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*:It's well referenced. Do you have an actual question? Comments about article content can be made on its talk page. ]|] 09:23, 30 January 2023 (UTC)
*:Giving this snippet of trivia a subsection (with a tabloid title!) of its own calls the notion of undue weight to mind. The terminology of "freshly killed muscle meat" is questionable – while the organism is dead, some of the tissue may still be alive (see e.g. ]). --] 10:21, 30 January 2023 (UTC)
{{hab}} ] (]) 14:04, 30 January 2023 (UTC)
== Dichroicprism?==
= December 24 =
== Unknown species of insect ==
]
Hi, a quick question about the article ], which defines its topic as "a prism that splits light into two beams of differing wavelength (colour)", is illustrated by the image on the right, which is a featured picture. However, it looks to me like there are quite a few more colours than just two in this image. Can anyone explain this? I would have asked on the article talk page, but it doesn't seem like it's a well-watched article so don't know if I'd get an answer. Cheers — ] (]) 14:35, 30 January 2023 (UTC)
:{{re|Amakuru}} The photographer is {{re|User:XRay}}, who is more active on Commons at ]. ] (]) 14:43, 30 January 2023 (UTC)
::You can find a small explanation at the file page at Commons. ;-) --] (]) 15:05, 30 January 2023 (UTC)
:::{{ping|XRay}} thanks for the response. The description at Commons says {{xt|"To explain what is shown: The prism lies on a black cardboard with a rough surface to make the light visible. The light from a flashlight with white light is focused by a lens (telephoto lens) onto the prism from below (right), with a small part of the white light passing the prism."}} - is this what you're referring to? I'm still confused from this explanation, though, what would make it a ''dichroic'' prism. There are clearly more than two colours being emitted. Thanks — ] (]) 17:57, 30 January 2023 (UTC)
::::It is an explanation of the creation of the image. It is not a physical experiment. In the center you can see the prism, whose description is dichroic prism. --] (]) 18:35, 30 January 2023 (UTC)
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)
]
I'm not familiar with the term ''dichroic prism'', but here's a photo I took of a color separation prism assembly I designed (for the ] Studio Camera). It has ''dichroic mirrors'' between the prism pieces, to reflect and transmit different wavelength bands. It looks to me like the "dichroic prism" has a variety of different dichroic mirrors on its external and internal surfaces. ] (]) 10:49, 31 January 2023 (UTC)
:<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)
== Why does the late Holocene Susquehanna mouth look like New England? ==
::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)
If Chesapeake Bay is the drowned valley of the Susquehanna River then why does the river enter so far from the apex and look like a canal instead of the typical drowned river shape of the rest of the area? ] (]) 07:41, 31 January 2023 (UTC)
:Sorry, I don't follow your question. Can you clarify? --]] 10:00, 31 January 2023 (UTC)
:It would be helpful if you linked to an image showing what you refer to, but ], including canalization and channelization, and ] could be factors. {The poster formerly known as 87.81.230.195} ] (]) 14:39, 31 January 2023 (UTC)
::There was no river engineering. According to "The Susquehanna is so old that the mountains and valleys formed around it, rather than the river shaping the valleys." <span style="font-family: Cambria;"> ] (])</span> 17:02, 31 January 2023 (UTC)
:::Au contraire, there's ''considerable'' engineering in the form of ]; consider the ] which lies just a few dozen kilometers from the mouth of the river. Water flow along the Susquehanna (like ''most'' east-coast rivers) has been heavily controlled and engineered for well over a century by now. --]] 17:08, 31 January 2023 (UTC)
::::Not in the way User:Sagittarian Milky Way was asking, no straightening. The Susquehanna is not navigable, and it drops steeply, so the linearity is natural. <span style="font-family: Cambria;"> ] (])</span> 17:15, 31 January 2023 (UTC)
:::::Yes, that much is true; the Susquehanna largely follows the course that it has for thousands of years. However, I still am not sure ''what'' Sagittarian Milky Way was asking, which is why I asked them to clarify. I'm still not sure what they mean by "looks like a canal" and "apex" and the terminology they are using. I have crossed the Susquehanna many times, at a large number of places along its course. At no point does it look like a canal, IMHO. I have ''looked'' at it many times, and I have looked at a great many canals as well. The Susquehanna doesn't look particularly like a man-made waterway anywhere I have seen; especially not near the mouth. The views off of the ] don't look particularly canal-like, nor do the views from the Tidewater Grille in ], which has a lovely back deck right on the river. --]] 17:31, 31 January 2023 (UTC)
]
::::::Okay canal is an exaggeration. On Google Maps (not Street View) it resembles some of the river mouths in New England (especially the Thames) more than it resembles most of the Chesapeake Bay and North Carolina Sound estuaries. i.e. it doesn't look like the Potomac or Patapsco estuary. ] says the very tip of this embayment is the New York Bight Apex. I guess if you squint you can sort of see the valley turn left at the last minute so it follows the Susquehanna instead of the Elk or North East River but it sure does look like one of those rivers is where the main vein should come from. Maybe the Delaware once drained there aggrandizing those minor Susquehanna tributaries? Sort of like how Glacial Lake Ontario once augmented the Hudson River discharge making it wider than if the ice age never happened (this Niagara of water also stopped the Hudson from draining through the exact tip of the bay by creating a strait through Statenlong Island). ] (]) 07:14, 1 February 2023 (UTC)
:::::::A possible explanation is that it is that the "drowned river" effect runs out at that point. The Chesapeake is not just a drowned river due to sea level rise, it is because of the ]. The bolide impact cracked all the limestone underlying the whole area, allowing continuous dissolution of the substrata as water infiltrates. This causes slow and steady subsidence, which may end at the "apex", as you put it, far from the epicenter. <span style="font-family: Cambria;"> ] (])</span> 10:28, 1 February 2023 (UTC)
::::::::The reason that the Susquehanna is the main river feeding into the area near the north of the bay (but not the northernmost point; which is arbitrary anyways, the fact that the bay continues north of the mouth of the Susquehanna is meaningless, and the northernmost point is not the "apex" in any meaningful sense), is that the Susquehanna is the river with the largest basin in that area. The rivers that empty in further north are rivers like the ], which drains a relatively small area. Given the size of the wide ], it all has to get to the sea somehow, and the Susquehanna is it. The reason why the mouth is relatively straight and not very estuarine is that the Susquehanna is a relatively fast flowing river (or was before extensive engineering and flood control) given that it changes elevation relatively quickly. It doesn't really meander. Before the formation of the Chesapeake Bay, it likely had a proper estuary and delta region near its mouth, but all of that is currently under Hampton Roads now. --]] 17:36, 1 February 2023 (UTC)
::::::::Interesting. The estuariness also peters out on the Carolina coast at about the same distance from the crater, maybe not a coincidence. ] (]) 20:12, 1 February 2023 (UTC)
:::::::::The Carolina Coast is ''very'' estuarine. Much of the sounds inside of the ] is marshy, brackish, and otherwise perfectly typical of an estuary. The mouths of places like the ] and the ]/] River and places like that are as typically estuary as you are going to find. The Neuse has a that starts at about ] and continues to the main body of the ]; a similar geography exists on the Tar/Pamlico starting at about ], and on the ]/] rivers before they reach the ], etc. The Carolina coast is ''very'' different from what you describe. --]] 12:43, 2 February 2023 (UTC)
:::::::::::The ] is probably relevant too. While the Susquehanna doesn't have a distinct break with an attendant city the way the Potomac and dozens of other rivers along the East Coast have, it has a fast, steady fall from Harrisburg to the bay that would tend to keep it straight if no other geological processes interfere. The Susquehanna spreads its falls along the whole stretch, is quite shallow and wide, and has many small rapids or riffles instead of one big drop. It is very un-canal-like. '''<span style="font-family: Arial;">] <small>]</small></span>''' 12:55, 2 February 2023 (UTC)
::::::::::::Contrast the ], most of which below Albany is a glacial fjord, very deep, and tidal to Albany. There was no glacial influence for the Susquehanna, which is not navigable to any significant extent. '''<span style="font-family: Arial;">] <small>]</small></span>''' 13:00, 2 February 2023 (UTC)
::::::::::PART of the Carolina coast is very estuarine. After awhile it starts getting less estuarine though some is unavoidable as the Atlantic Coastal Plain is very flat. Myrtle Beach looks very different from Pamlico Sound on a road map. ] (]) 17:31, 2 February 2023 (UTC)
:::::::::::The river mouths of places in South Carolina look pretty much exactly like the places I described above if you are, you know, standing there ''looking'' at it. Myrtle Beach doesn't because Myrtle Beach is not a river outlet; there is none there. Go to ], and the mouth of the ] is surrounded by the kind of brackish water marshlands you find in estuaries. That's the first river mouth you find in South Carolina. You would know that if you ''go'' to Georgetown and look around. You keep saying things which are wrong, and then trying to qualify your wrongness by saying more wrong things. Please stop that. --]] 12:01, 3 February 2023 (UTC)
::::::::::::Sure if I ever stand there (I bet it's idyllic right before the extra bad South-only dew points and pest species start) it'd look like a similar mouth in "NC lagoon" probably all the way to the horizon in every direction (which is as little as 3-3.5 miles). But instead of assuming I can't tell the difference between X and opposite X and nitpicking language it seems obvious I must've always been referring to some aspect of the south Carolinas coast that's different from the bigger, wider indentations further north. Probably the bigger, wider indentations! I always wondered why Delaware Bay, Chesapeake Bay and some NC things like Ablemarle are bigger and wider than anything in SC, GA or East FL ds and who knows maybe it's an asteroid cracking limestone. ] (]) 20:52, 3 February 2023 (UTC)
:::::::::::::So, what happened in SC is that has caused the former barrier islands to basically collide with the land; that's what a mainland beach ''is''. The ] around Myrtle Beach was, thousands of years ago, a barrier island system that migrated shoreward and ran into the mainland. It would have looked more like the Outer Banks back then. Further northward, you can also see this process happening along the ] and ], where the sound is very narrow, and the barrier islands (], ], ]), where they are much closer to shore than they are in NC, but still further out than SC. --]] 14:05, 6 February 2023 (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)
= February 1 =
:Perhaps it is the ] ]. Shown . ] (]) 16:09, 24 December 2024 (UTC)
== Animals, insects, trees in snow ==
::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)
= December 25 =
All those places where temperature is extremely negative, how do animals survive? I am not talking about Polar beer, penguin.
I once saw a picture in national geographic where a Canadian eskimo was in igloo in snow and he was covered in mosquitoes. Why those mosquitoes did not freeze to death?
== Mass of oscillating neutrino ==
And how do trees survive brutal cold. Trees can die due to poisoning, forest fire then how do trees survive such cold, where humans have to put on so much thermals, gloves, jackets, coats. ] (]) 17:32, 1 February 2023 (UTC)
From the ] it follows that a particle that is not subject to external forces must have constancy of mass.
:Hi {{u|Stargty6}}! Trees survive brutal cold because of their bark. According to the , it states {{tq|Bark provides insulation and protection against freezing and cracking during the winter.}} It isn't just the bark, however. The trees drop their leaves to reduce water loss.
:{{clear}}
:Now for the mosquitoes. For the female mosquitoes, they survive by using a form of hibernation called ]. According to the , it states {{tq|The key to survival for female mosquitoes is a form of hibernation called “diapause.” As cold temperatures settle in, females fatten up approximately 10 times their usual fat accumulation and enter diapause.}} Not only that, but mosquitoes also enter indoors to survive from the cold (but most times IMO they're going to be really annoying in your houses as they <s>sting</s> bite and create itch spots.) ] ] 17:47, 1 February 2023 (UTC)
::@] They ], not sting. ] (]) 20:03, 1 February 2023 (UTC)
:::Oops, I did not think of "bite". Thank you, {{u|Bazza 7}}. ] ] 20:43, 1 February 2023 (UTC)
:::Actually, to "bite" us, mosquitos first saw a hole into one's skin, through which they then insert a bundle of needles, including a hollow one to suck up blood while another hollow needle drips in mosquito saliva to make sure it will itch like hell.<sup></sup> Calling this "biting" instead of "stinging" is a somewhat arbitrary choice. --] 10:33, 2 February 2023 (UTC)
::::To be strictly accurate, the mosquito saliva isn't "to make sure it will itch like hell" but "saliva contains substances that keep our blood flowing". Without the saliva the blood would quickly congeal and Mrs Mosquito wouldn't get the blood she needs for her eggs. Itching is a by-product felt after she's flown safely away from slaps by aggrieved victims. ] (]) 10:45, 2 February 2023 (UTC)
::::@] The ], and others leading from it, are fairly clear it's a bite. Is there an interesting ] difference in the definition of "bite" and "sting"? ] (]) 13:12, 2 February 2023 (UTC)
:::::IMHO, a bite involves the use of mouthparts. --]] 14:13, 2 February 2023 (UTC)
:::::The idiomatic term in English is "bite". But the basic sense of "]" is to cut into something by clamping one's teeth, which is very different from what mosquitos do. So how did it become "bite" in English? In French one says, more to the point, ''piqure de moustique'', literally "mosquito sting", and in Italian likewise ''puntura di zanzara''. --] 15:04, 2 February 2023 (UTC)
::::::''La piqûre'' actually is better translated as "poke" or "prick"; it is also used when describing injections, which actually better describes BOTH what a bee and a mosquito do. The French is better translated as "mosquito prick" or "mosquito injection" rather than "sting". The sensation of "sting" is ''cuisant'' en français. --]] 15:28, 2 February 2023 (UTC)
:::::::Albeit mosquitoes don't bite with ''teeth'', they do it with their mouthparts and they do it to eat. I think that's reasonably distinguished from a "sting", which is an injection of venom with the purpose of harming the recipient rather than gaining calories from them, at least immediately. (A sting might be used to incapacitate the victim, after which they would be a source of calories, but that would be a separate step.) --] (]) 02:50, 3 February 2023 (UTC)
:I've always wondered if there really is a biome band of mildest mosquito season. From what they say it sounds like midsummer mosquitoes eat you alive in the boreal forest of North America (and tundra?). ] (]) 20:26, 1 February 2023 (UTC)
::Of course, not all trees drop their leaves; see . ] (]) 23:25, 1 February 2023 (UTC)
:::And in Australia, the Snowgum, or ]. ] (]) 00:28, 2 February 2023 (UTC)
::::One of the few eucalypts that will actually grow in England. ] (]) 22:21, 2 February 2023 (UTC)
:::In North America, several species of hardwood trees also keep their leaves; some are only located in places where winter weather is rare or very mild, like the '']'' a ], though there are some hardwood trees that you can find in colder climates that have real, cold, freezing winters, that also keep their leaves, such as several common species of ], as well as ], which is widespread in the eastern third of the U.S. Usually, these kinds of trees have very thick, leathery leaves which perhaps protects them in freezing weather. A magnolia leaf and a holly leaf are both very unlike a maple or an elm leaf. --]] 17:36, 3 February 2023 (UTC)
::Among significant populated places, the only truly mosquito-free place is Iceland. Per ], "Mosquitoes are cosmopolitan (world-wide): they are in every land region except Antarctica and a few islands with polar or subpolar climates. Iceland is such an island, being essentially free of mosquitoes." Also noteworthy is that not all mosquitoes feed on humans. Per ], "Many, if not all, blood-sucking species of mosquitoes are fairly selective feeders that specialise in particular host species", which is to say you may live in an area which has plenty of mosquitoes, but which don't feed on human blood. There are also mosquitoes which don't feed on blood at all, see ] for one such genus, although there are many others. --]] 14:18, 2 February 2023 (UTC)
:::Mosquitoes bite you even in the city sometimes but the taiga and tundra biting season seem worse I wonder why. Tropical and subtropical biting seasons are also probably worse and sometimes transit malaria, Zika, dengue, yellow fever, West Nile etc. West Nile virus did start homegrown American transmission with New York City mosquitos but it probably started there cause it has lots of intercontinental planes and ships and was first found in 1930s Uganda as far as anyone knows. ] (]) 18:00, 2 February 2023 (UTC)
::::That largely has to do with the fact that pathogens are mosquito specific, a specific species of mosquito is only able to survive in a specific environment, and only specific mosquito species feed on specific humans. In order to get, say, ], you need to be bitten by an '']'' (or a few other related species) of mosquito which is infected. And those don't live in taiga or tundra. Dozens of species ''do'' live in the arctic, but they don't carry yellow fever. --]] 11:55, 3 February 2023 (UTC)
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)
= February 2 =
: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)
== Pills as seeds ==
= December 27 =
Is it possible to bury some kind of a pill or other medicine in the ground and for it to grow into something? <!-- Template:Unsigned IP --><small class="autosigned">— Preceding ] comment added by ] (]) 06:25, 2 February 2023 (UTC)</small> <!--Autosigned by SineBot-->
:Not unless it's an actual seed. ←] <sup>'']''</sup> ]→ 08:13, 2 February 2023 (UTC)
== Low-intensity exercise ==
:There are that resemble pills, and there are encapsulated seeds that are coated with fertilizer that also resemble pills. Just plant them, water them. and watch them grow. ] (]) 20:27, 2 February 2023 (UTC)
::Those are ''actual seeds''. If the OP plants a medicine pill to watch it grow, why stop there? The OP could plant money and see if it produces a tree that money grows on. ←] <sup>'']''</sup> ]→ 21:40, 2 February 2023 (UTC)
:::<small>I once spread bird seed all over my yard; sure enough, soon there were birds on my lawn! ] (]) 05:03, 3 February 2023 (UTC)</small>
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)
:See also:
:Hows about you try it and report back? :) ←] <sup>'']''</sup> ]→ 21:31, 27 December 2024 (UTC)
*{{cite journal |last1=Qahtan |first1=Ahmad A. |last2=Abdel-Salam |first2=Eslam M. |last3=et |first3=al |last4= |first4= |last5= |first5= |title=An Introduction to Synthetic Seeds: Production, Techniques, and Applications |journal=Synthetic Seeds : Germplasm Regeneration, Preservation and Prospects |date=2019 |pages=1–20 |doi=10.1007/978-3-030-24631-0_1 |url=https://link.springer.com/chapter/10.1007/978-3-030-24631-0_1 |publisher=Springer International Publishing |language=en}}
::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)
:] (]) 20:32, 2 February 2023 (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)
===By the way...===
...There ''could'' be a WP article on ]:
== ] vs ] ==
* {{cite web |last1=Singh |first1=Anjali |title=Synthetic Seeds: Definition and Applications |url=https://www.plantcelltechnology.com/blogsynthetic-seeds-definition-and-applications/ |website=Plant Cell Technology |language=en |date=24 Nov 2022}}
* {{cite web |last1=Tran |first1=Nam |title=What is synthetic seed technology? |url=https://labassociates.com/what-is-synthetic-seed-technology |website=Lab Associates |date=22 July 2021}}
* via ]
--] (]) 05:41, 3 February 2023 (UTC)
**How many of those things are medicines? ←] <sup>'']''</sup> ]→ 18:47, 3 February 2023 (UTC)
Hi,
== ] versus ]. ==
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.
I find: "when it comes to comparing them to your average supernova, fall far short, whether it be in terms of luminosity or power". But it says: "A kilonova is an even stronger type of explosion than the typical supernova that happens when large stars blow up." Which is correct? The Misplaced Pages articles on these events do not contain data that allow for a comparison. When comparing events, one should also distinguish between the maximal ] (energy output per time unit) during an event and the total energy over the lifetime of an event. --] 12:11, 2 February 2023 (UTC)
:The sources in the Misplaced Pages article ] agree with your first source, and not the second. I'd ignore the second. --]] 12:47, 2 February 2023 (UTC)
:I believe the issue is the word "stronger." Neither is demonstrating physical strength. So, that word is not being used properly. What should be explained is relative brightness. The article on Misplaced Pages explains that the average brightness of a kilonova is much less than a supernova, but the peak brightness is far greater. ] (]) 19:51, 2 February 2023 (UTC)
:Kilonova emits only relatively weak electromagnetic radiation. However the total energy of the explosion is still enormous although it is mainly emitted in the form gravitational waves or neutrinos. ]_] 20:37, 2 February 2023 (UTC)
Thank you ] (]) 23:17, 27 December 2024 (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)
= February3 =
= December 28 =
== Paper with wrong enantiomer in a figure ==
== End of the sun ==
In the following reference:
Please read the whole section of this page:
:{{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? ==
...thatistitled"Willthesuneverstopshining??" (That is, keep reading until you reachthenext section, whichisaboutthemoonshining.)Dosomescientistsdisagreewithsomepartsof this?? ] (]) 00:34, 3February2023 (UTC)
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)
:It seems reasonably accurate for a very brief summary. See ] for a more detailed description. I don't think there's much scientific debate about the future evolution of the Sun in broad strokes, although there may be some disagreement about the details. For instance, it's not clear if the expanding Sun will envelop the Earth like it will swallow Mercury and Venus, since Earth's orbit is just on the boundary of where it might be enveloped. Of course, for some definition of "scientist" and some definition of "disagree", there are surely some "scientists" who "disagree" with "some parts of this". Is there a particular point that you have a question about? ] (]) 02:20, 3 February 2023 (UTC)
:They have some stuff backwards. So, to calibrate your thinking here, it's important to understand that stars get brighter with age on the ]. The reason is, as they fuse hydrogen in the core into helium, the core becomes denser. The core pressure thus goes up, and this is what determines the rate of fusion in the core, so the rate of fusion goes up, producing more light—a positive feedback loop, just a really slow one, to human time scales, since stars are really big. When the Sun formed it was only about 60% as bright as today: see ].
:When a planet is "too close" to its star, it gets enough light that it's too hot for liquid water to exist, and if there's a lot of water, a ] happens as the water evaporates into the atmosphere. ] is a really potent ]. Then, gradually, the H2O gets ] by ultraviolet light from the star into H and O, and the hydrogen can then escape into space, as terrestrial planets are too light for their gravity to hold on to the lightest element. This is why Earth doesn't have a bunch of hydrogen or helium floating around. The thinking among scientists has come around to believing this is likely the exact process that happened on ] billions of years ago. Venus is almost exactly the mass of Earth, Earth's "twin", and likely looked very similar when the Solar System formed. But, it was "too close" to the Sun, outside the ] (CHZ), and thus the Sun fried it and drove off all its water.
:Then if you put two and two together: the CHZ moves outward as a star ages, because it gets brighter. So, the Sun's CHZ has slowly been moving outward, and estimates are in around 600,000,000 years it will start moving outside of Earth's orbit, and the same processes that likely happened to Venus will repeat on Earth. The Sun still has 5 billion years left on the main sequence, which gives plenty of time for it to drive off all of Earth's water and leave it a dessicated husk like Venus.
:]]: Then, yes, the Sun will finish its life on the main sequence and enter the ] phase. There is no real debate here since the physics are quite well-understood. Eventually the core has used up enough hydrogen "fuel" that it stops producing enough energy to "inflate" the star's upper layers against gravity, which keeps trying to collapse the star. Gravitational collapse ensues until a "shell" around the core becomes hot enough to start fusing hydrogen. This halts the collapse, and in fact then starts to inflate the star hugely. The reason is the ]: the shell surrounds the core, so by definition it has a larger volume. Any shape's volume grows more quickly than its surface area does—the volume goes up with the cube of size, while surface area only goes up with the square. This is why elephants can't jump like rabbits among other things. In our star, the photon flux through any given "slice" of the star is now much higher, and so the outer layers of the star heat up and expand from all that energy. Then as more "fuel" gets used up, the helium core ignites, followed by fusion in upper layers, which gradually "blows off" the outer layers from the extreme ] produced (again, because of that square–cube law) and what's left is a ]. --] (]) 10:23, 3 February 2023 (UTC)
*If by "some" you mean "more than one" and if by "scientists" you mean "a person who does science", then I have no doubt you could find at least 2 scientists who disagree with 2 parts of that article, so the answer to your question should be an unambiguous yes. Undoubtedly some scientists disagree with some parts of that article. --]] 11:48, 3 February 2023 (UTC)
== So-called “Hydrogen water” ==
I was at a lecture on the history and future of the sun, some years ago. Afterward, a lady asked with alarm if it was really true that in a few million years the sun would swell up and kill the earth. The presenter said no, billions, not millions. The lady breathed a sigh of relief -- as if that difference mattered to her, or to humanity. ] (]) 12:09, 5 February 2023 (UTC)
:{{small|That's an old... I say, that's an old joke, son. :) ←] <sup>'']''</sup> ]→ 13:15, 5 February 2023 (UTC)}}
I saw an ad promoting a device which presumable splits water into
== Kidney theft in real life? ==
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)
I just watched the wonderfully silly Jean-Claude Van Damme movie, ''Pound of Flesh'' - which has the premise of "they stole JCVD's kidney - and now he's going to kill all the bad guys to get it back!".
: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 =
Features the old "guy wakes up in a bath of ice after being drugged, to find his kidney removed" story. I used to think it was just a urban legend - but hasn't this actually really happened a few times now, with organ trafficking gangs? Anyone know of any actual specific examples? ] (]) 17:15, 3 February 2023 (UTC)
:Misplaced Pages has an article titled ]. The classic story of someone waking up in a bathtub of ice and a note on their chest, having had their kidneys removed, is not a thing that has ever happened, but there ''are'' documented cases of shady organ trafficking schemes, but these usually fall under the realm of coercing people who are either prisoners, or poor, into giving away their organs against their own interests. --]] 17:20, 3 February 2023 (UTC)
::Forgive this psuedo-] divergence, as this is definitely not what the OP was inquiring about, but in the context of Jayron's response, felt rather apropos. '']]'' 05:42, 4 February 2023 (UTC)
== Potential energy vs. kinetic energy. Why not also "]" vs. "]"? E.g. in the following case: ==
: says it's a myth. ] (]) 23:12, 3 February 2023 (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''.
== Ehlers-Danlos and beeing fast ==
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.
It's true, that Humans with ] have usually a talent with running and speeding running. ] (]) 23:37, 3 February 2023 (UTC)
Reasonable?
:See ]. Do you have a question? ]|] 09:15, 4 February 2023 (UTC)
:The notion of "having a talent" is hard to define. If they have this talent, they should be advised that at least some physical therapists think that patients with EDS should be encouraged to avoid high-impact activities, <u>including running</u>.<sup></sup> --] 22:00, 4 February 2023 (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.
= February 4 =
] (]) 12:26, 29 December 2024 (UTC)
== Global warming causing cold wave ==
: 'kinetic velocity' is just 'velocity'. 'potential velocity' has no meaning. ] (]) 13:56, 29 December 2024 (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 =
I have seen that some areas are facing record cold wave, and most places also face record heat wave during summer. Antarctica glaciers are melting, some areas don't have snowfall like 1960s. Then how global warming is causing extreme cold in some areas?
== Saltiness comparison ==
I understand how rising temperatures can increase cloud burst, cyclones, tornadoes, storms, floods, but this cold wave due to global warming is confusing. ] (]) 06:28, 4 February 2023 (UTC)
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)
:Changing wind patterns. In general, it gets warmer, but there are a few areas where in winter winds from high latitudes get more common. For example, in some central and eastern parts of North America, winds from the Arctic get more common in winter, leading to extreme cold outbreaks. These winds change because of regional changes in air pressure, which in turn result from changes in temperature at high latitudes. ] (]) 11:00, 4 February 2023 (UTC)
:See this BBC article: , and this ''Science'' article: . --] 11:38, 4 February 2023 (UTC)
:The article ] has some more references. ] (]) 12:05, 4 February 2023 (UTC)
:A lot of it is due to the ] wiggling more violently so it goes up and down more. See yhe first picture in that article for how it goes up and down. When it comes down the area behind can get very cold. ] (]) 16:04, 4 February 2023 (UTC)
:'''Global warming cooling''' was a recognised descriptive issue ages ago,that's why we now call it climate change, and there are a group of people whose intent is to attribute every bit of weather to it. https://climateattribution.org/ ] (]) 21:37, 4 February 2023 (UTC)
::You do realize that a change to the ''climate'' would necessarily mean impacts on ''the '''majority''' of weather events'', you know, since the climate is made of the collection of individual weather events taken together as trends. In fact, the surprising thing would be if we could only attribute a small minority of extreme cases to climate change, since they would, by definition, be outliers and not constitute the trend. A far smaller group of people don't seem to understand this, and expect the opposite (or likely just are trying to find other ways to basically deny anthropogenic impacts upon, and changing, climate exists). --] (]) 22:53, 4 February 2023 (UTC)
: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)
== Voltage multiplier for rectified flyback transformer? ==
::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)
I have a flyback transformer with built-in diode. Since the output is pulsed, I thought I could use a voltage multiplier to increase the voltage. However, after looking at the ], I doubt it can work, since the rectifier diode will make the source an open circuit when the voltage drops. Am I right in thinking that multiplying the voltage (using only capacitors and diodes) is simply impossible? ] 22:55, 4 February 2023 (UTC)
:From ]: "The pulse train coming from the flyback transformer windings is converted to direct current by a simple half wave rectifier. There is no point in using a full wave design as there are no corresponding pulses of opposite polarity. One turn of a winding often produces pulses of several volts. In older television designs, the transformer produced the required high voltage for the CRT accelerating voltage directly with the output rectified by a simple rectifier. In more modern designs, the rectifier is replaced by a '''voltage multiplier'''." So it is both possible and routine. ] (]) 00:51, 5 February 2023 (UTC)
::For the flyback they used a flyback transformer though as it could produce the big current with the nice sawtooth shape needed for the coils in an old TV. Is this to drive an old CRT? ] (]) 01:03, 5 February 2023 (UTC)
:::The flyback comes from an old CRT tv. I want to use it to generate high voltage for some experiments, preferably 50kV or more. ] 02:20, 5 February 2023 (UTC)
::I know the diode can be ''replaced'' by a multiplier. But I can't remove the diode, since it is inside the housing, and the whole thing is ]. The question is, is it possible to add a multiplier after the diode. ] 01:46, 5 February 2023 (UTC)
:::I think the diode forms the first stage of the voltage multiplier. The usual anode voltage for 20 to 26 inch colour ] was 25kV and I would never come near that potential except with a special long-reach high voltage probe. Please tell someone what your "experiments" will be. ] (]) 18:16, 5 February 2023 (UTC)
::If you want to produce really high voltages you're better off with the diodes and capacitors. The transformer might break down with flashing between coils. Also I think you're less likely to klll yourself with the voltage multiplier. ] (]) 11:13, 5 February 2023 (UTC)
:I found a solution: the Cockcroft-Walton multiplier will work when a "pull-up" resistor is added, connecting the output of the flyback (+ diode) and the ground. That way, the capacitor at the input of the multiplier will be pulled to ground when the output of the flyback is zero. I ran simulations in Qucs, with good results, so I'm pretty sure it will work (haven't tested it yet, I'm waiting for the HV diodes I ordered). ] 21:01, 5 February 2023 (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)
:<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)
= February 6 =
::::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)
== Different way of improving SWIFT's frequency response ==
: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)
Continuation of ] and ]. I made the the different version of alpha-SWIFT in which it is cascaded in series similar to typical IIR filters do instead of subtracting the slow-decaying one with a fast decaying one calculated in parallel. But here's the question, is it simpler to adjust than it is described in as you only have to adjust the filter order? ] (]) 19:40, 6 February 2023 (UTC)
::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". ==
== Service Ceiling for aircraft ==
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'''.
What sort of ref do we need for this and for what sort of performance? This just came up in the F-22 article for unknown reasons and ISTR that the invulnerability of the B-36 was based on USAF jet fighters of the time being able to climb up to its height, but not turn at that height. So when then they tried to attack they'd stall. (Not a problem for USN or USSR of course.) ] (]) 21:43, 6 February 2023 (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"?'''
] (]) 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)
::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? ==
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)
:]. --] (]) 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 =
== Brightest spot of a discharge tube ==
]
]
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)
= January 1 =
== Two unit questions ==
#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"?
#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)
: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)
:::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? ==
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)
:<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>
::<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)
::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? ==
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)
: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)
::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)
:::::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)
= January 5 =
Latest revision as of 22:38, 5 January 2025
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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)
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)
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)
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. 
