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Old 10-02-2010, 08:38 PM
f_m
 
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Quote:
Originally Posted by PITTSTON2SARASOTA View Post
contrary to the previous post...an atmosphere is not necessary for a shockwave
Although, nowhere in my post did it say shockwave.
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Old 10-02-2010, 08:59 PM
 
Location: Sarasota, Florida
15,400 posts, read 19,048,902 times
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You implied there would be no explosion...any explosion is essentially a shockwave with various effects >>>>>

YouTube - Space Nuclear Weapon Test


YouTube - July 9, 1962: Nuclear Weapons Test In Space!!!!!!
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Old 10-02-2010, 09:06 PM
f_m
 
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Quote:
Originally Posted by PITTSTON2SARASOTA View Post
You implied there would be no explosion...any explosion is essentially a shockwave with various effects >>
No, I did not imply there would be no explosion. Did you read the QUOTE I posted? It says "in a vacuum...," which is true and mentions nothing about shockwave of electromagnetic phenomena or lack thereof.

If you want to use wikipedia, then see that their definition of nuclear explosions refers to blast as in physical medium propagation (fluid/gas), which is apparently what the NASA quote refers to.

Effects of nuclear explosions - Wikipedia, the free encyclopedia

Also, I don't know why you are yelling in your posts. Very inappropriate.
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Old 10-04-2010, 03:05 PM
 
Location: St. Louis
9,457 posts, read 16,424,092 times
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Quote:
Originally Posted by sponger42 View Post
As others have said, there would be an explosion and a pulse of ionizing radiation, but there would be no physical shockwave and only a tiny "fireball" as the materials of the bomb itself vaporized and dispersed.

However, the radiation emitted from the bomb would be very intense close to the explosion. It would look like a fizzle rather than a blast, but if you were close enough to see it with the naked eye (through a viewport or helmet or whatever) you would probably die instantly from a massive dose of ionizing radiation. Even miles away, electronics would be destroyed and you would be sickened or killed by the high radiation flux.
This is very interesting as I'm trying to picture what would happen. So it would look like a fizzle as the fireball would go out almost immediately, yet it would disperse nuclear materials as quickly as it would if it exploded on earth--you just wouldn't really see it happening? Wow.

OK, so I think the problem too is the semantics of the word "explosion." Most of us picture a fireball when we think of explosion, or a big pop, but in this case they just disperse rapidly but silently and invisibly? And in the superman movies we need the fireball for dramatic effects.

Quote:
Originally Posted by PITTSTON2SARASOTA View Post
THANKYOU.......I think people assume you need an atmosphere for a shockwave to propagate, which is not correct and there are different types of shockwaves depending on the medium and type of explosion.

Also the sun as you say is simply a "controlled" thermonuclear (fusion) explosion balanced by the inward pull of gravity versus the outward pressure of the "explosion". .
Do we know how that works? As in, assuming that if you could gather the materials, could you actually make a sun? I know that's a dumb question, but I've often wondered why it doesn't burn out quickly and disperse. Yeah, gravity, but gravity isn't stronger than a blast.

Quote:
Originally Posted by RoundRoundGetAround View Post
Wow!
That IS an amazing question from a kid...that truly is special.
You must find your job very rewarding.

BIG THANKS from all of us for doing what you do!
Yes, I love this job. I know this seems like an amazing question from a sped kid, but it's actually not unusual--1/2 of our kids have learning disabilities, and the def of LD is someone with average to way above average intelligence who has trouble with some sort of administrative task that the rest of us take for granted. They are usually very visually oriented, so they can picture the most incredible things and if we could just manage to harness their brainpower without torturing them with the things they can't do well, it would be a much more workable world.

I enjoyed the movies too.
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Old 10-09-2010, 03:27 PM
 
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Indeed it would go off. Back in the heyday of nuclear weapons development, it was even suggested that setting off nuclear bombs behind a spacecraft could be used as a mean of propulsion(!) - Project Orion.
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Old 10-09-2010, 09:36 PM
 
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O.k, I have no knowledge on this sort of subject what so ever
But some of you have already explained, the nuclear weapon would lose much of its fireball effect
Does this mean its lost most of its energy? Would this weapon not be as effective in destroying say...an extinction sized incoming asteroid!
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Old 10-10-2010, 09:31 AM
 
Location: Bike to Surf!
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It depends on what sort of vacuum, but yes. The video shows spherical fireball at 50 miles. The atmosphere is thin there, but there's enough of it to light up pretty good as the energy pulse ionizes what molecules there are up there.

Further out in space, the fireball would be smaller still, but it would exist, cosisting of the very evenly vaporized bomb components ( I don't want to give the impression you'd see chunks of bomb casing flying apart or anything, because the energy is so intense it would render the weapon down to a very fine vapor of its component atoms ).

As for destroying an asteroid; silo-launched nuclear weapons would be mostly useless. Those bombs are delicate instruments that must detonate before impact. So, most of the energy wouldn't even touch the asteroid. You'd just cook the surface.

However, if you buried the weapons (ala Deep Impact/Armageddon) or used a bunker-buster nuke (one hardened for surface impact and tunneling) you'd get good vaporization of rock and ice, which would give the asteroid a nudge in the direction opposite where you detonated the bombs.

Unfortunately, ELE asteroids are so large that you'd need to intercept it months, preferably years, in advance in order for the tiny perturbation--a nuclear detonation would introduce--to make it miss the Earth. A better idea would be to land on the asteroid years in advance, build an engine or mass driver to throw available materials off into space, and slowly change the momentum vector that way. Or, if you had a suitably massive spacecraft and enough time, you could simply design an orbit which would fly-by the asteroid often enough for the spacecraft's gravitational pull to tug the asteroid off-course. But that would mean seeing the rock coming years or maybe centuries in advance. Which is not possible with today's observatories, computing power, and thus ability to find objects and make precise orbit determination calculations.
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Old 10-10-2010, 11:10 AM
 
Location: Moving through this etheria
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In other words, we're doomed?
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Old 10-11-2010, 04:03 PM
 
Location: Bike to Surf!
3,080 posts, read 9,694,073 times
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Unless we leave the planet, yes.

But we're probably doomed anyway, since the Sun will destroy the Earth in 5 billion years. Even if we get away from that, in some quadrillion or so years the universe will supposedly die a heat death where entropy becomes constant.

But all of this is on a geological or even astronomical time-scale, which is simply unimaginable to us. We've gone from gathering berries and throwing pointy rocks on sticks at animals to visiting the moon in 10,000 years. From horse-and-buggy to cell phone apps which can access data from orbiting satellites in the past 100.

The human race is incredibly fast compared to how the universe works. In fact, we're probably faster than the biosphere's feedback systems. At this point, we may already have killed the world's natural cycles (aka "mother nature"), but it's likely we'll have the technology to fix it or leave before she hits the ground.

Big asteroid impacts have a period of millions of years. Unless we're incredibly unlucky or we hit some sort of species-wide self-destruction point, we'll have the technology to save ourselves long before an impactor wipes us out.

People were a little overly-optimistic in the 50's, predicting that we'd have colonies on other planets in 50 years, however it's reasonable to guess we might get there in 200 years, and have a self-sustaining presence on various other planets and moons in the solar system within 1000 years. Not to mention all sorts of Flash-Gordan stuff which will make asteroid impacts as dangerous to the human race as smallpox is today.

So really, it's probably the Universe that's doomed, and in a ridiculously short time (comparitively). Especially should we ever figure out how to travel faster than the speed of light. And then you have to add really far-out debates about aliens and xenosocialogy etc. to this whole wildly off-topic rant.
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