# What would it be called if a galaxy exploded **URL:** \ **Category:** In My Humble Opinion\ **Created:** [October 8, 2007, 10:16pm UTC](https://boards.straightdope.com/t/what-would-it-be-called-if-a-galaxy-exploded/422001 "2007-10-08T22:16:25Z")\ **Posts on this page:** 13\ **Page:** 3
**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:** [October 10, 2007, 4:22am UTC](https://boards.straightdope.com/t/what-would-it-be-called-if-a-galaxy-exploded/422001/41 "2007-10-10T04:22:12Z")
> [@](#): > > The force of gravity, should we ever come up with a theory of quantum gravity, would be mediated by virtual gravitons, and they aren’t constrained by the speed of light. Indeed. And by the same token, if a black hole has a charge (electric or magnetic), the electromagnetic field (mediated by virtual photons, which we do have a theory for) would also be able to get out. ---
**Author:** ![samclem](https://avatars.discourse-cdn.com/v4/letter/s/a9a28c/32.png) [@samclem](https://boards.straightdope.com/u/samclem)\ **Post date:** [October 10, 2007, 4:24am UTC](https://boards.straightdope.com/t/what-would-it-be-called-if-a-galaxy-exploded/422001/42 "2007-10-10T04:24:52Z")
Since this entertaining thread probably was destined to have no factual answer, perhaps it can go to IMHO. **samclem** GQ moderator ---
**Author:** ![Ale](https://avatars.discourse-cdn.com/v4/letter/a/f19dbf/32.png) [@Ale](https://boards.straightdope.com/u/Ale)\ **Post date:** [October 10, 2007, 4:41am UTC](https://boards.straightdope.com/t/what-would-it-be-called-if-a-galaxy-exploded/422001/43 "2007-10-10T04:41:34Z")
But _IF_ a galaxy exploded for real, the explosion couldn´t travel faster than the speed of light. So let´s say a very pissed off race of space aliens from that other galaxy over there think that we sent radio waves the wrong way and decide to go postal on us they plant a Big Whooping Galaxy Asploder on the center of the Milky Way, pull the pin, count to three and off it goes… it´ll take 100.000 years for the whole thing to go up in smoke, heck, it´ll take over 25.000 years before the explosion front reaches the Earth. So, it wouldn´t just blow up in an instant, unless all parts of the galaxy are wired with a metric assload of BWGAs that go off at the right timing so the effects of all the explosions are perceived simultaneously at some point in the universe, let´s say the space aliens home planet. Everyone else would see a sloooooooow conflagration or a chaotic collection of smaller events. ---
**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:** [October 10, 2007, 1:53pm UTC](https://boards.straightdope.com/t/what-would-it-be-called-if-a-galaxy-exploded/422001/44 "2007-10-10T13:53:38Z")
Fortunately for us, our galaxy has a three-plus-billion solar mass black hole at its center, so our alien foes would watch with crushing disappointment as their carefully-constructed Big Whooping Galaxy Asploder™ was sucked away harmlessly into oblivion. ---
**Author:** ![The\_Controvert](https://avatars.discourse-cdn.com/v4/letter/t/dec6dc/32.png) [@The\_Controvert](https://boards.straightdope.com/u/The_Controvert)\ **Post date:** [October 10, 2007, 2:26pm UTC](https://boards.straightdope.com/t/what-would-it-be-called-if-a-galaxy-exploded/422001/45 "2007-10-10T14:26:57Z")
[QUOTE=Q.E.D.] Fortunately for us, our galaxy has a three-plus-billion solar mass black hole at its center, so our alien foes would watch with crushing disappointment as their carefully-constructed Big Whooping Galaxy Asploder™ was sucked away harmlessly into oblivion. [/QUOTE] You’re assuming the Asploder doesn’t function by reversing the polarity of said black hole. ---
**Author:** ![Ale](https://avatars.discourse-cdn.com/v4/letter/a/f19dbf/32.png) [@Ale](https://boards.straightdope.com/u/Ale)\ **Post date:** [October 11, 2007, 10:07am UTC](https://boards.straightdope.com/t/what-would-it-be-called-if-a-galaxy-exploded/422001/46 "2007-10-11T10:07:02Z")
[QUOTE=The Controvert] You’re assuming the Asploder doesn’t function by reversing the polarity of said black hole. [/QUOTE] Well, Duh!, it also crosses the lines for good measure… you can never be too sure. ---
**Author:** ![H3Knuckles](https://avatars.discourse-cdn.com/v4/letter/h/ba8739/32.png) [@H3Knuckles](https://boards.straightdope.com/u/H3Knuckles)\ **Post date:** [October 11, 2007, 10:36am UTC](https://boards.straightdope.com/t/what-would-it-be-called-if-a-galaxy-exploded/422001/47 "2007-10-11T10:36:21Z")
[QUOTE=Ale] Well, Duh!, it also crosses the lines for good measure… you can never be too sure. [/QUOTE] _ahem_ _adjusts glasses slightly by pushing upward on the bridge with left pointer finger_ I believe you meant to say, “It also crosses the _streams_…” assuming you were referring to the revelation of the good Dr. Spengler. ---
**Author:** ![msmith537](https://avatars.discourse-cdn.com/v4/letter/m/d9b06d/32.png) [@msmith537](https://boards.straightdope.com/u/msmith537)\ **Post date:** [October 11, 2007, 2:42pm UTC](https://boards.straightdope.com/t/what-would-it-be-called-if-a-galaxy-exploded/422001/48 "2007-10-11T14:42:06Z")
[QUOTE=SlickRoenick] But what if the black hole was the _size_ of our sun, not compressed, with mass equal to whatever a black hole of that size would be? [/QUOTE] What do you mean by “size”? The event horizon is the same radius as the sun? Not possible (not that it would make a difference as I will explain). All object have what is called a “Schwarzschild radius” which is the radius for a given mass where it would compress into a singularity (IOW black hole). Objects that are smaller than their Schwarzschild radius form black holes with the surface formed by the Schwarzschild radius as the event horizon (the point past which nothing escapes). Objects larger than their Schwarzschild radius (like the sun) don’t. The Suns Schwarzschild radius is about 3 km. So to answer your question, what would happen to the Earth if the Sun did become a black hole for some reason? Nothing (at least gravitationally). It would still have the same mass and thus the Earth would continue to orbit what was once the sun just as it always had, safely outside the event horizon. (gravity being a function of mass and distance) ---
**Author:** ![JThunder](https://avatars.discourse-cdn.com/v4/letter/j/e95f7d/32.png) [@JThunder](https://boards.straightdope.com/u/JThunder)\ **Post date:** [October 11, 2007, 2:55pm UTC](https://boards.straightdope.com/t/what-would-it-be-called-if-a-galaxy-exploded/422001/49 "2007-10-11T14:55:22Z")
I propose calling it a _galactic nova_. So there. ---
**Author:** ![bbs2k](https://avatars.discourse-cdn.com/v4/letter/b/e495f1/32.png) [@bbs2k](https://boards.straightdope.com/u/bbs2k)\ **Post date:** [October 11, 2007, 3:03pm UTC](https://boards.straightdope.com/t/what-would-it-be-called-if-a-galaxy-exploded/422001/50 "2007-10-11T15:03:23Z")
Kablooey! ---
**Author:** ![Marley23](https://avatars.discourse-cdn.com/v4/letter/m/45deac/32.png) [@Marley23](https://boards.straightdope.com/u/Marley23)\ **Post date:** [October 11, 2007, 3:10pm UTC](https://boards.straightdope.com/t/what-would-it-be-called-if-a-galaxy-exploded/422001/51 "2007-10-11T15:10:16Z")
What, no love for the Illudium PU-36 Explosive Space Modulator? There’s no reason to believe a big one couldn’t blow up a galaxy. [QUOTE=Bearflag70] Perhaps the OP means each star in a galaxy exploding simultaneously … you know, like everyone in China jumping off a chair? [/QUOTE] It’s actually more like a fleet of planes taking off from treadmills. ---
**Author:** ![Nars\_Glinley](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/nars_glinley/32/8177_2.png) [@Nars\_Glinley](https://boards.straightdope.com/u/Nars_Glinley)\ **Post date:** [October 11, 2007, 6:57pm UTC](https://boards.straightdope.com/t/what-would-it-be-called-if-a-galaxy-exploded/422001/52 "2007-10-11T18:57:35Z")
It would be the mother of all BFD’s. ---
**Author:** ![Miller](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/miller/32/481_2.png) [@Miller](https://boards.straightdope.com/u/Miller)\ **Post date:** [October 11, 2007, 8:12pm UTC](https://boards.straightdope.com/t/what-would-it-be-called-if-a-galaxy-exploded/422001/53 "2007-10-11T20:12:56Z")
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