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August 15

Would 1368x208x208 of solid wood sway more than a skyscraper? Or collapse easier?

Dimensions are the aboveground portion in feet, belowground part is let's say 208x208x208 feet with half in soil and half in strong bedrock but just a tight fit mating, not glued, piledriven or otherwise attached. Wood type, grain direction, part of tree, lumber dimensions is strongest possible, skyscraper is Manhattan code, not supertyphoon and strong earthquake resistant like Taipei. Does it depend if fastening is skillful nailing, skillful screwing, skillful gluing (thin layer only) or skillful piece interlocking (like pagodas, no fasteners whatsoever)? Can it have a stairway big enough for a man to reach the roof or even some rooms too and still be strong enough? It would of course remain a useless fire risk that might rot unless exposed faces are sealed. Sagittarian Milky Way (talk) 02:36, 15 August 2020 (UTC)[reply]

This question sounds vaguely familiar. In any case, we have List of tallest wooden buildings, and it's possible you could branch out from there to find more info. ←Baseball Bugs ^{What's up, Doc?} carrots→ 05:09, 15 August 2020 (UTC)[reply]

The strength of solid wood in compression seems to be a few tens of megapascals, which for a density of 1, should support a few hundred meters.. There are trees around 100 meters high too. Anyway with your 400 meter building you are close to the limit for many kinds of wood, where it would fail under load. The stiffness of wood is about 8 to 12 gigapascals, if you can workout how that would sway, but I would expect a solid bar of wood like you suggest would be stiff. I guess that you could build a stairwell space inside and even rooms without them collapsing. if you glued many laminates to make a 208 foot thick plywood, that would do the job! to see what happene if wood is over loaded see https://www.youtube.com/watch?v=deWKSD6KBzQ Graeme Bartlett (talk) 06:01, 15 August 2020 (UTC)[reply]

On first reading I thought you (SGM) meant a solid wooden block of some 60 million cubic feet, which would sequester a lot of carbon. But I assume you envisage an assembly of wooden trusses. The rather unpredictable effects of spontaneous wood warping, at this scale, might cause a wooden structure to deform sufficiently to cause rupture of elements due to various stresses, such as the bending moment caused by gravitational forces due to asymmetric bending, even without the effects of wind or quakes. The dimensions of the structure are almost equal to those of One World Trade Center. It should be able to accommodate plenty of spacious boardrooms while leaving enough space for umpteen wide stairways. Does the floor plan have to be square, or can it be circular? The latter should be a lot easier to calculate through. (Not that I'm going to attempt this; too much depends on the specifics of the design for a back-of-the-envelope calculation.) --Lambiam 06:18, 15 August 2020 (UTC)[reply]

So no hollow space is more likely to work. Would a 2496 by 2496 (like a 2 by 4 but bigger) 1576 feet long work if it could exist? I'm not sure what's the most fair way to extrapolate a width and height that cannot exist for a non-fungible substance with a concentric tube grain. Presumably megapascals would decrease with size from the nanoscopic defects in all materials. Sagittarian Milky Way (talk) 23:49, 15 August 2020 (UTC)[reply]

Gravity and fatigue

I'm aware of the known issue of muscular deterioration in space, requiring regular physical exercises. But, on the other hand, would humans experience less fatigue in a low-gravity environment (roughly comparable to that on Mars or Moon), particularly due to less strain on muscles (such as when standing) and due to less muscular effort required for many movements and tasks? Thanks. 212.180.235.46 (talk) 17:55, 15 August 2020 (UTC)[reply]

Immersion in shallow water, reaching to say the neck of the patient, has been used for revalidation therapy of injuries of the locomotion system, such as sprained ankles and ruptured muscles. By Archimedes' principle, the immersion results in a considerable loss of weight (not of mass), putting less strain on muscles, joints, etcetera and thereby facilitating certain exercises. The point is not to reduce fatigue and I don't know if anyone has studied this. Wading through water, in spite of the reduced weight, takes more effort for the same distance than walking on flat terrain. Walking on the Moon (at about one sixth of Earth's gravity) and on Mars (at about three eighths of Earth's gravity) should be easier than wading through water but will still require the walker to adjuat their gait, especially on the Moon. People who actually walked on the Moon reported no difficulty in moving around, though.^[1] Walking on flat Earth terrain does not require one's muscles to work "against" gravity like they need to do when walking up a ramp; so in that respect the reduction in effort is not large. To travel a larger distance it may be easier to hop or jump-run than to walk "normally" (Earth-style). This may require a similar energy per unit of time, but less for the same distance bridged. In the end it may depend on the specifics of the activities. Push-ups will definitely be easier. --Lambiam 19:15, 15 August 2020 (UTC)[reply]

A quick Google revealed that fatigue in space is a big issue because of the difficulty of getting sufficient sleep. [2] Alansplodge (talk) 13:43, 16 August 2020 (UTC)[reply]

Is moving while in water a good comparison with moving in a low-gravity environment? I would have thought the physical effects are quite different, despite the reduced weight similarity - for a start, someone moving through water is working against a medium of much greater density than air, so I would expect the effects on muscles to not be wholly comparable. PaleCloudedWhite (talk) 14:27, 16 August 2020 (UTC)[reply]

Above I wrote: "Wading through water, in spite of the reduced weight, takes more effort for the same distance than walking on flat terrain." This indeed establishes that when it comes to moving "from A to B" immersion in water is not a good model for walking in a low-gravity environment? But what about fatigue reduction "due to less strain on muscles (such as when standing)", which was part of the question? --Lambiam 17:24, 16 August 2020 (UTC)[reply]

Wading through water is hard because you have to displace a large mass of water. Because the wannabe astronaut is moving (water) sideways, gravitational force plays no role here, but inertial mass does. This seems to be an unsurmountable problem, because any medium dense enough that humans float in it, is by consequence massive. 93.136.48.85 (talk) 03:28, 17 August 2020 (UTC)[reply]

[Edit Conflict] Unfortunately, there are no good comparisons available, as simulating a lower gravity environment within a higher one is extremely difficult. Water immersion has proved a useful preparation for zero-g working because the water resistence somewhat mimics the effects of wearing an inflated spacesuit in a vacuum.

For low- (but not zero-) g conditions, elaborate systems of suspending people on carefully calibrated springs and harnesses from an overhead freely-moving framework have been tried by the Mars Society and others with questionable success (for one thing, they cannot mimic the effects of lower gravity within the body), and a modified parabolic flight path on the "Vomit Comet" to yield a low- rather than zero-g environment must surely have been tried, but would be limited both spacially and temporally.

Unfortunately the Mars Gravity Biosatellite program has been discontinued. Artificial gravity may include some further pointers. {The poster formerly known as 87.81.230.195} 2.122.61.94 (talk) 17:43, 16 August 2020 (UTC)[reply]

Chemical Sensors: New fields of study and application

Hi I have seen the description of the said topic but I wanted to get updated with latest advancements in this field of study, the field of chemical sensors is large I wanted to know about those sensors which detect chemical compounds or elements in traces and thir cost dependence i.e. which type are most costly. thank you.

regards. — Preceding unsigned comment added by 120.57.38.139 (talk) 18:28, 15 August 2020 (UTC)[reply]

I assume you have read the section Chemical sensor of our article Sensor. A freely available source is the e-book version of Progresses in Chemical Sensor, and another (non-free, somewhat older) text is Chemical Sensors and Biosensors: Fundamentals and Applications. The journal Chemical Reviews had a special issue last year devoted to the topic. (Accessing the contents requires an institutional login.) This Google Scholar search will produce references to recent scholarly contributions to the field.

As to the issue of cost, that is not something that can be answered in general terms. If depends crucially on the specific chemical or family of chemicals that needs to be detected as well as the desired detection threshold. --Lambiam 20:37, 15 August 2020 (UTC)[reply]

Is a more space-efficient genetic molecule possible and/or a less convoluted genetic molecule to diverse amino acid-strings system..

..that still allows easy copying and turning sperm and ova genetic molecules into an alloy molecule with half info from each and a human-like mutation rate? Too rare a mutation is suboptimal too right? Can we skip some steps with better molecules? Why can't we have a ribosome-like organelle that can work on copies of the genetic molecule directly? (besides RNA genomes only working at tiny mutation reduction-friendly scales and Earth abiogenesis only happening once so we have to use whatever worked first whether optimal or not, and that it also has to bootstrap itself from primordial soup while it is not implausible that the optional genetic molecule requires an intelligent designer who doesn't seem to exist to make the first cell)

And is an organic genetic molecule possible that can store a human genome of information in less volume and still allow easy copying, reproductive gene shuffling, a human-like mutation rate and a not more convoluted way to turn genes into unattached strings of at least 20 amino acid types? Some kind of polymer or double helix with physically smaller phonemes perhaps, or a nucleic acid system with 6 or 22+ base types and 33 or 67 percent less bases. Could such systems even be chemically possible? I don't care much whether a better system can evolve from primordial soup by itself (no one could know probably), I'm just wondering if it would work. Sagittarian Milky Way (talk) 23:11, 15 August 2020 (UTC)[reply]

Synthetic biology investigates such questions on xeno-nucleic acids and related alternatives. Google Scholar indicates that there are thousands of papers on the subject. You may also look at viroids who may be "fossils" of an ancient acellular biotope. Hypothetical types of biochemistry may provide some useful references. --194.166.102.61 (talk) 05:54, 16 August 2020 (UTC) Oops, forgot to log in. --Cookatoo.ergo.ZooM (talk) 05:55, 16 August 2020 (UTC)[reply]

By the way why do you think that a more space efficient genetic molecule should be / have been an advantage? Or messenger-DNA instead of messenger-RNA? And what if ribosomes could operate directly on genes without the copying step? Would this not be an advantage? Or maybe not? A more 'space efficient' code would also possess less redundancy, thus probably allowing less efficient error correction, for example.

We can think that no other system has existed and competed with our DNA/RNA/20 aminoacids system, but we don't know. Maybe thousands of different systems have existed and only the really best-of-the-best one has survived. 2003:F5:6F0C:E600:4528:4457:E96E:9CF (talk) 10:00, 16 August 2020 (UTC) Marco PB[reply]

Wouldn't 6 base types and maybe smaller phonemes (not A, C, G, T or U) and/or thinner molecule spines still allow repeats for redundancy and be able to curl into a smaller chromosome? It may not be better but it'd be aesthetic. Sagittarian Milky Way (talk) 14:33, 16 August 2020 (UTC)[reply]

More code letters would request for a more complex and error prone t-RNA system, beside that redundance doesn't reside in repetition alone. Maybe molecular machines that process DNA such as helicases, recombinases and polymerases cannot be much smaller and still function resp. they could not process smaller NAs. And first of all, why do you think that smaller chromosomes should be a bonus? As far as I know only some viruses with huge genomes have any problem getting it into the capsid, but most nuclei are small in comparison with the cells that host them but large in comparison with the genome they support. 2003:F5:6F0C:E600:4528:4457:E96E:9CF (talk) 15:08, 16 August 2020 (UTC) Marco PB[reply]

So the current system might be pretty good after all. Sagittarian Milky Way (talk) 15:14, 16 August 2020 (UTC)[reply]

See Base pair#Unnatural base pair (UBP), which I found via a link from Synthetic genomics. DMacks (talk) 15:18, 16 August 2020 (UTC)[reply]

"Or messenger-DNA instead of messenger-RNA? " Messenger-DNA would probably be too stable to be useful. Remember, mRNA is read and disassembled quickly. It's basically a genetic post-it note. The structure of DNA is more durable than that of RNA. Making mDNA would be like leaving a note for your husband saying "buy milk" on high quality parchment.--Khajidha (talk) 12:16, 17 August 2020 (UTC)[reply]

Is tDNA possible? But too parchment-like probably. Sagittarian Milky Way (talk) 17:27, 17 August 2020 (UTC)[reply]

I think we are mixing here two very different questions: 1) are such fantasy biochemistries possible? Yes, why not? A genome out of marshmallow would code information just as well and instead of aminoacids some completely different molecules could also build up suitable structural bricks and catalysts. But 2) would such alternatives give some advantage to the life form using them? Here I dare to be skeptical. On one side it is true that every time one particular solution has taken a foothold, other solutions maybe just as good or even better don't find any more room to develop. But on the other side: 3.5 billions years and 1 billion cubic kilometers of water that is an awful lot of time and place for experiments, and I do believe that if for example DNA would give a messenger just as good as mRNA, then at least some form of life would exist that use mDNA.

So I do repeat my question to Sagittarian above: in your opinion, what kind of advantage would smaller chromosomes or different aminoacids offer to any form of life on this planet? 2003:F5:6F08:AF00:F87A:34E2:BFA7:387C (talk) 19:05, 19 August 2020 (UTC) Marco PB[reply]

One of those links led me to Glycol nucleic acid where the sugar skeleton is just a 3-carbon string. Sagittarian Milky Way (talk) 00:53, 17 August 2020 (UTC)[reply]

How to accelerate plastic biodegrading

I don’t really understand the biodegradablity of plastic. I live at high altitude. I did scan the articles. If I managed to greatly limit my plastic from retail purchases, could I accelarate the biodegration by putting them on my balcony in the winter to make them brittle, and leave them there during the summer to be hit by high altitude ultraviolet? But does that just turn it into powdery plastic? Also, is powdery plastic just as bad pollution as plastic bottles? Is there a next step, maybe mixing it with food waste, that would further biodegrade it? (I realize my project as currently envisioned would be pretty impractical, but the answers could still help in other ways).Rich (talk) 23:17, 15 August 2020 (UTC)[reply]

You may be able to feed your plastic to meal worms, Waxworm or termites which may have bacteria in their guts to eat some plastics. I would guess that most people will not have the space to photodisintegrate plastic. If you are going to do that you may as well use mirrors, and catalysts to speed it up, but why not just burn them if you a re trying to turn them into water and carbon dioxide? Half burning oxidation may yield something that bacteria can munch on better. Graeme Bartlett (talk) 06:39, 16 August 2020 (UTC)[reply]

Biodegradation in landfills does not immediately release the carbon dioxide into the atmosphere, which is a reason to not just burn plastic waste. Carbonization might be something to look into.^[3] --Lambiam 07:57, 16 August 2020 (UTC)[reply]

Not an answer to the question, but here is something about additives that speed up plastic photodegradation. It does not address the issue that you end up with microplastic powder or flakes that you don't want to wind up in the oceans. If the residue goes to landfills and the plastic was biodegradable to start with, I'd be surprised though if a thorough preliminary break-up does not aid in the process. --Lambiam 07:57, 16 August 2020 (UTC)[reply]

Well, would rendering plastic into smaller than nanoplastic, ie ”picoplastic” powder (the size of large proteins maybe)much finer than we currently see be possible? One would think such small particles would be much more “vulnerable” to sunlight and chemical reactions. (But with the large amount of plastic on earth, would the large amount of whatever those chemical reactions would be, be harmful to life?Rich (talk) 18:32, 17 August 2020 (UTC)[reply]

Those pico plastics would be very easily eaten by bacteria, as they have a large surface area and can be easily ingested. Bacteria that degrade crude petroleum would be like to consume plastic so small it would be in solution. Graeme Bartlett (talk) 00:49, 18 August 2020 (UTC)[reply]

August 17

Is it possible any of the 100 billion humans has acquired infection resistance for too many things?

Or at least someone in contrived future scenario when you can 3D-print any wild or invented germ you want dead, live or weakened and be acquiring many immunities at once at all times till you're 100 years old?

What would happen if you try to make the immune system remember too many things? The blood gets thick with antibodies and memory cells? Number of memory thingies in body level off before they cause serious problems, at the cost of reducing the effectiveness of some acquired immunities or losing some entirely? Which memory thingies get reduced first? Those for mild or easy to fight germs?Ones that haven't been used in a long time? Everything reduced equally? Protections are cut in some sort of suboptimal pecking order? (like how Jenner's cowpox was temporary but you'll never get the sane exact cold again?) Protections are cut at random?

2. How many new germs can the immune system learn at once? If it's not numerous enough then it may not be arithmetically possible for even a 130 year old immune system to have seen too many strains. Sagittarian Milky Way (talk) 17:23, 17 August 2020 (UTC)[reply]

While memory B cells can survive for a long time, they do not survive forever. The mass of an antibody (an immunoglobulin molecule) is about 250×10⁻²⁴ kg. A ballpark figure for the total mass of the red blood cells in the human body is 540×10⁻⁶ kg. That leaves room for an awful lot of antibodies before they begin to contribute significantly to the protein content of the blood. --Lambiam 07:47, 18 August 2020 (UTC)[reply]

Animals such as goats and deer, that go foraging around and eating garbage and stuff, have ridiculously powerful immune systems. Maybe even more for scavengers, bats, etc. I do wonder how much it affects their general health. Like if you have that much learned immunity going on, maybe it can make you more prone to autoimmune disorders? I know it is possible to acquire allergies, which are basically false-alarm immune responses. 2602:24A:DE47:BB20:50DE:F402:42A6:A17D (talk) 08:35, 19 August 2020 (UTC)[reply]

It's worth considering that other animals can have different strategies for immune response and protecting against infection. Bats, for example, don't do much of an inflammation response to viruses, and use different antiviral strategies to us. These strategies result in viruses evolving to counter them, including needing faster cell to cell transmission rates. SARS-CoV-2 likely evolved many of its properties that are so dangerous to us as a response to bat immune response. --OuroborosCobra (talk) 19:02, 20 August 2020 (UTC)[reply]

August 18

"Understanding the Quantum World"

There is an advertisement in the Science News mag of Aug 15 2020 about this title which is a DVD. I wonder if anybody is familiar with it. I am mostly interested if it is a popular book or has some mathematical foundation like Roger Penrose's "The Road to Reality?" Thanks, AboutFace 22 (talk) 14:22, 18 August 2020 (UTC)[reply]

Is it this one? If so, that's associated with a series known as The Great Courses. As far as I know, they use actual college professors to teach their video courses. --Jayron 32 15:42, 18 August 2020 (UTC)[reply]

Yes it is. The author is Prof Erica Carlson from Purdue University but I still want to hear from someone who had a chance to look inside. Thanks, - AboutFace 22 (talk) 16:06, 18 August 2020 (UTC)[reply]

There are tons of video lectures on these subjects on youtube, enough that I wouldn't think of buying a DVD unless I had reason to think it was exceptionally good, or the lecturer was someone I particularly wanted to listen to, etc. If you want to learn the subject with some rigor, you're also probably better off reading a book than watching videos. 2602:24A:DE47:BB20:50DE:F402:42A6:A17D (talk) 08:39, 19 August 2020 (UTC)[reply]

Irukandji jellyfish defense mechanism

Apparently the sting from Carukia barnesi is barely perceptible. The symptoms are delayed and can appear as much as two hours later. [4] What is the motive for such a defense mechanism? (As opposed to a bee or hornet sting which immediately signals "go away, I can hurt you") Or are humans little affected initially because they're much bigger than the jellyfish's usual predators? 95.168.121.117 (talk) 17:13, 18 August 2020 (UTC)[reply]

Courtesy links: Irukandji syndrome and Carukia barnesi. --Jayron 32 18:05, 18 August 2020 (UTC)[reply]

Also, as an aside, evolution doesn't have motives. It just has things that work or don't. If the defense mechanism didn't keep predators away long enough to be passed on to offspring, it wouldn't have evolved. There is no motivation. There are just random changes that either work to increase survivability of genes or those that don't. --Jayron 32 18:07, 18 August 2020 (UTC)[reply]

The sting of a jellyfish is not just a defense mechanism, it's also the means by which they immobilise or kill their prey. In both cases it's optimised (subject to even further natural selection) for the marine creatures they interact with frequently, rather than the very occasional land mammal with a very different metabolism that a very few of them might accidentally encounter once in a blue moon, so in such land mammals (i.e. us) their sting's effects are of no importance to the jellyfish one way or another. The fact that these effects happen often to be very painful and/or harmful for us is just our bad luck. {The poster formerly known as 87.81.230.195} 2.123.25.153 (talk) 19:20, 18 August 2020 (UTC)[reply]

One could argue that our having not evolved an immunity or resistance to jellyfish stings is for the same reason. ←Baseball Bugs ^{What's up, Doc?} carrots→ 22:13, 18 August 2020 (UTC)[reply]

August 19

A "car-sized" asteroid

This Sunday, A car-sized asteroid made the closest Earth flyby a space rock has ever survived. The scariest part was that it was undetected. If it collided on Earth, what sort of impact would it have made? Of course, the effect would depend of whether it hit on land or sea, and it would partially burn up in the atmosphere. The asteroid responsible for meteor crater, Arizona, was relatively^* small (about 50 meters across). --2606:A000:1126:28D:4010:D10A:69ED:7785 (talk) 01:31, 19 August 2020 (UTC)[reply]

The Chelyabinsk meteor was larger, with a diameter around 20 meters. The other main variables are its velocity and the angle at which it impacts the atmosphere. The shallower the angle, the more time before it can impact the ground, which makes it more likely to break up or explode in an air burst. --47.146.63.87 (talk) 05:14, 19 August 2020 (UTC)[reply]

A 4-meter rock would probably produce a brief light trail as it disintegrates in the atmosphere. Bigger rocks buzz the Earth every couple of days; see e.g. spaceweather.com "Near Earth Asteroids" table. Every now and then a bored newspaper editor has nothing better to do than write a clickbait story about one of them. 85.76.78.82 (talk) 05:23, 19 August 2020 (UTC)[reply]

And of course the effects are very different depending of the composition of the body in question: the Arizona crater was produced by a compact and heavy block of iron-nickel with a density of about 8, while the Chelyabinsk meteor]was a rather brittle mix of rocks and iron with a density of about 3.7. It is estimated that about half of the mass of the Arizona meteorite reached the ground and produced the crater while the Chelyabinsk meteor would probably not have reached the ground at all even if it had fallen vertically. But of course the shock wave reaching the ground can still be impressive.

Thanks Iblis for the link. I used some credible parameters for a car sized stony chunk [[5]] and it gives:

-The projectile begins to breakup at an altitude of 56600 meters = 186000 ft

-The projectile bursts into a cloud of fragments at an altitude of 37500 meters = 123000 ft

-The residual velocity of the projectile fragments after the burst is 16.7 km/s = 10.4 miles/s

-The energy of the airburst is 6.07 x 1012 Joules = 0.14 x 10-2 MegaTons.

-No crater is formed, although large fragments may strike the surface.

2003:F5:6F08:AF00:F87A:34E2:BFA7:387C (talk) 18:25, 19 August 2020 (UTC) Marco PB[reply]

On that calculation, is it 0.14 x 10^-2 i.e; 0.0014 Mt (1.4 kilotons)? -- — Preceding unsigned comment added by 2606:A000:1126:28D:F936:DCD9:CC6E:A4F9 (talk) 20:40, 19 August 2020 (UTC)[reply]

Yes, I forgot the superscript but the original has 10^-2 as you write. So 1.4 kilotons make rather a noteworthy bang but 123,000 ft over ground after all. 2003:F5:6F08:AF00:BD9C:D95E:7C63:1799 (talk) 18:44, 20 August 2020 (UTC) Marco PB[reply]

_____
 *Relative to the size of the crater --2606:A000:1126:28D:4010:D10A:69ED:7785 (talk) 05:34, 19 August 2020 (UTC)[reply]

You can use this online program to calculate the effects of an impact. Count Iblis (talk) 14:04, 19 August 2020 (UTC)[reply]

Egg laying vs live birth Snakes, venomous vs non-venomous snakes

Recently on YouTube, I watched a well-done short documentary, (Smithsonian or National Geo) which showed the eggs of a wild black mamba snake (native to Africa) hatching. A few videos later, I saw a home video of a young, probably American couple, who had cared for snake eggs found in a backyard, which they placed in an aquarium type enclosure. On camera, they noted that the eggs had hatched, and the young woman started searching around in the sawdust-type material, with her bare hands!, to locate the baby snakes, so they could identify the snake species. (They were “racers”.)

My question: Do only non-venomous snakes in North America give birth by “eggs”? Or to put it another way, were the eggs a sure indication (in North America) that the snakes were non-venomous? Probably a stupid question, here.

But I wonder if there is some sort of world-wide divide, in terms of venomous vs non-venomous, and egg laying vs live young. Are the black mambas an exception? Hope this makes sense....thanks! Tribe of Tiger ^{Let's Purrfect!} 02:28, 19 August 2020 (UTC)[reply]

@Tribe of Tiger: So snakes have three general modes of reproduction (general because there's exceptions all over the place). They can be oviparous, which means that they're egg-laying, they can be viviparous, meaning that the embryo develops internally and then comes out in a live birth, or they can be ovoviviparous, which means that they retain eggs inside the mother, which often hatch internally and come out looking like a live birth. Parity and venom only really correlate insofar as they may be shared between members of the same family, but independently there isn't really a big correlation. Boas, for example, are nonvenomous and generally ovoviviparous, while the superficially similar (and nonvenomous) pythons are egg-layers. Vipers are venomous, and the majority are ovoviviparous, but some specific genera like the bushmaster snakes lay eggs. Terrestrial Elapids like the black mamba or cobras lay eggs (as you mentioned), but sea snakes in the same family mostly have live young, and some of those guys are really venomous. bibliomaniac 1 5 03:31, 19 August 2020 (UTC)[reply]

As to the North America question, this site says that coral snakes lay eggs and are the only venomous snakes in North America that do. So a person from Canada or the north or central US, where coral snakes don't live, might be justified in assuming that an egg-laying snake is non-venomous. --174.89.49.204 (talk) 04:10, 19 August 2020 (UTC)[reply]

Well there is certainly a wide variety, as noted, no cut and dried sort of classification, worldwide! Thanks very much for this good outline, I shall study. Also for the answer regarding North American snakes. This makes sense. I believe that coral snakes are found in Texas, and my YouTubers did not appear to be clueless people, so I will cease to worry about their safety.

I gather that there are many snake enthusiasts in the US who collect non-native snakes, and there are problems with escaped exotics in Florida, pythons/boas? which are disturbing the natural food chain, as imported predators. But as noted, they are not venomous. However, an escaped Bushmaster might be unable to survive, even in Florida, which I suppose is the closest environment to its native habitat. Thanks so much to both of you for the conversation. Regards, Tribe of Tiger ^{Let's Purrfect!} 04:47, 19 August 2020 (UTC)[reply]

It does freeze every year or two in Florida, except very south. Perhaps higher land animals don't freeze till 31 as seawater is 4 times as salty and freezes at 28 and pure brine is 39 times as salty and freezes at 0. Sagittarian Milky Way (talk) 14:23, 19 August 2020 (UTC)[reply]

I know some snakes hibernate/brumate together underground, avoiding the frost. I guess it depends on the species and the climate though. Zindor (talk) 18:50, 19 August 2020 (UTC)[reply]

Have now discovered that the couple in the video live in Arkansas. Although coral snakes live there, these people live in an area too far north for them to survive. Snakes, not people! :-) The note above, by Zindor is a point well-taken. I know that the endangered Eastern Timber Rattlesnake brumates, in areas as far north as New Hampshire, I think. So I suppose an escaped Bushmaster might survive in Florida. Tribe of Tiger ^{Let's Purrfect!} 08:52, 20 August 2020 (UTC)[reply]

I assume even newly hatched snakes would have venom, if the species is venomous, as parental care in most snakes is pretty rudimentary. However, a big portion of the danger of a snakebite is the amount of venom injected and this would obviously tend to be much less in a baby snake than an adult. But... refraining from using your fingers to poke around is still a great idea. If you must poke around, using a small stick would seem to be the wise choice. Matt Deres (talk) 16:52, 21 August 2020 (UTC)[reply]

Can you catch pneumonia from inhaling an infected fart?

I asked this on an article talk page but realized I might get a quicker answer here. My question is: since Klebsiella pneumoniae is normally present in the rectum and it also causes pneumonia, can someone catch pneumonia by inhaling a fart? John Dong Longson (talk) 20:20, 19 August 2020 (UTC)[reply]

When it comes to medical advice you would be better to ask a doctor than random people on the internet, which is why we are not allowed to give you medical advice. Also please note that article talk pages are not for asking questions; see WP:TALK.--Shantavira|^{feed me} 07:00, 20 August 2020 (UTC)[reply]

I believe KP is normally acquired as the result of aspiration, not inhalation, per our article. Tribe of Tiger ^{Let's Purrfect!} 08:59, 20 August 2020 (UTC)[reply]

In case of SARS it was established that some people got infected by inhaling fecal material containing SARS that aerosolized after flushing the toilet. Count Iblis (talk) 11:57, 20 August 2020 (UTC)[reply]

This article discusses the possibility of this backdoor transmission path for COVID-19. So, folks, wear bottom masks (aka pants) in crowded areas and public transport, and keep your windows open. The article "Aerosol Transmission of Infectious Disease" (paywall) mentions the role of toilet flushing but not specifically K. pneumoniae infection, nor a role of flati. Based on the available information, this transmission path cannot be excluded, even though it may be so rare as to have escaped clinical notice. --Lambiam 12:39, 20 August 2020 (UTC)[reply]

August 21

ISS size, and micrometeorite damage.

Could someone please give me a reference to a good graphic showing the size of the ISS habitable components compared to a bus? And are there any close-up pictures showing micro-meteorite damage? Is this a major problem for the ISS? Thanks in advance 49.197.86.59 (talk) 04:20, 21 August 2020 (UTC)[reply]

you can see https://www.youtube.com/watch?v=E30J7C3NDko starting around 51 seconds in, to see a bus with the ISS. Graeme Bartlett (talk) 07:39, 21 August 2020 (UTC)[reply]

Thanks Graeme Bartlett. That's exactly what I was looking for. Any thoughts on how micrometeorite damage manifests itself on the ISS? (OP)49.182.39.157 (talk) 04:37, 22 August 2020 (UTC)[reply]

If a collision caused by the ill-considered Starlink project leads to an ablation cascade,^[6][7] this will be a major problem for the ISS, almost certainly requiring to abandon it. --Lambiam 08:44, 21 August 2020 (UTC)[reply]

Great Smokies Rat Snake Size

How long can a rat snake in the Great Smokies (the southern foothills of the Apallachians) get? I was at one of my cabins yesterday and I came upon a black snake that looked likea rat snake, but it was extremely long. After I scared it off, which took some trouble because it wasn't really scared of me, I measured from where the tail and head was. It was at least 13 feet long. So, I am wondering if it isn't one of our standard rat snakes, but someone's pet that got loose. 97.82.165.112 (talk) 11:57, 21 August 2020 (UTC)[reply]

In the Smokies, if it were a rat snake, it would have been a Eastern rat snake, and those have never been recorded longer than 7.5 feet. Black racers are of a similar size and appearance, so while they may be confused with a rat snake, they wouldn't be 13 feet long. Doing some research, the longest snake EVER recorded in North America in the wild is the Eastern indigo snake, which again, being a long black colubrid, and could easily be mistaken for a rat snake. They can get up to 9 feet in length. So either a) it was an introduced snake (escaped pet) or b) it was one of those, on the long side, but less than your estimate of 13 feet. List of largest snakes contains nothing that could easily be confused for a black rat snake, except MAYBE the Apodora if you didn't get a really good look at it, but given their rarity on the exotic pet market, would be highly unlikely to be wandering around Cades Cove. --Jayron 32 12:21, 21 August 2020 (UTC)[reply]

Thanks. I have a strong feeling it is an escaped pet. There are plenty of people here that keep exotic snakes for some reason. As for the length, I measured it by knowing that the tail was on the front steps of the cabin and the head was at the corner. That's 13 feet. It was a bit of a surprise to seet it pop up when I came up from the side of the cabin. I've been trying to find it on the property, but it is raining today, so it might be hiding. 97.82.165.112 (talk) 13:39, 21 August 2020 (UTC)[reply]

Yeah, but as an escaped pet, long, black, and skinny is unlikely. The most common super long snakes kept as pets are things like Boa constrictors and Burmese pythons, and it's particularly hard to confuse those with a black rat snake. Here is a list of the most commonly kept pet snake species. There's nothing there that would be 13 feet long and look like a rat snake. --Jayron 32 13:46, 21 August 2020 (UTC)[reply]

Some foreign poisonous snakes are black. Black mambas are extremely venomous,fast, 14ft, dark brown to gray depending on individual Sagittarian Milky Way (talk) 16:41, 21 August 2020 (UTC)[reply]

Those are extremely aggressive, have a distinctive neck flap they display when threatened, and usually not as black as a black rat snake, and hard to confuse with one. It would be a very odd choice to keep as a pet. Again, anything is possible, but among the likely contenders, fairly low on the list. --Jayron 32 17:23, 21 August 2020 (UTC)[reply]

You are right, the rat snake seems to be more scaly and the mamba shape is slightly different. Sagittarian Milky Way (talk) 17:44, 21 August 2020 (UTC)[reply]

This one wasn't aggressive, but I had to swipe at it with my weed wacker many times to make it run off. It didn't look like rat snakes I'm used to. If I had my phone on me, I would have got a photo of it. It looked exactly like the image of the eastern indigo snake. All black. Fat body. Thin head. I've checked under the cabin. Just chipmunks. No snakes. Renters are showing up in a couple hours. I'm just going to tell them that I saw a very long black snake. If they see it, assume it is poisonous and leave it alone. Perhaps I should add it to the warnings: If you see a bear, walk away. If you see a mountain lion or cougar, walk away. If you see a wolf or coyote, walk away. If you see some crack heads making drugs, walk away. 97.82.165.112 (talk) 17:49, 21 August 2020 (UTC)[reply]

It's a rare visit to the Smokies where one doesn't see at least one, if not all, of those. Especially the bears. Make sure your renters know to not leave food out, lock the car, etc. Bears are wily. --Jayron 32 18:50, 21 August 2020 (UTC)[reply]

I thought that was coyotes. Still, at least the bears haven't started cooking meth yet.{The poster formerly known as 87.81.230.195} 90.197.25.111 (talk) 19:00, 21 August 2020 (UTC)[reply]

I have always wondered about the declarations of "the largest snake (or whatever) recorded". We can't go out and measure every snake! I live an area of NC which is similar in terrain, etc. to Cades Cove. Thirty years ago, I was hiking in a fairly remote area, and entered a small clearing, where I was surprised to see a long thick piece of black "hose" on the ground...until it moved! I stared in surprise for a minute or two, and decided to leave it in peace. It was evidently basking in the sun. When I arrived home, I measured out the estimated length, adjusting for perspectve, etc. and came up with an estimate of as at least ten feet, probably closer to twelve. It was what we call, in this area, a black snake, which would be the Eastern Rat Snake. (I think I am too far north for the indigo snake.) There are plenty of its favored foods in the deciduous forests, and few predators. From my own experience, I could believe thirteen feet, even for a rat snake. Tribe of Tiger ^{Let's Purrfect!} 05:57, 22 August 2020 (UTC) Good photo of our local black snake [8] Tribe of Tiger ^{Let's Purrfect!} 06:05, 22 August 2020 (UTC)[reply]

Longest recorded does generally imply that there are potentially longer ones, I think few would claim it's impossible they exist. However for any population which is fairly well studied, which I would assume applies to most US snakes, such outliers would likely be extremely rare, unless there is some genetically unique population that has somehow been missed by science which again is probably not particularly likely in the US, or there is some very unusual dietary or life peculiarity which causes abnormal growth which seems even more unlikely. Noting of course it's not just about largest recorded, but observed size ranges. So if someone claims to have seen an extreme outlier, it is possible they just happened to see one where some situation like that applies. However the more likely scenario is they are simply wrong. Especially as in your case, where the method of length measurement doesn't seem particularly scientific and it's unclear if this memory is based on reliable recording of the size estimation, or is simply remembered. (The OP's case is a bit better. However this assumes they correctly remembered the two positions which given the frequent unreliability of human memory even in the short term, and the possibility that the terrain had a lot of similar patterns and features this still seems a big if. And I am assuming that a measuring tape or some other reliable method of determining length was used.) Nil Einne (talk) 10:26, 22 August 2020 (UTC)[reply]

Just an update if anyone is interested. I got a call from the renters, so I came by. They found a snake skin along the drive. It is almost as tall as I am (5'6"). I now have a feeling that I saw a snake shedding its skin, appearing to be much longer than it really is. 97.82.165.112 (talk) 13:25, 22 August 2020 (UTC)[reply]

After I made my previous post, I went searching around for info...Perhaps I was witnessing a shedding event also, or even two snakes stretched out side by side. Even at the time, I was astonished, which was why I did the tape measure estimate. Perhaps your snake was reluctant to move because it was trying to shed? Thanks for the update!! Tribe of Tiger ^{Let's Purrfect!} 20:54, 22 August 2020 (UTC)[reply]

August 22

Tears

what is the evolutionary advantage of children having tears that stream down their faces when they cry? Thanks. — Preceding unsigned comment added by 2A00:23C6:6884:6200:CD3A:16A0:165D:8FF8 (talk) 11:37, 22 August 2020 (UTC)[reply]

Their parents (or others) can see they want attention, and then assist them. Graeme Bartlett (talk) 12:11, 22 August 2020 (UTC)[reply]

While some scientists believe that human crying is an evolutionary trait, others believe it is behavioral. Therefore, it may well be a mix and fall into the nature vs nurture world. While it is accepted that humans are the only animals that cry with tears, there is evidence that pets, primarily dogs, can learn to mimic the behavior with positive reinforcement. 97.82.165.112 (talk) 13:23, 22 August 2020 (UTC)[reply]

Some hypotheses:

Why Cry? Evolutionary Biologists Show Crying Can Strengthen Relationships.

Teary-Eyed Evolution: Crying Serves A Purpose

Why Only Humans Shed Emotional Tears : Evolutionary and Cultural Perspectives

We also have an article, Crying. Alansplodge (talk) 14:03, 22 August 2020 (UTC)[reply]

Can we stabilize a radioactive nuclei?

We know that some nuclei exist for only a limited time. 1. why same configuration atoms decay differently? 2. can it be that the positions of the nucleons makes the difference? --Exx8 (talk) 17:01, 22 August 2020 (UTC)[reply]

Well for one thing, I would think a stronger gravitational field might make a difference. Although I have no idea whether or not anyone has ever bothered to test that hypothesis. Otherwise, yes, I would agree that the specific configuration of nucleons would likely effect the process. No reference for that either, unfortunately. Earl of Arundel (talk) 18:17, 22 August 2020 (UTC)[reply]

@Earl of Arundel: That's not correct. There's no way to stabilize radioactive nuclei, with one exception: nuclei that decay only by electron capture can be stopped from doing so by simply removing all the electrons around it (i.e. completely ionizing it). This is possible only for a select few radioactive nuclei, though. In one exceptional case, a technically-metastable nuclear isomer is stabler than its ground state (in practice, stable), namely Tantalum-180m, but converting the ground state to that is not a simple matter of rearranging nucleons–that is close to impossible to do in a surgical manner.

Stronger gravity only would make a neutron star. So you can argue that neutronium can be stabilized that way, but it doesn't help for any other nuclide.--Jasper Deng (talk) 18:27, 22 August 2020 (UTC)[reply]

What I meant was that an unstable isotope might decay slower near the surface of Jupiter for example. Or has that sort of thing already been tested for? Earl of Arundel (talk) 18:46, 22 August 2020 (UTC)[reply]

Gravity is by far the weakest of the four fundamental forces. It's almost irrelevant for the purposes of radioactive decay.--Jasper Deng (talk) 19:44, 22 August 2020 (UTC)[reply]

The questioners may be thinking of Gravitational time dilation, which would do it from an outside observer's perspective.John Z (talk) 20:17, 22 August 2020 (UTC)[reply]

Well there you go. So I was inadvertently correct. But seriously, without incontrovertible proof I don't think anyone can say for sure that large gravitational fields have absolutely no effect on (non-relativistic!) decay rates. Earl of Arundel (talk) 21:18, 22 August 2020 (UTC)[reply]

Decay rates assume the same frame of reference as the radioactive nucleus, so special relativity is irrelevant.--Jasper Deng (talk) 21:26, 22 August 2020 (UTC)[reply]

Some people are trying to find out if decay rates can change eg "Fluctuations in measured radioactive decay rates inside a modified Faraday cage: Correlations with space weather". Possibly neutrons and neutrinos have an effect. Also they mention a near zone effect. You may also wish to consider atmospheric electricity - the electric field in the air, negative or positive ions in the atmosphere, amount of carbon-14 around, and the magnetic field. These might affect your measurements, but only really affect the decay rate at some super-extreme. Graeme Bartlett (talk) 22:35, 22 August 2020 (UTC)[reply]

Just by the way, there's no such thing as "a nuclei". The singular is "nucleus". --Trovatore (talk) 22:49, 22 August 2020 (UTC) [reply]

@@ Line 152: / Line 152: @@
 :I assume even newly hatched snakes would have [[Snake venom|venom]], if the species is venomous, as parental care in most snakes is pretty rudimentary. However, a big portion of the danger of a snakebite is the ''amount'' of venom injected and this would obviously tend to be much less in a baby snake than an adult. '''But'''... refraining from using your fingers to poke around is still a great idea. If you must poke around, using a small stick would seem to be the wise choice. [[User:Matt Deres|Matt Deres]] ([[User talk:Matt Deres|talk]]) 16:52, 21 August 2020 (UTC)
+== Can you catch pneumonia from inhaling an infected fart? ==
+I asked this on an article talk page but realized I might get a quicker answer here. My question is: since Klebsiella pneumoniae is normally present in the rectum and it also causes pneumonia, can someone catch pneumonia by inhaling a fart? [[User:John Dong Longson|John Dong Longson]] ([[User talk:John Dong Longson|talk]]) 20:20, 19 August 2020 (UTC)
+:When it comes to medical advice you would be better to ask a doctor than random people on the internet, which is why we are not allowed to give you medical advice. Also please note that article talk pages are not for asking questions; see [[WP:TALK]].--[[User:Shantavira|Shantavira]]|[[User talk:Shantavira|<sup>feed me</sup>]] 07:00, 20 August 2020 (UTC)
+:I believe KP is normally acquired as the result of aspiration, not inhalation, per our article. <b>[[User:Tribe of Tiger|<span style="font-family:Segoe print;color:#B22222">Tribe of Tiger</span>]] [[User Talk:Tribe of Tiger|<sup style="font-family:Segoe print;color:#B22222">Let's Purrfect!</sup>]]</b> 08:59, 20 August 2020 (UTC)
+:In case of SARS it was established that some people got infected by inhaling fecal material containing SARS that aerosolized after flushing the toilet. [[User:Count Iblis|Count Iblis]] ([[User talk:Count Iblis|talk]]) 11:57, 20 August 2020 (UTC)
+:[https://www.news-medical.net/news/20200422/Lifting-the-lid-on-coronavirus-flatulence.aspx This article] discusses the possibility of this backdoor transmission path for COVID-19. So, folks, wear bottom masks (aka pants) in crowded areas and public transport, and keep your windows open. The article [https://journals.lww.com/joem/Abstract/2015/05000/Aerosol_Transmission_of_Infectious_Disease.4.aspx "Aerosol Transmission of Infectious Disease"] (paywall) mentions the role of toilet flushing but not specifically ''[[Klebsiella pneumoniae|K. pneumoniae]]'' infection, nor a role of [[Flatulence|flati]]. Based on the available information, this transmission path cannot be excluded, even though it may be so rare as to have escaped clinical notice. &nbsp;--[[User talk:Lambiam|Lambiam]] 12:39, 20 August 2020 (UTC)
 = August 21 =