A scientific fact/tidbit you recently learned that you thought was interesting

arthwollipot said:
Dark Oxygen.

Most of the O2 we have in our atmosphere was created by photosynthesis, in plants. Now they've discovered O2 (molecular oxygen, as opposed to atomic oxygen) that's being somehow synthesised in polymetallic nodules on the seafloor, well below the reach of the sun.

These were once considered a good source to mine for metals that are critical to battery technology, but given the ecosystems that seem to be nurtured by the dark O2, the environmental concerns are starting to outweigh the mining interest.

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Does anyone really think environmental concerns will stop the mining? I wouldn't bet on it.
 
shemp said:
Does anyone really think environmental concerns will stop the mining? I wouldn't bet on it.
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Fortunately, ocean nodule mining has been talked about since the early 1970's but has gone nowhere that I know of. Probably the most successful such project was actually mining for a Soviet submarine.
 
Trebuchet said:
Fortunately, ocean nodule mining has been talked about since the early 1970's but has gone nowhere that I know of. Probably the most successful such project was actually mining for a Soviet submarine.
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But currently, Norway is looking into it seriously.
 
Trebuchet said:
Fortunately, ocean nodule mining has been talked about since the early 1970's but has gone nowhere that I know of. Probably the most successful such project was actually mining for a Soviet submarine.
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It will be right after fusion power and flying cars. Maybe after fusion powered flying cars.
 
The Stone Age encompasses more than 95 percent of human history.
 
I haven't seen this with my own eyes, but you know how if you shine a light in the dark at a cat you see their eyes reflecting back? I just heard if you go into a room with a bunch of spiders and hold a flashlight just right, you can see their eyes reflecting back.
 
bruto said:
Every story has a beginning that's all there is until the rest is told. That doesn't seem like much of a fact until history stops.
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In light of the amount of history that we've had post Stone Age, it does feel surprising and amazing when you first learn that the period of human history that predates that was so much longer.
 
Roboramma said:
In light of the amount of history that we've had post Stone Age, it does feel surprising and amazing when you first learn that the period of human history that predates that was so much longer.
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I think it certainly is an interesting observation, and says something about how we look at history. Just not what I'd call a scientific fact.
 
CarbShark said:
I haven't seen this with my own eyes, but you know how if you shine a light in the dark at a cat you see their eyes reflecting back? I just heard if you go into a room with a bunch of spiders and hold a flashlight just right, you can see their eyes reflecting back.
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I'd think that very few people would like to test out that theory.
 
MinnesotaBrant said:
My daughter says that she learned in science class that hurricanes in the north hemisphere turn counter clockwise and clockwise in the south hemisphere
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Not only that, but it is physically impossible for a storm to cross the Equator. They loose energy before they get there.
 
Mikemcc said:
Not only that, but it is physically impossible for a storm to cross the Equator. They loose energy before they get there.
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Do you have citation for that? Not that I doubt you but I've never heard that before and it is interesting.

ETA: I looked it up, the internet agrees. Its basically that the Coriolis effect causes storms to move away from equator. If it wants to go the other way it has to fight the Coriolis effect and will lose energy. That is an interesting tidbit.
 
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The total population of Native California is estimated, by the time of extensive European contact in the 18th century, to have been perhaps 300,000. Before Europeans landed in North America, about one-third of all natives in what is now the United States were living in the area that is now California.[2] California indigenous language diversity numbered 80 to 90 languages and dialects, some surviving to the present although endangered.
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Granted, a lot of that may be that those living in the rest of what would be the US had died of smallpox, still that's pretty astounding. CA still has a similarly disproportionate population.
 
https://www.dwarkeshpatel.com/p/david-reich
The example that you mentioned is something that's been a big shock from the ancient DNA revolution. This is now maybe eight years, nine years old. The first large number of DNA sequences—from people who lived 6000 to 4000 years ago in the steppe north of the Black and Caspian Seas and in Europe—were being published around 2015. This group in Denmark, led by Eske Willerslev and Kristian Kristiansen and colleagues, looked at their DNA. They discovered in their sequence, from the 100 or so humans they sequenced, that there was also pathogen DNA. In 5-10% of the random people they sequence from around 4000-5000 years ago, there was Yersinia pestis, the agent of the black death, but actually without the plasmid that contributes to bubonic plague. That's required for flea-rat transmission. So it must have been pneumonic plague with an aerosolized transmission or something. 5-10% of random deaths means that the percent of people who were dying must have been even higher, because they weren't detecting everything that was there.

There’s a study by another group, Johannes Krause and colleagues, of people in plague pits in London from the 1300s epidemic. They found that when you apply this method to people we know died of black death, you only find a quarter of the people. So the rate was even higher. If people are bacteremic when they die, if they have bacteria in their teeth, they almost certainly died of that agent.

A paper just came out a few weeks ago in Scandinavia. It was looking at these tombs from about 5000 years ago of farmers who were just on the verge of encountering people from the steppe. A huge fraction of them have Black Death when they die. They're buried in tombs and normal and they have rates that are even higher than 5-10%. It’s this whole pedigree with many, many generations. It's not all at the same time. It’s like the parents and generations and generations with a very large fraction. Well more than 10% have Black Death and have Yersinia infection.

So it looks like this particular agent has been killing people for 4000-5000 years in western Eurasia. In fact, it’s killing a scarily large fraction of the population. As the quantitative person I am reading this literature, I think people are embarrassed by the implication. The implication is that a quarter to a half of deaths in this entire period are from this. It's so unbelievable and so ridiculous that such a high proportion of people over such a long period of time are dying from this one agent.
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Same source:
There was a super interesting series of papers. They made many things clear but one of them was that actually the proportion of non-Africans ancestors who are Neanderthals is not 2%. That’s the proportion of their DNA in our genomes today if you're a non-African person. It's more like 10-20% of your ancestors are Neanderthals.

What actually happened was that when Neanderthals and modern humans met and mixed, the Neanderthal DNA was not as biologically fit. The reason was that Neanderthals had lived in small populations for about half a million years since separating from modern humans—who had lived in larger populations—and had accumulated a large number, thousands of slightly bad mutations. In the mixed populations, there was selection to remove the Neanderthal ancestry.

That would have happened very, very rapidly after the mixture process. There's now overwhelming evidence that that must have happened. If you actually count your ancestors, if you're of non-African descent, how many of them were Neanderthals say, 70,000 years ago, it's not going to be 2%. It's going to be 10-20%, which is a lot.

Maybe the right way to think about this is that you have a population in the Near East, for example, that is just encountering waves and waves of modern humans mixing. There's so many of them that over time it stays Neanderthal. It stays local. But it just becomes, over time, more and more modern human. Eventually it gets taken over from the inside by modern human ancestry.
This is what happens to northern European hunter-gatherers. They become farmer over time, but they are intact on the male line. Culturally they stay on the male line intact. I'm not trying to be politically correct, I'm just saying that you can actually have scenarios where this happens, for example in elephants.
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The part about elephants is actually pretty cool:

If you look at forest elephants, which are the smaller of the two species of elephants in Africa, they're very matrilocal. They have these female lines that are very intact over a long period of time. If you look at the savanna elephants, which are the bigger elephants in eastern and southern Africa, they have savanna elephant DNA overall. But their mitochondrial sequences are forest elephant, which are the smaller West African elephants. The interpretation of this is that you just have waves and waves of dominant male bulls from the savanna coming into populations and eventually just replacing all of the genome in waves and waves of an intact forest population. So all that's left is the mitochondrial sequence, which is passed in the maternal line.
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Another very interesting bit from the same source:

It's very clear that there is extreme overrepresentation of change on variants that affect metabolism and immune traits. If you look at traits that we know today affect immune disease or metabolic disease, these traits are highly overrepresented by a factor of maybe four in the collection of variants that are changing rapidly over time. Whereas if you look at traits that are affecting cognition that we know in modern people modulate behavior, they're hardly affected at all. Selection in the last 10,000 years doesn't seem to be focusing, on average, on cognitive and behavioral traits. It seems to be focusing on immune and cardiometabolic traits, on average, with exceptions. On average, there's an extreme over representation of cardio metabolic traits.
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Mostly what I would have expected: the majority of human evolution over the past 10,000 years has been in genes related to the immune system and metabolism. Changes in the diseases we're affected by have created huge selection pressures. Another major change that comes with agriculture is related to both the sorts of foods we eat and the scarcity/abundance of that food over time, so selection related to that also makes sense. Still, very interesting the have actual data on this.
 
Apropos of discussion, I was just viewing a video on the expansion of a small tribe and its later world domination. Of interest is the identification of changes in the soft tissue of the vocal tract which then gave modern-izing humans an apparent advantage, allowing for ostensible richer communication and information storage. This is then followed by indications that the dominance of the first most successful tribe was not genetic in nature, but cultural. In short, the best user of the new smarts everyone had took over.

Sort of a racial dominance buster, for one thing. Stronger hunters may win in direct encounters, but the smarter toolmakers win the wars, and all it takes is learning the craft, not a better birthright.
 
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Nitroglycerine for the heart is the same stuff as is used as a high explosive (albeit at a much diluted concentration.) I'm not sure how that was discovered.
 
Exploding is a perfectly normal medical phenomenon. In many fields of medicine nowadays, a dose of dynamite can do a world of good. For instance, athlete's foot - an irritating condition - can be cured by applying a small charge of TNT between each toe.
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- MPFC
 
arthwollipot said:
Since it was discovered, it has been known that excessive handling of the stuff could cause severe headaches via vasodilation. The medical use is simply an exploitation of that mechanism.

https://en.wikipedia.org/wiki/Nitroglycerin_(medication)#History
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Reminds of how they figured out flouride is good for teeth. Folks with crazy gross looking yellow teeth but with no cavities and how they figured out that Rogaine grew hair. Some kind of blood pressure med at first but they noticed everyone using it was growing hair like a werewolf.
 
ahhell said:
Reminds of how they figured out flouride is good for teeth. Folks with crazy gross looking yellow teeth but with no cavities and how they figured out that Rogaine grew hair. Some kind of blood pressure med at first but they noticed everyone using it was growing hair like a werewolf.
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As was viagra.
 
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