# New supernova in nearby galaxy \[M-101\] **URL:** \ **Category:** Miscellaneous and Personal Stuff I Must Share\ **Created:** [May 23, 2023, 1:00pm UTC](https://boards.straightdope.com/t/new-supernova-in-nearby-galaxy-m-101/984468 "2023-05-23T13:00:35Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![John\_DiFool](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_difool/32/19543_2.png) [@John\_DiFool](https://boards.straightdope.com/u/John_DiFool)\ **Post date:** [May 23, 2023, 1:00pm UTC](https://boards.straightdope.com/t/new-supernova-in-nearby-galaxy-m-101/984468/1 "2023-05-23T13:00:35Z")
> **[Bright Supernova Blazes in M101, the Pinwheel Galaxy](https://skyandtelescope.org/astronomy-news/bright-supernova-blazes-in-m101-the-pinwheel-galaxy/)** > > A supergiant star exploded as a supernova in the prominent galaxy M101 in Ursa Major. It's now bright enough to see in a 4.5-inch telescope! Just so turns out that the local astronomy club will have its monthly viewing session 5 miles from me on Saturday-after a cold front clears out the rainy skies we have had for a week now. Appropriate soundtrack:[Stars Die - YouTube](https://youtu.be/8cjLX9J5Yb8) ---
**Author:** ![Alessan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alessan/32/465_2.png) [@Alessan](https://boards.straightdope.com/u/Alessan)\ **Post date:** [May 23, 2023, 1:31pm UTC](https://boards.straightdope.com/t/new-supernova-in-nearby-galaxy-m-101/984468/2 "2023-05-23T13:31:13Z")
How long do supernovae usually remain visible? ---
**Author:** ![John\_DiFool](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/john_difool/32/19543_2.png) [@John\_DiFool](https://boards.straightdope.com/u/John_DiFool)\ **Post date:** [May 23, 2023, 2:15pm UTC](https://boards.straightdope.com/t/new-supernova-in-nearby-galaxy-m-101/984468/3 "2023-05-23T14:15:39Z")
Maybe a month 6 weeks. Note you’ll need a fairly hefty scope to see it (we’re still waiting for a naked eye one in the Milky Way, 500+ years now). ---
**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:** [May 23, 2023, 2:37pm UTC](https://boards.straightdope.com/t/new-supernova-in-nearby-galaxy-m-101/984468/4 "2023-05-23T14:37:28Z")
Probably longer than that-- It’s about six months, usually, before they’re significantly dimmer than they were at peak. It depends, of course, on how much they were above whatever threshold you’re setting as “detectable” to begin with. > [@John\_DiFool](#): > > (we’re still waiting for a naked eye one in the Milky Way, 500+ years now) Well, the Magellanic Clouds are almost the Milky Way, and 1987a was naked-eye visible. ---
**Author:** ![Alessan](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/alessan/32/465_2.png) [@Alessan](https://boards.straightdope.com/u/Alessan)\ **Post date:** [May 23, 2023, 3:40pm UTC](https://boards.straightdope.com/t/new-supernova-in-nearby-galaxy-m-101/984468/5 "2023-05-23T15:40:28Z")
> [@John\_DiFool](#): > > (we’re still waiting for a naked eye one in the Milky Way, 500+ years now). Isn’t that one of those “be careful what you wish for” situations? I mean, I’m sure it would be nice to see one from up close, but not from _too_ up close… ---
**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:** [May 23, 2023, 4:03pm UTC](https://boards.straightdope.com/t/new-supernova-in-nearby-galaxy-m-101/984468/6 "2023-05-23T16:03:29Z")
A few hundred light years away would be safe enough. ---
**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:** [May 23, 2023, 4:06pm UTC](https://boards.straightdope.com/t/new-supernova-in-nearby-galaxy-m-101/984468/7 "2023-05-23T16:06:56Z")
Depending on aim. EDIT: Actually, let me amend that. Any star that would be, so far as we know, capable of going supernova, and which is within a few hundred ly, would be a bright naked-eye star; all of those are fairly well-studied; and I don’t think we’re close to the axis of any of them. I know specifically that Betelgeuse is significantly off-axis, and that’s the one that I would bet on being the next to blow, of the relatively nearby stars. eta Carina is also a strong contender, and is even better-studied, and is also very definitely off-axis (and also significantly further away than Betelgeuse). Betelgeuse probably WILL be bright enough to be painful to look at with the naked eye, though, and might disrupt some species for whom moonlight is significant. ---
**Author:** ![JohnGalt](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johngalt/32/184_2.png) [@JohnGalt](https://boards.straightdope.com/u/JohnGalt)\ **Post date:** [May 24, 2023, 12:35am UTC](https://boards.straightdope.com/t/new-supernova-in-nearby-galaxy-m-101/984468/8 "2023-05-24T00:35:02Z")
> [@Chronos](#): > > Betelgeuse probably WILL be bright enough to be painful to look at with the naked eye, though, and might disrupt some species for whom moonlight is significant. Seeing Betelgeuse go supernova is on my bucket list. Every time I get a chance to see Orion, I make a wish that I would be one of the first people in the world to see it. But: would it be harmful to a viewer when it explodes? ---
**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:** [May 24, 2023, 1:15am UTC](https://boards.straightdope.com/t/new-supernova-in-nearby-galaxy-m-101/984468/9 "2023-05-24T01:15:05Z")
We’re seeing 21 million years into the past. That’s a real mindfuck if you start thinking really hard about it. ---
**Author:** ![Thing.Fish](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thing.fish/32/9168_2.png) [@Thing.Fish](https://boards.straightdope.com/u/Thing.Fish)\ **Post date:** [May 24, 2023, 4:53am UTC](https://boards.straightdope.com/t/new-supernova-in-nearby-galaxy-m-101/984468/10 "2023-05-24T04:53:07Z")
Don’t have the cite handy but one of Randall Munroe’s books describes a supernova that was visible with the naked eye for a brief period of time from TEN BILLION light years away. The most distant thing we can typically see with the naked eye is Andromeda, which is “only” about three million LY. ---
**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:** [May 24, 2023, 10:44am UTC](https://boards.straightdope.com/t/new-supernova-in-nearby-galaxy-m-101/984468/11 "2023-05-24T10:44:24Z")
> [@JohnGalt](#): > > But: would it be harmful to a viewer when it explodes? Only in the same sense that looking at the Sun is harmful. It’d be painful to look directly at it, and you would reflexively blink or look away, but if you forced yourself not to, you could cause eye damage. ---
**Author:** ![markn\_1](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@markn\_1](https://boards.straightdope.com/u/markn_1)\ **Post date:** [May 24, 2023, 1:24pm UTC](https://boards.straightdope.com/t/new-supernova-in-nearby-galaxy-m-101/984468/12 "2023-05-24T13:24:10Z")
Don’t get too close though. One of Munroe’s what-if columns notes that a supernova at the distance of the Sun from the Earth would be over a billion times brighter than the detonation of a hydrogen bomb pressed against your eyeball. [https://what-if.xkcd.com/73/](https://what-if.xkcd.com/73/) ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [May 24, 2023, 1:44pm UTC](https://boards.straightdope.com/t/new-supernova-in-nearby-galaxy-m-101/984468/13 "2023-05-24T13:44:38Z")
This isn’t news at all. You guys are stuck in the Aquitanian Age. That star blew up millions of years ago.