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Author Topic: what is a shockwave made of ?  (Read 2915 times)

Offline acecharly

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what is a shockwave made of ?
« on: 03/06/2013 14:30:30 »
When a bomb goes off and a shockwave is produced what would cause damage the energy or the air that is around being affected by it? If a bomb went off in space where there is no atmosphere how would that energy move from its origin, and if it was a nuke and could be made super efficient to a point where pretty much no mass was left what would the energy release do with no particle to convey it.

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Ace


 

Offline distimpson

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Re: what is a shockwave made of ?
« Reply #1 on: 03/06/2013 15:36:21 »
It will depend to some degree on the type of bomb/explosion but in general shock waves are high pressure/compression zones propagating though the surrounding medium, I'm not sure on terminology, shock wave may technically refer only to the supersonic condition. We show the video of the recent Russian meteorite fall near Chelyabinsk, the air blast that did so much damage originated from the meteoroid air burst explosion and subsequent shock waves. By the time the main air blast hit the surface it was a large wall of compressed air moving at the speed of sound, I've seen estimates of 20 times atmosphere for pressure of the wave. The pressure wave from the air burst produced the damage in Chelyabinsk, not pieces of meteorite. This video is pretty good: http://www.youtube.com/watch?v=tq02C_3FvFo

In space no medium to compress but a nuclear explosion would produce a wide spectrum of electromagnetic radiation and as you say some high velocity small particles from the original device. The em radiation would heat and vaporize part of a target, say an asteroid. Ejection of the heated material from the surface would impart a force on the remaining body and could be used to deflect without fragmenting the asteroid (more complicated if the asteroid is already a “rubble pile”). The closer (or deeper) the device was to the asteroid the more em energy would be absorbed and converted to kinetic energy to give more deflection force.

We have a small meteorite museum so my comments are usually slanted to that subject, my best understanding here, verify anything/everything if it is important to you.
 

Offline acecharly

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Re: what is a shockwave made of ?
« Reply #2 on: 03/06/2013 16:00:51 »
Thanks for the reply. Is em a particle or a wave that becomes a particle?  I guess my point is what would happen to energy if it did not have a way to express itself. For example you talk of the airburst meaning that the energy was expressed through the air. When a nuclear explosion takes place matter is changed to energy but what would happen to that energy if it was a total transfer from the original mass in some kind of vacuum if that makes sense. Could there possibly be points in space with huge amounts just waiting for some way to convey there selves. Even the likes of the big bang.
 

Offline distimpson

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Re: what is a shockwave made of ?
« Reply #3 on: 03/06/2013 16:49:47 »
The electromagnetic radiation is thought of as photons ("particles of light") or light waves but not particles with mass. If the detonation was in a substantially empty region of space with no matter to scatter or absorb the em energy then the energy would just propagate at the speed of light, expand and dissipate like 1/r2, kind of like a flash bulb in a camera (but with x-ray, gamma-rays and such). The farther away you are from the explosion the dimmer it would look. I don't know about the points in space with huge amounts of energy, you maybe mean something like a supernova type explosion?
 

Offline evan_au

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Re: what is a shockwave made of ?
« Reply #4 on: 04/06/2013 11:27:16 »
One of the principles of physics is that energy can't be created or destroyed, only converted from one form to another.
Perhaps the concept you are looking for would be a "neutrino bomb", where a large amount of energy is converted entirely to ghostly neutrino particles which disappear, almost without a trace. If it could be made very efficient, the energy would just "disappear" - there would be no flash and no shockwave. It would not damage nearby objects.

It would be a lot of effort for something which might only be detectable by one of the several neutrino detectors buried in various deep mines around the world. 
 

Offline distimpson

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Re: what is a shockwave made of ?
« Reply #5 on: 04/06/2013 19:22:04 »
neutrino bomb, very interesting line of thought, I think I see where you're going, "Could there possibly be points in space with huge amounts just waiting for some way to convey there selves", yes, maybe along the lines of dark matter or energy? It seems to be abundant but does not interact much, or has no "way to express itself" other than gravity. As far as I know, dark matter seems to be found in "blobs" using our current foggy goggles, if a shock type structure was discovered it may give some more clues about dm physical properties, but "imaging" by way of gravitational lensing is pretty low resolution.
 

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Re: what is a shockwave made of ?
« Reply #5 on: 04/06/2013 19:22:04 »

 

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