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August 3

Heat capacity, sand battery, check calculation

Could someone please check my work? Sand has a specific heat capacity of around 800 kJ/kg·K. I calculate that if you put 10 000 kWh (10 MWh) into 900 kg (0.6 cubic metres) of it, you raise its temperature by 50 °C. This video is talking about a massive ~40 cubic metre sand battery but it's capacity is only ~10 MWh? Either I'm wrong or the video is wrong, right? https://www.youtube.com/watch?v=KVqHYNE2QwE&t=377s 80.46.251.32 (talk) 01:05, 3 August 2024 (UTC)

According to the article Thermal energy storage, there is a prototype 8 MWh sand battery, built in Finland in 2022. The source given on this system says it is a "steel container, which is 4 m wide and 7 m high, [and it] is filled with 100 tonnes of builder’s sand", and is heated to 500 °C. There is a picture of the silo. So it seems that your calculation must be wrong. Abductive (reasoning) 06:09, 3 August 2024 (UTC)

The specific heat capacity of quartz sand is more like 800 J/kg·K, lower by a factor of 1000. The specific heat capacity is temperature-dependent. At 500 °C it is substantially higher, about 1230 J/kg·K.^[1]  --Lambiam 10:47, 3 August 2024 (UTC)

August 4

density of solid tritium

Has anyone ever actually measured this? I've only seen the density of the liquid discussed in the literature. Double sharp (talk) 07:08, 4 August 2024 (UTC)

see https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4922399/ where they measured the molar volume, effect of pressure and temperature on volume. Also see https://link.springer.com/article/10.1007/BF00683620 . Graeme Bartlett (talk) 11:01, 4 August 2024 (UTC)

Interferometer116.68.77.174 (talk) 17:48, 4 August 2024 (UTC)

My company got a new project - milk analyzer using FTIR spectroscopy. Now we are conducting a research about interferometer for this milk analyzer and got informations like beamsplitter - [material : KBr or other material that transmit and refract IR beam of 2.5 to 20um wavelength, 50/50 beam splitting coating, anti-reflective coating in mid IR region flatness-1 um for 10um lambda, smoothness-RMS roughness of less than 10nm, thickness- 1 to 5mm]; lens - [plano convex lens that should effectively transmit 2.5 to 20um range wavelength effectively]; Compensating Plate : [Material : Same as beamsplitter, Coating: anti-reflective in the mid-IR range, Anti-reflective coating : Effective in mid IR range, Flatness : 1um for 10um lambda, Smoothness : RMS roughness of less that 10nm, Thickness : match the optical path length difference introduced by your beam splitter]; Mirror: [Reflectance max from 2µm to 20µm, Flatness : 1um for 10um lambda]. Should I proceed with finding optics with these specifications? Do the provided details suffice to initiate the process? And also 2 mirrors are used in this interferometer. One is fixed and other is have a linear motion. When I asked the displacement range of moving mirror in chatgpt 1st time it replied as 0.625mm to 1.25mm. I again asked this question and it replied as 'in a Michelson interferometer, the moving mirror displacement is often around a few millimeters to achieve the desired spectral resolution. Specifically, a displacement range of 1 to 5 millimeters is common, though some high-resolution instruments may require larger displacements.'. I am confused. What is your opinion about this? 116.68.77.174 (talk) 17:48, 4 August 2024 (UTC)

My opinion is that it is unsafe to rely on ChatGPT for any project-critical information. It can however be a useful source of links that you will have to trace and verify. In Wikipedia find Michelson interferometer and FTIR (Fourier-transform infrared spectroscopy). External links that I think may help are: Fourier Transform Infrared Spectroscopy as a Tool to Study Milk Composition, Standardization of milk mid-infrared spectra from a European dairy network, Visible and near-infrared spectroscopic analysis of raw milk for cow health monitoring: Reflectance or transmittance? and Human Milk Analysis Using Mid-Infrared Spectroscopy. Philvoids (talk) 23:32, 4 August 2024 (UTC)

IMO one cannot rely on ChatGPT for any factual information, critical or not. It may answer any factual question in an authoritative tone with something that sounds plausible but has no relation to reality.  --Lambiam 23:39, 5 August 2024 (UTC)

It sounds like ChatGPT is ready to run for public office. ←Baseball Bugs ^{What's up, Doc?} carrots→ 23:55, 5 August 2024 (UTC)

Villar A, Gorritxategi E, Aranzabe E, Fernández S, Otaduy D, Fernández LA (December 2012). "Low-cost visible-near infrared sensor for on-line monitoring of fat and fatty acids content during the manufacturing process of the milk". Food Chemistry. 135 (4): 2756–60. doi:10.1016/j.foodchem.2012.07.074. PMID 22980869. Philvoids (talk) 13:53, 6 August 2024 (UTC)

August 6

Is there any natural process (i.e. without human intervention), conserving the kinetic energy, without conserving the speed (i.e. the absolute value of velocity)?

By conserving the KE without conserving the speed, I mean the following:

Let a system, carry (at the initial moment) an initial mass $m_{1}$ and an initial velocity ${\vec {v}}_{1}$ and an initial kinetic energy $E_{K1},$ and carry (at the final moment) a final mass $m_{2}$ and a final velocity ${\vec {v}}_{2}$ and a final kinetic energy $E_{K2}.$

Is it natural (i.e. without human contact), that $E_{K1}=E_{K2},$ but $|{\vec {v}}_{1}|\neq |{\vec {v}}_{2}|$ [for every reference frame]? while the reference frame remains the same - during the whole process?

Mathematically, it's possible of course, but I wonder if it's also physically possible in any natural process.

Note, that I'm only asking about a change in speed, rather than about a change in velocity, because no question would arise, had I replaced speed by velocity, in which case there would be natural processes conserving the KE without conserving the velocity, e.g. when the system is any given body that elastically collides with a wall sharing a reference frame with an observer who measures the body's kinetic energy. HOTmag (talk) 07:10, 6 August 2024 (UTC)

This can only happen when the mass changes inversely proportional to the square of the speed. It can be done naturally through clever accounting. Suppose a rock changes speed and breaks into four equal parts; a natural process. We can choose to define our system such that three of the parts of the rock leave the system, reducing the mass to one quarter. We can also choose a frame of reference in which the speed of the remaining fragment doubles compared to the speed of the original rock. Then your condition is met. Obviously, this has no physical relevance. PiusImpavidus (talk) 09:04, 6 August 2024 (UTC)

Oh, I forgot to add a crucial condition: the reference frame must remain the same, during the whole process. Thanks to your exmaple, I've just added this crucial condition I'd forgotten (See above). Sorry for the confusion. HOTmag (talk) 12:35, 6 August 2024 (UTC)

I don't change the reference frame during the process; I just conveniently choose it beforehand. If both speed and mass change, I can always find a reference frame where the kinetic energy is conserved and I can also find one where it isn't. And as the physics cannot depend on the chosen reference frame (principle of relativity), this conservation of kinetic energy can't have physical relevance. PiusImpavidus (talk) 20:24, 6 August 2024 (UTC)

Ok, my question wants this process to be independent of the reference frame. I've just added this new condition [in brackets] to my original post. Again, I apologize for the confusion.

Let's put my original question this way: Some natural forces (e.g. the elastic force exerted by a spring), conserve the kinetic energy for the long term (with respect to the "initial moment" defined as such), for every reference frame. Is there any combination of natural forces - that conserves the kinetic energy (in the above sense), but at some moments - at which the kinetic energy turns out to have been conserved (with respect to the "initial moment" defined as such) under that force for every reference frame - the speed (i.e. the absolute value of velocity) does not? HOTmag (talk) 07:43, 7 August 2024 (UTC)

I take the rest frame of the system before the process happens. The speed of the system is 0, and so is the kinetic energy. Now the process happens and the speed changes. My reference frame is no longer the rest frame of the system, so the kinetic energy can no longer be 0. Which proves that I can always find a reference frame in which your condition is violated. This means that there is no process that satisfies your condition in every reference frame. PiusImpavidus (talk) 09:58, 8 August 2024 (UTC)

Your consideration can also be used to prove, that if the kinetic energy is conserved for every reference frame, then not only the speed - but also the velocity - is conserved for every reference frame, right? HOTmag (talk) 11:30, 8 August 2024 (UTC)

Yes, if the kinetic energy is conserved in every reference frame, the velocity must be conserved too. The mass too. In other words, not much can have happened. (Note: I've assumed we're dealing with inertial reference frames. I think you assumed that too.) PiusImpavidus (talk) 15:54, 9 August 2024 (UTC)

Thank you. HOTmag (talk) 17:34, 10 August 2024 (UTC)

Metastasis of glioblastoma

From Glioblastoma#Surgery:

GBM cells are widely infiltrative through the brain at diagnosis, and despite a "total resection" of all obvious tumor, most people with GBM later develop recurrent tumors either near the original site or at more distant locations within the brain.

Why is this cancer so widely infiltrative? Nyttend (talk) 22:03, 6 August 2024 (UTC)

The glial cells thought to be involved are astrocytes, which are like neurons in many ways except they don't carry electrical signals. They reach out along the same pathways as neurons and if they become cancerous are predisposed to reach into distant areas. Here is a review article. Combine that with the fact that the somatic immune system is barred from the brain, and they cannot be stopped or contained. Abductive (reasoning) 23:02, 6 August 2024 (UTC)

Abductive, could you add something to the article explaining this? Proper understanding of the review article demands a higher-than-I-possess understanding of human biology. Even the bits that I can understand are hard to interpret in context, e.g. I understand "Glioblastoma cells generally invade as single cells", but I don't know if it's at all relevant to the "why" question, and I don't want to go dumping content into the article and accidentally cause it to imply something not in the source. Nyttend (talk) 19:45, 7 August 2024 (UTC)

I gave it a shot. Neurobio is the most difficult biology field, along with immunobio. Abductive (reasoning) 20:15, 7 August 2024 (UTC)

It may not be especially infiltrative as compared to other tumors. The problem is that in case of brain the resection of tumors with sufficiently wide margins is impossible for obvious reasons. Ruslik_Zero 19:16, 7 August 2024 (UTC)

You might consider reading the review article I linked above. Abductive (reasoning) 19:47, 7 August 2024 (UTC)

Sound effects for Jeopardy dollar amounts heard on 1960s phones

I have this memory of using a telephone in the early 1960s and if I couldn't hear anything else, I could hear a sound (very faint) similar to the old sound effects of dollar amounts appearing on Jeopardy!. a sound effect used in the opening of Jeopardy! Masters. Any idea what I was hearing?— Vchimpanzee • talk • contributions • 22:10, 6 August 2024 (UTC)

• Old relays. Here is a Youtube video with the sound amplified. Abductive (reasoning) 23:08, 6 August 2024 (UTC)

That doesn't seem to be it. It was much more of an electronic or robotic sound. Maybe it was a change in the technology from the old relays to something new.— Vchimpanzee • talk • contributions • 15:55, 8 August 2024 (UTC)

I recall those rapid electronic sound effects when Jeopardy revealed the dollar amounts (here is a Youtube clip [2] of them)... and on the telephone system they were called Touch-Tones. From Push-button telephone: "In 1963, the Bell System introduced to the public dual-tone multi-frequency (DTMF) technology under the name Touch-Tone, which was a trademark in the U.S. until 1984. The Touch-Tone system used push-button telephones. In the decades after 1963, rotary dials were gradually phased out on new telephone models in favor of keypads and the primary dialing method to the central office became touchtone dialing." In fact, DTMF touch-tones are still in use with landlines, but have become less noticeable with speed-dialing. In addition, in the U.S.landline phone use is way down, with 73% of households only having cell phones. [3] Modocc (talk) 17:55, 8 August 2024 (UTC)

I'm guessing what I was hearing was what replaced relays on the newer systems that could handle touch tone telephones.— Vchimpanzee • talk • contributions • 21:21, 8 August 2024 (UTC)

Most likely, although in those early days I rarely used the telephone and when I did it was only to answer an incoming call. :-) Modocc (talk) 23:05, 8 August 2024 (UTC)

That sound effect reminds me of DTMF touch-tone dialing. But, like automatic dialing like a computer might do.

Did you have a phone with an auto-dial feature? You might be remembering the sound that made, but only when it was actually dialing. For that matter, you might be thinking of the sound it makes when you dial manually.

Another possibility is that your phone was getting interference from something. Either from something in your house (In which case we'll never guess what it was), or some kind of cross-talk with other phone wires. ApLundell (talk) 06:50, 17 August 2024 (UTC)

August 7

Density of Iridium and Osmium

Note A at Iridium says

"At room temperature and standard atmospheric pressure, iridium has been calculated to have a density of 22.65 g/cm3 (0.818 lb/cu in), 0.04 g/cm3 (0.0014 lb/cu in) higher than osmium measured the same way. Still, the experimental X-ray crystallography value is considered to be the most accurate, and as such iridium is considered to be the second densest element" with a reference to https://technology.matthey.com/content/journals/10.1595/003214089X3311416

I am curious: has anyone ever directly measured the density of a pure crystal of each by immersing them in water and experimentally confirmed these calculations? Or is the difference too small to measure using conventional methods?

Looking at Isotopes of iridium and Isotopes of osmium, would the answer be different if the pure crystals were made from the heaviest stable isotope? Are we even able to seperate the isotopes of iridium and osmium?

Note the "At room temperature and standard atmospheric pressure". See https://technology.matthey.com/content/journals/10.1595/147106714X682337 for some other temperatures and pressures.

Interesting but not reliable: https://www.answers.com/natural-sciences/What_is_densest_material_in_world The bit about plutonium surprised me.

--Guy Macon Alternate Account (talk) 15:07, 7 August 2024 (UTC)

Sure we can separate the isotopes. Isotopically pure ¹⁸⁴Os (the lightest stable-ish isotope) should be less dense than isotopically pure ¹⁹³Ir. Double sharp (talk) 12:39, 9 August 2024 (UTC)

August 8

Butch Wilmore

In the top image on [https://www.bbc.co.uk/news/articles/cg4yqepr469o], what's the blurring on Wilmore's chin? Any ideas? --Dweller (talk) Old fashioned is the new thing! 12:25, 8 August 2024 (UTC)

Looks like a bandage. It's visible in some Google Images pics. But I can't find an explanation. ←Baseball Bugs ^{What's up, Doc?} carrots→ 12:47, 8 August 2024 (UTC)

I only see it on pictures of him in a space suit, but it is present on a picture associated with a postponed launch (so it probably wasn't a shaving accident). I see that his chin is much closer to the collar of his space suit than is Sunita Williams's chin to her collar. I wonder if it was chafing. One size doesn't quite fit all? -- Verbarson  ^talk_edits 17:36, 8 August 2024 (UTC)

Possibly a protective anti-chafing patch.  --Lambiam 21:12, 8 August 2024 (UTC)

Seems likely. Thanks. --Dweller (talk) Old fashioned is the new thing! 15:14, 9 August 2024 (UTC)

August 9

Total daytime per latitude

Since the southern hemisphere's summer comes during the perihelion, I'm thinking it should be slightly shorter than the winter since the Earth moves slightly faster, so the same latitude on the northern hemisphere should have a little more total daytime over the course of the year. Now, I know that since any part of the Sun's disc above the horizon is counted as daytime, the day is "too long" by the time it takes the Sun to rise/set from nothing to half a disc being visible. In middle latitudes this takes longer than on the equator because the Sun's path is closer to horizontal. I'm wondering how are these two effect related in size. Do you have a shorter total daytime length over 1 year at 45°S than 40°N for example 78.2.180.96 (talk) 06:49, 9 August 2024 (UTC)

Here [4] are sunrise and sunset times for a selection of latitudes north and south of the equator, generally at 5° intervals. 2A02:C7B:21D:5400:7905:88D1:43B9:344C (talk) 09:29, 9 August 2024 (UTC)

August 10

Since gravity is formed by the stress–energy tensor, which apparently depends on the reference frame, does gravity depend on the reference frame?

HOTmag (talk) 17:38, 10 August 2024 (UTC)

Suppose we have a planet in a circular orbit around a star, using a reference frame in which the star is stationary and the rest of the universe doesn't spin around it. This is an ordinary, Keplerian orbit, as predicted by classical physics.

Now suppose a spaceship passes at high speed (0.8c or thereabouts) through this planetary system, in the plane of the planet's orbit. We switch to the reference frame of that spaceship. Special relativity tells us there's length contraction. The orbit of the planet turns into an ellipse with the star in the centre – not at one of the focal points. This is not a Keplerian orbit, so gravity must have done something funny.

Theoretically, it should be possible to apply the Lorentz transformation to the stress-energy tensor and solve the Einstein field equations for the orbit of the planet, which should give the same result as the Lorentz transformation of the Keplerian orbit, but I won't do the maths for you. PiusImpavidus (talk) 18:39, 10 August 2024 (UTC)

You have a wrong premise here, or at least one not aligned with the current way of looking at these things.

The stress–energy tensor does not in fact depend on the frame of reference. The components of the tensor depend on the frame of reference.

But the tensor is not its components. The tensor (field) is the underlying Platonic entity that can be viewed in any local coordinate system and its components extracted with respect to those coordinates, but the underlying thing remains the same.

This is the coordinate-free approach, which has been the preferred one since the mid-20th century. You don't necessarily have to agree with it; it's not the kind of thing that's subject to scientific confirmation or disconfirmation. But you probably ought to be aware that it's the dominant approach. --Trovatore (talk) 21:35, 10 August 2024 (UTC)

To be clear, this approach predicts the same outcomes for observations as approaches in which the tensor is identified with its (frame-of-reference dependent) representation. It is preferred because it gives one fewer headaches.  --Lambiam 01:41, 11 August 2024 (UTC)

August 11

A hypothetical male version of Jeanne Calment

Would a hypothetical male version of Jeanne Calment, if one will ever actually exist (including in the future), be(come) around 119 years old? (Since Calment herself was almost 122.5 when she died (122.45 years, to be more specific) and 122.45 - 3 = 119.45.) Based on the data here (List of the verified oldest people), it seems like the men are generally around three years younger than the women of the equivalent rank (for instance, comparing the 100th oldest man ever to the 100th oldest woman ever, or the 50th oldest man ever to the 50th oldest woman ever, or the 25th oldest man ever to the 25th oldest woman ever, et cetera). 172.59.128.60 (talk) 05:19, 11 August 2024 (UTC)

Aside from the fact that we don't do such guesswork here, there is doubt about the age Jeanne Calment actually reached. ←Baseball Bugs ^{What's up, Doc?} carrots→ 06:09, 11 August 2024 (UTC)

"there is doubt".  --Lambiam 13:58, 11 August 2024 (UTC)

Was Jeanne Calment the Oldest Person Who Ever Lived—or a Fraud?

Some researchers have cast doubt on the record of the celebrated supercentenarian. By Lauren Collins The New Yorker 2020/02/17 [5]. This article is behind a paywall, hence I have not read it yet. Anyway, I've always wondered whether researchers were able to rule out familiar fraud in which the daughter at some point assumes their mom's identity. With an age difference of 23 years that would make her "only" 99 when she died. According to her article some family photos were deliberately burned which is a red flag that may or might not have been dealt with adequately. In addition, I expect that the growing popularity of genetic genealogy will be able to shed further light on her claim, either confirming or disproving it. hModocc (talk) 15:06, 11 August 2024 (UTC)

I suspect that she really was 122.45 years old when she died and that the people who argue otherwise are merely spewing a Russian conspiracy theory. However, maybe this question will eventually be settled with DNA testing. I don't know. Though if so, then I would expect the conspiracy theory proponents to be humiliated. 172.59.128.60 (talk) 21:13, 11 August 2024 (UTC)

I live in Hawaii, where the number of centenarians is staggering, to the point where you will inevitably meet one at some point. For me, the question is why aren't there more supercentenarians here. Something seems to happen between 103-106 or so, but I don't know what it is. Maybe poor eyesight leads to more falls, and premature death. Viriditas (talk) 23:16, 11 August 2024 (UTC)

It is really a matter of how you define the notion of a (hypothetical) "male version" of a female person. Life expectancy depends on many factors other than sex – where one lives, family, education, lifestyle. Would your hypothetical male version of Jeanne Calment also have led a leisurely lifestyle within the upper society of Arles, pursuing hobbies such as fencing, cycling, tennis, swimming, rollerskating, playing the piano, and making music with friends? If the defining characteristic is narrowed to dying at an age with the same percentage in actuarial tables for the separate genders, these tables are time-dependent and population-dependent. I don't know how easy it will be to find such tables for France around 1997. And they will not extend to the age of 122 anyway, so one would need to replace them by a plausible mathematical model that fits the available data.  --Lambiam 13:46, 11 August 2024 (UTC)

Yes, it's not obvious what "a hypothetical male version of Jeanne Calment" means precisely.

There's lifespan data for people with ~50% and ~25% samples of her genetic make-up, an example of the many factors at play.

Father - 93

Mother - 86

First son Antoine - 4

First daughter Marie - 1

Second son Francois - 97

Second daughter Jeanne - 122

Jeanne's daughter Yvonne - 36

Jeanne's grandson Frederic - 36

Sean.hoyland (talk) 15:07, 11 August 2024 (UTC)

Frederic died in a car accident, so he didn't live to his full potential. Or was it in a motorcycle accident? Either way, my point here still stands. 172.59.128.60 (talk) 21:14, 11 August 2024 (UTC)

Well, it's entirely possible, given Murphy's Law, that the gene interaction network presumably partially responsible for Jeanne's lifespan, increases the likelihood of death by traffic accident in males. Sean.hoyland (talk) 13:50, 12 August 2024 (UTC)

They answer is yes, but you're not going to like the implications: A "study followed 81 castrated men and found that their lifespan was on average 14.6 years longer than non-castrated males. A study in Italy in 2014 found similar results, with castrated men living on average 13.5 years longer than non-castrated males." Viriditas (talk) 23:01, 11 August 2024 (UTC)

But male supercentenarians generally aren't castrated, are they?

Male hormones may limit life expectancy. As to why these supercentenarian men defy the odds, I cannot say. Viriditas (talk) 23:08, 11 August 2024 (UTC)

We have an article, profoundly depressing, on forced sterilisation. This article does not seem to mention any effects on life expectancy. However, multiple websites state significant increases on life expectancy (20% - 60%) in neutered dogs and cats. --Cookatoo.ergo.ZooM (talk) 06:32, 12 August 2024 (UTC)

Russia having very few validated supercentenarians

Is the reason for Russia having very few validated supercentenarians in part due to the fact that both Communism and Nazism caused an extraordinarily massive number of premature deaths in Russia? (Ditto for Ukraine and Belarus?) 172.59.128.60 (talk) 23:03, 11 August 2024 (UTC)

Vodka. Abductive (reasoning) 00:54, 12 August 2024 (UTC)

The 2021 population pyramid of the Russian Federation shows a steep drop when going from the 70–74 bracket (people born in or after 1947) to the 75–79 bracket (people born in or before 1946), and an even steeper drop in the transition from the 80–84 to the 85–89 bracket. The Russian pyramid has a much thinner spire than that of the UK, which shows more gradual transitions. The strong relative lack of supercentenarians will continue for another 35 years. A connection with the extreme hardship of WWII appears plausible.  --Lambiam 12:01, 12 August 2024 (UTC)

It's also noticeable that male-female ratio in the older age groups is much lower in the Russian pyramid than in the British, even for the 65–69 and 70–74 groups. AndrewWTaylor (talk) 13:51, 12 August 2024 (UTC)

August 12

Moffat and ozone

Who was "Dr Moffat of Hawarden", who wrote papers about ozone, invented an ozonometer (see for example [6]), and after whom "Moffat's Ozone papers" ([7]) appear to be named? What more can we know about him? Was he Thomas Moffat MD FRAS ([8])?

How do the papers work? Andy Mabbett (Pigsonthewing); Talk to Andy; Andy's edits 14:44, 12 August 2024 (UTC)

Seems very likely it was Thomas Moffat, since the PMC2439974 article mentions ozone 13 times and was written in 1856, soon after ozone had been characterised for the first time by Christian Friedrich Schönbein in 1840. The Google books reference was also written in 1856, by David T. Ansted. Mike Turnbull (talk) 15:31, 12 August 2024 (UTC)

The full name is given as Thomas Barbour Moffat ([9], p.17), an obituary is here, and genealogical data here. --Wrongfilter (talk) 15:41, 12 August 2024 (UTC)

Thank you, both. I have compiled data from the above sources into Thomas Barbour Moffat (Q128923496). There is also an obituary in the BMJ, which describes him as "the author of many papers on geology, meteorology, sanitation etc."; though I can only find one other (On Medical Meteorology (Q58709971)).

Thomas Barbour Moffatt, of the distinguished Moffatt clan of Sundaywell, Dumfriesshire. What's the origin of the name "Sundaywell", sometimes written "Sunday Well"? 91.234.214.10 (talk) 17:41, 12 August 2024 (UTC)

According to the Dumfriesshire OS Name Books, 1848-1858 "Sundaywell - [Situation] At E. [East] end of Sundaywell Moor. A good Spring, the water of which is deepened by a Stone dam round it, seemingly very old, There is a tradition, that, at Some remote time, there were great numbers of people Baptised here, The farm takes the name from the well." and "Sundaywell - A large Farm House with extensive outbuildings and garden the property of trustees of the late Alexander Moffatt Occupied by John Edgar". Mikenorton (talk) 21:27, 12 August 2024 (UTC)

How did Carl Linnaeus know about the species he described?

I was reading about the Pied kingfisher, whose article states that it was first described by Linnaeus in 1758. I assumed he must have visited "Persia and Egypt" in order to catalogue the species, as that's where he says it lives—but I don't see reference to any such expedition on the catalogue's article. Were their earlier catalogues that Linnaeus drew from? How did he know about this bird? ꧁Zanahary꧂ 16:19, 12 August 2024 (UTC)

To quote from this webpage from Berkeley, "Linnaeus continued to revise his Systema Naturae, which grew from a slim pamphlet to a multivolume work, as his concepts were modified and as more and more plant and animal specimens were sent to him from every corner of the globe". Mikenorton (talk) 20:51, 12 August 2024 (UTC)

He was apparently quite happy to accept specimens, but very stingy in giving credit or sending some back (according to a German bio podcast I recently listened to). --Stephan Schulz (talk) 14:30, 14 August 2024 (UTC)

photons

Suppose the Sun were part of a binary: identical twins, separation several million miles. When the stars were 'side-by-side' in our line of sight, the radiation received on earth would be twice its present value. But what would happen when one star was eclipsing the other? Would photons from the distant star pass unscathed through the nearer one? If not what would the received intensity be? What spectral changes if any would be observed compared to the familiar G2 spectrum? Renshaw 2 (talk) 16:37, 12 August 2024 (UTC)

Subjecting our planet to double the usual solar radiation is likely to leave no one alive to make the interesting observation of whether a star is transparent. Philvoids (talk) 17:11, 12 August 2024 (UTC)

I heard that the average photon generated in the sun's core bounces around in there for hundreds of thousands of years before accidentally escaping to the surface. So I'm pretty certain that the sun isn't transparent. Abductive (reasoning) 23:10, 12 August 2024 (UTC)

"When this random walk process is applied to the interior of the sun, and an accurate model of the solar interior is used, most answers for the age of sunlight come out to be between 10,000 and 170,000 years."^[10]  --Lambiam 23:17, 12 August 2024 (UTC)

If the expected number of steps of a random walk process for getting a distance d away from the starting point equals n, the expected number of steps needed to traverse twice that distance, 2d, equals n². I don't know the average time between two hops of a photon, but I bet it is less than 3 seconds. This means that a randomly hopping photon takes more than 10⁷ hops in a year, and more than 10¹¹ hops in 10,000 years. To get all the way through the Sun instead of getting out from the core would then take more than 10²² hops or 10¹⁵ years, several orders of magnitude longer than the estimated age of the universe.. Of course, many incident photons would find their way out earlier, but in a very different direction than where they came from.  --Lambiam 23:42, 12 August 2024 (UTC)

Among the countless binary star systems there are probably such star systems elsewhere, two yellow dwarfs, each of approximately one solar mass. Photons reaching the surface of a hot star are almost immediately absorbed by the ions of it outer layer.  --Lambiam 23:12, 12 August 2024 (UTC)

Stars are pretty dense and full of free electrons, so they're very good at scattering light. The light from the other star will loose its identity in the photosphere (i.e., it will be scattered and frequency shifted to match the temperature of the gas).

Irradiating a star with light from a nearby star may raise the temperature a bit on the sides where they face each other. On the other hand, two stars close together will deform each other by tidal forces and the tidal bulges get a bit cooler than the lower parts. I don't know what effect will be dominant in the case of two G stars in a very tight orbit, but I expect the tidal deformation. Such an unequal temperature distribution can be seen in the spectrum. The absorption lines in the spectrum will deform as the binary spins and the hotter and colder parts alternate redshift and blueshift. PiusImpavidus (talk) 08:30, 13 August 2024 (UTC)

The OP's proposed reconfiguration of our solar system cannot be carried out as a practical test before reaching a political consensus on the work that it will involve. The project to split the Sun into a Binary star pair will lie beyond the resources of a space agency such as NASA unless significant new funding can be raised. In the present political climate this funding must wait while Environmental impact assessment statements are properly considered. The OP's proposal implies that the binary stars' orbit is in the Ecliptic plane of the Earth's present orbit so that solar-solar eclipses are periodically observed but a full calculation of the Orbital mechanics of the revised solar system will be needed. Shall we have an assessment of how Gravitational waves from a local binary star will affect life on Earth? An international body might be formed to collect, review and eventually override statements from affected stakeholders that will include publishers of tidal predictions, representatives of the Sunscreen manufacturers, weather forecasters whose computer models will need updating, Sun worshippers, astrologers and others. As an interim and less radical test of the Sun's opacity I suggest allocating more resources to Solar observation where one may try to detect prominent Sunspots as they rotate out of direct view to the far side of the Sun. Philvoids (talk) 20:45, 14 August 2024 (UTC)

August 13

Dogs barking at some people

A friend of mine told me that on two recent occasions dogs started barking uncontrollably at a new acquaintance of her, a young man, in both cases much to the embarrassment of the dog owners, who could not silence their dogs and saw no other solution than to walk their dogs away. She did not see anything in his behaviour or demeanor that could have triggered this and asked me for an explanation. Now this is purely anecdotal, and I've heard similar anecdotes before. My question: is there evidence (beyond the anecdotal) for some people unwittingly tending to alarm dogs more than others, and if so, have possible science-based explanations been offered for the phenomenon?  --Lambiam 00:02, 13 August 2024 (UTC)

There seems to be evidence that dogs can smell biological changes in humans which indicate the presence of a disease (COVID, cancer, etc). Medical detection dogs exist, but they must be trained to detect VOCs (volatile organic compounds). Of course, canines may bark for multiple other reasons. --2001:871:6A:1B71:4CD8:804D:2688:FD83 (talk) 06:28, 13 August 2024 (UTC) Oops, --Cookatoo.ergo.ZooM (talk) 06:29, 13 August 2024 (UTC)

Who knows what it's like to be a dog. It's such a diverse group. I know a Siberian Husky street dog with an apparent racist hatred of white people. He's a good dog though, mostly. My dog is more aggressive towards male strangers but will change direction and try to follow attractive female strangers, which is a little awkward. He also barks aggressively at fallen leaves, beetles (no size dependency), mynah birds, skinks, many things...not seeing a pattern so far. They can smell adrenaline of course, which might explain some cases. Sean.hoyland (talk) 07:51, 13 August 2024 (UTC)

Did she ever see her new acquaintance in sunlight? —Tamfang (talk) 16:57, 16 August 2024 (UTC)

Skin disorder

I have just got off the bus, where I was sitting behind a woman with globules all over her body. I have looked at List of skin conditions, (the longest article I have ever encountered), but am none the wiser. What is the name of it? 2A00:23D0:E1D:2D01:B1A1:2846:AA72:4934 (talk) 14:19, 13 August 2024 (UTC)

Lipoma...maybe. Sean.hoyland (talk) 14:56, 13 August 2024 (UTC)

Could also be neurofibromatosis. nmael^talk 15:08, 13 August 2024 (UTC)

Inches and lines

I'm working on Phobaeticus annamallayanus, described by James Wood-Mason. As a taxon author he is quite unhelpful, since he left only a brief and vague description ([11], see the second entry, Phibalosoma annamallayanum). Worse, he gave his measurements in inches and lines, something which was apparently in vogue at the time but is a pain at the moment, since a "line" can be anywhere between a tenth and fortieth of an inch. I'm willing to make approximations like "between two and three inches", but that's less than ideal. Does anyone have any idea which meaning of line 19th century entomologists likely meant?

Secondly, at the start of his measurements, he gives the total length as "8 in 9" lines. What does that mean? Surely not ⁸/₉.

Thank-you for any help you can provide. Cheers, Cremastra (talk) 16:20, 13 August 2024 (UTC)

In the last century, there was a useful booklet called Wightman's Arithmetical Tables. The first entry for Long Measure was "12 lines = 1 inch". This is also noted here [12]. These books have many alternative versions of the Thirty days hath September rhyme of which I was previously unaware. 91.234.214.10 (talk) 16:38, 13 August 2024 (UTC)

I feel that claiming it can mean anything from a tenth to a fortieth of an inch is an exaggeration. The different definitions were based on usage. It is not reasonable to think that he would be using the Russian ballistic definition of a line when referring to the size descriptions of an insect. The only real issue is that 1/12 of an inch was the standard for botany and entomology until the mid-1800's. Then, some (not all) areas of science (primarily the French) tried to "decimalize" it to 1/10 of an inch. So, the question is, did Wood-Mason use the newfangled definition of 1/10 of an inch or the long-standing definition of 1/12 of an inch. I personally see no reason he would update all of his research, which took place long before the 1/10 of an inch definition was introduced, to a new measurement. 12.116.29.106 (talk) 16:49, 13 August 2024 (UTC)

Agree that one twelfth is the most likely. See The Measures, Weights & Moneys of All Nations (p. 50) of 1890 which says: "A line is 1/12th part of an inch".

Also Great Britain's New Proposed Decimal Albert System of Weights, Measures and Coins (p.32) of 1869 which has "1 Line, or inch 1/12".

And an American textbook, Higher Arithmetic, Or, The Science and Application of Numbers (p. 150) of 1848 which says: "The inch is commonly divided into eigths or tenths; sometimes however, it is divided into twelfths which are called lines".

Alansplodge (talk) 17:40, 13 August 2024 (UTC)

The previous entry for Phibalosoma acanthopus (which should be the same as Phobaeticus serratipes, see [13]) gives us a simple math problem: "4 in. 6.5 lines + 12.5 lines = 5 in. 7 lines." That only works if one inch is twelve lines. The total length of "8 in. 9 lines" means 8 inches and 9 lines. --Amble (talk) 17:58, 13 August 2024 (UTC)

@Amble The total length of "8 in. 9 lines" means 8 inches and 9 lines Oh, I'm a moron. I didn't see the dot after "in".

Well, at least that wasn't too complicated.

Thanks for spotting the clue in the above entry; I was hoping it was 1/12, since that seemed standard, but I didn't want to guess. Thanks also to IPs and @Alansplodge for their research.

Cheers, Cremastra (talk) 18:58, 13 August 2024 (UTC)

In such cases I use BHL's "Search inside" button to search for "in. 10" and "in. 11". Indeed under "Phibalosoma acanthopus" is a "1 in. 11.75 lines". So clearly 12 lines per inch. JMCHutchinson (talk) 14:24, 15 August 2024 (UTC)

August 14

Indeed measuring the neutrino's mass is regarded to be extremely problematic (or hard), but why can't the following simple experiment solve the problem?

In Cowan–Reines neutrino experiment, anti-neutrinos created in a nuclear reactor by beta decay, reacted with protons to produce neutrons and positrons, by the following reaction:

ν
_e +
p⁺
→
n⁰
+
e⁺

Now I suggest the following calculation:

1. Both the proton's mass, the neutron's mass, and the positron's mass, are already known.

2. Hence, by the mass-energy equivalence, along with the kinetic energies in that experiment, both the proton's energy - the neutron's energy - and the positron's energy, are already known.

3. Hence, by the (quasi-)equation
ν
_e +
p⁺
→
n⁰
+
e⁺
, along with the conservation of energy, we receive the anti-neutrino's energy.

4. Hence, by the mass-energy equivalence, we receive the anti-neutrino's mass (Whereas if this mass is not the restmass we can receive the restmass by also considering the anti-neutrino's velocity in that experiment).

Where is the wrong stage? Maybe I'm not allowed to assume the conservation of energy? HOTmag (talk) 07:01, 14 August 2024 (UTC)

The neutrino speed is unknown.  --Lambiam 08:44, 14 August 2024 (UTC)

Unknown yet, but once we discover the anti-neutino's speed, the experiment I've suggested may simply solve the problem of measuring the anti-neutrino's restmass, right?

Additionally, even without measuring the anti-neutrino's velocity, still the quasi-equation
ν
_e +
p⁺
→
n⁰
+
e⁺
, along with the conservation of energy, and with the mass-energy equivalence, do determine the anti-neutrino's relativistic mass, right? HOTmag (talk) 09:39, 14 August 2024 (UTC)

The speed of a neutrino or anti-neutrino is not a physical constant. One may hope to measure it, but should then be aware that it varies with the frame of reference of the observer. In some frames of reference the (anti-)neutrino is at rest.  --Lambiam 22:42, 15 August 2024 (UTC)

I've never said this speed is constant. You said it was unknwon - you referring to the neutrino's varying speed, so I answered it was unknown yet - me referring to the neutrino's varying speed. Anyway, my previous comments still hold. HOTmag (talk) 08:07, 16 August 2024 (UTC)

You cannot measure its speed after it has disappeared in the interaction. If you succeed in measuring a neutrino's speed before the interaction with the positron has taken place, you thereby will have changed its speed. Moreover, how can you know that the particle whose speed you measured is the same particle that disappeared a few nanoseconds later? You can hardly tag it.  --Lambiam 01:30, 17 August 2024 (UTC)

Your first postulate is simply false, per Amble below. Remsense ‥ 诉 09:47, 16 August 2024 (UTC)

Your current indent is simply false, because you're responding to my response to a user other than the one you indicated. By "my previous comments", I referred to my comments to the user I was responding to. HOTmag (talk) 11:01, 16 August 2024 (UTC)

It's false regardless of who you were replying to. Remsense ‥ 诉 11:05, 16 August 2024 (UTC)

What's false? My first postulate? So again, also your indent was false. HOTmag (talk) 11:07, 16 August 2024 (UTC)

The first statement is not "false". Those masses are known, just not with sufficient precision to make HOTmag's proposal a viable way for measuring neutrino masses.--Wrongfilter (talk) 11:33, 16 August 2024 (UTC)

They asked where the flaw in their reasoning was, and if one had to pick a spot, it's that the first point is not the case. Apologies for coming off more pedantic about it than it sounded in my head. Remsense ‥ 诉 11:49, 16 August 2024 (UTC)

Besides the difficulty in measuring the small difference between the neutrino's speed and the speed of light, there's the problem that the neutrino's mass is small compared to the uncertainty on the masses of the other particles. For example, the standard uncertainty on the proton mass is 0.29 eV [14] and the standard uncertainty on the neutron mass is 0.48 eV [15]. These are very small errors in fractional terms, but the neutrino mass is even smaller: the sum of the three neutrino masses is below 0.120 eV (Neutrino#cite_note-Mertens-2016-mν-1). On the whole, an endpoint experiment like KATRIN can achieve much better sensitivity to the neutrino mass. --Amble (talk) 16:04, 14 August 2024 (UTC)

To put it another way, it's not a logic puzzle where each item is either "known" or "unknown". We know all of these things to within some level of uncertainty. In absolute terms, we know the neutrino mass better than we know the neutron or proton mass, or the difference between the two. Therefore, your procedure wouldn't improve our knowledge of the neutrino mass, it would (if anything) improve our knowledge of the proton-neutron mass difference, using our current knowledge of the neutrino mass as a "known" input. --Amble (talk) 16:52, 14 August 2024 (UTC)

In short, OP has proposed a purely logical solution for what remains a purely empirical problem. Remsense ‥ 诉 23:07, 15 August 2024 (UTC)

Yes, in the same vein I could measure the mass of a table tennis ball by throwing it at a known speed at a large wrecking ball and measuring how far the wrecking ball is deflected. Other ways might work better. NadVolum (talk) 10:09, 17 August 2024 (UTC)

August 15

Outdated species names of bees in Nomia and Nomadopsis

I've found a list of bees that the bee fly Heterostylum robustum parasitizes in a book written in 1973, but a lot of them are outdated. The list is: "Nomia bakeri Cockerell, N. triangulifera Vachal; Nomadopsis anthidius Fowler, N. scutellaris Fowler, and Halictus rubicundus (Christ.)." I have suspicions but I can't confirm them and would like to be sure, but can't locate any authoritative resource.

• Nomia bakeri I know has been reclassified as Nomia nevadensis baker ([16]), and I think may be Dieunomia nevadensis bakeri.
• Nomia triangulifera I am guessing is probably Dieunomia triangulifera
• Nomadopsis anthidius I think is Calliopsis anthidia: Calliopsis is a synonym but the second part apparently changed?
• Nomia scutellaris is still valid
• Halictus rubicundus is still valid

Does anyone know how to confirm any of this, or how to source it? Mrfoogles (talk) 07:10, 15 August 2024 (UTC)

• Have you tried asking at WT:WikiProject Insects? Or look at the sources in the taxobox at the bottom of the Nomia (bee) article or the sources in List of Nomia species? Abductive (reasoning) 08:01, 15 August 2024 (UTC)

This page syas: "Calliopsis anthidia - Synonyms: Calliopsis anthidius". Alansplodge (talk) 10:54, 15 August 2024 (UTC)

Also this page: "Dieunomia triangulifera - Synonyms: Nomia triangulifera" using this as a reference. Alansplodge (talk) 10:59, 15 August 2024 (UTC)

Thanks, this worked with a little extra googling for the last sources. Pretty much resolved now. Odd WorldSpecies, sourced to GBIF, has synonym listings it does not. Mrfoogles (talk) 00:20, 16 August 2024 (UTC)

Ancient Greek ὄψις (ópsis) is feminine, so Calliopsis from kalli- + opsis should be considered feminine as well. This means that Calliopsis anthidius (Fowler, 1899) did not conform to the gender-agreement requirement of the International Rules of Zoological Nomenclature introduced in 1905, and was changed to Calliopsis anthidia to make the gender of the specific epithet agree. (Due to an error in the introduction of the genus name Nomadopsis (Ashmead, 1898), this genus name was adopted by some but not accepted universally, which has led to some confusion.^[17])  --Lambiam 11:01, 15 August 2024 (UTC)

I thought it might have something to do with gender -- makes sense. Mrfoogles (talk) 00:32, 16 August 2024 (UTC)

August 17

Transmutation

I'd like to see a video of an element transmuting into another element. I quote Richard Dawkins and Yan Wong in their wonderful book 'The Ancestor's Tale', "The half-life of carbon 15 is 2.4 seconds. After 2.4 seconds you'll be left with half of your original sample. After another 2.4 seconds you'll have only a quarter of your original sample..." I realize that carbon-15 is not something you are going to readily find in a laboratory. I'm guessing it would appear to be sublimating into a gas. Ifyoucrydon'tlose (talk) 11:21, 17 August 2024 (UTC)

Does he say what it transmutes into? ←Baseball Bugs ^{What's up, Doc?} carrots→ 11:24, 17 August 2024 (UTC)

What happens when kids don't get enough sugar?

What happens when kids don't get enough sugar? 2A00:23C5:1C00:C001:8DB5:7D3A:7C98:F54A (talk) 11:24, 17 August 2024 (UTC)