universe. An infinite run is unobtainable due to the finite time to measure (frequency of measurements) and lifetime of that universe. NB: The "rarity" or low probability of a universe is irrelevant if you are in it. This one is probably one of the rare ones. ] (]) 12:10, 15 August 2011 (UTC)
The example given isn't well specified, because you have a continuum of superpositions of the form cos(theta)|A> + sin(theta)|B>. Then you could assume that for every theta there only has been one outcome (A or B), and this similarly generalized for more complicated superpositions. This is then equivalent to replacing the Born rule probability by a probability function that can only take the value of either zero or one. But then, you can't observe interference effects anymore, so you don't reproduce classical phenomena correctly, like refraction of light, sound waves etc. etc. ] (]) 15:32, 15 August 2011 (UTC)
:I think there could be such a universe (with a bit more specification), but I don't think there would be any scientists in it to carry out experiments. The existence of life as we know it depends on the principles of thermodynamics, which would completely break down in that universe. (The laws of thermodynamics are statistical, not directly physical.) ] (]) 16:13, 15 August 2011 (UTC)
::Also note that quantum effects aren't only measured or observed by humans in experiments, quantum states collapse everywhere due to a wide variety of phenomena. Alternate universes would be created unimaginably often in the ]. Many academics do not lend much credibility to the interpretation. ] (]) 16:39, 15 August 2011 (UTC)
:::{{citation needed}} ] (]) 17:14, 15 August 2011 (UTC)
::::You just have one big static multiverse, the state of this satisfies the equation H|psi> = 0. The splitting doesn't happen on the level of the multiverse, it's just what you get when you focus on a particular component of |psi> in the basis of "pointer states", apply the operator exp(-i H t) and then expand what you get again in that pointer basis. ] (]) 17:34, 15 August 2011 (UTC)
::::: I don't understand that, but you mentioned "splitting", and a couple of people spoke of universes being "created", and those are both conceptual pitfalls. The universes in the many worlds interpretation are equivalent to instants of time: therefore they don't change, or age, or have a point in time at which they are created or split apart. They ''are'' points in time, and pre-exist. Perhaps, though, that's what you just said? ] (]) 09:17, 16 August 2011 (UTC)
For the record, I meant things behave only in a seemingly deterministic manner in certain experiments (through sheer chance), not in all cases (i.e. everyday quantum interactions that happen constantly go on as usual). But, of course, as has been mentioned, you wouldn't be able to reproduce classical effects properly if you counted them as "quantum mechanics" experiments. But if classical physics (say, diffraction of light) works, and more fundamental, particle-physics-oriented stuff demanded a deterministic, non-probabilistic explanation, (suppose, for example, that the double-slit experiment, when done with a single particle emitted at a time, gave results that could be predicted deterministically) would everyone just be completely mystified as to how to explain physics? --] <sup>(])</sup> 05:05, 16 August 2011 (UTC)
== Growing catnip ==
I have got a packet of seed of ], when and where should I grow it. <span style="font-size: smaller;" class="autosigned">— Preceding ] comment added by ] (]) 13:33, 15 August 2011 (UTC)</span><!-- Template:Unsigned IP --> <!--Autosigned by SineBot-->
:It is not very demanding, but likes full sun in damp, uncompacted soil. It commonly grows as a weed along ditches and streambanks. Plant in the early spring, as soon as the soil thaws. Or you can start the plants indoors and transplant outdoors in mid-spring. If conditions are right, the plant will continue to grow in the same place for many years. Be careful where you plant it, because catnip can become quite an aggressive and invasive weed. ] (]) 14:24, 15 August 2011 (UTC)
:And we should also mention the obvious: Grow it where cats can't get to it, or you will likely find the plant ripped up by the roots and dirt all over the place. ] (]) 17:13, 15 August 2011 (UTC)
::can I grow it in the current season ? <span style="font-size: smaller;" class="autosigned">— Preceding ] comment added by ] (]) 08:08, 16 August 2011 (UTC)</span><!-- Template:Unsigned IP --> <!--Autosigned by SineBot-->
:::That depends on what season you're in, winter or summer. ] (]) 08:31, 16 August 2011 (UTC)
== manual ==
is there a COMPLETE list of army and cia manuals here <small><span class="autosigned">— Preceding ] comment added by ] (] • ]) 14:09, 15 August 2011 (UTC)</span></small><!-- Template:Unsigned --> <!--Autosigned by SineBot-->
:Would the ] article be of any help? —''']'''<sup>]</sup> 14:28, 15 August 2011 (UTC)
:We also have ] and ], if that leads you to any other information you may be looking for. —''']'''<sup>]</sup> 14:38, 15 August 2011 (UTC)
::There is also ] (and DKO for the consolidated services; similar resources for other services) but you don't have access unless you are in the Army, (or other branch of the United States armed forces); or, certain types of contractors or liaisons, or other special category. Even if you have access to AKO, it's implausible to expect a ''complete'' listing of ''all'' manuals for the Army; the institution is ''huge'', and there are lots of subject or domain-specific expertise documents that would be irrelevant to most users. Regarding the CIA, there are lots of resources available online at the CIA website. Most of these manuals will bore the average person to tears. ("Manual for operation of telephone in Ghana Field Office"). What sort of manuals are you looking for? You probably want to start with , which you can download free of charge, without needing to log in, from the United States Army website. Then, consider reading FM-3, "Operations." You can buy reprints of these manuals at almost any book retailer. You may find them to be disappointingly dry reading-material. ] (]) 16:57, 15 August 2011 (UTC)
:::Also, the CIA and US army are constantly revising existing manuals and creating new ones, so maintaining currency on more then a single field would require a major time commitment. ] (]) 18:08, 15 August 2011 (UTC)
== transformed circuit drawing for all electrical component ==
please send me the above mentioned subject drawing <span style="font-size: smaller;" class="autosigned">— Preceding ] comment added by ] (]) 14:32, 15 August 2011 (UTC)</span><!-- Template:Unsigned IP --> <!--Autosigned by SineBot-->
:I don't understand what you are asking for. ] (]) 16:09, 15 August 2011 (UTC)
::I suspect, based on your request, that you found one of our over 3.7 million articles and thought we were affiliated in some way with that subject. Please note that you are at ], the free online encyclopedia that ], and this page is for asking reference questions about science topics.--]|] 16:20, 15 August 2011 (UTC)
:::You may find what you want in the article ]. ] (]) 17:50, 15 August 2011 (UTC)
== Human survivability envelope on a newly discovered planet ==
I am trying to come up with the range of human compatible requirements for colonizing a distant planet or moon. I am thinking of places where humans are not going to need more equipment for survival then is commonly used on earth for long periods (central heating, clothes, sunblock, not SCUBA equipment or radiation suits). So I have thought up a list of things humans would require of a planet and would like to know what ranges people can handle long term (more then 20 years). Critical things to look at would be...
:Gravity. Obviously 1g on earth.
::There night be a wider range here than you'd think. Probably not more than 1.1 or 1.2 g, but on the low side we might be able to survive quite low gravities, with the proper exercise to save bones and muscles from atrophy. ] (]) 20:05, 15 August 2011 (UTC)
:Radiation. Background radiation on earth varies on location, but I think 0-10 miliseverts a year is typical
:Oxygen. Earth has 21% O2 at sea level with a standard pressure of about 101 kPa. Human habitation at high altitudes can be down to about 50-60 kPa.
::Our article ] says humans can survive partial O2 pressure of 16-180kPa, but don't know about long term.
:Temperature. Humans live in a temperature range with extremes of -100 up to 130 deg F, though we prefer a more mild climate and have special needs at extreme cold. Telling against this is the expensive equipment at Antarctic science bases.
:Lack of atmospheric toxins. Mostly concerning volcanic activity.
:Obviously humans need water, but how much depends on the environment they are in.
So what kind of ranges for these variables can humans take for the long term? ] (]) 18:34, 15 August 2011 (UTC)
<br>
::Atmospheric pressure is another important parameter. You would also ideally want a planet with a similar day/night cycle to earth. Lack of hostile native lifeforms is a plus! --] (]) 19:53, 15 August 2011 (UTC)
You should have a good background in ]'s ]. One recurring theme of his is the interesting consequences of a space colonization program that send colonist ships to worlds, ], ], ], where robots have found a point habitable to humans. ] (]) 19:58, 15 August 2011 (UTC)
:One other thing to mention is food. If we are to grow our own, we'd need sunlight, around 1% carbon dioxide in the air, and soil with all the necessary minerals and no toxins/poisons (or water with all the necessary minerals, and no toxins or poisons, if we are to grow food there). ] (])
::Adverse airborne bacteria et al.? 16th century explorers might have brought smallpox and others to South America, there could be nasty stuff awaiting us on other worlds as well. --] <small>(])</small> 07:53, 16 August 2011 (UTC)
::1% CO2 seems pretty high if the pressure is what it is on earth. Here we only are around 0.04% CO2 (400ppm). Sunlight would be needed to grow food though unless there is some kind of natural species that survive without it that we could eat. ] (]) 20:20, 15 August 2011 (UTC)
:::Thanks, for the correction. ] (]) 20:31, 15 August 2011 (UTC)
:Also, this planet can't have bad weather, like the 1000 mile an hour winds of Jupiter. And there can't be a constant barrage of meteors, as would be common in many new star systems. ] (]) 20:19, 15 August 2011 (UTC)
:An ozone layer, or some means of blocking UV light, seems important not just for people but also for any food we grow (plants or animals). ] (]) 20:35, 15 August 2011 (UTC)
:Our planet's axial tilt, which gives us seasons, and large moon, which, along with the Sun, gives us tides, are necessary for some plants and animals, but I'd guess we could survive without them. The partially molten core, on the other hand, is important in maintaining a strong magnetic field, which deflects the solar wind enough to allow for a thick atmosphere to remain. ] (]) 20:41, 15 August 2011 (UTC)
== How can I get rid of Acetone in my car ==
A few weeks ago I applied Acetone on my car windshield. The vapors and fumes got so bad that it irritated my body and eyes.
I will roll down the windows to air it out but its still there.
I tried almost everything. I even bought a car purifier but that didn't work. Please help me. Does anybody have any helpful suggestions?
It seems like the whole car is infected. How can I get rid of the fumes and vapors of Acetone in my car? <span style="font-size: smaller;" class="autosigned">— Preceding ] comment added by ] (]) 20:17, 15 August 2011 (UTC)</span><!-- Template:Unsigned IP --> <!--Autosigned by SineBot-->
:Something doesn't make sense here. Acetone is volatile, so should have all evaporated in short order. I suspect that something else must have been mixed with the acetone. Can you check the ingredients list, maybe an odorant was added ? The only other thing I can think of is that the acetone decomposed some of the materials it contacted, and they are now giving off that odor. Does the odor come from the paint, windshield, or where, exactly ? ] (]) 20:24, 15 August 2011 (UTC)
Thanks for your comments StuRat. I didn't read the product before I used it, made a mistake. I threw away the Acetone can. The odor comes mainly from the windshield. <span style="font-size: smaller;" class="autosigned">— Preceding ] comment added by ] (]) 20:28, 15 August 2011 (UTC)</span><!-- Template:Unsigned IP --> <!--Autosigned by SineBot-->
:Acetone is pretty volatile, so the best strategy is simply to air out the car as much as possible. You're probably also hypersensitve to the smell of acetone since you had a bad experience with it, and you're reacting a bit more strongly than you normally would. That's a normal reaction, and it should wear off soon. Time and air are the best solutions to both problems. Trying to mask the smell would probably make matters worse, and there is nothing that you can use to "absorb" the acetone. Just keep airing it out and not using the car for a few days, and things should return to normal. As StuRat said, there is the possibility that some other ingredient besides acetone is to blame, or that the acetone reacted with the coating on your windshield to produce a noxious product. However, I think that temporary hypersensitivity is the most like reason for your discomfort. ] (]) 20:33, 15 August 2011 (UTC)
:(EC) For the record, gasoline will do the same thing if it gets spilled in your car, so keep the gas can in the trunk. For the acetone, don't car windshields have plastic layers in the middle? I know that acetone will react with several different kinds of plastic so if you had a crack or chip in your windshield, acetone could have gotten to the plastic, and reacted with it to form a less volatile, longer lasting odorous compound. The same could happen if it got on other plastics in the car, like the dashboard. Beyond that, the only other things I can think of is to get some fans to blow air through the car while you have it parked to try and remove all the smell you can. Be prepared though, that there is a chance the smell will never fully go away. ] (]) 20:38, 15 August 2011 (UTC)
:OK, time to list some desperate measures:
:1) You could replace the windshield.
:2) You could sell the car to somebody with little sense of smell, like a smoker. ] (]) 20:56, 15 August 2011 (UTC)
::Or, a little less radical, take it to a body shop and let them bake the car in the oven for a few hours. With the windows down, of course. ] (]) 21:50, 15 August 2011 (UTC)
:::I wonder if you got some water with a few drops of something like ] or ] and gave the hard surfaces of the inside of the car a good rub down with it.. Might be worth a try. ] (]) 00:53, 16 August 2011 (UTC)
== what is the function of the iPhone's 3GS 6R8 coil? ==
It's this thing that relays power to the LCD display...but I'm curious why this seems to short out first upon water damage (or why coils tend to short out), and why use a coil at all? Is it an inductor? Why would you need an inductor -- surely everything in the circuit board is DC? ] (]) 22:05, 15 August 2011 (UTC)
:Any LCD screen has a ] to illuminate it. I don't know about in an iPhone, but for laptop LCDs, the backlight is a fluorescent bulb that runs on high-voltage AC <strike>current</strike>, so maybe the coil is part of a ]. ] (]) 22:45, 15 August 2011 (UTC)
::I thought that too but then thought surely all phones these days use LEDs for illumination? However I'm having trouble finding a confirmed source and there are several forums which don't seem to come to a confirmed conclusion as to whether the iPhone uses LED or CCFL backlight. I have found the 6R8 coil for sale on fleabay and it says that it is a part used in the repair of dead or dim backlight, but I'm not 100% sure if that confirms the backlight must be CCFL or that there is some other exotic LED circuit using a coil. . ] (]) 00:47, 16 August 2011 (UTC)
= August 16 =
== Relativity and Bernoulli ==
If I were moving in a car with the window open, and released a piece of paper very close to the open window, which way would the paper move? --<span style="text-shadow:gray 0.2em 0.2em 0.1em" class="texhtml">] <sup><sub>]</sub></sup><small><sub style="margin-left:-3.2ex">]</sub></small></span> 00:54, 16 August 2011 (UTC)
:I don't think relativity is relevant at the speed most of us drive, and I've never seen anything released from a car window move in any direction other than backwards, except when there was a forwards wind of greater velocity than that of the car. How can Bernoulli change this? ] 01:27, 16 August 2011 (UTC)
::Augh, I could've clarified (as I always seem to be unable to do). If I were moving in a car with the window open, and released a piece of paper very close to the open window, would the paper fly outside or stay in the car? Bernoulli states that a fluid moving at high speeds has a lower pressure (or something along those lines), so if I were in the car watching, the paper should fly out, as relatively, the air outside the car is moving faster. But if an observer outside the car were watching the experiment occur, relative to him, the air in the car should be the faster fluid, and the paper should stay in the car. Does the paper leave the car or stay in it? --<span style="text-shadow:gray 0.2em 0.2em 0.1em" class="texhtml">] <sup><sub>]</sub></sup><small><sub style="margin-left:-3.2ex">]</sub></small></span> 01:34, 16 August 2011 (UTC)
:::The only thing that matters is the speed of the air on either side of the paper; it has nothing to do with who is observing it. Both the person inside the car and outside the car would note that the speed of the paper is essentially moving the same speed as the air inside of the car, and that the air outside of the car is moving faster than the paper. Bernoilli's principle is about the air speed relative to the two sides of a surface; both observers will arrive at the same result for that relationship. --]''''']''''' 01:40, 16 August 2011 (UTC)
::::In my experience, airflows around an open car window are somewhat turbulent, but there tends to be a dominant current of air forcing itself into the car (generally towards the rear of the window), and another forcing itself back out again (generally towards the front of the window). So the short answer is that it will depend whereabouts in the plane of the window you let go of the paper. It'll either fly backwards inside the car, as Dbfirs suggested, or else it will be sucked out. As also noted, relativity has nothing whatsoever to do with it. --] ] 01:47, 16 August 2011 (UTC)
:::::I depends on the wind speed and direction relative to the car, the speed of the car, the contour of the car. The contour of the car determines the aerodynamics. Close to the car, a pressure differencial exists pushing the piece of paper outward by a certain amount. The piece of paper has a high surface area to weight ratio, so is majorly affected by air resistance. This means that relative to the ground, both the car and piece of paper will continue forward, although the piece of paper will have a high deceleration, and move outward from the car. Relative to the car, the piece of paper will be moving back, out and down. A wind speed and direction, complicates this. ] (]) 02:18, 16 August 2011 (UTC)
:::::Although ] certainly isn't useful in this problem, I think the OP might be referring to ], which does have some pertinence here. ] (]) 03:01, 16 August 2011 (UTC)
::::::Yes, apologies for misunderstanding the question (it was the early hours of the morning here). I've observed all of the behaviours described above, and turbulent airflow makes it very difficult to predict which one will actually happen at any particular position, but the probability of the paper initially moving outwards increases as you adjust the starting position further from the stationary air (relative to the paper) in the car. To achieve the opposite effect with greater probability, one would need to throw the paper backwards so that it was stationary relative to the outside air, then the faster airflow would be (on average) inside the car. As mentioned above, turbulence makes the actual behaviour very complicated and almost impossible to predict without a very complex computer model. If the paper initially moves out, it very quickly decelerates to approximately the speed of the outside air, then the moving air inside the car can draw it in again because the inside pressure is then lower relative to the paper, by Bernoulli's principle. Has anyone ever recorded the behaviour on a high-speed video camera? It would be interesting to see it in slow-motion. ] 06:40, 16 August 2011 (UTC)
== Strength of Immune System for healthy adult from 2010 versus 1810 ==
Have the medical / hygiene advances made in the last 200 years led to relatively weaker immune systems for modern humans? Would a healthy Londoner from 1810 have a better IDS than his 2010 counterpart? If we sent the 2010 Londoner back to 1810 in our theoretical time machine, would he be in greater peril than if we brought our 1810 guy forward? I'd put my money on the 1810 guy simply because he's healthy is a much worse environment, but he would lack vaccinations... are there scientists who study this sort of "historical immunodefense development"? ] (]) 02:57, 16 August 2011 (UTC)
:But we today are descended from people who survived the Spanish flu and polio epidemics of the 20th century. It's not an obvious call. ] (]) 08:05, 16 August 2011 (UTC)
:@Masked: I'd put my money on the 1810 guy, too, but for completely different reasons. The prevalence of infectious diseases is much, much lower today than it was in urban London in 1810. Smallpox doesn't exist anymore, and polio is virtually wiped out, too. Cholera, typhys, typhoid fever, tuberculosis, and a host of other bacterial and fungal diseases which were once rampant are now a lot less common, so the transfered 1810 individual would have to deal with fewer infections than the transferred 2011 individual. Nutrition nowadays is much better than what it was for the average Londoner 200 years ago. Same with health care, which was little more than beads and rattles compared to modern medicine. The 2011 individual would be placed in a seething brew of noxious microbes with little hope of effective treatment. The only advantages he would have are the fact that he has been inoculated against some microbial diseases, and that he comes from a population which, as HiLo48 has said, represents the survivors of 200 years of epidemics and pandemics. ] (]) 08:24, 16 August 2011 (UTC)
== Heat and salty taste perception ==
I've noticed that French fries and other foods which have a distinct salty taste when fresh and hot lose some of that flavor when allowed to cool (more so when refrigerated than when left at room temperature). Why does this happen? ] (]) 03:28, 16 August 2011 (UTC)
:Two things:
:#Substances must be soluble to be tasted. Solubility of most solids and liquids increases with increasing temperature; as does the ''rate'' at which they dissolve, so hot foods will dissolve more readily in saliva than cold foods, speeding the rate at which your tastebuds will pick them up.
:#Most of what people attribute to taste is actually smell; the nasal passages are connected to the mouth via the ], and lots of your sense of taste is actually picked up by your olfactory sensors in your nose. ] is directly related to temperature; so warmer substances form vapors more than colder ones do, meaning that more of the vapor will be detectable, and thus provide more intense flavors than if the food were colder. Note that while salt doesn't readily form a gas, you can "smell" salt because it does form a sort of ] whereby tiny particles of salt can become dispersed in the air; and this process is also temperature dependent.
: Does that help? --]''''']''''' 04:09, 16 August 2011 (UTC)
== energy and matter ==
How can energy and matter be equivalent when matter has gravity and energy does not? --] (]) 03:40, 16 August 2011 (UTC)
:What makes you think that energy does not exert gravitational attraction? --]''''']''''' 04:00, 16 August 2011 (UTC)
::Oh, and just to correct something you said. Energy and matter '''are not''' equivalent. It is energy and ''mass'' which are equivalent. See ]. Mass is merely one property of matter. --]''''']''''' 04:01, 16 August 2011 (UTC)
:(ec) It's only in ] that energy doesn't contribute to gravity. In ], all forms of energy contribute to gravity. In more technical terms, in the ], all components of the ] contribute to the curvature of spacetime. If you view Newtonian gravity as an approximation to general relativity, by assuming that only mass contributes to gravity, one basically is assuming (among other assumptions) that only the T<sup>00</sup> component of the stress–energy tensor is non-negligible. ] (]) 04:22, 16 August 2011 (UTC)
== Uterine fibroids ==
{{RD-deleted}}--]''''']''''' 04:00, 16 August 2011 (UTC)
== galactic orbits ==
Going by the measurements of the spirals of the stars orbiting the center point of a galaxy do the orbits of the stars comply with Kepler's laws of planetary motion and if so can it be determined if the orbits are elliptical? --] (]) 08:48, 16 August 2011 (UTC)
:''See ].'' ] (]) 09:21, 16 August 2011 (UTC)
::Kepler's laws are strictly valid only for the two-body problem, where both bodies are point masses. A galaxy is not a point mass but has an extended mass distribution with more or less complex structure. Therefore the laws of planetary motion do not hold for stars in galaxies. In particular, the orbits are not elliptical and they are not even closed, meaning that a star does not return to the same point after one rotation. The ] is closer to what the stars do in galaxies. Note that the one place where we can actually observe stellar orbits over full periods is at the ] and there the orbits are indeed ellipses and comply with Kepler's laws. This is strong indication that the mass in this region is dominated by a point mass, i.e. a central black hole. But this is true only at the very centre, but not in general. --] (]) 09:52, 16 August 2011 (UTC)
:Also see ]. ] (]) 09:54, 16 August 2011 (UTC)
== Dishwashers and salt ==
If I use the top of the range, all-singing all-dancing diswasher tablets, do I still need to load my dishwasher with salt?
:I've never heard of loading a dishwasher with salt. Is that the custom in some places? Where? ] (]) 10:36, 16 August 2011 (UTC)
::See ]. Per , you should still add salt to the separate container if you are using those combo tablets, as it is used by the machine's water softener. --<span style="font-weight:bold;">] <sub>]</sub></span></span> 10:42, 16 August 2011 (UTC)
:::I'm still interested in where? Is this an American thing, with Americans assuming that the whole world is just like them? I'm in Australia, a high school teacher teaching kids about ] right now. No-one in their right mind would think of adding salt to the environment here. And our dishwashers work fine. My dishes come out clean. Are you sure it's necessary? ] (]) 10:46, 16 August 2011 (UTC)
Latest revision as of 13:55, 7 January 2025
Welcome to the science section of the Misplaced Pages reference desk.
skip to bottom
Select a section:
The best answers address the question directly, and back up facts with wikilinks and links to sources. Do not edit others' comments and do not give any medical or legal advice.
I would say not necessarily a Japanese beetle, but almost certainly one of the other Scarab beetles, though with 35,000 species that doesn't help a lot. Looking at the infobox illustration in that article, 16. & 17., "Anisoplia segetum" looks very similar, but evidently we either don't have an article or (if our Anisoplia article is a complete list) it's been renamed. {The poster formerly known as 87.81.230.195} 94.1.223.204 (talk) 14:18, 24 December 2024 (UTC)
Yes, it's not the Japanese beetle for this beetle appears to lack its white-dotted fringe although its condition is deteriorated. Its shape is also more or less more slender; and not as round. Modocc (talk) 15:02, 24 December 2024 (UTC)
Any (flavored) neutrino that is really observed is a superposition of two or three mass eigenstates. This is actually the cause of neutrino oscillations. So, the answer to your question is complicated. Ruslik_Zero19:40, 25 December 2024 (UTC)
Important note: particle physicists today generally only ever use "mass" to mean "invariant mass" and never anything else: . Like the term says, invariant mass is well, invariant, it never changes ever, no matter what "external forces" may or may not be involved. Being proper particle-icans and following the standard practice in the field, then, the three neutrino masses are constant values. ..."Wait, three?" Yeah sure, turns out neutrinos come in three "flavors" but each flavor is a mixture of the three possible mass "states". As mentioned, due to Quantum Weirdness we aren't able to get these different states "alone by themselves" to measure each by itself, so we only know the differences of the squares of the masses. Yeah welcome to quantum mechanics.
Richard Feynman: "Quantum mechanics describes nature as absurd from the point of view of common sense. And yet it fully agrees with experiment. So I hope you can accept nature as She is – absurd." --Slowking Man (talk) 06:06, 26 December 2024 (UTC)
The equation uses invariant mass m0 which is constant if E and p are constant. The traveling neutrino has a varying mass mixture of different flavors with different masses. If a mixture of different masses changes, you would expect the resulting mass to change with it. But somehow this does not happen as the neutrino mass mixture changes. These mixture changes cannot be any changes. The changes must be such that the resulting mass of the traveling neutrino remains constant. My question is whether this is described somewhere. Hevesli (talk) 11:16, 26 December 2024 (UTC)
I freely confess I'm uncertain exactly what's being "asked for" or "gotten at" here. Have you looked at the neutrino oscillation article? From it: That is, the three neutrino states that interact with the charged leptons in weak interactions are each a different superposition of the three (propagating) neutrino states of definite mass. Neutrinos are emitted and absorbed in weak processes in flavor eigenstatesbut travel as mass eigenstates.
What is it that we're "doing" with the energy–momentum relation here? For the neutrino, we don't have a single value of "mass" to plug in for , because we can't "see" the individual mass eigenstates, only some linear combination of them. What you want for describing neutrino interactions is quantum field theory, which is special relativity + QM. (Remember, relativity is a "classical" theory, which presumes everything always has single well-defined values of everything. Which isn't true in quantum-world.) --Slowking Man (talk) 18:41, 26 December 2024 (UTC)
Not all potential evolutions of a linear combination of unequal values produce constant results. Constancy can only be guaranteed by a constraint on the evolutions. Does the fact that this constraint is satisfied in the case of neutrino oscillation follow from the mathematical formulation of the Standard Model, or does this formulation allow evolutions of the mass mixture for which the combination is not constant? If the unequal values are unknown, I have no idea of how such a constraint might be formulated. I think the OP is asking whether this constraint is described somewhere. --Lambiam00:51, 27 December 2024 (UTC)
I wanted to try it just today, but I had to exchange the under-desk elliptical trainer I got for Christmas for a different model with more inclined treadles because with the one I got, my knees would hit the desk at the top of every cycle. Anyway, I was hoping someone else tried it first (preferably as part of a formal scientific study) so I would know if I could control whether I got a runner's high from exercise or not? 2601:646:8082:BA0:9052:E6AF:23C7:7CAF (talk) 03:09, 28 December 2024 (UTC)
Also, sorry for adding to my own question, but here's a related one: is it known whether the length of a person's dopamine receptor D4 (which is inversely correlated with its sensitivity) influences whether said person gets a runner's high from exercise (and especially from low-intensity exercise)? 2601:646:8082:BA0:9052:E6AF:23C7:7CAF (talk) 03:14, 28 December 2024 (UTC)
What is the difference between an auxotroph and a fastidious organism? It seems to me the second one would have more requirements than the first one, but the limit between the two definitions is rather unclear to me.
Symbiosis aside, it would seem that most auxotrophs would be fastidious organisms, but there could be many more fastidious organisms that aren't auxotrophs. Auxotrophs specifically can't produce organic compounds on their own. There are a LOT of organisms that rely on the availability of non-organic nutrients, such as specific elements/minerals. For instance, vertebrates require access to calcium. Calcium is an element; our inability to produce it does not make us auxotrophs.
But perhaps symbiosis would allow an organism to be an auxotroph without being a fastidious organism? For instance, mammals tend to have bacteria in our guts that can digest nutrients that our bodies can't on their own. Perhaps some of those bacteria also assemble certain nutrients that our bodies can't? -- Avocado (talk) 14:27, 28 December 2024 (UTC)
December 28
Paper with wrong enantiomer in a figure
In the following reference:
Quack, Martin; Seyfang, Georg; Wichmann, Gunther (2022). "Perspectives on parity violation in chiral molecules: theory, spectroscopic experiment and biomolecular homochirality". Chemical Science. 13 (36): 10598–10643. doi:10.1039/d2sc01323a. PMID36320700.
I saw an ad promoting a device which presumable splits water into
hydrogen and oxygen and infuses water with extra hydrogen, to
a claimed surplus of perhaps 5 ppm, which doesn’t seem like much. I found a review article which looked at several dozen related studies that found benefits:https://pmc.ncbi.nlm.nih.gov/articles/PMC10816294/ .
I’ve noticed that carbon dioxide or chlorine (chloramine?) dissolved in water work their way out pretty easily, so I wonder if dissolved hydrogen could similarly exit hydrogen enriched water and be burped or farted out, rather than entering the blood stream and having health benefits. is it more than the latest snake oil? Edison (talk) 23:01, 28 December 2024 (UTC)
It's conceivable it might take out the chloramine, I guess. I don't think there's very much of it, but it tastes awful, which is why I add a tiny bit of vitamin C when I drink tap water. It seems to take very little. Of course it's hard to tell whether it's just being masked by the taste of the vitamin C. --Trovatore (talk) 02:12, 29 December 2024 (UTC)
I don't know if it is rubbish or not but a quick look on the web indicates to me it is notable enough for Misplaced Pages. I didn't see anything indicating it definitely did anything useful so such an article should definitely have caveats. I haven't seen any expression of a potential worry either so it isn't like we'd be saying bleach is a good medicine for covid. NadVolum (talk) 23:07, 1 January 2025 (UTC)
In a harmonic oscillator, reaching the highest point involves - both a minimal kinetic energy - along with a maximal potential energy, whereas reaching the lowest point involves - both a maximal kinetic energy - along with a minimal potential energy. Thus the mechanical energy becomes the sum of kinetic energy + potential energy, and is a conserved quantity.
So I wonder if it's reasonable to define also "potential velocity" vs. "kinetic velocity", and claim that in a harmonic oscillator, reaching the highest point involves - both a minimal "kinetic velocity" (i.e. involves what we usually call a rest) - along with a maximal "potential velocity", whereas reaching the lowest point involves - both a maximal "kinetic velocity" (i.e. involves what we usually call the actual velocity) - along with a minimal "potential velocity". Thus we can also define "mechanical velocity" as the sum of "kinetic velocity" + "potential velocity", and claim that the mechanical velocity is a conserved quantity - at least as far as a harmonic oscillator is concerned.
Reasonable?
Note that I could also ask an analogous question - as to the concept of "potential momentum", but this term is already used in the theory of hidden momentum for another meaning, so for the time being I'm focusing on velocity.
Per my suggestion, the ratio between distance and time is not called "velocity" but rather "kinetic velocity".
Further, per my suggestion, if you don't indicate whether the "velocity" you're talking about is a "kinetic velocity" or a "potential velocity" or a "mechanical velocity", the very concept of "velocity" alone has no meaning!
On the other hand, "potential velocity" is defined as the difference between the "mechanical velocity" and the "kinetic velocity"! Just as, this is the case if we replace "velocity" by "energy". For more details, see the example above, about the harmonic oscillator. HOTmag (talk) 15:14, 29 December 2024 (UTC)
You could define the potential velocity of a body at a particular height as the velocity it would hit the ground at if dropped from that height. But the sum of the potential and kinetic velocities would not be conserved; rather would be constant. catslash (talk) 18:54, 29 December 2024 (UTC)
'Potential velocity' has no meaning. You seem to be arguing that in a system where energy is conserved, but is transforming between kinetic and potential energy, (You might also want to compare this to conservation of momentum.) then you can express that instead through a new conservation law based on velocity. But this doesn't work. There's no relation between velocity and potential energy.
In a harmonic oscillator, the potential energy is typically coming from some central restoring force with a relationship to position, nothing at all to do with velocity. Where some axiomatic external rule (such as Hooke's Law applying, because the system is a mass on a spring) happens to relate the position and velocity through a suitable relation, then the system will then (and only then) behave as a harmonic oscillator. But a different system (swap the spring for a dashpot) doesn't have this, thus won't oscillate. Andy Dingley (talk) 00:00, 30 December 2024 (UTC)
Let me quote a sentence from my original post: Thus we can also...claim that the mechanical velocity is a conserved quantity - at least as far as a harmonic oscillator is concerned.
You have defined some arbitrary values for new 'velocities', where their only definition is that they then demonstrate some new conservation law. Which is really the conservation of energy, but you're refusing to use that term for some reason.
As Catslash pointed out, the conserved quantity here is proportional to the square of velocity, so your conservation equation has to include that. It's simply wrong that any linear function of velocity would be conserved here. Not merely we can't prove that, but we can prove (the sum of the squares diverges from the sum) that it's actually contradicted. For any definition of 'another velocity' which is a linear function of velocity.
It is a law of conservation of sanity. Lacking a definition of potential energy, other than by having been informed that kinetic energy + potential energy is a conserved quantity, there is not much better we can do. --Lambiam11:20, 31 December 2024 (UTC)
We have a perfectly viable definition of potential energy. For a pendulum it's based on the change in height of the pendulum bob against gravity. For some other oscillators it would involve the work done against a spring. Andy Dingley (talk) 16:33, 31 December 2024 (UTC)
Oops, I mistyped. I meant to write:
"Lacking a definition of potential velocity, other than by having been informed that kinetic velocity + potential velocity is a conserved quantity, there is not much better we can do."
Put two equally sized drops, one of each liquid, on a warm surface, wait for them to evaporate, and compare how much salt residue each leaves? Not very precise or measurable, but significant differences should be noticeable. {The poster formerly known as 87.81.230.195} 94.1.223.204 (talk) 10:21, 30 December 2024 (UTC)
The principle is sound, but the residue from one drop won't be measurable using kitchen equipment -- better to put equal amounts of each liquid in two warm pans (use enough liquid to cover the bottom of each pan with a thin layer), wait for them to evaporate and then weigh the residue! Or, if you're not afraid of doing some algebra, you could also try an indirect method -- bring both liquids to a boil, measure the temperature of both, and then use the formula for boiling point elevation to calculate the saltiness of each! 2601:646:8082:BA0:BD1B:60D8:96CA:C5B0 (talk) 18:22, 30 December 2024 (UTC)
Presumably the liquid preparations are not simple saline solutions, but contain other solutes - or else one could simply use a hydrometer. It is unlikely that Lambian is afraid of doing some algebra. catslash (talk) 18:57, 30 December 2024 (UTC)
Assuming the liquid preparations are water-based and don't contain alcohols and/or detergents one can measure their rates of dispersion. Simply add a drop of food dye to each liquid and then time how rapidly droplets of each liquid disperse in distilled water. Materials needed: food dye, eye dropper, distilled water, small clear containers and a timer.Modocc (talk) 21:09, 30 December 2024 (UTC)
The colligative properties of a solution will indicate its molarity, but not identify the solute. Liquid preparations that might be found in a kitchen are likely to contain both salt and sugar. Electrical conductivity is a property that will be greatly affected by the salt but not the sugar (this does not help in distinguishing Na from K ions though). catslash (talk) 22:23, 30 December 2024 (UTC)
Quantitative urine test-strips for sodium seem to be available. They're probably covering the concentration range of tens to hundreds millimolar. DMacks (talk) 00:58, 2 January 2025 (UTC)
Thanks, test strips seem more practical in the kitchen setting than an ohmmeter (why not call it a "mhometer"?), for which I'd need to devise a way (or so I think) to keep the terminals apart at a steady distance. Test strips require a colour comparison, but I expect that a significant difference in salinity will result in a perceptible colour difference when one strip is placed across the other. Only experiment can tell whether this expectation will come true. Salinity is usually measured in g/L; for kitchen preparations a ballpark figure is 1 g/L. If I'm not mistaken this corresponds to (1 g/L) / (58.443 g/mol) ≈ 0.017 M = 17 mM. I also see offers for salinity test strips, 0–1000 ppm, for "Science Education". --Lambiam11:40, 2 January 2025 (UTC)
Test strips surely come with a printed color-chart. But if all you are trying to do is determine which is more salty, then that's even easier than quantifying each separately. Caveat for what you might find for sale: some "salinity" tests are based on the chloride not the sodium, so a complex matrix that has components other than NaCl could fool it. DMacks (talk) 18:44, 2 January 2025 (UTC)
The (uncommon?) terms "relativistic length", and "relativistic time".
1. In Misplaced Pages, the page relativistic length contraction is automatically redirected to our article length contraction, which actually doesn't mention the term "relativistic length" at all. I wonder if there is an accepted term for the concept of relativistic length.
2. A similar qusestion arises, at to the concept of relativistic time: The page relativistic time dilation, is automatically redirected to our article time dilation, which prefers the abbreviated term "time dilation" (59 times) to the term "relativistic time dilation" (8 times only), and nowhere mentions the term "relativistic time" alone (i.e. without the third word "dilation") - although it does mention the term "proper time" for the shortest time. Further, this article doesn't even mention the term "dilated time" either. It does mention, though, another term: coordinate time, but regardless of time dilation in Special relativity. To sum up, I wonder what's the accepted term used for the dilated time (mainly is Special relativity): Is it "coordinate time"? "Relativistic time"?
Are you reading these things as "contraction of relativistic length" etc.? It is "relativistic contraction of length" and "relativistic dilation of time". --Wrongfilter (talk) 09:37, 30 December 2024 (UTC)
When I wrote: The page relativistic time dilation is automatically redirected to our article time dilation which...nowhere mentions the term "relativistic time" alone (i.e. without the third word "dilation"), I had already guessed that the term "dilation of relativistic time" (i.e, with the word "dilation" preceding the words "relativistic time") existed nowhere (at least in Misplaced Pages), and that this redirected page actually meant "relativistic dilation of time". The same is true for the redirected page "relativistic length contraction": I had already gussed it didn't mean "contraction of relativistic length", because (as I had already written): the article length contraction...doesn't mention the term "relativistic length" at all.
Anyway, I'm still waiting for an answer to my original question: Are there accepted terms for the concepts, of relativistic length - as opposed to proper length, and of relativistic time - as opposed to proper time? HOTmag (talk) 10:12, 30 December 2024 (UTC)
A term that will be understood in the context of relativistic length contraction is relative length – that is, length relative to an observer. --Lambiam10:55, 31 December 2024 (UTC)
Thank you. The middle source uses the term "comparative length", rather than "relative length". I couldn't open the third source. HOTmag (talk) 08:04, 1 January 2025 (UTC)
The text under the graph labelled Comparative length on page 20 of the middle source reads:
Graph of the relative length of a stationary rod on earth, as observed from the reference frame of a traveling rod of 100cm proper length.
Is there any metric unit whose ratio is not power of 10, and is divisible by 3? Is there any common use for things like "2⁄3 km", "5⁄12 kg", "3+1⁄6 m"?
Is a one-tenth of nautical mile (185.2 m) used in English-speaking countries? Is there a name for it?
What is more physiological (for a right-hander) left-hand drive or right-hand drive?
Has anyone determined whether it is better for a right-hander to have the left hand on the steering wheel and the right hand on the gear shift stick, or the other way round? Are there other tests of whether left-hand drive or right-hand drive is physiologically better (for a right-hander at least)? 178.51.7.23 (talk) 12:03, 1 January 2025 (UTC)
Supplementary question: I've only driven right-hand-drive vehicles (being in the UK) where the light stalk is on the left of the steering column and the wiper & washer controls are (usually) on the right. On a l-h-drive vehicle, is this usually the same, or reversed? {The poster formerly known as 87.81.230.195} 94.6.84.253 (talk) 12:12, 2 January 2025 (UTC)
Modern cars are designed for mass production in RH- and LH-drive versions with a minimum difference of parts. Steering columns with attached controls are therefore unchanged between versions. Philvoids (talk) 12:29, 2 January 2025 (UTC)
In the UK, sales of new automatics have just recently overtaken manuals - so probably still more manuals than automatics on the road. catslash (talk) 14:37, 2 January 2025 (UTC)
This may be tied to the rise of EVs, since they have automatic transmissions by default. {The poster formerly known as 87.81.230.195} 94.6.84.253 (talk) 05:29, 3 January 2025 (UTC)
In Australia, we drive on the left, and the indicator and wiper stalks are the opposite way to the UK. Having moved back from the UK after 30 years, it took me a while to stop indicating with wipers. TrogWoolley (talk) 05:08, 3 January 2025 (UTC)
This depends more on where the car came from I think. For European or American cars it tends to be in the UK direction. For Asian cars or I guess those odd Australian made cars which are out there, it tends to be in the other. See e.g. . The UK being a bigger market I think most manufacturers have come to follow the new UK norm for cars they intend to sell there although I suspect to some extent it's still true in the sense that I think most Asian car brands, at least assemble their cars in the EU or maybe the UK if they're destined for the UK (made a lot of sense pre-Brexit) . It sounds like the new UK norm is fairly recent perhaps arising in the 1980s-1990s after European manufacturers stopped bothering changing that part of the production for the reasons mentioned by Philvoids. As mentioned in one of the Reddit threads, the UK direction does make it difficult to adjust indicators while changing gear which seems a disadvantage which is fairly ironic considering the the UK has much more of a preference for manuals than many other RHD places with the other direction. Nil Einne (talk) 04:31, 6 January 2025 (UTC)
For further clarity, AFAICT, LHD vehicles generally have their indicators on the left and wipers on the right. As mentioned, assuming the gear stick is in the middle which AFAIK it is for most cars by now, this seems the better positioning especially on manual cars since you're much more likely to want to need to indicate while changing gear than you are going to want to adjust your wipers even in the rainy UK. The UK being LHT/RHD especially with their own manufactured cars tended to have the indicators on the right and wipers on the left in the more distant past so again the positions that made most sense.
While I don't have a source for this going by the history and comments, it sounds to me like what happened is European manufacturers who were primarily making LHD vehicles, with the UK and Ireland their main RHD markets but still small compared to the LHD market stopped bothering changing positions for RHD vehicles as a cost saving measure. So they began to put wipers on the right and indicators on the left even in their RHD vehicles no matter the disadvantage. I'm not so sure what the American manufacturers did or when and likewise the British but I think they were a fairly small part of the market by then and potentially even for them LHD was still a big part of their target market.
Meanwhile Asian manufacturers however still put their indicators on the right and wipers on the left in RHD vehicles, noting that Japan itself is LHT/RHD. I suspect Japanese manufacturers suspected, correctly, that it well worth the cost of making something else once they began to enter the LHD markets like the US, to help gain acceptance. And so they put the indicators on the left and wipers on the right for LHD vehicles even if they did the opposite in their own home market and continued forever more. Noting that the predominance of RHT/LHD means even for Japanese manufacturers it's generally likely to be their main target by now anyway.
Later I assume South Korea manufacturers and even later Chinese felt it worth any added cost to increase acceptance of their vehicles in LHT/RHD markets in Asia and Australia+NZ competing against Japanese vehicles which were like this. And this has largely continued even if it means they need to make two different versions of the steering column or whatever. It sounds like the European and American brands didn't bother but they were primarily luxury vehicles in such markets so it didn't matter so much.
This lead to an interesting case for the UK. For the Asian manufacturer, probably many of them were still making stuff which would allow them to keep putting the indicators on the right and wipers on the left for RHD vehicles as they were doing for other RHD markets mostly Asian. And even if they were assembling them in the EU, I suspect the added cost of needing to ship and keep the different components etc and any difference it made to the assembly line wasn't a big deal.
So some of did what they were doing for the Asian markets for vehicles destined for UK. If they weren't assembling in the EU, it made even more sense since this was likely what their existing RHD assembly line was doing. But overtime the UK basically adopted the opposite direction as the norm no matter the disadvantages to the extent consumers and vehicle enthusiast magazines etc were complaining about the "wrong" positions. So even Asian manufacturers ended up changing to the opposite for vehicles destined to the UK to keep them happy. So the arguably better position was abandoned even in cases where it wasn't much of a cost saving measure or might have been even adding costs.
I've driven different (automatic) left-hand-drive vehicles with the light stalk on each side, but left side has been more common. Perhaps because the right hand is more likely to be busy with the gear shift? (Even in the US, where automatic has been heavily dominant since before I learned to drive.) -- Avocado (talk) 17:32, 2 January 2025 (UTC)
It's better for a right-hander to have both hands on the steering wheel regardless of where the gear lever is. See Rule 160. I suspect the same goes for a left-hander. Bazza 7 (talk) 14:39, 2 January 2025 (UTC)
I suppose that the question is whether right-handers have an easier time operating the gear stick when changing gears in manual-transmission cars designed for left-hand traffic, with the steering wheel on the right (like in the UK) or right-hand traffic, with the steering wheel on the left (like in most of continental Europe). Obviously, drivers will use their hand at the side where the gear stick is, so if it is in the middle and the driver, behind the wheel, sits in the right front seat, they'll use their left hand, regardless of their handedness. But this may be more awkward for a rightie. Or not.
In my personal experience (more than 10 years driving on each side of the road, in all four combinations of car handedness and road handedness) the question which hand to use for shifting gears is fairly insignificant. Switching from one type of car to the other is a bit awkward though. —Kusma (talk) 18:33, 2 January 2025 (UTC)
Distinguishing a picture of a sunset from the picture of a sunrise?
Is there a way (if you don't know which way is west and which way is east in a particular location) to distinguish a picture of a sunset from the picture of a sunrise? 178.51.7.23 (talk) 12:08, 1 January 2025 (UTC)
Generally, no, but there are a few tricks that sometimes work. In dry sunny weather, there's more dust in the air at sunset (due to thermals) than at sunrise, making the sky around the sun redder at sunset. But in moist weather, mist has the same effect at sunrise. If the picture is good enough to see sunspots, comparing the distribution of sunspots to the known distribution of that day (this is routinely monitored) tells you where the North Pole of the sun is. At sunset, the North Pole points somewhat to the right; at sunrise, to the left. If you see any cumulus or cumulonimbus clouds in the picture, it was a sunset, as such clouds form during the day and disappear around sunset, but absence of such clouds doesn't mean the picture was taken at sunrise. A very large cumulonimbus may survive the night. Cirrus aviaticus clouds are often very large, expanding into cirrostratus, in the evening, but are much smaller at dawn as there's more air traffic during the day than at night, making the upper troposphere more moist towards the end of the day. Cirrostratus also contributes to red sunsets and (to lesser extend, as there's only natural cirrostratus) red sunrises. Dew, rime, flowers and flocks of birds may also give an indication. And of course human activity: the beach is busier at sunset than at sunrise. PiusImpavidus (talk) 13:41, 1 January 2025 (UTC)
Supposing the photograph has high enough resolution to show Sunspots it can be helpful to know that the pattern of spots at sunrise is reversed left-right at sunset. Philvoids (talk) 13:21, 3 January 2025 (UTC)
At the equinox, the disk of the Sun with its pattern of sunspots appears to rotate clockwise from sunrise to sunset by 180 degrees minus twice your latitude (taking north positive). At my place, that's 75 degrees. Other times of the year it's less; at the start and end of polar day and polar night, there's no rotation. Sunset and sunrise merge then.
And I forgot to mention: cirrostratus clouds will turn red just after sunset or just before sunrise. At the exact moment of sunrise or sunset, they appear pretty white. PiusImpavidus (talk) 17:06, 3 January 2025 (UTC)
I differ: the same rotation is involved everywhere on Earth. If you stand on tiptoe at a N. or S. pole to take a picture of the Sun it is you who must pirouette 15 degrees per hour to keep facing the Sun. The Earth rotates you at this rate at all non-polar locations. If you stand within the arctic or antarctic circles, for parts of the year the 24-hour night or 24-hour daylight seem to prevent photographs of sunrise or sunset. However the terms "sunrise" and "sunset" can then be interpreted as times that are related to particular timezones which are generally assigned by longitude. In photographing the 24-hour Sun the equatorial rise and set times for your own longitude are significant elevation maxima worth mentioning even though the minimum elevation remains above the horizon. I maintain that the sunspot pattern observed from any location on Earth rotates 360 degrees per 24 hours and that "night", the darkness from sunset to sunrise, is when the Earth's bulk interrupts one's view of the rotation but not the rotation itself which is continuous.
Taking the Earth as reference frame, the Sun rotates around the Earth's spin axis. The observer rotates around his own vertical axis. The better both axes are aligned, the smaller the wobble of the Sun. In the northern hemisphere, it rotates clockwise from about 6 till 18 by 180 degrees minus twice your latitude and counterclockwise at night, in the southern hemisphere it's the opposite. Try a planetarium program if you want to see it. Stellarium shows some sunspots, does things right and is free and open source. PiusImpavidus (talk) 10:27, 5 January 2025 (UTC)
Relationship between Earth's axial tilt (ε) to the tropical and polar circlesWe deprecate the obselete Geocentric model and suggest Misplaced Pages references that are free and just one click away (no extra planetarium software needed). The axes of rotation of the Sun and Earth have never in millions of years aligned: the Ecliptic is the orbital plane of Earth around the Sun and Earth currently has an Axial tilt of about 23.44° without "wobbling" enough from this to concern us here. Philvoids (talk) 14:56, 5 January 2025 (UTC)
This isn't my field but sunspots aside, if you know the location and date, I assume the appearance of other astronomical objects like the moon or rarely another star probably Venus, in the photograph should be enough to work out if it's a sunset or sunrise. That said, to some extent by taking into account other details gathered from elsewhere's I wonder if we're going beyond the question. I mean even if you don't personally know which is east or west at the time, if you can see other stuff and you know the location or the stuff you can see is distinctive enough it can be worked out, you can also work out if it's sunset or sunrise just by working out if it's east or west that way. Nil Einne (talk) 03:54, 6 January 2025 (UTC)
In my experience (Southern England) they tend to be pinker at dawn and oranger(!) at dusk. {The poster formerly known as 87.81.230.195} 94.6.84.253 (talk) 03:23, 4 January 2025 (UTC)
Pink clouds must result from blending of reddish clouds with the blue sky behind. There's actually more air between the observer and the clouds than behind the clouds, but for that nearby air the sun is below the horizon. PiusImpavidus (talk) 10:27, 5 January 2025 (UTC)
The questioner asks for interpretation of a single picture. It is beside the point that more would be revealed by a picture sequence such as of changing cloud colours. Philvoids (talk) 12:41, 4 January 2025 (UTC)
Recalling Leonard Maltin's comment about the Green Berets movie, which was filmed in the American state of Georgia: "Don't miss the closing scene, where the sun sets in the east!" ←Baseball Bugscarrots→ 22:37, 5 January 2025 (UTC)
Which you can only tell if you know which way is east in the image. Maltin, or his writer, appears to have assumed that Vietnam has a seacoast only on the east, which is wrong. --142.112.149.206 (talk) 03:46, 6 January 2025 (UTC)
But as it was filmed in (The US State of) Georgia, it must actually show a sunrise, regardless of what the story line says – how do you know that wasn't what Maltin actually meant? {The poster formerly known as 87.81.230.195} 94.6.84.253 (talk) 10:35, 7 January 2025 (UTC)
I assume (not having seen the film) that, in the story line of The Green Berets , the closing scene takes place in the late afternoon, which means it shows a sunset. The plot section of our article on the film places the closing scene at or near Da Nang, which is on the east coast of Vietnam. This means that Maltin did not make an unwarranted assumption; he was just seeking an excuse to bash the film. --Lambiam13:55, 7 January 2025 (UTC)
January 6
Does the energy belonging to an electromagnetic field, also belong (or is considered to belong) to the space carrying that field?
It would be unusual to express the situation in such terms. Since the notion of energy "belonging to" some entity is not itself a physical concept – any practical approach to energy bookkeeping that satisfies the law of conservation of energy will do – this cannot be said to be wrong. It is, however, (IMO) not helpful. Does an apple belong to the space it occupies? Or does that space belong to the apple? --Lambiam23:37, 6 January 2025 (UTC)
First, I let you replace the notion of energy "belonging to" some entity, by the notion of energy "attributed to" some entity, or by the notion of energy "carried by" some entity, and the like. In other words, I'm only asking about the abstract relation (no matter what words we use to express it), between the energy and the space carrying the electromagnetic field, rather than about the specific term "belong to".
Second, I'm only asking about what the common usage is, rather than about whether such a usage is wrong or helpful.
The question is actually as follows: Since it's accepted to attribute energy to an electromagnetic field, is it also accepted to attribute energy to the space carrying that field?
So, is your first sentence a negative answer, also to my question when put in the clearer way I've just put it? HOTmag (talk) 03:28, 7 January 2025 (UTC)
The answer remains the same. It would be a highly unusual use of language to "attribute" electromagnetic energy to a volume of space, in quite the same way as it would be strange to "attribute" the mass of an apple to the space the apple occupies. But as long as an author can define what they mean by this (and that meaning is consistent with the laws of physics), it is not wrong. --Lambiam13:21, 7 January 2025 (UTC)
this guy is an oriental beetle? I was off-put by the green head at first, but the antennae seem to match. JayCubby 03:00, 24 December 2024 (UTC)
uses invariant mass m0 which is constant if E and p are constant. The traveling neutrino has a varying mass mixture of different flavors with different masses. If a mixture of different masses changes, you would expect the resulting mass to change with it. But somehow this does not happen as the neutrino mass mixture changes. These mixture changes cannot be any changes. The changes must be such that the resulting mass of the traveling neutrino remains constant. My question is whether this is described somewhere. 
, because we can't "see" the individual mass eigenstates, only some 
would be constant. 
