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Hubble finds that Betelgeuse's dimming is likely due to ejection of gases
- raxxorrax 6y ago> that the old star was about to go supernova I think the estimate is that Betelgeuse is about 10 million years old, some suggest it is closer to 8 million. Our sun is in its prime with 4.5 billion years. Glad that stars can have a vastly different life expectancy.
- cninja 6y agoEvery star has the force of gravity that is pressing all the gas to collapse, and heat from fusion that is pushing all the gas apart. These forces are balanced in a stable star: fusion reaction provides the energy that prevents the gas from collapsing. In comparison to our sun, a larger star like Betelgeuse needs to sustain a higher level of fusion to fight off the effects of the higher gravitational force. Larger stars have shorter lifespans because they burn through their fuel faster.
- throwaway5752 6y agoRed dwarfs have to counter less gravity pressure and can be fully convective - they can burn for trillions of years: https://en.wikipedia.org/wiki/Red_dwarf https://en.wikipedia.org/wiki/Red_dwarf
- formerly_proven 6y agoThe absolute magnitude scale is hilarious: logarithmic and inverted. A value lower by 5 means it's 100 times brighter.
- bonzini 6y agoThe magnitude (absolute or apparent) actually started as an ordinal number: in Italian we still say sometimes first magnitude instead of magnitude 1. Of course that doesn't work too well for the Sun's magnitude of -26.
- marcosdumay 6y agoSo, that graph on the GP's link has a total scale of 10^14 times between the smallest and largest point. What is roughly the difference between the energy of electrical and nuclear phenomena.
- _ph_ 6y agoFor hydrogen-burning stars, the life expectancy is reciprocal to their mass. As Betelgeuse is much more massive than the Sun, its lifetime is considerably shorter. As it is already a red giant, it is in its last phase before going supernova. One far day in the future, the Sun is also going to become a red giant, extending out till the Mars orbit. But that is still much smaller than Betelgeuse is right now. Actually it is so large, that its diameter can be directly measured by astronomers.
- T-hawk 6y agoIt's more than reciprocal. Fusion rate and luminosity go up enormously with stellar mass, like m^4 or even higher, so the lifetime goes more like 1/m^4. Sirius for example is 2x the mass of the sun, but 25x as luminous, therefore 2/25 the lifetime until it runs out of hydrogen.
- lightlyused 6y agodupe: https://news.ycombinator.com/item?id=24148796 https://news.ycombinator.com/item?id=24148796
- eganist 6y ago> dupe: https://news.ycombinator.com/item?id=24148796 https://news.ycombinator.com/item?id=24148796 I found this out recently: HN doesn't have a programmatic de-duping system the way Reddit does, so they permit multiple submissions of the same link and don't dedupe until one gets traction. If a link has already had some amount of discussion on it and it's resubmitted soon after, that's when they de-dupe.
- dang 6y agoCorrect. Described, along with much else, in the recently expanded FAQ: https://news.ycombinator.com/newsfaq.html https://news.ycombinator.com/newsfaq.html.
- antupis 6y agoPlease go boom.
- maskedinvader 6y agoyes, please , pretty please, imagine having something as bright as the full moon visible even during the day, decorating our evening skies for a few weeks. oh please happen in my lifetime, please !
- 0xfaded 6y agoAlso, please happen during wintertime in the northern hemisphere. Covid means I won't be escaping the gloom this year.
- EarthIsHome 6y agoHow long would it last?
- pchristensen 6y agoMonths.
- Cofor 6y agoWouldn't we be showered by particles/gamma rays though? I mean... its not only visible light reaching us... but I'm not an astrophysicist
- TheOtherHobbes 6y agoThere might be a small increase in background radiation, but B is too far away to do anything dangerous or dramatic.
- Ma8ee 6y agoThat would be a fitting end to the year 2020.
- zentiggr 6y ago
- ryneandal 6y agoAwesome to have an explanation now. Recently watched this video, and this reason was one of the suggestions for explanation: https://www.youtube.com/watch?v=5bvuwTuGnkc https://www.youtube.com/watch?v=5bvuwTuGnkc
- jug 6y agoImagine the scientific gains by observing a nearby supernova event “live” (you know what I mean). I heard most likely is that it would become either a neutron star/ pulsar or black hole depending on retained material in the innermost region following the supernova.
- angel_j 6y agoAh, the language of science in our times, a universe described as "violent" and "traumatic".
- dang 6y agoI noticed that weirdness as well. Replaced with representative language from the article body.
- Iwan-Zotow 6y agoBetelgeuse is farting! Ignobel prize is coming!