Science desk
< July 12	<< Jun \| July \| Aug >>	July 14 >

Welcome to the Wikipedia Science Reference Desk Archives
The page you are currently viewing is a transcluded archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

July 13[edit]

Can I see old aviation maps or airport diagrams for pilots?[edit]

Sagittarian Milky Way (talk) 17:37, 13 July 2023 (UTC)[reply]

I've found this to be difficult online. I imagine that a serious library might have them. Abductive (reasoning) 19:13, 13 July 2023 (UTC)[reply]

http://www.departedflights.com/airports.html have many airport diagrams. Philvoids (talk) 20:41, 13 July 2023 (UTC)[reply]

Any ones from decades ago? Sagittarian Milky Way (talk) 21:07, 13 July 2023 (UTC)[reply]

Here's a subject search at archive.org for aeronautical charts. I see a large number of charts from the 1920s ("experimental"!) and several Jeppesen charts for Montana from the 1940s. Some files link to this selection at davidrumsey.com. Card Zero (talk) 23:21, 13 July 2023 (UTC)[reply]

Energy costs of megalith construction[edit]

Was the construction of megaliths energy-consuming to the extent that it required a reliable and stable source of food rather than merely hunting-gathering? The timeline indicates that most such constructions happened after the First Agricultural Revolution, suggesting a supply of cattle meat and plant food may have played a role in feeding all those builders (who possibly spent less efforts and time since then when compared to e.g. a mammoth hunt). Brandmeister^talk 18:44, 13 July 2023 (UTC)[reply]

Göbekli Tepe predates agriculture. I think people misunderstand just how productive certain areas can be for hunter-gathers, because current hunter-gathers have been pushed into the marginal lands. In the area that became the cradle of agriculture, there was abundant food. Like, insanely abundant. A Garden of Eden, one might say. Abductive (reasoning) 19:11, 13 July 2023 (UTC)[reply]

Actually I do not think that it predated agriculture. Though it may have predated pottery. Ruslik_Zero 20:41, 13 July 2023 (UTC)[reply]

Again, this is bias creeping in, from people who can't imagine what the situation was like at the time, or the direction of causality. Abductive (reasoning) 21:15, 13 July 2023 (UTC)[reply]

Founder crops is relevant. Einkorn wheat says the process of domestication might have taken only 200 years, 10,000 years ago. There were at some point semi-domesticated grain fields, where the seeds were distributed accidentally on purpose during repeated foraging. Card Zero (talk) 23:50, 13 July 2023 (UTC)[reply]

I hope that the 200 generations figure is for accidental domestication. Most evolutionary biologists go with 6 generations. Abductive (reasoning) 04:59, 14 July 2023 (UTC)[reply]

"20 to 200 years" says the article, I was going with the upper estimate. Card Zero (talk) 05:04, 14 July 2023 (UTC)[reply]

One of the sections of that Neolithic Revolution page is Diet and health. It mentions risk of famine due to crop failure and the allocation of resources towards reproduction over somatic effort. So stability might be the wrong idea here. There's also the section on Social change which mentions a social elite who [...] monopolized decision-making. Note that compared to hunter gatherer societies, everybody is short, weak, fat, vitamin deficient, sick, and their teeth are falling out, so we're talking quantity over quality. So we have large numbers of somewhat desperate people and a few chiefs or priests, who likely organized the agriculture on which they all depended, with forest clearance, irrigation, and calendars, and notionally protected it in a spiritual capacity. This novel bossiness filled a vacuum left where once people would cooperate to hunt animals, and frequently resulted in the decision that the community should cooperate to put thousands of stones in a big pile, build artificial hills, or move 20-ton megaliths around, often for the purpose of protecting the bodies of the elite after death. Card Zero (talk) 00:29, 14 July 2023 (UTC)[reply]

The article Einkorn wheat mentions: "One theory by Yuval Noah Harari suggests that the domestication of einkorn was linked to intensive agriculture to support the nearby Göbekli Tepe site.^[12]" --Lambiam 03:06, 14 July 2023 (UTC)[reply]

They needed to support the maintenance budget for Göbekli Tepe, so they invented agriculture. Abductive (reasoning) 04:59, 14 July 2023 (UTC)[reply]

Perhaps they also invented entrance fees. Might it be that the chiselled pillars at the site are discarded tickets? --Lambiam 10:56, 14 July 2023 (UTC)[reply]

Why did it take so long to invent pottey? Did no one ever put clay in fire to see what would happen or leave it in the sunny dry season and thought, hey maybe fire can make it even harder and I can make a cup with this? Also why'd it take awhile to invent non-"coil stack" pottery? For something wide-mouthed you could just smoosh the coils smooth on both sides without pottery wheels or tools. Sagittarian Milky Way (talk) 18:07, 14 July 2023 (UTC)[reply]

People used containers made of tree bark. You can even boil water in them (not in the way one initially pictures). Pottery wasn't invented until after the invention of the house mouse. Abductive (reasoning) 18:21, 14 July 2023 (UTC)[reply]

Physics behind a flying object getting under the wing of another flying object and tipping it over in flight[edit]

Something I saw today. There were some very large gulls chasing a grey heron (not sure how it started, but there were about six chasing it - I assume it had messed with their chicks) and one of the gulls was wing-to-wing with the heron and it kinda got to the side and under and used its wing to flip the heron's wing - which sent it spinning out of control for a time. This was down the side of a bridge (railway underneath) and the heron went spinning down, out of control, with the gulls following it. I guess that they were intending to follow it down for the kill (there was another one that made contact and was trying to piledrive it into the ground, it looked like), but the heron managed to recover in flight before it hit the ground and get away - this all happened in about 10 seconds. I'd never seen anything like that from birds before - but it reminded me of World War II stories of British Spitfire pilots flipping the wings of German V1 bombs to crash them. I was just wondering about the physics behind this - can anyone explain how this works? I'm assuming from this that the seagulls have something of an instinctive understanding of how it works, or at least can learn to figure out how to do it. Wish I'd been able to film this, but it all happened so fast. Birds can be brutal, it seems. Iloveparrots (talk) 21:54, 13 July 2023 (UTC)[reply]

Possibly the gulls, as habitual formation flyers, had some awareness of the interaction between wingtip vortices and a following wing, and used this to their advantage? The gull species I've observed most closely can be fairly aggressive towards each other, and it may be a familiar harassing tactic for them. Herons tend to be solitary, and thus less familiar with the consequences of close interaction. Whether such interaction between the birds concerned could actually result in a wingtip stall, I don't know, but one can easily imagine it being disorienting to an already-distracted heron, resulting in a momentary 'loss of control' if not an incipient spin. On the other hand, I've seen birds being mobbed use drop-like-a-stone tactics to escape, or at least to signal their compliance with mob rule and their intent to slink away. Mobbing can be brutal, but most of the time it is probably more the threat of violence than the violence itself that resolves the conflict. AndyTheGrump (talk) 22:46, 13 July 2023 (UTC)[reply]

I live near the sea and from what I've seen from watching the (sea)gulls they do seem to have some understanding of aerobatics. I've seen them doing Immelmann turns and aileron rolls for sure. They also love ridge lift. They really love ridge lift - and whatever large ship that's going out to sea, they slipstream the hell out of it. Iloveparrots (talk) 23:15, 13 July 2023 (UTC)[reply]

This is very common with gulls and birds of prey. See Mobbing (animal behavior). Shantavira|^{feed me} 16:59, 14 July 2023 (UTC)[reply]

I've seen them chasing crows and hawks before, but never something as big as a heron and never actually making contact like this. To be honest, I didn't even think that the gulls would think of a heron as a threat, but obviously they know better. Iloveparrots (talk) 18:07, 14 July 2023 (UTC)[reply]

Obviously from reading the article, they do eat the chicks of other birds though. I never really thought about herons enough to read up on them until now, to be honest. At one time, I'd just assumed from how they look that they were flightless birds too, lol. Then I saw one flying. Iloveparrots (talk) 18:10, 14 July 2023 (UTC)[reply]

Nature's killing machines[edit]

I've been reading about giant petrels tonight. I watched a few Youtube videos about their hunting behaviors too. It seems that from a lineage of mostly fish-eaters, somehow an extremely aggressive land predator has emerged, somehow - killing and eating penguins, seals, sheep, etc. (multiple videos of them covered in gore). It looks like the thing is built like a battle tank with a huge reinforced beak, unlike its more slender albatross relatives.

My question - can you think of examples of other lineages of animals that are generally non-predatory that have an occasional member that has become a killing machine? I'm quite familiar with birds and parrots (as my name suggests!) and I can think of the Antipodes parakeet, which often eats seabirds and their chicks. But apart from that, I'm not sure. Iloveparrots (talk) 22:35, 13 July 2023 (UTC)[reply]

Further to that, I was going to suggest the ferret, but then from reading the article I see that it's not actually a rodent. So, never mind. :) Iloveparrots (talk) 22:46, 13 July 2023 (UTC)[reply]

Vampire ground finch? Not exactly a killer, but a fine example of natural selection finding a way to exploit a new niche while working from an unlikely starting point. AndyTheGrump (talk) 23:02, 13 July 2023 (UTC)[reply]

Just thinking. The opposite way around is the giant panda. Well, now it's been established that it's a bear. When I was at school it was something like "an herbivorous mammal that resembles a bear". Iloveparrots (talk) 23:30, 13 July 2023 (UTC)[reply]

Rats are definitely an omnivorous rodent. Pigs among ungulates, maybe? -- Avocado (talk) 02:46, 14 July 2023 (UTC)[reply]

My great uncle used to have a farm - "don't feel bad about eating a pig - he wouldn't feel bad about eating you, if he only thought of it first" he'd say, probably rightly. Iloveparrots (talk) 18:16, 14 July 2023 (UTC)[reply]

There are apparently 137 kinds of carnivorous sponge. Also the Dayak hunters of Borneo say that the tufted ground squirrel will jump from low branches to ambush deer, bite them in the jugular and then disembowel them (a story for which the world is not yet prepared). Card Zero (talk) 05:26, 14 July 2023 (UTC)[reply]

My first thought was Homo sapiens, which is far more aggressive and carnivorous than other primates. The most extreme example though is probably from the Unglates: the group that includes sheep, pigs, horses, giraffes ... and killer whales. Iapetus (talk) 10:13, 17 July 2023 (UTC)[reply]

Mock turtles[edit]

Is there actually an animal called the mock turtle? As in something that resembles a turtle but technically isn't related to turtles? Google is useless as it throws up Alice in Wonderland references or references to the band. 146.200.127.4 (talk) 23:55, 13 July 2023 (UTC)[reply]

See mock turtle soup. Not a turtle, but an imitation of a product made from turtles. Lewis Carrol then created the obvious parody. AndyTheGrump (talk) 00:00, 14 July 2023 (UTC)[reply]

The body of a turtle with a cow's head and hooves. Perfect. :) (And standing on hind feet, a la Gary Larson's typical cow.) ←Baseball Bugs ^{What's up, Doc?} carrots→ 01:20, 14 July 2023 (UTC)[reply]