What-If 0015: "Mariana Trench Explosion"

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AvatarIII
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Re: What-if 0015: Mariana Trench Explosion

Postby AvatarIII » Wed Oct 10, 2012 11:49 am UTC

rmsgrey wrote:Either way, it doesn't end the world, nor even have a significant death-toll. A glass gets shattered, some water gets sprayed around, and some observers get mostly superficial injuries from flying/falling glass. It's possible that someone might be blinded, or need significant medical attention, but I'd expect standard first aid to be sufficient most of the time.

See also the robot apocalypse and SAT guessing...


One potentially bad injury is a tragedy; seven billion deaths is just a statistic.

hatten
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Re: What-if 0015: Mariana Trench Explosion

Postby hatten » Wed Oct 10, 2012 1:42 pm UTC

This one was way below the quality of the rest IMO. Either nothing happens or we multiply the explosion a million times and the world blows up, duh.

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Himself
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Re: What-if 0015: Mariana Trench Explosion

Postby Himself » Wed Oct 10, 2012 2:27 pm UTC

Interestingly, we could get an even bigger explosion than Tsar Bomba if we just used that cat.
"Looking me am a civilization person"
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freshyq314
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Re: What-if 0015: Mariana Trench Explosion

Postby freshyq314 » Wed Oct 10, 2012 3:52 pm UTC

I've never looked at anything on this scale (natch), but if it is indeed at the _bottom_ of the trench, would we get an asymmetric jet like one does in inertial cavitation? (see the sketch here http://en.wikipedia.org/wiki/Cavitation) This is not really the same regime as inertial cavitation (momentum of outgoing water might be important, given bubble size/ocean depth ratio), but could be similar?

Such a jet could be fun... punch a hole into the mantle even with just Tsar Bomba? I call "not it" on doing the estimates, though.

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San Fran Sam
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Re: What-if 0015: Mariana Trench Explosion

Postby San Fran Sam » Wed Oct 10, 2012 4:03 pm UTC

I'm not sure, but i think the questioner was thinking of something along these lines...

http://www.sfreviews.net/forgeofgod.html

Vertices
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Re: What-if 0015: Mariana Trench Explosion

Postby Vertices » Wed Oct 10, 2012 9:46 pm UTC

Tormuse wrote:
niky wrote:You kind of figure that a nuclear bomb isn't going to do much that deep under.

Heck, that's the standard trope for any runaway nuclear explosion: "Fly/drop/throw it into the ocean!"


Just make sure your plane has an auto-pilot. ;)


Or is being flown by Jack Bauer.

juandule
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Re: What-if 0015: Mariana Trench Explosion

Postby juandule » Thu Oct 11, 2012 7:02 am UTC

Hmmm... Randall says "The explosion at the bottom of the Mariana Trench will create a quickly-expanding spherical cavity of hot steam."

If the explosion is at the bottom of the trench (presumably the ocean floor), in order for it to create a spherical cavity, one of two things would have to happen:

either

1) The explosion would leave the ocean floor undisturbed and produce a spherical cavity in the water above with a center 580 meters above the ocean floor.

or

2) The explosion would vaporize a portion of the ocean floor, leaving a crater equal to or less than half of the sphere.

If #1 would happen, well then the answer doesn't change, but it seems to me that would be a really weird way for a sphere to form from an explosion -- like blowing a balloon underwater, no? I imagine that the sphere would grow from the center. But I readily admit that I have very little knowledge of physics, so I am also ready to admit the limits of my imagination. But at the least I would appreciate seeing some text addressing that in the answer, and also a bit of drawing like the near-surface explosion.

If #2 would happen, that really changes the answer to the question, and then he would need to estimate how big of a crater in the ocean floor the explosion would produce, the strength of the resulting seismic shock (if any), and the effects of one or both.

What seems the most likely to me is that some of the ocean floor beneath the explosion would be vaporized, and some of the water above would be vaporized, and it might look kind of like the picture in this article: http://en.wikipedia.org/wiki/Trinity_site. The visible explosion there is somewhat spherical, but not totally, because part of it is below the surface of the ground. It seems most likely to me that the underwater explosion would also create a crater in the ocean floor because the explosion in that article was a surface (actually 30 meters above the surface, but close enough to be called a surface detonation, right?) detonation equal to only 20 kilotons of TNT (far less than Tsar Bomba's 50 megaton yield), and it "left a crater of radioactive glass in the desert 10 feet (3 m) deep and 1,100 feet (330 m) wide." I am guessing that could only result from the heat from the blast that melted the sand below it. Would an explosion from Tsar Bomba not do the same to the ocean floor?

So, if #1 would actually happen, at the least, he should explain why none of the ocean floor would be vaporized or even shocked, even though it is next to the explosion. It doesn't seem likely that such a blast, located on the ocean floor, would not at least make the ocean floor shake, causing a seismic shock which could possibly cause a tsunami. Wikipedia says that the actual Tsar Bomba produced a seismic body wave with a magnitude of about 5 to 5.25 on the Richter scale, and that the energy yield was around 8.1 on the Richter scale but, since the bomb was detonated in air rather than underground, most of the energy was not converted to seismic waves (http://en.wikipedia.org/wiki/Tsar_Bomba).

Thoughts?

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Re: What-if 0015: Mariana Trench Explosion

Postby JJH » Thu Oct 11, 2012 11:47 am UTC

Max™ wrote:
JJH wrote:Well that was... predictable. Nuke the Mariana trench and get no effect. “Well that didn’t work.” Supersize it and get a Mythbusters level destruction.

What I’m more interested in is the Freeman Dyson memo that Randall mentions, it looks like it would make an interesting read.

Image

Casaba-Howitzer

According to Freeman's model, something originally in the shape of a cigar expands into the shape of a pancake, and something originally in the shape of a pancake expands into the shape of a cigar. This was "very directly relevant to the expansion of a bomb," he explains. "If you have something that starts in the form of a pancake and you heat it up to a very high temperature it will expand more sideways along the axis, and less at the edges. The pressure gradient is highest along the axis, so then after a while, since the velocity is highest along the axis, it becomes cigar-shaped. So you get inversion, something that begins like a pan­cake becomes like a cigar, and something that begins as a cigar becomes a pancake, if you just let it expand freely. It goes roughly with the square root, if you start with a pancake where the ratio of the diameter to thick­ness is ten, then it will end up as a cigar where the ratio of the length to the diameter is square root of ten, roughly speaking. That would be quite helpful, of course, if you had a real Orion, to start out with a pan­cake and it will produce then a jet that is collimated within 20 degrees or so quite nicely. The fact that it's so easy to make an asymmetrical explosion may still be classified, for all I know."


oh, that was lovely, thanks.
I've always wondered how a nuclear shaped charge works. I'd have a good long poke at the site if my recent raid at the library hadn't been so successful.

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Re: What-if 0015: Mariana Trench Explosion

Postby Max™ » Fri Oct 12, 2012 12:36 am UTC

The site is very fun for all the different sci-fi technologies examined in the context of real technologies and physics implications.
mu

mishka
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Re: What-if 0015: Mariana Trench Explosion

Postby mishka » Sun Oct 14, 2012 5:45 pm UTC

I believe the technical term for a water explosion is either surface zero or subsurface zero.


Might be worth looking at this:

http://www.alternatewars.com/BBOW/ABC_W ... urface.htm
The website has more on nuclear weapons on naval targets.

kylos
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Re: What-if 0015: Mariana Trench Explosion

Postby kylos » Mon Oct 15, 2012 7:53 pm UTC

So this What-if serves as confirmation that Randall is black hat guy, right? I mean, black hat guy is holding Randall's cat.

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mathmannix
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Re: What-if 0015: Mariana Trench Explosion

Postby mathmannix » Mon Oct 15, 2012 8:06 pm UTC

kylos wrote:So this What-if serves as confirmation that Randall is black hat guy, right? I mean, black hat guy is holding Randall's cat.


I think the implication is more that BHG wickedly put the cat on the keyboard. He is Randall's nemesis (or the evil side of his split personality...)
I hear velociraptor tastes like chicken.

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Quizatzhaderac
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Re: What-if 0015: Mariana Trench Explosion

Postby Quizatzhaderac » Wed Oct 17, 2012 5:35 pm UTC

AvatarIII wrote:
rmsgrey wrote:Either way, it doesn't end the world, nor even have a significant death-toll. A glass gets shattered, some water gets sprayed around, and some observers get mostly superficial injuries from flying/falling glass. It's possible that someone might be blinded, or need significant medical attention, but I'd expect standard first aid to be sufficient most of the time.

See also the robot apocalypse and SAT guessing...


One potentially bad injury is a tragedy; seven billion deaths is just a statistic.

The SAT one has statistics, therefore is has seven billion deaths.
The thing about recursion problems is that they tend to contain other recursion problems.

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mathmannix
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Re: What-if 0015: Mariana Trench Explosion

Postby mathmannix » Wed Oct 17, 2012 8:41 pm UTC

Quizatzhaderac wrote:
AvatarIII wrote:
rmsgrey wrote:Either way, it doesn't end the world, nor even have a significant death-toll. A glass gets shattered, some water gets sprayed around, and some observers get mostly superficial injuries from flying/falling glass. It's possible that someone might be blinded, or need significant medical attention, but I'd expect standard first aid to be sufficient most of the time.

See also the robot apocalypse and SAT guessing...


One potentially bad injury is a tragedy; seven billion deaths is just a statistic.

The SAT one has statistics, therefore is has seven billion deaths.


I call Fallacy of Affirming the Consequent!
I hear velociraptor tastes like chicken.

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Quizatzhaderac
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Re: What-if 0015: Mariana Trench Explosion

Postby Quizatzhaderac » Thu Oct 18, 2012 2:52 pm UTC

I invoke the reflective property of being!
("is" in this third person case.)
The thing about recursion problems is that they tend to contain other recursion problems.

rmsgrey
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Re: What-if 0015: Mariana Trench Explosion

Postby rmsgrey » Thu Oct 18, 2012 4:30 pm UTC

Quizatzhaderac wrote:I invoke the reflective property of being!
("is" in this third person case.)


It's not a statement of identity - "X is Y" - but rather a statement of membership - "X is a Y" - when talking about what you know about Y from that, the former statement does indeed imply "Y is X", but the latter only tells you that "a Y is X".

There may or may not be a Y which is not X...


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