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May 9

Washington Metro

Would a lineside signal have prevented the June 2009 Washington Metro train collision? Or would the same parasitic oscillations which fooled the automatic systems have also given Train 112 a false green light on the lineside signal as well? 73.162.86.152 (talk) 00:36, 9 May 2023 (UTC)

You are asking for speculation as to how a lineside signal would have been controlled if there had been one. We can't do that. --174.89.12.187 (talk) 03:57, 9 May 2023 (UTC)

According to the NTSB report (which I didn't read completely), the cause of the accident was faulty train detection. Train detection is separate from signalling. Choosing lineside signals instead of automatic control doesn't imply a different type of train detection, nor does automatic control imply this particular type of train detection. So, no, a lineside signal wouldn't have prevented this accident. Axle counters instead of track circuits might have, or a different type of track circuits. PiusImpavidus (talk) 18:43, 9 May 2023 (UTC)

You are concluding that if there had been lineside signals, they would have used the same train detection as in the actual system. We can't do that. --174.89.12.187 (talk) 03:46, 10 May 2023 (UTC)

In fact, there is also an implicit assumption in the devout and intrepid editor's contribution that if there had been lineside signals, there would have been trains running on that day. The absence of trains would have meant no collision, so. But IMO it is fair to conclude that, everything else having been the same, the change of control from ATC to signalling control would not have prevented this accident. What might (and likely would) have prevented the accident is not another type of control, but an alternative type of detection. Ultimately, though, all devices can fail, including axle counters.  --Lambiam 07:20, 10 May 2023 (UTC)

Thanks! So, the answer is, it would not have prevented the wreck -- right? (Which is what I thought, too.) 73.162.86.152 (talk) 21:30, 10 May 2023 (UTC)

Largest storm

What was the largest storm? Typhoon Tip is the result that comes up when I look up the question. This is despite the fact this source said that extratropical cyclones can stretch 3000 km and the WMO says the largest tropical cyclones only get to 1000 km. ✶Mitch199811✶ 17:17, 9 May 2023 (UTC)

Depends on how you define the words "largest" and "storm". That's the problem with superlatives; you can get different answers depending on how you tweak the parameters. Typhoon Tip is the largest tropical cyclone ever recorded, but those have fairly well-defined parameters; once you get outside of those parameters, into the realm of Extratropical cyclone, you run into issues that many of these cyclones are not reasonably well defined, nor are many of them "storms" under normal understandings of the word. The strongest (not geographically largest, though) non-tropical storm was the Braer Storm of 1993, but if you just want to know "What is the largest extratropical cyclone ever recorded in terms of geographic extent?" that's probably harder to determine; many if not most of such features are unremarkable weatherwise, bringing some rain and wind, maybe, but nothing you'd call a "storm". Additionally, they don't have well-defined boundaries the way that a hurricane does. Any time you watch the weather on the TV, every one of those big red "L" symbols is the center of an extratropical cyclone. Whatever continent you're on right now there's probably 3-4 over it as we speak. --Jayron32 17:52, 9 May 2023 (UTC)

Are extratropical cyclones the largest storms if they are to be counted as singular storms? ✶Mitch199811✶ 18:06, 9 May 2023 (UTC)

Let's start again. Most extratropical cyclones are not storms, under any reasonable definition of the term. They are rotating masses of air (cyclones) centered on a low-pressure area. That's all they are. Some may have stormy weather, most might have clouds and light showers associated with them. Also, unlike tropical cyclones like hurricanes/typhoons, most are not as well organized and thus don't have well-defined boundaries. We can define the size of something like Typhoon Tip because it is highly organized, and has clearly defined boundaries that we can measure. Most extratropical cyclones are not easily defined, don't have complete cloud coverage, and lack clear boundaries we could even delineate a size of. In summary: we don't define "largest storm" for an extratropical cyclone because 1) most aren't "storms" in the sense that a hurricane is and 2) they aren't as easy to define in terms of extent anyways. --Jayron32 18:44, 9 May 2023 (UTC)

Now, if we're talking mid-latitude storm events, you probably want to look for squall lines, though a quick google search turns up no records kept for "longest squall lines" or anything like that. Continent-spanning squall lines of thousands of kilometers are somewhat rare, but not unheard of. Such squall lines aren't given names like hurricanes or typhoons, and there are no records kept on their size, but they are probably the largest mid-latitude synoptic scale weather systems one could reasonably call "a storm" in the same way you think of a hurricane or a typhoon. --Jayron32 18:52, 9 May 2023 (UTC)

In the winter, nor'easters can get very large, the Ash Wednesday Storm of 1962 is often cited as among the most intense such storms, but I don't know if the cloud cover was bigger than, say, Typhoon Tip. --Jayron32 18:56, 9 May 2023 (UTC)

Now, if Mitch199811 wants to know examples of long squall lines, some of them can be from just an organized line (say, August 2020 Midwest derecho) of storms capable of producing wind damage spanning a couple hundred miles long to QLCS' that span over a thousand miles long. What's neat about extratropical cyclones (especially in the Northeast U.S.,) is that they can drop +24 millibars in order to be classified as a bomb cyclone. About the distance? I would say in terms of distance, Typhoon Tip may be a large storm, but as Jayron32 noted, we can't define it because it is highly organized. Tip was definitely an intense typhoon, though! But in meteorology terms, we don't classify most systems as "storms", like Mesoscale Convective System or Low Pressure Area. Tails Wx 19:25, 9 May 2023 (UTC)

@Mitch199811: Adding to @Jayron32's helpful contributions, you should note that "storm", as well as being a general term for unpleasant weather, has a specific meaning in meteorology. In the part of the world I am in, there are several a year and they are named. Bazza (talk) 18:59, 9 May 2023 (UTC)

And of course there is always the Great Red Spot. Shantavira|^{feed me} 19:04, 9 May 2023 (UTC)

Or geomagnetic storms. ✶Mitch199811✶ 19:08, 9 May 2023 (UTC)

May 10

Why is there meteorites from Mars on Earth bt none from Venus?

why — Preceding unsigned comment added by 115.188.152.213 (talk) 10:19, 10 May 2023 (UTC)

Two reasons I can think of are firstly that Venus has an atmosphere that would stop most things getting in or out, and secondly Venus is in a gravity well compared to Earth, I think a deflection by a close pass to Venus or Mars would be needed in either case but probably the deflection by Mars to go into an orbit near earth would be easier. NadVolum (talk) 10:57, 10 May 2023 (UTC)

Just looking up about this and it seems some people think there may be meteorites which came from Mercury being struck by another large body when it was new and some of the bits could have been pushed out to join the asteroid belt by the solar wind. So solar wind could get bits of Vewnus here too if they could get through its thick atmosphere. NadVolum (talk) 11:08, 10 May 2023 (UTC)

No such meteorites have so far been found (on Earth), but some astronomers have proposed that they could theoretically exist: see for example https://ui.adsabs.harvard.edu/abs/2018DDA....4910202D/abstract.

Of course, most meteorites that have reached the Earth's surface from any source have not been found, since the majority fall into the sea, and on land they can become buried by normal geological processes, and are in any case very rare and difficult to spot amongst all the non-meteoritic rocks; some ice-fields in Antarctica are searched for meteorites because their flow concentrates objects in accessible (if remote and cold) areas and dark rocks are easier to spot on/in white ice.

It has been proposed that Venusian/Cytherian meteorites may be findable on the surface of the Moon (once you're there), which has not had appreciable surface processing for a very long time: see for example https://www.futurity.org/venus-meteorites-moon-2453822/. {The poster formerly known as 87.81.230.195} — Preceding unsigned comment added by 90.199.210.77 (talk) 11:25, 10 May 2023 (UTC)

How would we know if a rock is from Venus? It's not like we have independent samples to match. —Tamfang (talk) 03:17, 16 May 2023 (UTC)

How exactly does the Law of Conservation of Mass apply to expansion?

I heard that pouring hydrogen peroxide on a tick stuck to a leg would cause the tick to swell up as a result of the blood mixing with the hydrogen peroxide. I know that this is a strange series of statements, but how exactly does the Law of Conservation of Mass apply to these two substances, or any two substances that "swell" something? It is to my understanding that there is something that I am, well, misunderstanding. I can't make sense of the reasoning because I have been struggling to find it. Parameci (talk) 19:27, 10 May 2023 (UTC)

Maybe it would be useful for you to articulate more precisely what exactly you think is in tension with conservation of mass in this particular scenario. The only thing I can see is that the tick gets bigger, but you've both added stuff to the tick and the stuff itself is becoming less dense, so I don't see any conflict there. If you could help us understand your thought process better we might be able to help more. --Trovatore (talk) 19:37, 10 May 2023 (UTC)

If it helps, the weight of the tick remains the same, from just before it starts swelling up until is all swollen up. Foam takes up a lot of space but does not weigh much.  --Lambiam 20:18, 10 May 2023 (UTC)

(edit conflict) I suspect this relates to density, for example, heating a balloon will cause it to expand, while not changing its mass. In the tick's case, hydrogen peroxide produces O₂ bubbles when in contact with blood (specifically, the enzyme catalase); these bubbles might form in the tick causing it to expand (?). --136.56.52.157 (talk) 20:29, 10 May 2023 (UTC)

Yes, I believe it is density I am thinking of. To clarify knowing this is about density now (thank you!), what allows the dioxygen produced to rapidly exceed the tick's limits? Is this a matter of scale and volume? Parameci (talk) 21:52, 10 May 2023 (UTC)

I haven't tried this, but I suppose the H₂O₂ permeates the blood sac membrane (alloscutum), and if the tick has already gorged to near max capacity, then the reaction (as described here) produces oxygen gas which expands, thus causing the critter to burst (not a pleasant image to imagine, tbh), 136.56.52.157 (talk) 05:58, 11 May 2023 (UTC) ... To more directly answer your question, the chemical reaction sort of rearranges the atoms to form different molecules, one of which is a gas. The result has the same mass because the same atoms are there, but the O₂ molecule, being a gas, expands since gas is less dense than liquid or solid, therefore the overall density decreases as the volume increases.

One mol of hydrogen peroxide (H₂O₂) produces one mol of dioxygen (O₂). The molar mass of hydrogen peroxide is 34 g/mol and the density at 20 °C is about 1.45 g/cm³, so the volume of one mol is 34 g / (1.45 g/cm³) ≈ 23.5 cm³. The molar mass of dioxygen is 32 g/mol and the density at STP is about 1.43 g/L, which means that it is about 1.33 g/L at 20 °C. So the volume of one mol of dioxygen is about 32 g / (1.33 g/L) ≈ 24 L = 24,000 cm³. The expansion in volume is thousandfold.  --Lambiam 11:30, 11 May 2023 (UTC)

May 11

Artificial gravity on Haven-1

The California based startup Vast has announced that they are going to launch a small space station to Low Earth Orbit. According to the press materials on their homepage (vastspace.com), they will have "Opportunities for lunar artificial gravity by spinning." They also say that the station will have a diameter of 3.8 m. This would require a rotational speed of 0.654 0.9248 radians per second. At that speed, would the Coriolis effect be noticeable enough to be troublesome? Would passengers be able to jog around around the circumference of the station without flying towards the center or being pushed too hard against the wall? Puzzledvegetable^{Is it teatime already?} 00:42, 11 May 2023 (UTC) + edit (forgot to convert diameter to radius) --Puzzledvegetable^{Is it teatime already?} 04:46, 11 May 2023 (UTC)

This sounds very dubious to me: with that diameter (12 feet 5 inches in imperial), if internal, a 6-foot tall person standing upright would have their head only 3 inches below the centre of the capsule, effectively at zero-g and spinning at 12 rpm – even sitting down would be seriously disorienting. I notice they are offering "Opportunities for lunar artificial gravity by spinning" (my underscore: did you factor that into your calculation?), which suggests the artificial gravity would not be present all the time, and unless they are proposing a spinning chamber inside a non spinning outer hull, I can't see how such a spin would be compatible with efficient operation of the solar panels shown in the illustrations. {The poster formerly known as 87.81.230.195} — Preceding unsigned comment added by 90.199.210.77 (talk) 01:13, 11 May 2023 (UTC)

Can you post the exact link where the diameter is discussed? ←Baseball Bugs ^{What's up, Doc?} carrots→ 02:11, 11 May 2023 (UTC)

It's listed directly on the homepage at vastspace.com. If you scroll to the diagram of the station and select the "specs" menu, you should see it right there. They also have a page where they go into further detail about their plans for artificial gravity stations (which appears to be their primary focus), located here: https://www.vastspace.com/roadmap. They confirm on this page that the Haven-1 station will use artificial gravity at least some of the time. Puzzledvegetable^{Is it teatime already?} 02:51, 11 May 2023 (UTC)

It says "over 7 meters in diameter". The 3.8 you mention (which is not in that link) could be the radius. ←Baseball Bugs ^{What's up, Doc?} carrots→ 04:10, 11 May 2023 (UTC)

The starship-class station that they are planning to launch in the 2030s is 7 meters in diameter. The Haven-1 mission, which is planned for 2025, will use a different station, also called Haven-1 (I think, the terminology is confusing) that is 3.8 meters in diameter. The 3.8 number, as well as the rest of the specs for Haven-1, are listed directly on the website homepage. The URL for that is vastspace.com Puzzledvegetable^{Is it teatime already?} 04:37, 11 May 2023 (UTC)

I linked to that page and I don't find any "3.8". ←Baseball Bugs ^{What's up, Doc?} carrots→ 11:17, 11 May 2023 (UTC)

I'm not sure what to tell you. I see it on the homepage. It might look different based on screen size or something. Puzzledvegetable^{Is it teatime already?} 11:58, 11 May 2023 (UTC)

I don't see that illustration on the page, but I'll take your word for it. ←Baseball Bugs ^{What's up, Doc?} carrots→ 13:03, 11 May 2023 (UTC)

The speed of the outer wall (square root of (acceleration times radius)) is about equal to ordinary walking speed, so if you walk one way, you'll be weightless, if you walk the other way, you'll feel four times lunar gravity – at your feet; your head will be weightless either way. So to astronauts, it will be very unlike real lunar gravity. It could still be useful for smaller and slower things. For example, you could make sure your espresso machine works in lunar gravity, which is of vital importance to espresso addicted moon travellers. PiusImpavidus (talk) 08:40, 11 May 2023 (UTC)

vacuumbnb -- Verbarson  ^talk_edits 19:41, 11 May 2023 (UTC)

May 12

Genus in Animalia with the most species.

i need to know.

I hope you are not in a hurry. There are many genera in Animalia. There are probably several thousands of genera in the class Insecta alone. Also, most species have not yet been described, so any answers can only be provisional. Camponotus, comprising over 1,000 extant species, may be a candidate for the title.  --Lambiam 09:52, 12 May 2023 (UTC)

Googling your query led me to the Wikipedia article Agrilus as the first link, the sole prose sentence of which states "Agrilus is a genus of jewel beetles, notable for having the largest number of species (about 3000) of any single genus in the animal kingdom." --Jayron32 11:44, 12 May 2023 (UTC)

Be aware that any such count of species (or even genera) is subject to debate between lumpers and splitters. There really isn't any way to get a definitive answer.--User:Khajidha (talk) (contributions) 21:36, 12 May 2023 (UTC)

Storm Shadow for Ukrainian Air Force

The Storm Shadow article says this: "The UK government announced in May 2023 that export Storm Shadows were "going into" or already supplied to the Ukraine military during fighting following the Russian invasion of Ukraine from 2022. Can these be carried by the Ukrainian Air Force's MiG-19s and Su-27s, or does it need western jets to use them? Thanks. 86.187.161.178 (talk) 18:43, 12 May 2023 (UTC)

They haven't announced how they will launch it, but it will surely be integrated with Ukraine's existing aircraft (as announcing western jets would be a much bigger deal yet). This story claims Su-24 and Su-27 could carry it (from a payload perspective). Whatever aircraft, it's unlikely they will integrate it into the aircraft's own weapons systems - when Germany inherited the GDR's Mig-29s, they elected not to adapt them to carry NATO ordnance (as the cost was too high, and they'd be retiring them pretty soon), so they kept the Warsaw Pact ordnance they had which worked with the 29s. When Ukraine received HARM anti-radiation missiles and deployed them on its Mig-29s, they apparently had some kind of jury-rigged iPad-like thingy in the cockpit (perhaps some adaptation of existing diagnostic or training software). They could do that with HARM because it's pretty clever. Similarly, as that article I linked above says, Storm Shadow can be programmed on the ground (again with whatever maintenance gubbins the RAF already has for it) and the carrier aircraft doesn't have much to do. This loses flexibility, but the Ukrainians will surely get so few Storm Shadows, they'll be using them very carefully and conservatively. This effectively makes the carrier aircraft into a "bomb truck", that does little more than fly to a designated place and chuck out its smart munitions, which go off on their own and do the work they were preprogrammed for. -- Finlay McWalter··–·Talk 19:50, 12 May 2023 (UTC)

errrrm, "from a payload perspective" I guess you mean they are not too heavy? But these things need pylons or rails to carry and launch them? How on earth can the ancient avionics system of the MiG-29s be upgraded to allow Storm Shadows to be integrated? Perhaps they will also get n iPad-like thingy in the cockpit! lol. 86.187.161.178 (talk) 19:58, 12 May 2023 (UTC)

Yes, I mean weight. Someone will have had to make an adapter for the pylons. And I think (but no-one will say publically) they they won't try to do any integration at all, beyond the iPad thingy. Which is like having a GPS glued to your car windscreen (hey, like a Russian su-25 already does) rather than the nice built-in one from the manufacturer. This is a duct-tape based war. -- Finlay McWalter··–·Talk 20:05, 12 May 2023 (UTC)

Yes. Too bad the Storm Shadow is a bit too heavy for a drone to carry. But a real different strategy for the Ukrainians - from light and flexible to heavy and precision. They will be able to takeout major ordnance depots and supply logistics centers with these. Especially if, as Prigozhin says, the Russians have started to run away. But I guess Ukrainian Air Force can't say much more about the Storm Shadows, as sources will be hard to find. 86.187.161.178 (talk) 20:14, 12 May 2023 (UTC)

We don't know how many Storm Shadows the UK has supplied, and what specific range and geofence restrictions they may have. It's surely not a large number (a few dozen, maybe). But fear of the Storm Shadows must surely engender a change in Russia's behaviour, which alone could be of benefit to Ukraine. The missiles may now (or may soon) threaten air and navy bases in Crimea, and the Kerch Bridge. Russia may feel it wise to either withdraw forces from there, or to move air defence systems there (perhaps from the front lines). HIMARS/GMLRS forced Russia to move its command locations back, and disperse its logistics operations - both of which threaten efficiency and effectiveness. Similarly, the Ukrainian drone attack on Engels-2 airbase reportedly caused Russia to redeploy strategic bombers away from there (a Ukrainian source). So the threat of Storm Shadow might be more effective than the relatively few things Ukraine can actually destroy with them. -- Finlay McWalter··–·Talk 21:36, 12 May 2023 (UTC)

This video (by the Ukrainian Airforce) purports to be a Ukrainian Mig-29 firing a HARM in anger, and shows some interesting stuff in the cockpit. It seems the "iPad like thingy" is mounted (in some shots, not all) to the head-up-display frame (in the top-middle of the dashboard), and some shots briefly show its colour display. To the right of that is what appears to be a civilian aircraft GPS unit with a monochrome LCD screen. Somewhat comically, when the Mig fires its 30mm cannon, the vibration makes the GPS fall off, presumably leaving it banging around the pilot's feet. Anyone who has ever had a car GPS with a suction cup mount has surely experienced the same problem. -- Finlay McWalter··–·Talk 19:31, 13 May 2023 (UTC)

Although the central thingy does not appear to change when the first HARM is fired, and is missing entirely when the second one is. So maybe it's not the secret sauce (filming that would seem a bit reckless) but some other kludgy gadget. -- Finlay McWalter··–·Talk 19:36, 13 May 2023 (UTC)

True. Firing my car's 30mm cannon causes all sorts of problems. Iapetus (talk) 10:08, 15 May 2023 (UTC)

An extreme example of the "bomb truck" idea is the Rapid Dragon (missile system) idea - it's just a pallet of smart munitions (in that example, JASSM cruise missiles, which are quite similar to Storm Shadow) that they literally shove out of the back of an unmodified cargo aircraft (in uncontested airspace). The JASSMs are dispensed from the pallet and fly off. The cargo aircraft contributes only the work of moving the missiles to a convenient place to start their journey. Frankly, for all we know, Ukraine could be doing likewise with an adequate cargo aircraft like a Antonov An-26. -- Finlay McWalter··–·Talk 19:56, 12 May 2023 (UTC)

Wow that does sound dumb. But I guess if they have been programmed on ground where to go, that's the easiest way to deploy them. But you won't get a pallet onto a MiG-29, etc. haha. 86.187.161.178 (talk) 20:01, 12 May 2023 (UTC)

Even dumber was the Argentinian Air Force in the Falklands War that just rolled conventional 500lb bombs out of the back of a C130 Hercules transport onto a ship that they thought was part of the British task force, but turned out to be a civilian Liberian tanker. Fortuantely the bomb bounced off. [1] Alansplodge (talk) 12:49, 13 May 2023 (UTC)

Note that, last spring, American engineers quickly kluged U.S.-supplied High-Speed Anti-Radiation Missiles onto Ukrainian MiG-29s and Su-27s. Storm Shadow might be even easier to integrate than HARM was. MBDA’s predecessors designed Storm Shadow for ease-of-use in what Italian air force test pilot Enrico Scarabotto described as “an incredibly low pilot workload cockpit environment.”... All that is to say, a pilot doesn’t have to do very much to launch a Storm Shadow except deliver it to an initial point that the missile recognizes. Thus the work of integrating Storm Shadow onto a new plane type mostly involves installing a physical interface — a pylon — and testing the plane-missile pairing to make sure there are no aerodynamic surprises. Ukraine Should Have No Problem Arming Its Old Soviet Jets With New British Cruise Missiles Alansplodge (talk) 15:30, 13 May 2023 (UTC)

Yes, an excellent source there. Also this: "Most of the work of programming a Storm Shadow takes place on the ground, before a mission. Technicians use Storm Shadow’s Data Programming System to tell the missile where to strike and at what angle. ... Storm Shadow navigates toward GPS coordinates, but corrects its course by scanning the terrain passing below it and matching it to known features. As it approaches its target, the missile pops open its nose to reveal an infrared seeker scans for the target’s heat profile—and guides the weapon to impact." 86.187.236.117 (talk) 08:57, 14 May 2023 (UTC)

Ben Wallace comments on integration 1:19:21. fiveby(zero) 01:43, 14 May 2023 (UTC)

---

References

May 13

Life expectancy and DNA repair

Is there a study on a correlation between life expectancy of life forms and their ability to repair DNA? 2A02:908:424:9D60:410D:5:DD2C:326F (talk) 20:51, 13 May 2023 (UTC)

There are many studies demonstrating a correlation. There's a causality problem; species (or populations) that are selected for long lives have generally better or more active DNA repair mechanisms, but are likely to have evolved them in response to the selection for long life spans. Us humans are already maxed out on all known life-extending genes, alleles, pathways, etc. No intervention will increase our lifespans, unlike those tried successfully in mice and fruit flies. Abductive (reasoning) 21:14, 13 May 2023 (UTC)

@Abductive Do you have a reliable source for that last sentence? Life expectancy says "there is no evidence for [a] limit on human lifespan". Mike Turnbull (talk) 15:15, 14 May 2023 (UTC)

that should read no evidence for a "hard" limit... Abductive (reasoning) 17:16, 14 May 2023 (UTC)

So the apparent fact that everyone dies is merely anecdotal? ←Baseball Bugs ^{What's up, Doc?} carrots→ 16:39, 14 May 2023 (UTC)

A Source would be great. 2A02:908:424:9D60:F060:FADC:D109:CB60 (talk) 16:07, 14 May 2023 (UTC)

The source is, every hyped discovery in the lay media in mice or fruitflies, followed by it already maxed in humans in the scientific literature. Abductive (reasoning) 17:16, 14 May 2023 (UTC)

As a lifelong follower of science news (and a former science textbook editor), I am familiar with the first half of your assertion, but not the second. Can you give us two or three specific examples of relevant discoveries that were found to be "already maxed in humans in the scientific literature."? {The poster formerly known as 87.81.230.195} 90.199.210.77 (talk) 06:50, 15 May 2023 (UTC)

Try superoxide dismutase. Abductive (reasoning) 18:39, 15 May 2023 (UTC)

May 14

Odd glasses effect

Trolling
The following discussion has been closed. Please do not modify it.
So I just got new glasses. The prescription seems to be right - because I can actually read what I am typing here. But the shape of anything that is circular, like the top of cup for example, is changed to an upright oval. I have never experienced this before. What is causing this? Will this damage my eyesight? 86.187.236.117 (talk) 09:00, 14 May 2023 (UTC) WP:NOMEDICAL All that can be suggested is reading our existing articles such as Corrective lens, Eyeglass prescription or Astigmatism. Martin of Sheffield (talk) 09:24, 14 May 2023 (UTC) Thanks. Do you know if this topic is mentioned in any of those articles? 86.187.236.117 (talk) 09:26, 14 May 2023 (UTC) I can't say. Read the topics if you want to, but for real advice see an optician. There's no point is asking for more help here, we are not allowed to give any, see the notice above. Martin of Sheffield (talk) 09:56, 14 May 2023 (UTC) "Wikipedia is not an optician". Too bad. I was hoping Jimmy Wales could fit me in for a quick eye test at 9am on Monday. I'm not sure why you are recommending those articles if you don't know what's in them. What if I had framed the question like this: "Sometimes spectacles can distort shapes by making circles appear as ovals. How does this happen?" I thought the answer might be a simple one. But thank you for replying anyway. 86.184.26.97 (talk) 10:20, 14 May 2023 (UTC) Standard prescription eyeglasses, that is, not meant to correct for any other issue than myopia or hyperopia, should not change the subjective experience of the aspect ratio. Look with one eye through one glass at a circle. Rotate your glasses (but not your head). Does the oval rotate with them? Then the effect is due to your glasses. You should refer to either the optometrist who wrote the prescription, or the optician who dispensed your glasses. If the prescription was not intended to also correct for some other issue, something is wrong with the glasses. If the prescription was intended as a correction, it appears to be working; you'll get used to it in a week or so.  --Lambiam 11:44, 14 May 2023 (UTC) Yes, the oval rotates if I rotate the glasses. It's not being caused by my eyes, obviously! You mean this distortion is common with glasses that have a new prescription and this will disappear in a week or so? Is that written down in some Wikipedia article? Thanks. 86.184.26.97 (talk) 11:54, 14 May 2023 (UTC) We are urging the OP to consult their optician without knowing whether "just got new glasses" was on personal prescription or by guesswork. A common spherical lens does not change its image distortion when it is rotated. An exception is a progressive or graduated prescription lens whose Optical power varies smoothly from top to bottom. This type of lens distorts strangely when rotated and it is prescribed exclusively for use right-way-up by the one person (often elderly) who was examined by their optician. Human Visual perception is a process that unconsciously corrects for many distortions (including the obvious distortion of the physical image on the retina being upside down) and it is learned over time. This means that a distortion apparent with new spectacles depends on how one previously viewed the world i.e. one can become so habituated to view through a distorting lens that the undistorted view without a lens seems wrong. To the OP: for the advice you seek, please do consult a qualified Optician who will be aware of these factors as they may apply in your case. Philvoids (talk) 13:39, 14 May 2023 (UTC) The general incompetence demonstrated by this particular optician over the previous six months suggests to me that they don't really know what they are doing. Or that they have a very unreliable supplier. They originally offered to re-glaze my expensive titanium Stepper frames and recommended varifocal lenses. Then, after a delay of over two months, they managed to get those frames "lost in the post". When I was able to choose alternative new Stepper frames, the glasses that came back were unusable for working at my computer terminal - there was only a tiny area of adequate magnification right at the bottom of each lens. They offered to "adjust" the fitting - but when they came back again, weeks later, they were just as bad. Having decided to forget about varifocals, they made up single prescription glasses and these now turn circles into ovals. I'll not be going back to that optician again. But thanks again for the advice. And yes, I realise that "Wikipedia is not an agony aunt." 86.184.26.97 (talk) 17:15, 14 May 2023 (UTC) My question was a genuine one. I wanted to know if the optician was likely to be at fault, or if it is a common phenomenon. I still don't know. But I suspect that there is no answer to that question at Wikipedia. But my question is now labelled as "trolling". I'll ask elsewhere next time. 86.184.26.97 (talk) 17:56, 14 May 2023 (UTC)

You're a banned user. Go away. ←Baseball Bugs ^{What's up, Doc?} carrots→ 18:12, 14 May 2023 (UTC)

May 15

ToC to me

Is it just me, or is this Science Desk the only refdesk that doesn't have a ToC? 136.56.52.157 (talk) 06:43, 15 May 2023 (UTC)

Good eye! Now that I use Vector2022, I don't see the TOC unless I intentionally look for it, and that's not something I usually do on the RefDesks. Now we just need to figure out why... DMacks (talk) 07:04, 15 May 2023 (UTC)

Sorry, I had missed this discussion. § Odd glasses effect above used to include WP:NOMEDICAL, and WP:NOMEDICAL apparently contains (by including Template:Disclaimer header) the "magic word" __NOTOC__ which suppresses the table of contents on *this* page. Should be fixed for now. Tea2min (talk) 08:30, 15 May 2023 (UTC)

Thx.

Resolved

 – 136.56.52.157 (talk) 16:10, 15 May 2023 (UTC)

Parrot and kittens

This video just turned up in my Youtube recommendations. Anyone have any idea how this happened? Iloveparrots (talk) 08:38, 15 May 2023 (UTC)

Hmmmmm, Iloveparrots, if you take a look at your own username, you should get some powerful clues. Cullen328 (talk) 08:43, 15 May 2023 (UTC)

lol, it's true - I have a pretty good idea *why* that vid turned up in my recs. Was really meaning to ask if any one knew how a litter of kittens could end up being brooded by a parrot... Iloveparrots (talk) 08:59, 15 May 2023 (UTC)

• Why do animals adopt?
• RESEARCHERS PONDER WHY ANIMALS ADOPT OTHER SPECIES’ ORPHANS
• Why Animals "Adopt" Others, Including Different Species

Wikipedia doesn't seem to have a relevant article; perhaps a project for somebody? Alansplodge (talk) 09:49, 15 May 2023 (UTC)

It's mentioned in Interspecies friendship#Protection: "This is often observed in interspecies adoptions in which a member of one species 'adopts' a member of another that is orphaned or hurt." Clarityfiend (talk) 00:00, 16 May 2023 (UTC)

living species most distanty related to another living species

living species most distantly related to another living species and is closing living relative — Preceding unsigned comment added by 115.188.134.165 (talk) 08:55, 15 May 2023 (UTC)

Monotypic taxon might be what you want but I'm sure the differences in more ancient groups are far higher than in the plants and animals shown there. NadVolum (talk) 09:59, 15 May 2023 (UTC)

• In terms of land vertebrates, I think that Rhynchocephalia (Tuatara) is the only monospecific order, while among sea vertebrates, class Actinistia is has two living species, both in genus Latimeria, making it a monogeneric class. In terms of gymnosperm plants, Ginkgoales is an order with only one extant species, the Ginkgo biloba. --Jayron32 12:08, 15 May 2023 (UTC)

Parakaryon myojinensis seems to be neither eukaryotic nor prokaryotic, and it is known from only a single sample of one cell. --Amble (talk) 21:13, 15 May 2023 (UTC)

Would this seltzer taste different?

There's apparently one seltzer factory left in New York. [2] Would you expect their product to taste any different from commercial seltzer? Do their customers pay for nostalgia or a unique drink? Thank you. Imagine Reason (talk) 10:10, 15 May 2023 (UTC)

As stated in the big blue box above, we don't answer requests for opinions, predictions or debate. Shantavira|^{feed me} 10:23, 15 May 2023 (UTC)

Having a magnetic field without an electric field.

A magnetic field can exist without an electric field if there is motion of charged particles but no net charge. An electric field can exist without a magnetic field if there is no motion of charged particles. Without the electric field, the magnetic field exists in permanent magnets and also with current-carrying conductors, and without magnetic field, electric field exists in charges at rest.

However, is it possible to create a magnetic field without an electric field, and without a magnet? 67.173.182.93 (talk) 22:46, 15 May 2023 (UTC).

Juices industry.

Do large companies that produce fruit juices, do they buy fruit from the farms and juice them, or do they harvest their own fruit in their own farms, to juice them? Tropicana, Minute Maid, Ocean Spray, etc. Or can it also depend on the fruit? Although I am from USA, I will accept non-USA answers too. I'm wondering if a large corporation can sometimes do both. Thanks. 67.173.182.93 (talk) 22:48, 15 May 2023 (UTC).

I'm not aware of large companies owning fruit farms. (In South Africa). Farmers and juice companies tend to stick to their core business. Farmers have no use for a juicing factory for a major part of the year - while the fruit matures. Juice companies have no use for orchards for the same reason. They will source seasonal fruit from other farmers in other parts of the country. Some farms do have roadside stalls that sell in-season juice on a small scale. 41.23.55.195 (talk) 05:24, 16 May 2023 (UTC)