Wikipedia:Reference desk/Archives/Science/2024 August 19
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August 19
editHow did people find out which mushrooms are safe to eat?
editEdible mushroom says: "To ensure safety, wild mushrooms must be correctly identified before their edibility can be assumed. Deadly poisonous mushrooms that are frequently confused with edible mushrooms include several species of the genus Amanita, particularly A. phalloides, the death cap. Some mushrooms that are edible for most people can cause allergic reactions in others; old or improperly stored specimens can go rancid and cause food poisoning. Additionally, mushrooms can absorb chemicals within polluted locations, accumulating pollutants and heavy metals including arsenic and iron—sometimes in lethal concentrations."
So, if some primitive society of humans had no knowledge about whether mushrooms are edible at all, how would they end up obtaining the detailed knowledge about which mushrooms are edible and which not without that leading to many deaths? Because once people start to die then you would think that they would no longer be interested in this and just classify most mushrooms as toxic. Count Iblis (talk) 15:11, 19 August 2024 (UTC)
- People would rub the item on their arm, taste and spit it out, eat a small amount and wait for any discomfort, and (probably) try to feed it to dogs or other tamed animals. Abductive (reasoning) 16:54, 19 August 2024 (UTC)
- The obvious answer is trial and error. Early hominins were mainly hunter-gatherers it seems, relying heavily on nuts, seeds, fruits and fungi, all of which may be toxic. If the more adventurous members of a group of such people tried out a few new things every generation and passed on the results in their oral history e.g. "this one made me very sick and killed my brother, but this one tastes really good", I think that over longer periods this would build up their "repertoire". Periods where normal food sources became scarce would provide more than enough incentive to give something a try. I've tried to find sources for this, but struggled so far. One thing I did find is the suggestion that the early hominins would check out what other animals were eating. Mikenorton (talk) 21:04, 19 August 2024 (UTC)
- Also keep in mind that there are edible fungi that don't resemble poisonous ones; that not everything grows everywhere; and that traditional knowledge includes knowing where to find particular foods, not just how to identify them out of context. --Amble (talk) 21:25, 19 August 2024 (UTC)
- That is why, in every language, humans built up little sayings to remember things. We don't need them now because we avoid nature. So, we've mostly forgotten the exact words and come up with silly jibberish like "red on black makes a wasp attack by pee turns yellow is a happy fellow." Therefore, it is difficult to imagine a society where these sayings were well known and taught important lessons. I just wonder about Australia. Wouldn't the sayings simply have been: "If it moves, it will kill you. If it doesn't move, it will likely still kill you." 12.116.29.106 (talk) 12:57, 20 August 2024 (UTC)
- We still use those sorts of sayings. Things like "red touches black, ok Jack; red touches yellow, turns your blood to Jello" for colorations of snakes that aren't vs are venomous; "touch the white, you'll be alright; touch the black, you won't be back" for the neutral vs hot conductors in US electrical wiring. DMacks (talk) 14:06, 20 August 2024 (UTC)
- That is why, in every language, humans built up little sayings to remember things. We don't need them now because we avoid nature. So, we've mostly forgotten the exact words and come up with silly jibberish like "red on black makes a wasp attack by pee turns yellow is a happy fellow." Therefore, it is difficult to imagine a society where these sayings were well known and taught important lessons. I just wonder about Australia. Wouldn't the sayings simply have been: "If it moves, it will kill you. If it doesn't move, it will likely still kill you." 12.116.29.106 (talk) 12:57, 20 August 2024 (UTC)
- There are old mushroom hunters. There are bold mushroom hunters. There are no old, bold mushroom hunters. 41.23.55.195 (talk) 04:47, 21 August 2024 (UTC)
- Thanks everyone for your answers! Count Iblis (talk) 18:00, 25 August 2024 (UTC)
Too big
editI was watching an episode of Star Trek: Discovery, and the people is having a problem with a black hole that is way too big. As in, five light-years in size. So I checked the article Supermassive black hole, to check how big can they get, and it says "with its mass being on the order of hundreds of thousands, or millions to billions, of times the mass of the Sun". It's hard to keep perspective with numbers, sizes and distances so high, so just to be clear... 5 light-years in size would be obcenely big even for a supermassive black hole, right? Cambalachero (talk) 18:57, 19 August 2024 (UTC)
- Sounds like it was this item: Dark Matter Anomaly. The Schwarzschild radius of a black hole is directly proportional to its mass. If you take the Schwarzschild radius to be (5 light-years) / 2 = 2.5 light years and plug it into the formula, you will get a mass of 8 x 10^12 solar masses. That is several times larger than the mass of the Milky Way galaxy, or around 1000 times as large as the mass of the very large supermassive black hole M87*. So yes, that is way too big. —Amble (talk) 20:02, 19 August 2024 (UTC)
- related question: how big would a black hole be if it would contain the whole mass of the universe? Or formulated otherwise: what's the absolute maximum Schwartzschild radius? 176.0.144.239 (talk) 18:50, 2 September 2024 (UTC)