# Betelgeuse, Betelgeuse, Be.. When the star goes supernova, should we worry? **URL:** \ **Category:** Factual Questions\ **Created:** [February 11, 2008, 5:36pm UTC](https://boards.straightdope.com/t/betelgeuse-betelgeuse-be-when-the-star-goes-supernova-should-we-worry/437171 "2008-02-11T17:36:07Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [February 11, 2008, 5:36pm UTC](https://boards.straightdope.com/t/betelgeuse-betelgeuse-be-when-the-star-goes-supernova-should-we-worry/437171/1 "2008-02-11T17:36:07Z")
As if Google Earth was not already a great waste of time. 🙂 Google Earth now has the Space view (available in the latest download) just press the space icon and then see the night sky in unprecedented detail, I decided to take a stroll around Orion an did a close up on Betelgeuse. A few years ago, I asked in the Straight Dope if there was something to worry if this star did go supernova. Even **The Bad Astronomer** mentioned that it was going to be a spectacular sight but because the star was about 600 light years away it was determined that Earth would barely be affected by the explosion. Then on Google Space I notice the link to an astronomy site and… did something change? Now even Wikipedia is reporting that the latest SIMBAD satellite query showed that Betelgeuse is actually 427 light-years away from Earth. Mmm. Should we worry now? :dubious: (Not that it will be likely go supernova now, but should our descendants worry?) ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [February 11, 2008, 6:00pm UTC](https://boards.straightdope.com/t/betelgeuse-betelgeuse-be-when-the-star-goes-supernova-should-we-worry/437171/2 "2008-02-11T18:00:13Z")
About the only way I can see the impending supernova causing us trouble is if one of Betelgeuse’s poles is lined up on us, and we receive the brunt of a [gamma ray burst](http://en.wikipedia.org/wiki/Gamma_ray_burst). Still, I keep an extra jar of [bug juice](http://www.turtlewax.com/main.taf?p=2,5,3,1) in the garage, just in case. ---
**Author:** ![Anne\_Neville](https://avatars.discourse-cdn.com/v4/letter/a/b9e5f3/32.png) [@Anne\_Neville](https://boards.straightdope.com/u/Anne_Neville)\ **Post date:** [February 11, 2008, 6:29pm UTC](https://boards.straightdope.com/t/betelgeuse-betelgeuse-be-when-the-star-goes-supernova-should-we-worry/437171/3 "2008-02-11T18:29:55Z")
[QUOTE=Squink] About the only way I can see the impending supernova causing us trouble is if one of Betelgeuse’s poles is lined up on us, and we receive the brunt of a [gamma ray burst](http://en.wikipedia.org/wiki/Gamma_ray_burst). [/quote] [If what we think is one of Betelgeuse’s poles in fact is, it looks like we might be safe from that.](http://en.wikipedia.org/wiki/Betelgeuse#Observation) > [@GIGObuster](#): > > A few years ago, I asked in the Straight Dope if there was something to worry if this star did go supernova. Even The Bad Astronomer mentioned that it was going to be a spectacular sight but because the star was about 600 light years away it was determined that Earth would barely be affected by the explosion. Then on Google Space I notice the link to an astronomy site and… did something change? Now even Wikipedia is reporting that the latest SIMBAD satellite query showed that Betelgeuse is actually 427 light-years away from Earth. Determining distances to stars is a tricky business. But we think we’re safe if a supernova of the type that Betelgeuse could become happens more than 100 light-years away (unless we’re in the path of a gamma ray burst from it), so either way, we think we’re still OK. ---
**Author:** ![tdn](https://avatars.discourse-cdn.com/v4/letter/t/94ad74/32.png) [@tdn](https://boards.straightdope.com/u/tdn)\ **Post date:** [February 11, 2008, 6:55pm UTC](https://boards.straightdope.com/t/betelgeuse-betelgeuse-be-when-the-star-goes-supernova-should-we-worry/437171/4 "2008-02-11T18:55:46Z")
Here’s something that I’ve been wondering about for a while. Let’s suppose that a nearby star went supernova and we were caught in the blast radius. Would we even know about it? Would the light from the event reach us before the blast material does? ---
**Author:** ![RickJay](https://avatars.discourse-cdn.com/v4/letter/r/bb73d2/32.png) [@RickJay](https://boards.straightdope.com/u/RickJay)\ **Post date:** [February 11, 2008, 7:59pm UTC](https://boards.straightdope.com/t/betelgeuse-betelgeuse-be-when-the-star-goes-supernova-should-we-worry/437171/5 "2008-02-11T19:59:06Z")
1. No. 427 LY is still far enough. 2. When you see distances to stars printed - no matter where - bear in mind they’re not quite wild-ass guesses, but they’re pretty close. Except for the very nearby stars, those distances are **extremely** rough estimates. 3. If I recall correctly, there is, in fact, NO star close enough to Earth that can possibly go supernova that could harm life here. ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [February 11, 2008, 8:00pm UTC](https://boards.straightdope.com/t/betelgeuse-betelgeuse-be-when-the-star-goes-supernova-should-we-worry/437171/6 "2008-02-11T20:00:39Z")
[QUOTE=tdn] Let’s suppose that a nearby star went supernova and we were caught in the blast radius. Would we even know about it? Would the light from the event reach us before the blast material does? [/QUOTE] Well, yes. Light being what it is, travels at the speed of, well, light. Other stuff, not so fast. ---
**Author:** ![Anne\_Neville](https://avatars.discourse-cdn.com/v4/letter/a/b9e5f3/32.png) [@Anne\_Neville](https://boards.straightdope.com/u/Anne_Neville)\ **Post date:** [February 11, 2008, 8:10pm UTC](https://boards.straightdope.com/t/betelgeuse-betelgeuse-be-when-the-star-goes-supernova-should-we-worry/437171/7 "2008-02-11T20:10:52Z")
[QUOTE=Q.E.D.] Light being what it is, travels at the speed of, well, light. Other stuff, not so fast. [/QUOTE] Supernova remnant stuff travels at about 1% of the speed of light. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [February 11, 2008, 8:11pm UTC](https://boards.straightdope.com/t/betelgeuse-betelgeuse-be-when-the-star-goes-supernova-should-we-worry/437171/8 "2008-02-11T20:11:29Z")
I certainly don’t think we should _worry_. If it’s a significant and serious risk, then maybe you should try to finish that book you’ve only been dipping into, but _worrying_ isn’t going to stop it happening, or alter its severity if it does happen. ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [February 11, 2008, 8:18pm UTC](https://boards.straightdope.com/t/betelgeuse-betelgeuse-be-when-the-star-goes-supernova-should-we-worry/437171/9 "2008-02-11T20:18:05Z")
[QUOTE=Q.E.D.] Other stuff, not so fast. [/QUOTE] [Neutrinos are no slouches:](http://en.wikipedia.org/wiki/SN_1987A#Neutrino_emissions) > [@](#): > > Approximately three hours before the visible light from SN 1987A reached the Earth, a burst of neutrinos was observed at three separate neutrino observatories. This is due to the neutrino emission (which occurs simultaneously with core collapse) preceding the emission of visible light (which occurs only after the shock wave reaches the stellar surface). > … > the distance to SN1987A, which is about 168,000 light-years. ---
**Author:** ![tdn](https://avatars.discourse-cdn.com/v4/letter/t/94ad74/32.png) [@tdn](https://boards.straightdope.com/u/tdn)\ **Post date:** [February 11, 2008, 8:18pm UTC](https://boards.straightdope.com/t/betelgeuse-betelgeuse-be-when-the-star-goes-supernova-should-we-worry/437171/10 "2008-02-11T20:18:16Z")
[QUOTE=Anne Neville] Supernova remnant stuff travels at about 1% of the speed of light. [/QUOTE] Really, that slow? I guess when I think about it the matter couldn’t possibly travel at the speed of light. It would have to have basically no mass in order to do so. ---
**Author:** ![Anne\_Neville](https://avatars.discourse-cdn.com/v4/letter/a/b9e5f3/32.png) [@Anne\_Neville](https://boards.straightdope.com/u/Anne_Neville)\ **Post date:** [February 11, 2008, 8:36pm UTC](https://boards.straightdope.com/t/betelgeuse-betelgeuse-be-when-the-star-goes-supernova-should-we-worry/437171/11 "2008-02-11T20:36:52Z")
[QUOTE=tdn] I guess when I think about it the matter couldn’t possibly travel at the speed of light. It would have to have basically no mass in order to do so. [/QUOTE] It would have to have exactly no mass to travel at the speed of light. (There’s a short story by Isaac Asimov where this is a plot point) It would have to have imaginary mass (ie, involving the square root of -1) to travel faster than light. > [@Squink](#): > > Neutrinos are no slouches Neutrinos have mass (at least that’s the current scientific opinion), so they travel slower than light. They managed to reach us from Supernova 1987A before the light did because the process in the supernova that emits them happens before the process that emits the light. They had a head start, in other words. This isn’t the case for the supernova remnant stuff, at least not AFAIK (IANAsupernova expert). ---
**Author:** ![Sean\_Factotum](https://avatars.discourse-cdn.com/v4/letter/s/50afbb/32.png) [@Sean\_Factotum](https://boards.straightdope.com/u/Sean_Factotum)\ **Post date:** [February 11, 2008, 8:54pm UTC](https://boards.straightdope.com/t/betelgeuse-betelgeuse-be-when-the-star-goes-supernova-should-we-worry/437171/12 "2008-02-11T20:54:33Z")
[QUOTE=RickJay] 1. If I recall correctly, there is, in fact, NO star close enough to Earth that can possibly go supernova that could harm life here. [/QUOTE] Not even that big yellow one that shines in my eyes every morning as I drive to work? 😉 ---
**Author:** ![GIGObuster](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gigobuster/32/421_2.png) [@GIGObuster](https://boards.straightdope.com/u/GIGObuster)\ **Post date:** [February 11, 2008, 8:58pm UTC](https://boards.straightdope.com/t/betelgeuse-betelgeuse-be-when-the-star-goes-supernova-should-we-worry/437171/13 "2008-02-11T20:58:04Z")
[QUOTE=Mangetout] I certainly don’t think we should _worry_. If it’s a significant and serious risk, then maybe you should try to finish that book you’ve only been dipping into, [/quote] How did you know? Oh wait, you mean reading it, not writing it. 😉 [QUOTE=Mangetout] but _worrying_ isn’t going to stop it happening, or alter its severity if it does happen. [/QUOTE] IIRC on the last thread there was talk that if the distance was less than 500 light years away then we have to worry not only about gamma rays but also x-rays. However, at that distance the damage would be limited to satellites and some roasted astronauts. So it is not that I’m worrying much for humanity, but the problems some could encounter when it happens. As I noticed that Betelgeuse is closer than 500 light years, then I wanted to investigate how much more then would Betelgeuse going supernova could affect us. Thanks to **Anne Neville** for the explanations. ---
**Author:** ![Voyager](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/voyager/32/133_2.png) [@Voyager](https://boards.straightdope.com/u/Voyager)\ **Post date:** [February 11, 2008, 9:15pm UTC](https://boards.straightdope.com/t/betelgeuse-betelgeuse-be-when-the-star-goes-supernova-should-we-worry/437171/14 "2008-02-11T21:15:52Z")
[QUOTE=Sean Factotum] Not even that big yellow one that shines in my eyes every morning as I drive to work? 😉 [/QUOTE] Nope. The Sun’s too small. It will kill us in other ways, just as effectively. I’m too lazy to compute what percent of Betelgeuse’s mass would reach us as a part of the surface of a sphere with a radius of 427 LY. Would we even be able to detect it? ---
**Author:** ![Anne\_Neville](https://avatars.discourse-cdn.com/v4/letter/a/b9e5f3/32.png) [@Anne\_Neville](https://boards.straightdope.com/u/Anne_Neville)\ **Post date:** [February 11, 2008, 9:23pm UTC](https://boards.straightdope.com/t/betelgeuse-betelgeuse-be-when-the-star-goes-supernova-should-we-worry/437171/15 "2008-02-11T21:23:40Z")
[QUOTE=Sean Factotum] Not even that big yellow one that shines in my eyes every morning as I drive to work? 😉 [/QUOTE] It can’t go supernova. To be able to go supernova, a star has to either be at least eight or nine times as massive as the Sun, or be a white dwarf and have a mass of at least 1.4 solar masses. White dwarfs generally get a mass of more than 1.4 solar masses from a companion star that has expanded to a red giant. The outer layers of the red giant aren’t held very tightly, and if the white dwarf is close enough, it might be able to pull those layers onto itself. When the white dwarf gets a mass greater than about 1.4 solar masses (depending somewhat on its rotation), it collapses and creates a Type Ia supernova. There actually is a star within 10 light years that may eventually become a Type Ia supernova- Sirius B, the white dwarf companion of Sirius. But Sirius B isn’t gaining mass now, as far as we can tell- it won’t until Sirius A becomes a red giant. (A stellar collision could probably do it, but that’s incredibly unlikely) We think that, by the time Sirius B could go supernova, it will have moved far enough away from us so as not to be a problem. > [@Voyager](#): > > I’m too lazy to compute what percent of Betelgeuse’s mass would reach us as a part of the surface of a sphere with a radius of 427 LY. Would we even be able to detect it? Me too, but my guess is that we wouldn’t. ---
**Author:** ![tdn](https://avatars.discourse-cdn.com/v4/letter/t/94ad74/32.png) [@tdn](https://boards.straightdope.com/u/tdn)\ **Post date:** [February 11, 2008, 9:48pm UTC](https://boards.straightdope.com/t/betelgeuse-betelgeuse-be-when-the-star-goes-supernova-should-we-worry/437171/16 "2008-02-11T21:48:26Z")
[QUOTE=Anne Neville] (IANAsupernova expert). [/QUOTE] Really? ---
**Author:** ![Squink](https://avatars.discourse-cdn.com/v4/letter/s/b5e925/32.png) [@Squink](https://boards.straightdope.com/u/Squink)\ **Post date:** [February 11, 2008, 9:53pm UTC](https://boards.straightdope.com/t/betelgeuse-betelgeuse-be-when-the-star-goes-supernova-should-we-worry/437171/17 "2008-02-11T21:53:38Z")
[QUOTE=Anne Neville] Neutrinos have mass (at least that’s the current scientific opinion), so they travel slower than light. They managed to reach us from Supernova 1987A before the light did because the process in the supernova that emits them happens before the process that emits the light. They had a head start, in other words. [/QUOTE] Sure, a few hours, or maybe a day. But to precede the photon front after a run of 168,000 light years, they’d still have to be ripping right along. ---
**Author:** ![Polycarp](https://avatars.discourse-cdn.com/v4/letter/p/82dd89/32.png) [@Polycarp](https://boards.straightdope.com/u/Polycarp)\ **Post date:** [February 11, 2008, 9:53pm UTC](https://boards.straightdope.com/t/betelgeuse-betelgeuse-be-when-the-star-goes-supernova-should-we-worry/437171/18 "2008-02-11T21:53:50Z")
So supernovas in the immediate stellar neighborhood are no concern right now, but given the potential at Alpha Canis Majoris, in astronomical time scales, it could be a Sirius problem? ---
**Author:** ![Astroboy14](https://avatars.discourse-cdn.com/v4/letter/a/df705f/32.png) [@Astroboy14](https://boards.straightdope.com/u/Astroboy14)\ **Post date:** [February 11, 2008, 10:36pm UTC](https://boards.straightdope.com/t/betelgeuse-betelgeuse-be-when-the-star-goes-supernova-should-we-worry/437171/19 "2008-02-11T22:36:02Z")
[QUOTE=Polycarp] So supernovas in the immediate stellar neighborhood are no concern right now, but given the potential at Alpha Canis Majoris, in astronomical time scales, it could be a Sirius problem? [/QUOTE] When Cthulhu comes, you will be among the last consumed. ---
**Author:** ![IAmNotSpartacus](https://avatars.discourse-cdn.com/v4/letter/i/cc9497/32.png) [@IAmNotSpartacus](https://boards.straightdope.com/u/IAmNotSpartacus)\ **Post date:** [February 12, 2008, 1:39am UTC](https://boards.straightdope.com/t/betelgeuse-betelgeuse-be-when-the-star-goes-supernova-should-we-worry/437171/20 "2008-02-12T01:39:01Z")
Why are we so worried about the gamma ray burst? What will happen if we take one head on? [Next page](https://boards.straightdope.com/t/betelgeuse-betelgeuse-be-when-the-star-goes-supernova-should-we-worry/437171.md?page=2)