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What happens when Betelgeuse explodes?
- astletron 12y ago"Nighttime will be a different story. The brightness of Betelgeuse’s supernova is about the same as the quarter moon." This will last maybe a couple of weeks, but we don't expect it for 100K years.
- themartorana 12y agoNo, but with billions of stars in our own galaxy, and more beyond, wouldn't (my misunderstanding of) the probability of witnessing a past supernova event during one's lifetime be higher than it feels like it is?
- onion2k 12y agoNot really. There are a huge number of stars, but most of them are moving away so fast that the light from their death wouldn't ever reach us, and their light would be shifted in to parts of the spectrum we can't see. Similar to Olbers' Paradox - http://en.wikipedia.org/wiki/Olbers%27_paradox http://en.wikipedia.org/wiki/Olbers%27_paradox
- mabbo 12y ago> most of them are moving away so fast that the light from their death wouldn't ever reach us Correct me if I'm wrong, but I believe that's mistaken. Given enough time, even things moving away from us at the speed of light will eventually be seen by us. http://en.wikipedia.org/wiki/Ant_on_a_rubber_rope http://en.wikipedia.org/wiki/Ant_on_a_rubber_rope
- pharke 12y ago> ...galaxies that are more than approximately 4.5 gigaparsecs away from us are expanding away from us faster than light. We can still see such objects because the Universe in the past was expanding more slowly than it is today, so the ancient light being received from these objects is still able to reach us, though if the expansion continues unabated, there will never come a time that we will see the light from such objects being produced today (on a so-called "space-like slice of spacetime") and vice versa because space itself is expanding between Earth and the source faster than any light can be exchanged. https://en.wikipedia.org/wiki/Metric_expansion_of_space https://en.wikipedia.org/wiki/Metric_expansion_of_space The rate of expansion of space-time is currently accelerating so the ant on a rubber rope analogy does not hold. Edit: from the ant on a rubber rope article you linked > However, the metric expansion of space is accelerating. An ant on a rubber rope whose expansion increases with time is not guaranteed to reach the endpoint.[3] The light from sufficiently distant galaxies may still therefore never reach Earth.
- Steuard 12y agoThis is complicated. Given the accelerating expansion of the universe, there's an eventual "horizon" where light beyond that limit will never manage to get here, simply because the empty space between here and there will expand faster than the light can make up the distance. My understanding is that under current cosmological models, a likely scenario is that eventually (on the order of multiple billion years), everything beyond our local gravitationally-bound group of galaxies (us, Andromeda, and a few hangers-on) will be 100% invisible forever. Kinda makes you wonder what distant-future astronomers might think of the old tales of "galaxy clusters" or "cosmic structure formation".
- astrobe_ 12y agoMoreover, A good number are in the Milky way or the Andromeda galaxy, which is bound to collide with ours; plus the respective satellite galaxies of the Milky Way + Andromeda. Will Univers' expansion make even them "disappear"?
- jerf 12y agoFirst of all, the "pastness" of looking out into space doesn't really affect probability of witnessing them. Second, supernova occur quite frequently: http://en.wikipedia.org/wiki/List_of_supernovae http://en.wikipedia.org/wiki/List_of_supernovae That's not even a complete list, just the "important" ones. The odds of one occurring within our lifetime that is naked-eye visible are really quite good. The odds of it being spectacular much less so. It's likely to just be a point in the sky that wasn't there last week and won't be there next week.
- smeyer 12y agoIt depends in part on what you mean by "witness" a supernova. We discover supernovae all the time (hundreds a year), but pretty much all of those are too faint to be seen with the naked eye. There's a decent chance of seeing a supernova visible with the naked eye in your lifetime, but a pretty small chance of one as bright as betelgeuse.
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- robinhoodexe 12y agoI'm pretty sure Ford Prefect would be rather disappointed that his home planet got blown up...
- yourad_io 12y agoDon't worry, he won't know for about 600 years. And they can always construct a new one.
- adwn 12y agoTo get a feel for the tremendous size of that star: https://en.wikipedia.org/wiki/File:Star-sizes.jpg https://en.wikipedia.org/wiki/File:Star-sizes.jpg
- jahnu 12y agoI feel those images are a little misleading. One might erroneously assume there is a dense surface akin to our star at the outer edge of these massive stars but.. "In the outer reaches of the photosphere the density is extremely low, yet the total mass of the star is believed to be no more than 20 M☉. Consequently, the average density is less than twelve parts per billion (1.119 × 10−8) that of the Sun. Such star matter is so tenuous that Betelgeuse has often been called a "red-hot vacuum"." https://en.wikipedia.org/wiki/Betelgeuse#Density https://en.wikipedia.org/wiki/Betelgeuse#Density
- gunn 12y agoAlso: "estimates of its mass are poorly constrained, but range from 5 to 30 times that of the Sun". Amazing for having on the order of 16 billion times its volume.
- jjoonathan 12y agoHow does that happen? Is its fuel more energetic in some sense or does the gravity-vs-pressure equilibrium simply favor lower densities for a total mass of 20M☉?
- nate_meurer 12y agoYou're right on both counts! Betelgeuse is burning helium now (post main-sequence). The higher output of helium fusion inflates the outer atmosphere like a giant floppy balloon.
- hellbanner 12y agoThose images accurately show size, correct? Stars are big.
- Starwatcher2001 12y agoThe remnents of the supernova that occurred in 1054 is known as the "Crab Nebula", AKA M1 on Messier's catalog. I remember observing this from my back garden some 10 years ago with a small telescope, but that's quite difficult now due to light polution. It's getting hard for people to see stars in many big cities, let alone fainter objects.
- agrona 12y agoThere's a guide (in development) at eyesonthesky.com[1] aimed at newcomers, who may be using poor telescopes in poor atmospheric and lighting conditions. I've been following it quite successfully from my back yard in Seattle. It focuses on the brightest galaxies and nebulae, interesting clusters, and binary stars. [1] http://eyesonthesky.com/StarCharts/FirstLightGuides.aspx http://eyesonthesky.com/StarCharts/FirstLightGuides.aspx
- kijin 12y agoOther than slightly brighter-than-normal nights, will there be any adverse effects on Earth? The wikipedia article on near-Earth supernovae [1] suggests that Betelgeuse will be pretty safe because of its distance. But exactly how safe? What about all the delicate electronics that we've sent up to space? I suppose anything that can withstand a daily dose of solar radiation would probably be okay, but are there any specific wavelengths that could cause an issue? [1] https://en.wikipedia.org/wiki/Near-Earth_supernova https://en.wikipedia.org/wiki/Near-Earth_supernova
- aruggirello 12y agoActually, a supernova would look like an impossibly tiny point source, much smaller than even your average laser pointer. I'm pretty sure the consequences of this haven't been thoroughly explored yet. I'm not sure the Betelgeuse supernova, at a brightness around that of the full moon, would ignite fires, but I certainly wouldn't want to gaze at it with naked eyes, even at that brightness. IMHO such a light, given sufficient strength, could permanently damage the retina in your eyes.
- avian 12y agoI doubt it. Even without knowing exact surface power density that can cause damage to retina, the magnitudes discussed here sound far from dangerous. You should know that even an impossibly tiny point source will get projected to a spot of finite size on the retina. The eye is not perfect - there is always some optical aberration. Plus, since we're talking about a star, there's also atmospheric distortion to think about. The chances of light from Betelgeuse igniting a fire are very much zero. We're talking about light intensity about 10x lower than moonlight.
- ksmiley 12y agoYour reasoning reminds me of the danger of retinal damage when observing a solar eclipse - a human's natural inclination to not stare at the sun is sharply reduced because the viewable area is so much smaller than usual. Looking at a thin slice of the sun is as dangerous as looking at the unobscured sun, even if it doesn't feel like it. But I don't think Betelgeuse would be dangerous in this way. It would be more like watching a lunar eclipse, which may be done without safety equipment.
- dghf 12y agoAny risk of a gamma-ray burst affecting Earth?
- Lewton 12y agoEvery second of every day :)
- Filligree 12y agoNot from a supernova. Gamma-ray bursts are a wholly different phenomenon.
- smeyer 12y agoNot all supernovae have a GRB and not all GRBs have a supernova, but most long burst GRBs are thought to be from a supernova, no? I've been out of supernova research for a few years now, but that's what I recall.
- jgh 12y agoBased on my degree in astrophysics from the University of Popular Science Blogs IIRC they're from quasars or something.
- smeyer 12y agoSo, I definitely didn't study GRBs in any depth, but based on my increasingly vague memories from my degree in astrophysics, quasars don't have much to do with it. All of the major proposed mechanisms I recall for GRBs are on the scale of a star or two (supernovae, neutron star mergers, and the like) whereas quasars are a phenomenon involving supermassive black holes in galactic nuclei. Please, definitely correct me if I'm wrong!
- antognini 12y agoYou're correct. It's thought that long GRBs originate in certain kinds of supernovae. (What kinds of supernovae specifically isn't really known.) Short GRBs are thought to originate in mergers between neutron stars.
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- youonlyliveonce 12y agoNo need to get bothered. Not everyone took science classes after high school.
- youonlyliveonce 12y agothanks for the downvotes. bitches
- maxerickson 12y agoYou don't see any qualitative difference between a millisecond and a year? To me one is imperceptible and the other is hard to reason about as a whole (of course I can make use of an abstract idea of a year, but imagine the experiences of a year all at once? Nope.)
- d_theorist 12y ago"Betelgeuse is already one of the brightest stars in the night sky, sitting somewhere around the 8th or 9th brightest star in the night sky. (These lists don’t include the Sun, which is somewhat obviously always the brightest object in the sky.)" A good point, although it is fairly rare to see the sun in the night sky these days.
- whoisthemachine 12y agoDepending on your definition of "night sky", I would argue it's incredibly easy to see in the night sky!
- amoruso 12y agoThis article reminded me of something I read a few years ago. What is it like to be really near a supernova? It's a quick read and entertaining too. Life (Briefly) Near a Supernova: http://www.nagt.org/files/nagt/jge/abstracts/Dutch_v53n1.pdf http://www.nagt.org/files/nagt/jge/abstracts/Dutch_v53n1.pdf
- nsxwolf 12y agoThe transition of the star to nebula will also permanently alter the appearance of the constellation Orion, which is both exciting and sad.
- rquantz 12y agoI like the maxim "this too shall pass." It's easy to think of on a generational level - our fathers' generation will disappear, and so will ours. But on the level of a civilization, it becomes both stranger and sadder. Orion is a shape in the sky that humanity has always been able to see (so long as we've lived in the northern hemisphere), and one day, assuming we still grace this planet in 100,000 years, it will no longer resemble the hunter the Greeks imagined. But then, billions of years hence, all the stars will have realigned, the Milky Way will have combined with andromeda. And beyond even that, the energy will so diminish that the bonds of the atoms will release. This too shall pass.
- sixdimensional 12y agoI agree with you. I have found that the beauty of the temporary nature of everything (especially when considered in enormous time scales) highlights the beauty of the here and now.. and the need to enjoy it. In fact, while some say not to think of the future and stay in the present, sometimes I find that imagining far into the future is precisely what brings me back to the importance of and focus on the present. Also, there's a feeling of pure awe I get when trying to imagine the unimaginable scale of the future (for us at least). It's a specific sensation.. I am not even sure awe is the right word to describe it.
- shrikrishna 12y agoStarts-With-A-Bang is a must-follow blog collection for anyone mildly interested in Physics. They're all frequent, up to date, and most importantly, accurate.
- cgtyoder 12y agoAll that said, Betelgeuse isn’t expected to explode for another 100,000 years or so. Total click bait title.
- TazeTSchnitzel 12y agoWhen I read that title, I assumed it had something to do with Douglas Adams.
- lotsofmangos 12y agoYou are maybe thinking of the Great Collapsing Hrung Disaster that wiped out all the old Praxibetel communities on Betelgeuse Seven.
- mkramlich 12y agosemi-related: Betty From Betelgeuse is the name of one of the main characters in my book series The Dread Space Pirate Richard. I chose Betelgeuse partly as a nod to HHGG and partly for the way it read and sounded when pronounced aloud. I think of all the star names it is possibly the most beautiful and memorable.
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