# Is Orion going to have a bum shoulder? **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [December 27, 2019, 8:35pm UTC](https://boards.straightdope.com/t/is-orion-going-to-have-a-bum-shoulder/845468 "2019-12-27T20:35:06Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Northern\_Piper](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/northern_piper/32/5304_2.png) [@Northern\_Piper](https://boards.straightdope.com/u/Northern_Piper)\ **Post date:** [December 27, 2019, 8:35pm UTC](https://boards.straightdope.com/t/is-orion-going-to-have-a-bum-shoulder/845468/1 "2019-12-27T20:35:06Z")
Betelgeuse, normally one of the brightest stars in the sky, has been steadily dimming over the past two months, to the point it’s no longer in the top ten for magnitude. Betelgeuse is a red super-giant, and there’s speculation that the sudden dimming could be a sign IT’S GONNA BLOW! If it does, it would be the first supernova in our galaxy since Kepler’s time, early in the 17th century. Likely could be visible by daylight, or as bright as the moon at night. Or it could all just be a hiccup and nothing will happen for 800,000 years. Will be fascinating if we do get to see it. Couple of news articles: > **[Astronomers are wondering whether Orion's shoulder will soon explode | CBC News](https://www.cbc.ca/news/science/betelgeuse-dimming-1.5407038)** > > The dramatic dimming of a giant star has astronomers wondering whether it's getting ready to go supernova. If Betelgeuse, the shoulder on the left side in the constellation Orion, were to explode, it would become as bright as a full moon. > **[Is Betelgeuse About To Explode?](https://www.forbes.com/sites/startswithabang/2019/12/25/is-betelgeuse-about-to-explode/#45680d1d47bf)** > > It's a supergiant star in the final stage of its life, and it just dimmed by an enormous amount. What's going on? ---
**Author:** ![DCnDC](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/dcndc/32/2842_2.png) [@DCnDC](https://boards.straightdope.com/u/DCnDC)\ **Post date:** [December 27, 2019, 8:40pm UTC](https://boards.straightdope.com/t/is-orion-going-to-have-a-bum-shoulder/845468/2 "2019-12-27T20:40:41Z")
Serious question: how we know it hasn’t already? Or don’t we? ---
**Author:** ![Gatopescado](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/gatopescado/32/5711_2.png) [@Gatopescado](https://boards.straightdope.com/u/Gatopescado)\ **Post date:** [December 27, 2019, 8:46pm UTC](https://boards.straightdope.com/t/is-orion-going-to-have-a-bum-shoulder/845468/3 "2019-12-27T20:46:26Z")
Say it three times fast. Would be quite a show. ---
**Author:** ![Broomstick](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/broomstick/32/246_2.png) [@Broomstick](https://boards.straightdope.com/u/Broomstick)\ **Post date:** [December 27, 2019, 8:59pm UTC](https://boards.straightdope.com/t/is-orion-going-to-have-a-bum-shoulder/845468/4 "2019-12-27T20:59:31Z")
> [@DCnDC](#): > > Serious question: how we know it hasn’t already? Or don’t we? Since information can only travel at the speed of light and Betelgeuse is believed to be 640 light years away whatever we’re seeing now happened 640 years ago. So it if pops off in reality that happened 640 years ago and we’re just seeing it now. ---
**Author:** ![Northern\_Piper](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/northern_piper/32/5304_2.png) [@Northern\_Piper](https://boards.straightdope.com/u/Northern_Piper)\ **Post date:** [December 27, 2019, 8:59pm UTC](https://boards.straightdope.com/t/is-orion-going-to-have-a-bum-shoulder/845468/5 "2019-12-27T20:59:49Z")
It could have happened, but would be undetectable until the light and neutrinos arrive. When we look at stars, we are always looking into the past, but from our frame of reference, it’s the present. ---
**Author:** ![Jackmannii](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jackmannii/32/311_2.png) [@Jackmannii](https://boards.straightdope.com/u/Jackmannii)\ **Post date:** [December 27, 2019, 9:18pm UTC](https://boards.straightdope.com/t/is-orion-going-to-have-a-bum-shoulder/845468/6 "2019-12-27T21:18:18Z")
> [@](#): > > If we were in the way of the beam-type explosion — which we’re not — or if Betelgeuse was a lot closer, we’d be in trouble. How the hell do they know for sure we’re _not_ “in the way of the beam-type explosion”??? Damn, I’m going to have seconds on pie tonight. :eek: ---
**Author:** ![Darren\_Garrison](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/darren_garrison/32/92_2.png) [@Darren\_Garrison](https://boards.straightdope.com/u/Darren_Garrison)\ **Post date:** [December 27, 2019, 9:28pm UTC](https://boards.straightdope.com/t/is-orion-going-to-have-a-bum-shoulder/845468/7 "2019-12-27T21:28:44Z")
[This](https://earthsky.org/space/betelgeuse-fainting-probably-not-about-to-explode) article has a nice illustration of BJ’s size compared to our solar system. ---
**Author:** ![Northern\_Piper](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/northern_piper/32/5304_2.png) [@Northern\_Piper](https://boards.straightdope.com/u/Northern_Piper)\ **Post date:** [December 27, 2019, 9:36pm UTC](https://boards.straightdope.com/t/is-orion-going-to-have-a-bum-shoulder/845468/8 "2019-12-27T21:36:28Z")
> [@Jackmannii](#): > > How the hell do they know for sure we’re _not_ “in the way of the beam-type explosion”??? > > Damn, I’m going to have seconds on pie tonight. :eek: Seconds on pie is always a good idea, regardless the state of the universe. 😃 ---
**Author:** ![VOW](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/vow/32/3043_2.png) [@VOW](https://boards.straightdope.com/u/VOW)\ **Post date:** [December 27, 2019, 9:39pm UTC](https://boards.straightdope.com/t/is-orion-going-to-have-a-bum-shoulder/845468/9 "2019-12-27T21:39:05Z")
Oh great. That thing had BETTER blow up, and soon! If it doesn’t, Mr VOW will make my life a pure Hell for the next 10,000 years! ~VOW ---
**Author:** ![Aspenglow](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aspenglow/32/76_2.png) [@Aspenglow](https://boards.straightdope.com/u/Aspenglow)\ **Post date:** [December 27, 2019, 9:53pm UTC](https://boards.straightdope.com/t/is-orion-going-to-have-a-bum-shoulder/845468/10 "2019-12-27T21:53:41Z")
To see it would be fantastic. I mean, it’s going to happen – may as well happen while I get the chance to see it! I wonder how long will the brightness will remain for us to observe? ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [December 27, 2019, 9:54pm UTC](https://boards.straightdope.com/t/is-orion-going-to-have-a-bum-shoulder/845468/11 "2019-12-27T21:54:23Z")
If there’s a beam, it’ll be along the axis of rotation. We know we’re not along Betelgeuse’s axis of rotation, because it gets starspots (similar to sunspots), which cause small but detectable changes in brightness as they rotate on and off the portion of the surface that face us. We wouldn’t see that if the axis is pointed towards us, because if it did, we’d always see the same hemisphere. And yes, there’s a good chance that even if we don’t see it blow imminently, we might see it blow sometime in the next 640 years. Which in turn means that there’s a good chance that it has in fact already blown. It’s one of the very few, possibly the only, naked-eye star for which that’s true. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [December 27, 2019, 9:55pm UTC](https://boards.straightdope.com/t/is-orion-going-to-have-a-bum-shoulder/845468/12 "2019-12-27T21:55:38Z")
> [@](#): > > I wonder how long will the brightness will remain for us to observe? The timescale on which supernovas fade is on the order of months. ---
**Author:** ![Aspenglow](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/aspenglow/32/76_2.png) [@Aspenglow](https://boards.straightdope.com/u/Aspenglow)\ **Post date:** [December 27, 2019, 9:59pm UTC](https://boards.straightdope.com/t/is-orion-going-to-have-a-bum-shoulder/845468/13 "2019-12-27T21:59:04Z")
> [@Chronos](#): > > The timescale on which supernovas fade is on the order of months. Thank you. 🙂 ---
**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\ **Post date:** [December 27, 2019, 10:34pm UTC](https://boards.straightdope.com/t/is-orion-going-to-have-a-bum-shoulder/845468/14 "2019-12-27T22:34:28Z")
Here’s a better view of the relative sizes of some stars including the Armpit of the Central One (or whatever translation of Betelgeuse you like). [![](https://en.wikipedia.org/wiki/File:Star-sizes.jpg) ](https://en.wikipedia.org/wiki/File:Star-sizes.jpg) As the images make clear, you should gather up some pie and a lawn chair and a sleeping bag, and settle in for quite a show. My money says a few hundred years worth of pie is about right for a first estimate. ---
**Author:** ![RioRico](https://avatars.discourse-cdn.com/v4/letter/r/f04885/32.png) [@RioRico](https://boards.straightdope.com/u/RioRico)\ **Post date:** [December 28, 2019, 12:18am UTC](https://boards.straightdope.com/t/is-orion-going-to-have-a-bum-shoulder/845468/15 "2019-12-28T00:18:54Z")
After the particle storm sweeps away 90% of Terrestrial life, any surviving human culture will worship The Burning God whose laser projector cools at His shoulder. Believers will offer themselves for ritual immolation. Water will be damned. The Burning God wants us hot! Burn, baby, burn! ---
**Author:** ![Robot\_Arm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robot_arm/32/18280_2.png) [@Robot\_Arm](https://boards.straightdope.com/u/Robot_Arm)\ **Post date:** [December 28, 2019, 1:34am UTC](https://boards.straightdope.com/t/is-orion-going-to-have-a-bum-shoulder/845468/16 "2019-12-28T01:34:10Z")
> [@Aspenglow](#): > > To see it would be fantastic. I mean, it’s going to happen – may as well happen while I get the chance to see it! > [@Chronos](#): > > The timescale on which supernovas fade is on the order of months. Would it be better to see it right away, though? Will there be a sudden burst at the beginning, or gradually getting brighter and then gradually dimming? ---
**Author:** ![Northern\_Piper](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/northern_piper/32/5304_2.png) [@Northern\_Piper](https://boards.straightdope.com/u/Northern_Piper)\ **Post date:** [December 28, 2019, 1:39am UTC](https://boards.straightdope.com/t/is-orion-going-to-have-a-bum-shoulder/845468/17 "2019-12-28T01:39:39Z")
A sudden burst, I think? But **Chronos** is the expert so will wait for his comment. ---
**Author:** ![Sam\_Stone](https://avatars.discourse-cdn.com/v4/letter/s/ecccb3/32.png) [@Sam\_Stone](https://boards.straightdope.com/u/Sam_Stone)\ **Post date:** [December 28, 2019, 2:52am UTC](https://boards.straightdope.com/t/is-orion-going-to-have-a-bum-shoulder/845468/18 "2019-12-28T02:52:07Z")
When astronomers say a Supernova is ‘imminent’’ they are talking about timescales measured in thousands to hundreds of thousands of years. It could go off today, or 10,000 years from now. ---
**Author:** ![Little\_Nemo](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/little_nemo/32/3120_2.png) [@Little\_Nemo](https://boards.straightdope.com/u/Little_Nemo)\ **Post date:** [December 28, 2019, 3:17am UTC](https://boards.straightdope.com/t/is-orion-going-to-have-a-bum-shoulder/845468/19 "2019-12-28T03:17:22Z")
> [@Aspenglow](#): > > I wonder how long will the brightness will remain for us to observe? Or how long we will remain to observe the brightness. ---
**Author:** ![RickJay](https://avatars.discourse-cdn.com/v4/letter/r/bb73d2/32.png) [@RickJay](https://boards.straightdope.com/u/RickJay)\ **Post date:** [December 28, 2019, 3:24am UTC](https://boards.straightdope.com/t/is-orion-going-to-have-a-bum-shoulder/845468/20 "2019-12-28T03:24:27Z")
Or 1,000,000. Most of what we know about Betelgeuse is approximate. It could be 640 light years away, but that’s plus or minus a few hundred light years. We do not know its size for sure - it is certainly a red giant and will go supernova some day, but the time frame for that is dependent upon its size, and our guesses on that have a pretty wide margin of error, too. Its size determines its lifespan, and if you don’t really know the former you don’t know the latter. It could have already gone poof and we’ll see it by Easter, or it might not go poof for a length of time beyond human imagination. Of course, I sure hope it goes now, because it would be a sight unlike anything else - brighter than the Moon, visible during the day, something unlike any celestial object most humans have, or will ever get, to see. [Next page](https://boards.straightdope.com/t/is-orion-going-to-have-a-bum-shoulder/845468.md?page=2)