[HN Gopher] How A Supernova Explodes (1985) [pdf] ___________________________________________________________________ How A Supernova Explodes (1985) [pdf] Author : rwmj Score : 61 points Date : 2023-06-16 20:55 UTC (1 days ago) (HTM) web link (astro.uconn.edu) (TXT) w3m dump (astro.uconn.edu) | pixel_tracing wrote: | Fun fact: Betelgeuse has been predicted to go supernova in our | lifetimes. There is usually a live stream on YouTube you can | observe of Betelgeuse | throwbadubadu wrote: | What is the real one? Too many "happening now" :/ | kristianc wrote: | The problem is that it could also happen at any time in the | next 10,000 to 100,000 years. | irrational wrote: | But, it could also happen tomorrow! I do hope it happens | tomorrow, because that would be so cool. | Sharlin wrote: | That's not a very accurate way of saying "it could go supernova | anytime in the next 100,000 years" meaning that it almost | certainly won't go during our lifetimes. Unless we'll live for | a long time which of course is not entirely out of the | question. | | Also, I'm pretty sure there's no non-fake live stream of | Betelgeuse on Youtube because it would require several robotic | telescopes around the world programmed to coordinate and stream | from wherever it's a) night and b) Betelgeuse in the sky. | shagie wrote: | https://en.wikipedia.org/wiki/Betelgeuse#Media_reporting | | > Due to misunderstandings caused by the 2009 publication of | the star's 15% contraction, apparently of its outer atmosphere, | Betelgeuse has frequently been the subject of scare stories and | rumors suggesting that it will explode within a year, and | leading to exaggerated claims about the consequences of such an | event. The timing and prevalence of these rumors have been | linked to broader misconceptions of astronomy, particularly to | doomsday predictions relating to the Mayan calendrical | apocalypse. Betelgeuse is not likely to produce a gamma-ray | burst and is not close enough for its X-rays, ultraviolet | radiation, or ejected material to cause significant effects on | Earth. | | > Following the dimming of Betelgeuse in December 2019, reports | appeared in the science and mainstream media that again | included speculation that the star might be about to explode as | a supernova - even in the face of scientific research that a | supernova is not expected for perhaps 100,000 years. Some | outlets reported the magnitude as faint as +1.3 as an unusual | and interesting phenomenon, like Astronomy magazine, the | National Geographic, and the Smithsonian. | | > Phil Plait, in his Bad Astronomy blog, noting that | Betelgeuse's recent behaviour, "[w]hile unusual . . . isn't | unprecedented," argued that the star is not likely to explode | "for a long, long time." Dennis Overbye of The New York Times | agreed that an explosion was not imminent but added that | "astronomers are having fun thinking about it. | | --- | | Evolutionary tracks for Betelgeuse | https://arxiv.org/abs/1406.3143v2 | | > The best-fit MESA model left the main sequence about 10e6 | yrs. ago, while for the EG model it was only about 3 x 10e5 | years ago. Both models reached the base of the RGB about 40,000 | years ago. We followed the star through the final ex- haustion | of core helium burning in both codes, followed by brief epochs | of core-carbon, neon, oxygen and silicon burning until core | collapse and super-nova an age of 8.5 Myr since the ZAMS for | the MESA code. Our best guess is that the star will supernova | in less than ~ 100, 000 yrs (even longer in the EG model). We | note, however, that there error ellipse encompasses the entire | track so that the star could be further along in its evolution. | The constraint that it has passed the first dredge-up, however, | means that the star is ascending the RSG phase. Our result is | based upon mass loss from the base of the RGB is therefore a | lower limit to how far it has evolved as a RSG. | OldGuyInTheClub wrote: | Repeating this recommendation from a recent comment thread | involving the Bethe/Brown article[0]. | | Youtuber "But Why?" has a very nicely animated explanation of the | current state of affairs of core-collapse supernovae at | https://www.youtube.com/watch?v=Yt-SBT7nNfU | | [0] Comment section of | https://news.ycombinator.com/item?id=36362770 | ramraj07 wrote: | Thanks, always on the lookout for new supernova YouTube videos, | which surprisingly there are very few of which explain actual | details as opposed to the drivel that is kurzgesagt. Many of | these Popsci videos are even straight out wrong, they'll say | crap like the core produces one neutrino per proton - like the | math doesn't even add up dudes. Your video finally explains why | there's so many neutrinos produced. | | Your video perfectly complements the two others I love. I'd say | the perfect watching order would be to first see the general | supernova discussion by launch pad astronomy[1], followed by | your suggestion, then the "how to build a black hole" by pbs | space time [2]. | | 1. https://youtu.be/RZkR9zdUv-E | | 2. https://youtu.be/xx4562gesw0 | OldGuyInTheClub wrote: | I enjoy Launch Pad's detailed look at things, as well. But, I | also like Kurzgesagt. There's something about the pacing and | editing of PBS videos that I find hard to watch for long | periods of time. No qualms about the content, it seems like | they edit out all the pauses. | ramraj07 wrote: | I'm not a fan of Kurzgesagt at all unfortunately. I'm not a | physicist so I'll say maybe there's some justification that | I don't fathom that explains why their fundamental | explanation of the science is so terrible. | | But I am a biologist and I can assure you a good load of | videos they make on it are at best not great explanations | or at worst fundamentally unsubstantiated drivel. Like | their latest one about how your body "kills cancers every | day". I went through their massive google doc "evidence" | and as suspected not a single real reference to any proof | that this is true. It COULD be true, but it's not proven. | I'm not even sure the evidence we have is actually pointing | towards this direction. If it's true that your immune | system clears cancers every day, then immunosuppression | should instantly plunge you into cancer. Does it? Not | really. May be some blood cancers but that's it. | | Point is, they show shiny videos explaining almost | plausible sounding scientific concepts. But often it's | still michio kaku level sensationalism. I personally | believe this disingenuousness is the root cause of | degradation in trust in science. The average person does | have the ability to sniff bullshit and it eventually | catches up to them in their mind that these scientists have | no idea what they're talking about (like my observation | that these videos say there's one neutron per proton in a | supernova; I could instantly smell something rotten). | Eliezer wrote: | I miss reading things like this. | moffkalast wrote: | I miss having the patience to read things like this too. | guender wrote: | [dead] ___________________________________________________________________ (page generated 2023-06-17 23:00 UTC)