The two A-bombs dropped over Japan, how far above ground were they detonated?

[NFS4]

I know that with convential bombs that they hit the ground (or burrow down into the ground, then explode). But from what I understand, the two A-bombs were detonated above ground. This goes against my conventional understanding of bombs.

Is this true, and how far above ground are they detonated...and how does the blast radius do damage. Is it down and out?

 

[Scouzer]

Hmm... didn't know that. Now I'm interested too.

 

[RSI]

<< Hmm... didn't know that. Now I'm interested too. >>

Same here. Bump!

-RSI

 

[Aves]

The Hiroshima bomb detonated ~580 meters above ground.

Link

 

[peto]

Jeebus, I thought you were posting news. I just saw "two A-bombs dropped over Japan" and was like oh sh!t.

 

[conjur]

1900 feet (Hiroshima)
1650 feet (Nagasaki)

click here

 

[jbod]

Yes, I do remember reading that the bombs exploded some distance from the ground probably a couple hundered feet. By doing so, it would create optimal dispersion and reflection of the energy. If the blast hit the ground, the energy would reflect upward instead of outward.

Just a guess.

 

[BrunoPuntzJones]

<< If the blast hit the ground, the energy would reflect upward instead of outward. >>

bingo

 

[glen]

Also, if they hit the ground, it would scatter the nuclear mass and the explosives so they wouldn't detonate.

 

[jbod]

Maybe true for Fat Boy, but they have bombs now that can burrow deep into the ground and still be deadly.

 

[LongCoolMother]

oooh cool, i thought all bombs explode on impact....im pretty stupid, lol

 

[glen]

You want critical mass, so you get slightly les than critical mass, then pack explosives all around it. WHen they go off, it compresses the tennis ball size to a golf ball size and then...BOOM.

 

[KennyTheGreat]

when did this happen again?

 

[jbod]

Stardate l33t.4.2

 

[Iron Woode]

Its called an air burst.

Going off above the ground is actually better than the alternative. Air burst delivers less radiation and destroys more buildings.

If exploded on contact the radiation levels would have been much higher for much longer. The dirt and debris ejected from the explosion would have been highly irradiated and spread over a much larger area. The poison "rain" falling down would have been very nasty.

"You want critical mass, so you get slightly les than critical mass, then pack explosives all around it. WHen they go off, it compresses the tennis ball size to a golf ball size and then...BOOM. "

Thats not quite correct. You want critical mass, but you can't have critical mass before the bomb gets to its target. The mass is usually broken into equal pieces (ei: 1/2, 1/6,etc) and then forced together (usually by small explosives) and it must stay together for the critical mass to achieve nuclear fission. Usually measured in milliseconds. It dosen't have to be compressed, just brought together.

 

[Loach]

The "A" bomb was fission correct ??? While the hydrogen bomb is fussion ??

 

[rc5]

Those two A-bombs were laughably small, for 0.02 megaton.

If anti-matter bomb comes to true, a same size bomb can be made as big as one million megaton.

Can you say planet-buster?

 

[Random Variable]

<< The "A" bomb was fission correct ??? While the hydrogen bomb is fussion ?? >>


Not quite. There is no such thing as a pure fusion bomb because there needs to be a fission reaction first in order to generate enough heat energy to initiate the fusion reaction (I think ).

 

[Random Variable]

<< If anti-matter bomb comes to true, a same size bomb can be made as big as one million megaton. >>


A large meteor slamming into the earth would release far more energy that any matter-antimatter annihilation bomb.

 

[Antoneo]

Atomic weapons were exploded above the ground rather than on it because the intent was to destroy as many buildings as possible. Mass Destruction is better "seen" when you have a whole city leveled flat than a deep pothole in the ground. Conventional weapons have nowhere close to the destructive power of a atomic weapon so it might as well just "hit" the target.

 

[StageLeft]

It's called ground zero is this is the source of the term used for the site of the 9/11 attack.

 

[jpsj82]

<< It's called ground zero is this is the source of the term used for the site of the 9/11 attack. >>



ground zero is a term used a lot. i believe it is just refering to the distance from the target. so i guess ground 150 is 150 meters away from hte target and ground zero is just the target.

 

[PsychoAndy]

<< Its called an air burst.

Going off above the ground is actually better than the alternative. Air burst delivers less radiation and destroys more buildings.

If exploded on contact the radiation levels would have been much higher for much longer. The dirt and debris ejected from the explosion would have been highly irradiated and spread over a much larger area. The poison "rain" falling down would have been very nasty.
>>



Air Bursts nowadays...er...after 1960 i guess, were to be used for the EMP effect, not for collateral damage. For instance, if the soviets air bursted three 20-megaton weapons 20,000 feet over the US on the west coast, east coast, and midwest, the main effect would be waves of EMP destroying communications and electronics, in a nutshell. But for collateral damage, they explode them <5000 feet, or at least I would assume. Also, a larger shock wave could probably be produced by an air burst slightly above ground, rather than in the ground.

 

[QueHuong]

Somewhat unrelated:

1) I heard that when the atomic bombs exploded, shadows were IMPRINTED to whatever it was on. Anyone able to explain how that works?

2) What's a "nuclear winter"?

 

[BrunoPuntzJones]

<< 1) I heard that when the atomic bombs exploded, shadows were IMPRINTED to whatever it was on. Anyone able to explain how that works? >>

just big, bad ass, bright light. this is shown at many wwii exhibits. you stand in front of this white sheet (dunno the material, but apparently absorbs light well) in a dark room. you hit this button and a bright light flashes (close your eyes ). you turn around and you can see the shadow puppets or whatever you made imprinted on the sheet (wears off after about a minute).

same principal applies to the nuke. if you were walking beside a building, the light would have been intense enough to leave your shadow on the wall.

ive also read accounts where anti aircraft gunners had their eyes melt and the ooze run down their face :disgust: from the intense heat/light.



<< What's a "nuclear winter"? >>

not as much as a fear today (for other countries) as nukes have become a lot "cleaner". a nuclear winter is just the result of fallout over a particular area. sky becomes dark, atmosphere becomes cooler. think of it as the thing that killed the dinosaurs. we should fear it from other countries that have less sophisticated weapons (India/Pakistan probably have pretty rough weps).

iirc, we could drop some b61 grav bombs over a target (very small nuke i think) and we would be able to land troops safely in 10 days, the radiation would be so low, and disapate that fast.