Cosmic Explosion Revision - Shockwaves Are Slow

[Agnaa]

This thread pertains to calculations involving images showing the destruction of large objects, such as this one.

It means to clarify that a shockwave being visible does not mean that the feat occurred in seconds, because shockwaves are slow. Shockwaves through the air are sound, and they travel at 343 m/s; you can see in this footage how many large explosions remain impressive for many many seconds due to this. Shockwaves through planetary rock travel through them between 7,000 miles per hour and 18,000 miles per hour. Or, 3,130 m/s to 8,050 m/s.

If calculations find speeds of rocks and the shockwaves that are vastly incongruent to this, they shouldn't be used. Existing calculations like this should be revised. A piece of instruction text mentioning this should be placed somewhere, but I'm not exactly sure where; ideas would be welcome.

This doesn't apply to most cases of similar feats in live action, animations, and games, as those have a temporal grounding that a timeframe can be based on. Although I wouldn't be too opposed if we still applied that there, and took the short timeframe as cinematic timing aimed to make it more watchable.

It obviously doesn't apply to cases with stated timeframes, or any other mitigating factor you can imagine that would be good textual evidence for the event taking place quickly.

EDIT: Turns out that shockwaves can be arbitrarily fast, removing one of the cornerstones of this proposal. I still think we shouldn't assume short timeframes from these, as large explosions can remain impressive for quite a while, and shockwaves can travel relatively slowly.

Pinging some random CGMs, @Mr. Bambu @Jasonsith @Wokistan @Migue79 @CloverDragon03 @DemiiPowa

 

[CloverDragon03]

This doesn't apply to most cases of similar feats in live action, animations, and games, as those have a temporal grounding that a timeframe can be based on. Although I wouldn't be too opposed if we still applied that there, and took the short timeframe as cinematic timing aimed to make it more watchable.

At the very least, I strongly disagree with this part. That is, applying this proposal to animated versions of such feats under the pretense of "cinematic timing." That, to me, is a massive appeal to reality since it amounts to ignoring what we're directly shown just to try and fit it into real life standards.

Of course, this isn't the primary point, so I won't dwell on it for long. As for the rest, I'm inclined to disagree for similar reasons - primarily how this appeals to reality and would require us to ignore self-evidently quick movements of large parts of planets - such as these cases.

However, it's still mad early into the thread, so I'll reserve a definitive stance on the proposal at large for later once others have commented.

 

[Agnaa]

At the very least, I strongly disagree with this part. That is, applying this proposal to animated versions of such feats under the pretense of "cinematic timing." That, to me, is a massive appeal to reality since it amounts to ignoring what we're directly shown just to try and fit it into real life standards.

If we had a consistent stance on this; taking arrows, bullets, missiles, and lasers as slow if they're visible to the viewer, I'd be fine with this. But I don't like going inconsistently "Oh it's cinematic timing" to upgrade a feat, and "No that's appeal to reality!" to avoid a downgrade to a feat.

So I'd prefer the consistent route of deferring to phenomena in reality for timing, unless there's other good indicators that they're inaccurate (characters talking, stated timeframes and speeds, etc.)

But if y'all disagree, then it is what it is.

Of course, this isn't the primary point, so I won't dwell on it for long. As for the rest, I'm inclined to disagree for similar reasons - primarily how this appeals to reality and would require us to ignore self-evidently quick movements of large parts of planets - such as these cases.

I think the former case has great evidence for it being quick; characters are talking all throughout that, so the movement has to be quick. I, personally, wouldn't want the second one to be treated as fast.

 

[CloverDragon03]

If we had a consistent stance on this; taking arrows, bullets, missiles, and lasers as slow if they're visible to the viewer, I'd be fine with this. But I don't like going inconsistently "Oh it's cinematic timing" to upgrade a feat, and "No that's appeal to reality!" to avoid a downgrade to a feat.

So I'd prefer the consistent route of deferring to phenomena in reality for timing, unless there's other good indicators that they're inaccurate (characters talking, stated timeframes and speeds, etc.)

But if y'all disagree, then it is what it is.

I don't think this is at all a good equivalence to make, of course bullets and lasers are going to be slowed down to be visible to us because we can't perceive bullet speed, much less light speed. By this logic, nothing with visible lasers should ever be light speed - and that reaches a level of ignorance that I don't think is actually a good thing. As with most things, we take things case by case, rather than demanding for a one-size-fits-all approach to every feat.

I think the former case has great evidence for it being quick; characters are talking all throughout that, so the movement has to be quick. I, personally, wouldn't want the second one to be treated as fast.

Good to know for the first one. I'm inclined to disagree for the second, though, considering the planet had burst apart as he was traveling at speeds with which he quickly crosses planets.

 

[Agnaa]

I don't think this is at all a good equivalence to make, of course bullets and lasers are going to be slowed down to be visible to us because we can't perceive bullet speed, much less light speed.

And planet-size explosions, displayed in real-time in media, would take over 5 hours (or if you go for a high-end view of the expected speed, about 15 minutes) to show. I think it's a good equivalence due to how unrealistic both of those viewing experiences are.

By this logic, nothing with visible lasers should ever be light speed - and that reaches a level of ignorance that I don't think is actually a good thing.

That's the opposite of my logic; I think these explosions should be treated as slow, because visible lasers should still be light speed.

As with most things, we take things case by case, rather than demanding for a one-size-fits-all approach to every feat.

Fair enough, not much to say to that.

Good to know for the first one. I'm inclined to disagree for the second, though, considering the planet had burst apart as he was traveling at speeds with which he quickly crosses planets.

Eh, I think scaling to speed from other feats is really weird. Feats aren't statements, speed can vary especially during long journeys, etc. Still, I do recognize that that is some level of backing I hadn't considered.

 

[CloverDragon03]

And planet-size explosions, displayed in real-time in media, would take over 5 hours (or if you go for a high-end view of the expected speed, about 15 minutes) to show. I think it's a good equivalence due to how unrealistic both of those viewing experiences are.

That's the opposite of my logic; I think these explosions should be treated as slow, because visible lasers should still be light speed.

Fair enough, not much to say to that.

I'll cover this all at once because I think it all ties into what I wanna say here: My point overall is that I can't really support trying to put a standard on this. If we try to go for a one-size-fits-all approach to what we consider cinematic timing, for instance, we end up with a mess that frankly just leads to some level of ignorance (i.e. if we treat the explosions as fast, that must surely mean that all real light is not actually light speed because the viewer can see it - even though that's absolutely not an anti-feat by any stretch). That's primarily why I don't see myself agreeing with this thread in lieu of additional arguments (which I anticipate will be coming as more CGMs comment).

Eh, I think scaling to speed from other feats is really weird. Feats aren't statements, speed can vary especially during long journeys, etc. Still, I do recognize that that is some level of backing I hadn't considered.

Just to clarify what I mean here, by the time we see the debris had traveled that distance, the dude's already a considerable distance away from the planet - enough to most definitely reach MHS+ to Sub-Rel speeds, which lends support to the debris traveling at such speeds.

 

[Agnaa]

I'll cover this all at once because I think it all ties into what I wanna say here: My point overall is that I can't really support trying to put a standard on this. If we try to go for a one-size-fits-all approach to what we consider cinematic timing, for instance, we end up with a mess that frankly just leads to some level of ignorance (i.e. if we treat the explosions as fast, that must surely mean that all real light is not actually light speed because the viewer can see it - even though that's absolutely not an anti-feat by any stretch). That's primarily why I don't see myself agreeing with this thread in lieu of additional arguments (which I anticipate will be coming as more CGMs comment).

Fair enough.

Just to clarify what I mean here, by the time we see the debris had traveled that distance, the dude's already a considerable distance away from the planet - enough to most definitely reach MHS+ to Sub-Rel speeds, which lends support to the debris traveling at such speeds.

My point is that, looking at it in a vacuum, since the dude isn't a real object, he can't tell us about the speeds of real objects.

And if we try to bring in the context of other scenes, especially if those other scenes are feats rather than explicit statements about how quickly he travels through space, that runs into the usual issues we get with calc stacking. Which are exacerbated by us (likely) not knowing how long it takes for him to reach top speed while traveling through space.

So I get your point, but I still find it a hard justification to side with.

 

[CloverDragon03]

My point is that, looking at it in a vacuum, since the dude isn't a real object, he can't tell us about the speeds of real objects.

And if we try to bring in the context of other scenes, especially if those other scenes are feats rather than explicit statements about how quickly he travels through space, that runs into the usual issues we get with calc stacking. Which are exacerbated by us (likely) not knowing how long it takes for him to reach top speed while traveling through space.

So I get your point, but I still find it a hard justification to side with.

I suppose there's some merit in that. I guess my line of thinking is along the lines of "okay, we have this calculated debris speed, and we see Marx appear to travel at a speed that would support this being legit" - also helped by this all being within the very same panel, which I think would lead it away from being calc stacking.

 

[Agnaa]

I suppose there's some merit in that. I guess my line of thinking is along the lines of "okay, we have this calculated debris speed, and we see Marx appear to travel at a speed that would support this being legit" - also helped by this all being within the very same panel, which I think would lead it away from being calc stacking.

Oh, are you talking about going to that weird cartoon star thing in the bottom-left panel? Since I'm not seeing anything else in the same panel or page you could be talking about.

If so, and there's context about that object being in another solar system (rather than being something like a nearby spaceship or asteroid), then I think it'd be fair to consider it quick.

Or are you saying that a character moving in that same panel means that we should apply the general panel timeframe (i.e. a few seconds) to that movement, and so the explosion would be comparable to that? If so I think that's a pretty solid argument, I'd be like 40/60 agree/disagree on that.

 

[CloverDragon03]

Oh, are you talking about going to that weird cartoon star thing in the bottom-left panel? Since I'm not seeing anything else in the same panel or page you could be talking about.

If so, and there's context about that object being in another solar system (rather than being something like a nearby spaceship or asteroid), then I think it'd be fair to consider it quick.

Or are you saying that a character moving in that same panel means that we should apply the general panel timeframe (i.e. a few seconds) to that movement, and so the explosion would be comparable to that? If so I think that's a pretty solid argument, I'd be like 40/60 agree/disagree on that.

I'm referring to this specific panel (the top left one of the whole page), so I think it's more like the latter.

 

[Flashlight237]

I have a concern about this. Why use shockwaves as a basis for any of this? Shockwaves are sound waves with a sound pressure of 194 dB or higher, and sound cannot travel in a vacuum (which is what space is).

 

[Agnaa]

That is, indeed, also an issue. But to be fair, one could imagine the shockwaves from these examples being in a latent atmosphere present on the body (although this wouldn't work for moon feats), in the rocks themselves (which would involve the high-end speed mentioned), or in the dust spread by those rocks breaking (if this does work, it would typically involve speeds slower than mach 1).

Still, I'd understand just ignoring the presence of shockwaves entirely in feats like this; I believe I already suggested something similar for a speed feat a short while back.

 

[Agnaa]

@DontTalkDT You usually weigh in on discussions like these.

 

[DontTalkDT]

It means to clarify that a shockwave being visible does not mean that the feat occurred in seconds, because shockwaves are slow. Shockwaves through the air are sound, and they travel at 343 m/s;

Shockwaves actually travel faster than sound waves. See this calculator for the case of chemical explosives as an example. I think, in principle, a sufficiently strong attack can create relativistic shockwaves, just since the KE sends the air molecules (or the plasma that's left of them) flying that fast.

As others have pointed out, shockwaves through the atmosphere don't apply to space though. And I have no idea how rock shockwaves would work, so one could at best downscale to rock soundwaves for them.


What the cinematic time issue is concerned we have standards that I think clarify this? They should be applied.
Edit: That is to say, estimation via physical effects always takes precedence. Of course, we need to actually have a proper estimation of the physical effects for that. So when using shockwaves vs cinematic time for a downgrade, we would at least need to have some quantification of the shockwave speed more precise than that being faster than sound, so that we have some idea of an upper limit on the possible speeds derived from the physical phenomenon.

 

[Agnaa]

Huh, I didn't realise that there was no upper bound like that. From playing around with that calculator, it looks like values can get arbitrarily high at the start, and eventually degrade.

However, I think the presence of a shockwave still wouldn't necessitate a short timeframe, but it also wouldn't rule out a fast timeframe in audio-visual media. Maybe you could technically argue that it would if the explosion is shown decaying in that time, since that should probably still take a while regardless of the energy of the initial impact, but that's an even tougher argument that involves tougher maths.

I'll edit the OP accordingly.

 

[Dragonite007]

Bump

 

[Agnaa]

Bump.

 

[DontTalkDT]

If you have a proper shockwave expanding through some media (not the stuff in that Medaka Box calc, expanding dust clouds, expanding fireballs, expanding destruction of the environment, energy waves or similar, nor stuff going through space vacuum either, not stuff that aren't waves but actual transportation of matter either) then I think determining an upper border for how long the timeframe was based on the assumption that the wave travelled with at least the speed of sound in the reference medium is fine. Like, I would also accept actual soundwaves as scaling sticks. I ultimately don't see the problem with that.
Of course, the travel distance of the wave needs to also actually be scaled and the timeframe calculated from that. Just saying that a wave exists isn't enough to assume an arbitrary timeframe.

 

[Agnaa]

I mostly agree, but I'd add a little bit of a caveat. Shockwaves can get slower than the speed of sound in lower-density gases, so I'd think Mach 1 would be a bad assumption for some stellar objects; ones which are likely to have less of an atmosphere than Earth. Although, in some of these cases, a shockwave could go through the ground (i.e. an earthquake) where reference values from Earth are probably still applicable.

But when that issue isn't present, doing that to find a timeframe sounds good.

 

[DontTalkDT]

One should use the speed of sound of the medium through which the wave travels, yes.

 

[Agnaa]

So, does this seem like enough acceptance to write it into a standards page?

 

[DontTalkDT]

Which standard exactly do you wish to add?
That shockwaves aren't evidence for a timeframe of mere seconds when happening over large distances, as the only thing we can actually confirm is that the timeframe isn't longer than distance / (speed of sound in the reference medium) unless we can do an actual shockwave speed calc?

 

[Agnaa]

Which standard exactly do you wish to add?
That shockwaves aren't evidence for a timeframe of mere seconds when happening over large distances, as the only thing we can actually confirm is that the timeframe isn't longer than distance / (speed of sound in the reference medium) unless we can do an actual shockwave speed calc?

Yeah basically.

 

[DontTalkDT]

I think the rest hasn't really come back to commenting on that take on the idea in particular.
The note would presumably go on this page (god, I need to get that calculator deleted from it at some point), so I would suggest you write up what to change on that page, tag the calc group and if we don't get any further objections in two days we add it.

 

[Agnaa]

Hm, that one is a little bit narrower than what I'm thinking. It only allows the use of actual explosive materials, so maybe the note I add should also discuss the shockwave as a lower bound?

So at the end of "In which cases can it be used"

However, in more strange cases, if there is at least a shockwave present, then the speed of sound in the material can be used as a lower estimate. Note that the presence of a shockwave does not allow one to skip that estimation process and assume a small timeframe, as over large distances shockwaves can still take quite a while to travel.

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[Flashlight237]

Hm, that one is a little bit narrower than what I'm thinking. It only allows the use of actual explosive materials, so maybe the note I add should also discuss the shockwave as a lower bound?

So at the end of "In which cases can it be used"

@Executor_N0 @Spinosaurus75DinosaurFan @Mr. Bambu @Therefir @Ugarik @DMUA @Damage3245 @TheRustyOne @DemonGodMitchAubin @Jasonsith @Wokistan @Migue79 @Armorchompy @Psychomaster35 @CloverDragon03 @Dark-Carioca @AbaddonTheDisappointment @Aguywhodoesthings @Dalesean027 @DemiiPowa @Flashlight237 @SeijiSetto @SunDaGamer @Vzearr

I do think it's fine. Oddly enough the block-quoted part of this post lines up with the crossed-out part of the OP.

 

[Agnaa]

I do think it's fine. Oddly enough the block-quoted part of this post lines up with the crossed-out part of the OP.

Eh, the OP was initially intending to cap timeframes at that amount. But I guess it is a bit of a backtrack on the "shockwaves can be arbitrarily fast" thing. But the only way I can see us fully backtracking on that is if we remove the restriction about calculating unnatural explosions that way.

 

[Flashlight237]

Eh, the OP was initially intending to cap timeframes at that amount. But I guess it is a bit of a backtrack on the "shockwaves can be arbitrarily fast" thing. But the only way I can see us fully backtracking on that is if we remove the restriction about calculating unnatural explosions that way.

True, which is a double-edged sword if you ask me.

 

[DMUA]

Turns out that shockwaves can be arbitrarily fast, removing one of the cornerstones of this proposal. I still think we shouldn't assume short timeframes from these, as large explosions can remain impressive for quite a while, and shockwaves can travel relatively slowly.

I guess? But in the same vein as planet busting never being actively presented as GBE accurate, I doubt they'd make something like this accurately slow

The main thing with your specific example is that it kinda seems like there is no actual presentation of the bust in question

 

[Agnaa]

I guess? But in the same vein as planet busting never being actively presented as GBE accurate, I doubt they'd make something like this accurately slow

The main thing with your specific example is that it kinda seems like there is no actual presentation of the bust in question

Yeah, as I said, if there's a presentation of it being quicc then we can use that. We just shouldn't use shockwaves existing as the sole evidence for that.

 

[Agnaa]

Well, DT seems to agree with my newest suggestion, while Flashlight and DMUA seem a bit skeptical.

Is there anything you two think I could change about the wording, is my suggestion fine as-is, or should my suggestion be scrapped entirely?

Also, pinging others for more input @DemonGodMitchAubin @Dark-Carioca @Ugarik

 

[Flashlight237]

Well, DT seems to agree with my newest suggestion, while Flashlight and DMUA seem a bit skeptical.

Is there anything you two think I could change about the wording, is my suggestion fine as-is, or should my suggestion be scrapped entirely?

Also, pinging others for more input @DemonGodMitchAubin @Dark-Carioca @Ugarik

I think even with my skepticism, you should be gucci with the wording here. Just saying.

 

[DMUA]

Is there anything you two think I could change about the wording, is my suggestion fine as-is, or should my suggestion be scrapped entirely?

Isn't GBE based on escape velocity anyhow

This ruling would just be incredibly niche

 

[Agnaa]

Isn't GBE based on escape velocity anyhow

Yeah, successive shells of escape velocity, under the idea that the body never reforms.

This ruling would just be incredibly niche

Hmm really? I don't deal with many calcs on this level, so if you are and think it doesn't deserve those two sentences on the explosion speed page, I'd be willing to defer to you.

 

[DMUA]

Yeah, successive shells of escape velocity, under the idea that the body never reforms.

So if the mass instead moves at 343 meters per second, it'd get a much lower value that wouldn't genuinely destroy the celestial body entirely and you'd just not use the calc

 

[Agnaa]

So if the mass instead moves at 343 meters per second, it'd get a much lower value that wouldn't genuinely destroy the celestial body entirely and you'd just not use the calc

I think there's still other cases where it'd be relevant. Like, blowing a chunk off a terrestrial body.

But yeah, for entirely destroying an object, this just means "If the only context we have is a visual with a shockwave, just keep using the default GBE calc."

 

[Agnaa]

Bump?