Wikipedia:Reference desk/Archives/Science/2020 December 28

= December 28 =

Covid-19 vs. Spanish Flu, who would win?
Spanish flu had far more fatalities, but that has to be at least in part because treatment possibilities were a lot worse then. There were no ventilators, no antibiotics or antivirals, etc. Like if you compared a mass shooting (50 people struck by bullets, say) in 1918 to one in 2020, the 2020 one would have far higher survival rate because of blood transfusions and antibiotics (making wounded people much less likely to die of infections), even given identical guns for both shootings. You couldn't conclude that the 1918 guns were deadlier.

So is there a reasonable way to compare the virulence of a Covid-19 infection to a Spanish Flu one, given comparable levels of treatment? Similarly, what about the transmissibility? Any idea how the comparison would end up? Thanks. 2601:648:8202:96B0:0:0:0:313A (talk) 00:30, 28 December 2020 (UTC)


 * Sociology and epidemiology and psychology and it's just a flu bro people (1918 had them too) are too complex to know for sure without controlled time travel trials of many permutations of years, Covid, Spanish flu (only one per timeline) and patient zero events. Pick lots of different plausible people to be patient zeros and see what happens. To research who are plausible patient zeros start out with using your time machine to find out who was the real patient zero and how did he get it? Did he eat a bat or got bit by one or bit the head off or raped it or what? Find out how easy it is to become patient zero from each method (i.e. what kind of bat eating mishap, can you get it from kissing, how often do humans kiss bats vs drink bat blood vs touch it with an open wound vs breathe bat germs vs..), find out how much viral load you get by the different methods and where the precursor virus lived and things like that and develop a non-distorting unbiased distribution of patient zero events. Like an electron cloud of patient zeros, an electron cloud for each year and germ combination. Account for bat phenotypes too and so on to make sure you replicate the butterfly effect just right instead of favoring one result or the other by choosing to make the bat sneeze at millisecond 3 instead of 10 too often or making the average human a bat zoosadist too rarely or too often or whatever without knowing the real odds. That would be playing God instead of just finding out which virus is worse in an apples-to-apples comparison. Also this trial's unethical. Sagittarian Milky Way (talk) 00:47, 28 December 2020 (UTC)


 * On second thought maybe it is simpler to just make the random mutation dice non-deterministic in the progenitor virus species or strain instead of "it's deterministic cause it already happened" and let the patient zero chips do whatever happens. Repeat till you get many epidemics of each type and make a graph of ppm of Earth killed by badness percentile and see which looks worse. Sagittarian Milky Way (talk) 01:38, 28 December 2020 (UTC)


 * Hard to give a reference for this one, but it may be possible to say something useful.
 * First, Spanish flu hit at the worst time imaginable, which must be part of the reason why it's so infamous: right at the end of World War 1. Millions of soldiers were travelling around the world, spreading the virus, millions had been breathing diluted poison gas for a few years and even in European countries that stayed neutral, trade disruptions led to food and fuel shortages, so people were in a pretty bad condition.
 * I've read in newspapers and seen on tv news that about 10% of covid patients who end up in hospital in my small western European country die within a few weeks. At the same time, only about 0.2% of all people who get infected die, which means that about 98% recovers without significant treatment (although note that some patients die without ever getting to hospital, but those are the people who were expected to die anyway, even if they hadn't had covid). Those number seem to match with numbers reported for excess deaths and some signs of saturation, indicating that in some areas everybody has already been infected. If covid had struck in 1923, those 98% would have recovered too. It appears that Spanish flu mortality was higher than 2%. In the early 20th century, the population was younger, suffered less from welfare diseases (like obesity) and was more used to infections (which keep your immune system in shape), so was less sensitive to covid (but also to some extend to flu). And back then, it was considered normal that elderly people would die of pneumonia.
 * All combined, I guess that if covid had struck in 1923 (when the effects of WW1 were waning off), hardly anyone would have noticed. And maybe it did, as there are several coronaviruses that now only cause a common cold, but when first appearing would have been as unknown to our immune system as the current virus is now. But if Spanish flu hadn't struck in the aftermath of WW1, it wouldn't have been as bad as it came to be.
 * Note that I'm not a virologist or epidemiologist, although my understanding of history and statistics isn't worse than theirs. PiusImpavidus (talk) 10:54, 28 December 2020 (UTC)
 * The Spanish flu killed the strong immune systems, usually the young not the old. Sagittarian Milky Way (talk) 15:18, 28 December 2020 (UTC)
 * If the Spanish flu had struck in 1923 instead of 1918, it might have been a mere blip on the radar (but note that the similar 2009 swine flu pandemic was recognized as an outbreak in Mexico well before it became a pandemic). I am not convinced that this would also have been so for COVID-19, if only because of the suddenness of the transition from mild symptoms to a life-threatening situation as well as the long-lasting effects experienced by some recovered patients. I think there are too many unknowns to compare the respective virulences in a 1918 what if scenario.  --Lambiam 12:48, 28 December 2020 (UTC)


 * Perhaps worth reminding everyone that although it's commonly referred to as "Spanish flu," epidemiologists are fairly sure that it didn't originate in Spain, nor was it particularly prevalent there. Because many of the countries in which it first spread were in the the throes of WW1, their newspapers were censored to avoid damaging morale: Spain was neutral in the war, so Spanish newspapers freely reported the disease's progress in Spain, leading to a false impression that it had appeared there first. {The poster formerly known as 87.81.230.195} 2.122.56.237 (talk) 14:39, 28 December 2020 (UTC)
 * Kansas flu or Chinese flu? Sagittarian Milky Way (talk) 15:18, 28 December 2020 (UTC)
 * See Haskell County, Kansas. Alansplodge (talk) 16:43, 2 January 2021 (UTC)
 * So maybe inland Chinese mildness was just coincidental antibodies for a similar flu or incomplete data or transmission. Sagittarian Milky Way (talk) 16:57, 2 January 2021 (UTC)


 * And finally, here is a reference: "A new analysis of excess deaths in New York City this spring shows that the current pandemic’s peak had a dramatic impact on mortality in the city, one comparable to that of the 1918 H1N1 influenza pandemic. Investigators found that while the overall incidence rate of mortality was higher in the 1918 pandemic, the current increase was more striking, given that the baseline death rate today is substantially lower than it was a century ago" (September 2020)  Alansplodge (talk) 16:37, 2 January 2021 (UTC)
 * Which is interesting but doesn't strictly say if 1918 and/or 2020 would be worse if COVID and 1918 flu switched years. Someone knowledgeable about modern vs 1918 medical quality and the two diseases would make a better educated guess. Sagittarian Milky Way (talk) 16:50, 2 January 2021 (UTC)

How does Gravitational waves discovery useful in daily life?
How does Gravitational waves discovery useful in daily life? This discovery made three people won nobel prize in 2017. Rizosome (talk) 15:47, 28 December 2020 (UTC)


 * To make sure there aren't hostile aliens communicating to each other with gravitational waves, at least waves above our detection limit. Maybe they'd use gravitational waves or neutrinos cause they're hard to detect. If many more gravitational waves than is plausibly a natural frequency occur with no natural explanation that may be bad, especially if they appear to coding for something. Like evenly distributed small gaps of no gravitational waves when graphed by some aspects which would be ambiguous bits or trits or tetracontaits or whatever. So ruling that out is comforting in addition to the astrophysical knowledge gained. Sagittarian Milky Way (talk) 16:23, 28 December 2020 (UTC)


 * There is no need for it to be useful, see basic research. Fgf10 (talk) 16:45, 28 December 2020 (UTC)
 * The winners of the Nobel Prize must have conferred a great "benefit to humankind". It is not further defined how to make that determination. --Lambiam 00:35, 29 December 2020 (UTC)
 * Knowledge itself is a great benefit. Fgf10 (talk) 09:20, 29 December 2020 (UTC)
 * So the title of the novel The Faculty of Useless Knowledge contains an oxymoron. --Lambiam 12:56, 29 December 2020 (UTC)


 * Also learning this science required pushing the envelope of laser length accuracy and orthogonality and interferometry and the technology invented to find the waves may have practical benefits in other applications that will be invented in the 21st century and might not even be thought of yet. If you already know how to do it when the applications are invented in the future you won't have to waste time learning how to do it cause the envelope has already been pushed. Sagittarian Milky Way (talk) 00:59, 29 December 2020 (UTC)


 * It is useful to our modern lives by not having any use at all, thereby diverting resources that we would otherwise use in a destructive way. Count Iblis (talk) 07:47, 29 December 2020 (UTC)
 * And it keeps people at work and off the streets who otherwise might become hooligans or street robbers. --Lambiam 14:10, 29 December 2020 (UTC)
 * That's it. As I always said to my kids during their formative years, "You've got two choices, boys. Either become hooligans or street robbers, or go and discover gravitational waves. There's not much in the middle, frankly." --  Jack of Oz   [pleasantries]  21:52, 29 December 2020 (UTC)

When did GPS satellites launched in space?
When did GPS satellites launched in space? I didn't find any information about in this article. Rizosome (talk) 16:03, 28 December 2020 (UTC)
 * Actually, the article says "with the first prototype spacecraft launched in 1978 and the full constellation of 24 satellites operational in 1993." Mike Turnbull (talk) 16:25, 28 December 2020 (UTC)
 * That's the first generation, there have been replacement launches of new generation satellites pretty much continuously ever since. The last one was last month, see List of GPS satellites.Fgf10 (talk) 16:44, 28 December 2020 (UTC)
 * It was definitely usable at some level in 1982, as I did a project with Ferranti on it then. That implies there must have been 4 satellites at least. Greglocock (talk) 20:53, 28 December 2020 (UTC)

What's the difference between photovoltaic and photoelectric effect?
What's the difference between photovoltaic and photoelectric effect? Wiki says they are closely related. Rizosome (talk) 16:58, 28 December 2020 (UTC)
 * From the lead of the Photovoltaic effect article:
 * The main distinction is that the term photoelectric effect is now usually used when the electron is ejected out of the material (usually into a vacuum) and photovoltaic effect used when the excited charge carrier is still contained within the material. In either case, an electric potential (or voltage) is produced by the separation of charges, and the light has to have a sufficient energy to overcome the potential barrier for excitation. The physical essence of the difference is usually that photoelectric emission separates the charges by ballistic conduction and photovoltaic emission separates them by diffusion, but some "hot carrier" photovoltaic device concepts blur this distinction.
 * -- ToE 19:09, 28 December 2020 (UTC)