Wikipedia:Reference desk/Science

Welcome to the science section
of the Wikipedia reference desk.

skip to bottom

Select a section:

• Computing
• Entertainment
• Humanities
• Language
• Mathematics
• Science
• Miscellaneous
• Archives

Want a faster answer?

Main page: Help searching Wikipedia

   

How can I get my question answered?

• Select the section of the desk that best fits the general topic of your question (see the navigation column to the right).
• Post your question to only one section, providing a short header that gives the topic of your question.
• Type '~~~~' (that is, four tilde characters) at the end – this signs and dates your contribution so we know who wrote what and when.
• Don't post personal contact information – it will be removed. Any answers will be provided here.
• Please be as specific as possible, and include all relevant context – the usefulness of answers may depend on the context.
• Note:
  • We don't answer (and may remove) questions that require medical diagnosis or legal advice.
  • We don't answer requests for opinions, predictions or debate.
  • We don't do your homework for you, though we'll help you past the stuck point.
  • We don't conduct original research or provide a free source of ideas, but we'll help you find information you need.

Ready? Ask a new question!

How do I answer a question?

Main page: Wikipedia:Reference desk/Guidelines

• 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.

See also:

• Teahouse
• Help desk
• Village pump
• Help manual

April 24

What is more epinephrine agonist, tricyclic antidepressants (such as Amitriptyline), or tetracyclic antidepressants (such as Mirtazapine)?

Thanks. 2A10:8012:15:C48E:4400:7673:DFF0:2D67 (talk) 02:18, 24 April 2023 (UTC)

I saw one article (PMC 5715313) that states: "The SSRIs and other atypical antidepressants (eg, trazadone, mirtazapine, bupropion) do not have significant epinephrine or ephedrine interactions (Figure 4)." In another article specifically about mirtazapine (PMID 30085601), epinephrine is not mentioned in a list of drugs known to interact with mirtazapine. I do not know if this can be generalized to tetracyclic antidepressants in general.  --Lambiam 05:58, 24 April 2023 (UTC)

April 25

Infinity and zero

A number divided by zero, and a number divided by infinity.

Some Maths teacher are saying undefined, some maths teachers are saying infinity as answer. 2402:3A80:1C46:7462:508:3708:7AE5:926D (talk) 06:29, 25 April 2023 (UTC)

It depends on the context. We have an article on division by zero, which goes into some detail.

The short answer is that, for the ordinary sort of numbers you encounter in school, you can't divide by zero, and infinity is not one of those ordinary sort of numbers at all.

For other sorts of numbers and other notions of division, the answer may be different. See if the linked article helps.

For future reference, we have a mathematics reference desk. --Trovatore (talk) 06:33, 25 April 2023 (UTC)

Infinity is not a number. ←Baseball Bugs ^{What's up, Doc?} carrots→ 11:18, 25 April 2023 (UTC)

As Trovatore noted, it depends on what system you're working in. In the real numbers, infinity is not a number, but in the extended reals, infinity and negative infinity are both numbers. CodeTalker (talk) 15:04, 25 April 2023 (UTC)

What is infinity minus 1? ←Baseball Bugs ^{What's up, Doc?} carrots→ 16:45, 25 April 2023 (UTC)

In the extended reals, infinity minus one is still infinity. If you want to know more, I suggest reading the article CodeTalker linked. --Trovatore (talk) 17:05, 25 April 2023 (UTC)

As with anything mathematical (or really, and human created endeavour) whether something like "treating infinity as a number" or "treating division by zero as infinity" or whatever boils down to 1) is it useful 2) does it break the system we're working in. If the answer to 1) is "yes" and the answer to 2) is "no" then by all means, use it that way. There's all kinds of workarounds to these problems, such as limits, that allow us to do things like treat the limit of division by progressively smaller numbers as approaching infinity, thus for some meanings of "is equal to" we can treat something like 1/0 = ∞ as a meaningful concept. There are other contexts where 1/0 = (undefined) may make more sense. Similarly, we may treat infinity as a number (or at least, as a point on the number line somewhere out there too far to reach) in certain contexts where it is useful to do so. For example, This visual proof of the Basel problem uses the notion of a circle of infinite radius, so that there is some point, infinitely far away, at which the number line would "wrap around" and come back again. Using limits in a rigorous way one can say this without introducing any particular contradictions. --Jayron32 17:22, 25 April 2023 (UTC)

I recall in high school math, decades ago, where the teacher said you could invent something he called "R*", in which you have an object called "infinity". That's what the so-called "extended reals" are doing. ←Baseball Bugs ^{What's up, Doc?} carrots→ 17:45, 25 April 2023 (UTC)

Yes, I believe R* (or perhaps R^*?) is one of the standard names for the extended reals, though our article does not report it (the article gives ${\overline {\mathbb {R} }}$). You have to be a little careful because some of this nomenclature gets overloaded. For example I think (this is from memory) R* can also mean the multiplicative group of the nonzero real numbers. --Trovatore (talk) 18:04, 25 April 2023 (UTC)

R^* might use projective infinity (a single point at infinity, rather than separate positive and negative infinity). That is also usually how it is done when extending the complex plane to include infinity. 2601:648:8200:990:0:0:0:BC0F (talk) 19:18, 25 April 2023 (UTC)

Note in passing that, in the extended reals, you still can't divide by zero, for sort of a silly-seeming reason: You have $+\infty$ and $-\infty$, and they're different. So which one should ${\frac {1}{0}}$ equal? Because if ${\frac {1}{0}}=+\infty$, then you should have ${\frac {1}{-0}}=-\infty$. But $0=-0$, so that's a problem.

You can fix it in several ways.

• You can make $+\infty$ and $-\infty$ the same, so that the reals "circle around" at the point at infinity. That gets you what Wikipedia calls the projectively extended real line; I'm not sure this name is really standard
• You can do the same thing on the complex numbers, getting the Riemann sphere
• Or you can cut the Gordian knot by getting rid of the negative numbers, and look at the structure $[0,\infty ]$ of nonnegative reals plus a point at infinity. I don't know a name for this structure, but it's implicitly used a fair amount, especially in measure theory

In any of those structures, you can divide anything by zero except zero itself (${\frac {0}{0}}$ is still undefined), and get infinity (in particular ${\frac {1}{0}}=\infty$). --Trovatore (talk) 18:32, 25 April 2023 (UTC)

Thanks for adding formalism to some of my points above. I'm more of a recreational mathematics person, and while I understand the broader concepts, I lack the training to have the formal language to express it. --Jayron32 18:52, 25 April 2023 (UTC)

There are many infinities, of which the smallest is aleph-null. MinorProphet (talk) 21:36, 27 April 2023 (UTC)

While there is a sense in which that is true, in this context it is more likely to confuse than enlighten. Aleph null (like all aleph numbers) is a cardinal number, which means it is a measure of the cardinality (size) of a set. The infinities being discussed in this thread are points on the extended real number line, and have little relation to aleph numbers. In fact, our article on aleph null, which you linked to, says The aleph numbers differ from the infinity (∞) commonly found in algebra and calculus, in that the alephs measure the sizes of sets, while infinity is commonly defined either as an extreme limit of the real number line (applied to a function or sequence that "diverges to infinity" or "increases without bound"), or as an extreme point of the extended real number line. CodeTalker (talk) 01:55, 28 April 2023 (UTC)

Zerowater filter

A friend in an area with horrible tap water just got one of these. It purports to remove almost all of the dissolved solids from the water. Can anyone say how it manages to do that? I thought it was impossible to remove solutes by filtration, and you needed to distill the water or separate it with reverse osmosis. Is it possible to desalinate water with filters? Thanks. 2601:648:8200:990:0:0:0:BC0F (talk) 19:21, 25 April 2023 (UTC)

See ion-exchange resin which can remove metal ions, but may be not so great at removing chloride. Graeme Bartlett (talk) 22:12, 25 April 2023 (UTC)

What I would like is a good way to get rid of chloramine, which may indeed be a little safer than free chlorine from a public-health perspective, but has a very offensive taste. Bulky activated-carbon filters do work for a while but need to be replaced and seem wasteful. My workaround is to add a small dash of ascorbic acid powder, which I suppose reduces the chloramine to ammonium chloride (?), but it has its own taste and it's hard to tell whether it's really removing the chloramine or just covering it up. --Trovatore (talk) 23:12, 25 April 2023 (UTC)

Articles: water filter, point of use water filter, total dissolved solids. No, filtration can remove at least some contaminants. Here are listings from NSF International of filters certified by them for reduction of various contaminants.

Here's the problem with salt water: there's salt, and a lot of it. Total dissolved solids § Water classification: Drinking water generally has a TDS below 500 ppm. Higher TDS Fresh Water is drinkable but taste may be objectionable. Salt water by comparison is defined as having TDS of at least 10,000 ppm, orders of magnitude higher. Consumer filters are designed to filter fresh water; they will fail pretty quickly trying to handle salt water. I mean, in a sense you can think of a reverse osmosis membrane as just being an elaborate filter, that requires energy to force the water through it. Indeed, they even get "clogged" over time and require maintenance procedures to clean out buildup. RO and distillation are simply the most feasible ways to desalinate large quantities of water. A problem being the hypersaline brine produced by the solutes left behind, and here illustrating how much more "stuff" there is in salt water. Your typical consumer filter just traps contaminants within the filter itself; eventually it can't hold any more and then it needs replacement. --47.155.41.201 (talk) 23:38, 25 April 2023 (UTC)

Zerowater's website lists test results and notes that the filters have a limited capacity.[1] DMacks (talk) 19:49, 30 April 2023 (UTC)

April 26

Naming of UV absorbers

I noticed that for UV absorbers, the names are usually composed of the trade name of the product line and a number. Examples:

• Tinuvin 320 - Chisorb 320 - Sumisorb 320 ... [2]
• Tinuvin 770 - Sanol 770 - Uvaseb 770 ... [3]
• Tinuvin P - Uvazol P - Benazol P ... [4]
• Tinuvin 328 - CHISORB 328 ... [5]
• Tinuvin 360 - Milestab 360 ... [6]

In all of the above cases, there is also a name of the following schema: UV-320, UV-770, UV-P, UV-328, UV-928. I didn't find any information on such a naming convention among that industry. Are these somehow non-proprietary names, so that they may used without breaching property rights of companies? 2001:67C:10EC:574F:8000:0:0:1B1 (talk) 20:14, 26 April 2023 (UTC)

Perhaps a number like 360 refer to a point of 360 nm in the UV spectrum below which the UV absorption rate of the material meets some set standard. UB-770 would then cover not only the UV spectrum but also the visible spectrum.  --Lambiam 16:47, 27 April 2023 (UTC)

April 27

Translating a presumed typo

I'm working on an article about a series of bombings in 1970s California. The first news article I've found with any level of detail about the bombs says that an IRS (Internal Revenue Service) investigator thinks the bomb was "probably made of amtho and dynamite." Any ideas about "amtho" in this context? TIA! jengod (talk) 01:28, 27 April 2023 (UTC)

It's gotta be referring to ammonium nitrate. Abductive (reasoning) 01:57, 27 April 2023 (UTC)

Ah, now that I clicked the link, probably ANFO misheard by a reporter. Abductive (reasoning) 02:00, 27 April 2023 (UTC)

Oh that looks like a winner. Thank you v much Abductive for your contribution to this episode of Wikipedia Cold Case Detectives LOL. :) jengod (talk) 02:08, 27 April 2023 (UTC)

Melanoma and Parkinson's Disease

A paper published in 2009 says:

there appears to be an increased risk in the development of melanomas in patients with PD [Parkinson's Disease]... It is not known which factors are responsible for this increase in the development of melanomas in PD patients and this needs further investigation.

Has such investigation occurred? What is the up-to-date view? -- Andy Mabbett (Pigsonthewing); Talk to Andy; Andy's edits 11:33, 27 April 2023 (UTC)

Yes:

Brief overview from above sources {Perplexity.AI) --136.56.52.157 (talk) 12:36, 27 April 2023 (UTC)

Discussion continued at Talk:Parkinson's disease. SandyGeorgia (Talk) 13:42, 29 April 2023 (UTC)

References

What's the point of green hydrogen?

If we get our hands on electricity, which we can use to heat, move vehicles, run devices, generate light, and so on; why would we go the route of putting it into electrolysis (some loss through heat), losing some of it to compress the hydrogen, lose more of it through inevitable leaks, some more through accidents, then lose more of it at the end point? And maybe even transform it into electricity again!

Wouldn't it be much easier to electrify the whole chain instead of "hydrogenize" it? Bumptump (talk) 16:03, 27 April 2023 (UTC)

Electric car batteries require large amounts of somewhat rare metals, such as lithium, nickel and cobalt. Even setting aside concerns over the environmental and human-rights impact of mining for these, we may simply not be able to produce enough in time to cater for the needs of the transition from fossil fuel to other power sources.  --Lambiam 16:19, 27 April 2023 (UTC)

Hydrogen fuel cells are a non-greenhouse-gas-emitting means of powering automobiles, which is the primary use case for hydrogen. The problem with automobiles is they need a means of storing enough energy to allow them to travel a reasonable distance (something in the 200-300 mile range) to be a viable fuel source. The current non-emitting source is storage batteries, but those have issues and externalities of their own, including the problems in extracting, refining, and using the raw materials to build them, and on the flip side, in recycling or disposing of them when they are at the end of their life cycle. Fuel cells are an alternate way of doing the same thing, but have less issues than batteries do; the main problem with hydrogen currently is the lack of any infrastructure to deliver hydrogen in terms of fueling stations. Even battery charging infrastructure, while still lacking, has been much easier to set up than an entire hydrogen storage-and-delivery infrastructure. Indeed, that barrier to entry, more than anything else, is the main problem with hydrogen. --Jayron32 16:35, 27 April 2023 (UTC)

The idea of storing the supply in the vehicle between charges relates to the energy density--how much energy you can get from a given mass or volume of "cylinder of H₂" vs "battery". That article I linked has some data tables and related discussion. DMacks (talk) 18:13, 27 April 2023 (UTC)

Also important is efficiency. If hydrogen is half as energy dense as, say, gasoline but twice as efficient in terms of losses not used in propelling the vehicle, the effects cancel. --Jayron32 18:22, 27 April 2023 (UTC)

Renewable energy sources are generally intermittent. Solar panels produce nothing at all half of the time (when it's night) and almost nothing another quarter of the time (when it's overcast). Wind is slightly better. Spreading your solar panels and wind turbines over a large area helps a bit, but this area has to be pretty big with big transmission lines going all over the place.

So to ensure that at least 80% of the time your renewable energy sources produce all that you need, you have to install far more production capacity than your typical demand, so that a large fraction of the time your producers produce far more electric power than needed. You can either shut down some solar panels and wind turbines, wasting some potential production, or spend it on some inefficient process, not wasting it entirely. Making hydrogen may be inefficient, but it's better than not using the energy at all. The hydrogen can then be used to produce some electricity when intermittent production is low. Hydrogen may be inefficient storage of electricity, but it's better than no storage at all, and doesn't require the expensive raw materials of batteries.

Furthermore, hydrogen is an important feedstock for the chemical industry and can be used as energy source for mobile applications, in particular ships. There have been some experimental hydrogen-powered fixed-wing aircraft, but storage volume is an issue. Airships can afford the volume to store it at standard pressure and temperature, but airships aren't very practical. Hydrogen lorries could be useful, avoiding heavy battery packs that eat away much payload capacity. Or just add overhead wires to the motorways, so that electric lorries can recharge their last-mile batteries on the move. Hydrogen powered trains are silly. Just use overhead wires; most trains do so already. PiusImpavidus (talk) 19:46, 27 April 2023 (UTC)

Basically two things: storage and transportation.

Storage: E.g. if you have solar energy you need a way to store it if you want to use it when the sun doesn't shine. The same goes for wind energy when there is no wind.

Transport: The renewable energy source is not always where the energy is needed. E.g. you could place solar panels in the desert. But then you need a way to transport the energy. That can be done via hydrogen pipelines or transport vehicles. -- Random person no 362478479 (talk) 19:49, 27 April 2023 (UTC)

Hydrogen powered trains do have a sensible use where there is an infrequent service over a long distance. The capital cost of installing the overhead (or third rail) and the transmission losses can become ridiculous for one railcar per day. Today diesel, tomorrow perhaps hydrogen? Martin of Sheffield (talk) 22:02, 27 April 2023 (UTC)

Maybe, but at one railcar per day, why use rail at all? Now, maybe someone in the past handed you a non-electric railway, in days when that made sense at that location, and maybe there's a sweet spot in traffic density and distance where hydrogen outperforms overhead wires, batteries and road transport, but this would be so rare that your average railway company has one hydrogen railcar, one spare and one mechanic who knows how to fix it. I doubt it's worth developing new technology for that. PiusImpavidus (talk) 09:06, 28 April 2023 (UTC)

One useful thing is to use it to make easily transportable and widely used ammonia. There's a lot of taxpayer money being spent on green hydrogen, hence the enthusiasm from some people. Greglocock (talk) 22:57, 27 April 2023 (UTC)

Hydrogen as energy storage is probably not going to be a big thing for the reasons discussed. However hydrogen is used for lots of other stuff, and right now it's mostly produced by steam reforming of natural gas, because this is the cheapest way currently. Doing this via some method that doesn't contribute to global warming is preferable. (One use: speaking of electricity did you know large turbogenerators are generally filled with hydrogen for coolant and insulation? Though apparently a lot of that is produced by electrolysis already as-needed.) --47.155.41.201 (talk) 04:45, 29 April 2023 (UTC)

April 28

Vertigo

Is acrophobia amenable to treatment by exposure therapy, or does it require more invasive treatment (like anti-anxiety drugs, intensive psychotherapy, etc.), or maybe it's not amenable to treatment at all? (Not medical advice -- I suffer from mottaphobia (or, more precisely, papiliophobia or even more precisely, papilioglaucophobia), not acrophobia, and in any case this question was inspired by the film Vertigo.) 2601:646:9882:46E0:C6F:1E80:4BE5:575F (talk) 08:39, 28 April 2023 (UTC)

Vestibular rehabilitation therapy (VRT) is one such treatment.^[7] --136.56.52.157 (talk) 08:58, 28 April 2023 (UTC)

That is a therapy for vertigo, a condition in which the world seems to spin, also for patients at ground level. This condition is unrelated to acrophobia, "fear of heights".  --Lambiam 17:47, 28 April 2023 (UTC)

The OP seems confused about this. They asked about acrophobia, but the header is Vertigo. -- Jack of Oz ^{[pleasantries]} 20:43, 28 April 2023 (UTC)

Right, because that's the name of the movie which inspired the question -- so it wasn't me who was confused, it was Hitchcock! 73.162.86.152 (talk) 02:44, 29 April 2023 (UTC)

This is the first time that that movie has been referred to in this thread. -- Jack of Oz ^{[pleasantries]} 22:01, 30 April 2023 (UTC)

Not so -- I referred to it in my original post, how come you didn't notice? 73.162.86.152 (talk) 21:56, 1 May 2023 (UTC)

In Latin, vertigo is a non-medical term for "giddiness", such as may be experienced when gazing down from a great height or after imbibing a great deal of wine (or both). In English the term occurs as a non-medical term borrowed from Latin in the general sense of "giddiness"^[8][9][10] as well as the medical term for a specific condition, usually caused by a problem in the vestibular system.  --Lambiam 11:36, 29 April 2023 (UTC)

A meta-analysis of the efficacy of different interventions for acrophobia, including "VR coach-delivered psychotherapy", "in vivo exposure augmented with oppositional action" and "VR exposure therapy with 20 mg cortisol administration", found that these were "significantly superior than the placebo/control interventions", with "VR coach-delivered psychotherapy" (a term not further defined or explained in the article) being ranked as the most effective intervention for acrophobia.^[11] However, in the concluding section, the authors warn that the overall evidence was not sufficiently strong for this conclusion. So, apparently, exposure therapy for treating acrophobia is given in different forms that are at least somewhat effective.  --Lambiam 12:41, 30 April 2023 (UTC)

Thanks! So, there are some promising treatments, but these are somewhat more involved than ordinary exposure therapy (such as me looking at pictures of tiger swallowtails to get over my own phobia of them, which has been somewhat effective so far, at least in the case of the smaller Papilio rutulus), and they're not quite sure just how effective these treatments are yet -- right? 73.162.86.152 (talk) 21:56, 1 May 2023 (UTC)

Unusual bird call

I’ve recently heard a bird call I’ve never heard before, I was hoping someone may recognise it by description as I’ve not been able to get it on recording. It’s a short, sub-1 second, guttural deep warbling type call that essentially sounds like someone gargling mouthwash. It’s coming from a copse of mixed deciduous trees near my home. I live in the south west of the UK on a tidal estuary. The only bird I’ve visually identified in the copse is a group of jackdaws but not seen it to be them that make the noise. Googling it just brings me male brown cowbird but on YouTube comparison the cowbird is far too high pitched and too quiet, and I think are only found in the USA. This call is really loud. Thoughts? 2A02:C7F:2C68:D500:B5B4:AFF3:7763:AD63 (talk) 09:33, 28 April 2023 (UTC)

Jackdaws and rooks often roost together, and your description does sound vaguely corvid. Try an online birdsong identifier such as https://www.british-birdsongs.uk/ - if you're in the South West UK it could also be a carrion crow or a raven. Turner Street (talk) 09:46, 28 April 2023 (UTC)

Could it be a toad? Andy Mabbett (Pigsonthewing); Talk to Andy; Andy's edits 16:30, 28 April 2023 (UTC)

A fair question! But if it is it’s a toad that can throw its voice to the top of a cedar tree! I’ll YouTube some Corvid calls and see what comes up. 2A02:C7F:2C68:D500:5F:1DB4:4B22:FD1E (talk) 19:05, 28 April 2023 (UTC)

Heard it again this evening. It’s like someone talking underwater, or for a more niche reference it sounds like Richard Nixon shaking his jowls in Futurama… — Preceding unsigned comment added by 2A02:C7F:2C68:D500:30A4:1EAB:F159:428E (talk) 20:07, 28 April 2023 (UTC)

I managed to get a clip of it. You’ll have to turn the volume up a bit. Ignore the chirp at the very end, that’s something else and it was too close to the call I’m trying to ID to cut out. It’s the lower pitched, more guttural call I’m trying to identify. Here is the video 2A02:C7F:2C68:D500:5D4D:A32D:F2BF:F282 (talk) 06:56, 29 April 2023 (UTC)

MYSTERY SOLVED!! It’s a Little Egret. We finally spotted them. Never seen them in trees before. 2A02:C7F:2C68:D500:296A:F26B:CEF5:2400 (talk) 19:40, 30 April 2023 (UTC)

Harmless smoke

From what I've read it appears that every smoke and vapour (except possibly water vapour) is harmful to humans, regardless of its source (including herbal cigarettes). Is there a known substance whose burning would produce a harmless smoke/vapour in terms of inhalation? Or does burning in itself always inherently produce a toxic smoke, regardless of source? 212.180.235.46 (talk) 17:46, 28 April 2023 (UTC)

Any smoke has a complex composition because the high temperature facilitates chemical reactions that result in a large number of chemical compounds. Many of them will be toxic. So, yes any smoke is highly likely harmful. As to vapour: this term can be used for the gaseous phase of any chemical. So, a vapour many be harmless: oxygen, nitrogen, hydrogen, carbon dioxide etc. Ruslik_Zero 20:55, 28 April 2023 (UTC)

We have an article on theatrical smoke and fog which discusses how smoke effects can be obtained safely. Mike Turnbull (talk) 21:36, 28 April 2023 (UTC)

Burning itself tends to produce toxic chemicals. When you burn something organic at a few hundred degrees Celsius (like when people are smoking, or in a burning building), you get incomplete combustion, which produces a large number of different chemicals, many of which are toxic (expect some PAHs), along with some carbon monoxide. At higher temperatures and plenty of air, combustion tends to be more complete, but now you get NOx. PiusImpavidus (talk) 10:35, 29 April 2023 (UTC)

This being the Science desk, it intrigues me that Control of fire by early humans tells us that our ancestors have been deliberately using fire for maybe 2 million years, yet in modern times we seem to have discovered a lot of ways in which it does us harm. I would love to see discussion on those negative effects over those 2 million years. HiLo48 (talk) 00:44, 30 April 2023 (UTC)

Today's 8 billion people can produce a lot more smoke than 100,000 people could some 100,000 years ago.  --Lambiam 05:01, 30 April 2023 (UTC)

Moreover, with the low life expectancy of early humans, the adverse implication of smoke breathing, aside from straight-out suffocation, were practically non-existent. Zarnivop (talk) 15:32, 1 May 2023 (UTC)

Some aerosols are not produced by combustion, though. David10244 (talk) 06:13, 30 April 2023 (UTC)

Neurology: How does a Lobotomy affect the Patients Religiousity ?

Well, the USA has practiced Lobotomy intensivly in the 50s and is also a very religious country. Also Medical sites are ofter Churchrun or even staffed by Nuns. This means, that a Patient who had a Lobotomy certainly has encountered Religion. Was there any Notable change ? As Lobotomy does (as Dr. Freeman himself putted it) "Smash abstract thinking", and abstract thinking is important for Religion, you would expect them to loose faith, or at least ignore abstract concepts like Trinity and focus on nonabstract things, like Crosses, Jesus and the like. However, a Lobotomy also may reduce intelligence, and the Churches are often into Antipsychiatry, so some might turn to Religion even more. Also, the most interesting Question is: Has a Lobotomy ever been performed on a Salafist (maybe in a black site ...) ? Since Salafists hate everything nonabstract, you would expect them to completely lose touch with Islam. --87.168.89.233 (talk) 20:50, 28 April 2023 (UTC)

The effects seen on people who survive the procedure are unpredictable and random, but generally not for the better. The impairment is often completely debilitating, requiring permanent care taking of the patient.  --Lambiam 08:53, 29 April 2023 (UTC)

May 1

Changing the speed of light, when the medium is not a perfect vacuum.

Is it possible to exert forces, on light moving in a medium that is not a perfect vacuum, for example in water, in order to change the speed of light in that medium?

If it's impossible, then why ? After all, as we know, it is possible to apply forces that slow down - or accelerate - massive bodies, so why is it impossible to apply such forces also to the light when it moves in water etc., so that the forces will make the light move (in water) at a slower speed, for example at the speed at which light moves when it's in glass? Or so that the forces will make the light move (in water) at a faster speed, for example at the speed at which light moves when it's in the air? 2A06:C701:747E:800:D855:A0F7:59BA:AFAB (talk) 18:35, 1 May 2023 (UTC)

So, the thing about all of the physics involved is that the speed of light is invariable, full stop. That's part of what general relativity says; any "acceleration" supposedly experienced by light (whether changing direction or speeding up/slowing down) is not an acceleration, it's spacetime curvature. Light being "slowed" in a material is due to interactions with the photons with particles of the medium, see Speed of light, to wit "This type of behaviour is generally microscopically true of all transparent media which "slow" the speed of light..." Light still travels in the space between, say, atoms and molecules, at the speed of light, however interactions between photons and the atoms themselves results in the apparent speed of light to slow, photons move in straight lines at the speed of light; however the apparent speed at which light waves move through a medium is slowed due to quantum interactions between the photons and the particles of the medium. When you say "the speed of light in water" what you are saying is "the speed light appears to move in water due to quantum interactions between photons and atoms" or some such, the light itself, insofar as it is actually traveling, still moves at "c". --Jayron32 18:54, 1 May 2023 (UTC)

It is not completely true as speed of light in matter can exceed the speed of light in vacuum. Ruslik_Zero 20:13, 1 May 2023 (UTC)

What? it seems you confuse photons with electrons (in Cherenkov radiation). 2A06:C701:747E:800:D855:A0F7:59BA:AFAB (talk) 20:50, 1 May 2023 (UTC)

Fizeau experiment may be relevant. catslash (talk) 21:34, 1 May 2023 (UTC)