I was having a discussion with some people the other night, when one of them mentioned using all the nukes on Earth to blow it up. Using my handy-dandy portable wireless web browsing telephone thingy, I looked up the old BABB article in which the BA stated that it would take, if I recall correctly, 10^39 ergs of energy to do this. Making a few simple calculations, it was easy to show that all the nukes in existence are far from sufficient to do the job. I thought that argument had been won...

Then today he emails me to say that John Wheeler, apparently a science fiction author of some sort, had "proven" that if one were to focus "the pressure of the earth’s oceans and detonated a hydrogen bomb you could form a black hole at the center of the earth."

Anyone care to help me provide an effective counter-argument?

Aporetic

sounds like something From David Brin's Earth novel. The singularity in the earth I mean, not the method.

ask him how he is supposed to "focus" the pressure of the oceans? I mean isn't the very center point of the earth already the focal point for ALL of earths mass, not just the water? and what does a Hudrogen bomb have to do with it other than creating a temporary compression? I doubt that would be enough to create a singularity. The mass of the sun is far greater than the earth's and already has fusion taking place in it's core and it's not a singularity.

Sounds like a bit of a woo-woo to me and you cannot argue with one of them.

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Eagle Eye Observatory

Does it even have any meaning to "focus the pressure of the oceans"? What are you focusing it on? You can't focus pressure on, say, a point, or a rock, or something, because P=F/A. Change the area, and you change the pressure.

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Sure you can! Just don't expect to get anywhere.

As for his theory about forming a singularity, forgive me if I'm obtuse, but I have no idea how you're supposed to "focus" all the water on the earth. Does he mean fitting it into an incredibly minute space? Would it even stay as a liquid under such pressure? The earth's center, let's recall, is solid because the huge amount of pressure overcomes the enormous heat that would otherwise make it liquid (forgive me if I'm mistaken).

I guess he doesn't know how much mass it takes to create a singularity...

Greg Bear, The Forge of God--

the "bad" alien von nueman machines scurry along all the earths deep ocean trenches and fissues extracting hydrogen from the water to build hydrogen bombs to crack the earths crust, spinning their way into the core is a large chunck of neutronium and anti-neutronium..... earth goes boom....

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Or to put it another way - pressure isn't something you can "focus." Its a common misconception.

Thanks for your responses. I am going to tell him something like this:

All the pressure of the Earth's oceans, and all the pressure of everything else that constitutes the Earth, is already "focused" (although this term is itself misleading) on the very center of the Earth. So you are saying that if I detonate a nuclear weapon at the center of the Earth, it will blow it up. But this is still subject to the same problem from the BABB that I mentioned before - the explosion must still overcome the gravity of the entire planet on each particle that makes it up. Thus my previous calculations still apply.

I'll let you all know what happens.

Aporetic

John Wheeler is far from a woo-woo and he's not a science fiction writer either. He is one of the more respected Theoretical Physicists alive toda(he's 93). Students of his include Richard Feynman, Kip Thorne, and Charles Misner among a great many others.. His major concentration is Relativity Theory, although he is quite comfortable working in Quantum Mechanics also. He's coauthored two of the classic textbooks in Relativity. "SpaceTime Physics", for special relativity, and "Gravitation", for General Relativity. He is the person who coined the term "Black Hole" and he also worked on the American effort to produce the Fusion (Hydrogen) bomb. I would say there is a misunderstanding between you and your friend, or your friend misunderstood exactly he was saying.

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Neptune- The original Dark Matter.

The author feels that this technique of deliberately lying will actually make it easier for you to learn the ideas. - Donald Knuth

Also point out that the sun is way way WAY more massive than the earth and it's still nowhere near massive enough to form a black hole singularity.

For the Earth to become a black hole, the entire mass must be compressed within a sphere only 1 cm wide. The oceans are only probably .01% of the Earth's mass, so it's pretty much impossible.

No No I meant his friend

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Eagle Eye Observatory

Ahhhhh, sorry. ops: Thought you meant the guy that proposed the idea.

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Some try to tell me, thoughts they cannot defend,... - Moody Blues.

Neptune- The original Dark Matter.

The author feels that this technique of deliberately lying will actually make it easier for you to learn the ideas. - Donald Knuth

I thought that if you detonated a nuke in the Earth's core, every volcano on the planet would erupt.

(x-points for reference!)

- Maha (puts pinky to mouth) Vailo

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Thanks for clearing that up for me. I've no doubt that the guy I was talking to misconstrued Wheeler's argument.

Aporetic

I really prefer using a "death star" to shoot a giant "laser" at the Earth. It's just far more interesting that way.

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"Isn't that just...bread?"

Does that mean the earth has a weakness? I would hate to see a photon torpedo launched into Mt. Fuji and wipe us out.

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Eagle Eye Observatory

That was "proton torpedo", you're mixing up your Star **** movies. [-X
Edit: missing quote

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Whew, your right!

/em lowers his geek factor by 1 for getting it wrong

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Eagle Eye Observatory

I have just received an email reply for the guy. He quotes Stephen Hawking's "A Brief History of Time" in support of his idea that there may be black holes with much less mass than the Sun. "Such black holes could not be formed by gravitational collapse,
because their masses are below the Chandrasekhar mass limit:
stars of this low mass can support themselves against the
force of gravity even when they have exhausted their nuclear
fuel. Low-mass black holes could form only if matter was
compressed to enormous densities by very large external
pressures. Such conditions could occur in a very big
hydrogen bomb: the physicist John Wheeler once calculated
that if one took all the heavy water in all the oceans of
the world, one could build a hydrogen bomb that would
compress matter at the center so much that a black hole
would be created."

The guy then continues by saying that this hypothetical explosion could condense matter to a density of 10^17 kilograms per cubic meter, and reminds me that "black holes vary in size
the smallest possible black hole is around 10-35 metres
across (the so-called Planck Length)."

My initial comments are as follows:

1) It appears that Wheeler's theory here is that if one gathered all the heavy water on Earth and used it as fuel for a hydrogen bomb (is this even possible?), that one could create an explosion that would condense the matter at the center of the explosion enough to turn that matter into a black hole.

2) If this is true, and such a device was placed at the center of the Earth, wouldn't the event horizon of this black hole would be so small that it would have no effect on the Earth around it?

3) Is 10^17 kg per cubic meter enough pressure to create a black hole?

4) Wouldn't such a small black hole evaporate in an instant?

I appreciate your continued help with this.

Aporetic

Could they not evaporate to that size given enough time, although I don't know off hand, how long it would take.

Don't know, but given the answer to 3) below, I would guess not.

Again, don't know, but would guess it would evaporate before it had time to have an effect - even if it were remotely possible to 'place' something like that at the centre of the earth.

This is about the density of a neutron star (see link), not enough for a black hole.

Question is mute based on answer to 3), but a black hole is only as large as the mass that produced it.

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You could use Nicola Tesla's idea of harmonic vibration to pump up a vibrational wave in the Earth.

It works like this: Detonate an H bomb and the shock wave will travel through the Earth and rebound off of the other side. When the shock wave returns to you you Detonate another H bomb when the wave is at it's peak. You will then have added the power of the second detonation to the first shock wave thus amplifying it. Continue until the structure of the Earth cannot stand the degree of movement and it will shatter like a glass breaks by the harmonic of a singer's voice.

When Tesla described this he used the example of using a sledge hamer to produce the wave. He would hit the Earth in time with the Earth's harmonic and shatter the Earth that way. The problem there is that a Sledge hammer will only produce a wave of a certain energy. As the wave propagates through the Earth it losses energy by friction.

Is is a question as to whether an h bomb will produce enough energy to compensate for the energy loss due to friction to produce a wave of high enough amplitude to shatter the Earth.

It may be possible to amplify the wave as it travels by detonating h bombs along its path to amplify the wave before it has time to lose energy to friction.

http://www.stardestroyer.net/

http://www.theforce.net/swtc/

This sites have some calculations on how much energy the Death Star needs to destroy a planet.

Try out the planetary destruction calculator which calculates how much energy is needed to destroy a planet of given size.

Let's suppose for a moment, we would have a way to create a mini-black hole within the earth.
The mass of this black hole would be considerably smaller than that of the earth, because the material to create it would be taken from terrestrian material (a small fraction of earth's mass, maybe a cubic mile of rock compressed by an H-bomb or so).
The hole would be incredibly small (say, size of an atom or so) and settle down in the center of the earth since nothing could stop it from doing so (actually, due to its high mass and low friction it would, unless it is created at the very center, swing around the center for a long time before settling down).
But: It would certainly not harm the earth much in the foreseeable future; its surface is so minute, that it can only "eat" an incredibly small portion of earth's bulk at a time, that which accidentally crosses its event horizon - otherwise nothing would happen, since, as was said, the center of gravity of the earth would remain unchanged. (*)
May it rest in peace down there...

(*) It would be different if a black hole from outer space, with a mass of a considerable fraction of earth's, ran through the earth; again, no devouring much of it, but we'd have a tidal shock wave depending on its bulk.

Problem 1: Is just a typo. 10-35 metres is not the planck length. The planck lenght is the smallest meaninful distance. I think he's lost a few decimal places. Its something like 10^-35 metres (big difference, small typo).

[quote]My initial comments are as follows:

1) It appears that Wheeler's theory here is that if one gathered all the heavy water on Earth and used it as fuel for a hydrogen bomb (is this even possible?), that one could create an explosion that would condense the matter at the center of the explosion enough to turn that matter into a black hole.[

2) If this is true, and such a device was placed at the center of the Earth, wouldn't the event horizon of this black hole would be so small that it would have no effect on the Earth around it?

3) Is 10^17 kg per cubic meter enough pressure to create a black hole?

4) Wouldn't such a small black hole evaporate in an instant?

I appreciate your continued help with this.[/quote

1: Sounds about right, tons of focused energy would do the trick.

2: The event horizon would indeed be so small not much would happen.

3: While 10^17 kg per cubic meter is the pressure on a neutron star, exceeding that is enough to collapse a neutron star, and create a black hole, so thats the theoretical minimum threshold (exact numbers may vary 8) ).

4) Such a BH would evaporate in a very, very short timescale. Such BH's may be possible in the new supercollider being built/commissioned in Geneva, though they said that about the last big one built. An investigation into the danger said such BH's, even if created, posed no threat due to thier miniscules size, and rapid deterioration. Even if they absorb several atoms, heck a Kg, not much happens.




As for Tesla's "harmonic" method of destroying the earth: You still have to put all that energy The BA calculated (fun little calculation that!) to destroy it, though thats a nice way to blow off chunks of it.

Basically Tesla outlined a relatively efficient method, but the total energy required is the same.

I would beg to differ there. I know the kg was just rhetorical, and no such black hole would ever absorb that much before going *PFFT!* into thin air, but if it did somehow absorb a kg, the effect of the evaporation would be the same as putting a half kg of antimatter in there and combining it with a kg of matter. I.e., about 20 megatons of BOOM!

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20 megatons isn't much when you're trying to blow up the earth!

But yeah, the lab/city/countryside isn't enjoying it!

It shouldn't take that much if you correctly position, focus and time the explosion to produce a secondary nuclear reaction at the focal point of all the independant explosions (like a several Nuclear bombs arranged in a sphere). If the focal point is the center of the earth, and enough of the matter is displaced through volcanos and what not, the "gravitational center" of earth would be displaced causing the actual distruction of the planet. Probably an implosion.

I must admit that I totally guessing at most of this. ops:

still need to imput 10^36 (or whatever) ergs. No getting around it.


Now, you could try and focus the energy to create a BH in the center (you know, the suggestion of this thread) but there is no real mechanism to do that. Especially to create a BH of a size able to do anything, other than explode in a violent evaporative burb via hawking radiation.

Here's how you do it:

First, surround the entire Earth with shaped-charge explosives.

Second, initiate all the shaped charges within a very narrow time window, producing a highly-symmetrical inward-directed shock wave.

Third, stand well back and don eye protection (I protection?) as the shock wave compresses the Earth, raising it above the prompt supercriticality threshold.

Er...

No, wait, I'm thinking of something else. 8)

I got it!

We simply put Nancy in charge!

(now that I know who and what she is)


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Or, a simple four step process...

1) Build a machine that practically stops time for an individual.
2) Get in and turn on machine.
3) Wait until the sun does its inevitable thing.
4) Stop machine and look out window.

(bring sunglasses)