Looking at the mushroom.

[Badly Shaved Monkey]

The subject of atomic explosions has just come up, and here is another of BSMs odd questions.

Is it dangerous to look at the mushroom cloud of an atomic explosion?

I mean, there is a big burst of radiation at detonation and later on fallout may land on you and irradiate you from short range, but after the bang itself, is the mushroom cloud itself a radiation hazard if viewed from a reasonable distance like all those soldiers we see in 1950's footage walking around at nuclear test sites with the mushroom cloud hovering in the background?

 

[DaveW]

The flash itself (pre-mushroom cloud) is potentially very damaging. I also imagine that some of the fallout following a blast could have a severe effect on the eyes, but the mushroom cloud itself is after the initial burst of gamma radiation and is comprised mostly of dust if I am not mistaken, so should not pose a risk.

 

[rppa]

Oh no! You weren't looking at photographs of mushroom clouds WITHOUT WEARING SUNGLASSES, were you?

 

[RussDill]

The subject of atomic explosions has just come up, and here is another of BSMs odd questions.

Is it dangerous to look at the mushroom cloud of an atomic explosion?

I mean, there is a big burst of radiation at detonation and later on fallout may land on you and irradiate you from short range, but after the bang itself, is the mushroom cloud itself a radiation hazard if viewed from a reasonable distance like all those soldiers we see in 1950's footage walking around at nuclear test sites with the mushroom cloud hovering in the background?

I have a family friend, who during the cuban missile crisis, sat in a fighter jet, with the engine running, in shifts. He wore a lead patch over one eye, so that if the flash destroyed his other eye, he could take off the patch and still see to complete his mission.

 

[RussDill]

The flash itself (pre-mushroom cloud) is potentially very damaging. I also imagine that some of the fallout following a blast could have a severe effect on the eyes, but the mushroom cloud itself is after the initial burst of gamma radiation and is comprised mostly of dust if I am not mistaken, so should not pose a risk.

I think he means the fireball, the fireball would all be thermal radiation from hot gasses, not the gamma radiation, etc, from the initial reaction. Thermal radiation is just good ol' thermal radition, might give you a sunburn and a tan, prolongled, repeated exposure from the thermal radiation from the fireball in a thermonuclear explosion may cause skin cancer, wear sunblock. You might have other issues with the radiation from the actual reaction though...

 

[Brian the Snail]

In one of his books (I think it's Surely You're Joking, Mr Feynman?) Richard Feynman claimed to have watched the first atomic bomb test at Los Alamos without eye protection. Apparently he didn't suffer any ill effects afterwards.

Edited to add: Actually, that's not quite right. He used a truck windscreen to screen out UV:

http://en.wikipedia.org/wiki/Trinity_site

 

[Pragmatist]

The subject of atomic explosions has just come up, and here is another of BSMs odd questions.

Is it dangerous to look at the mushroom cloud of an atomic explosion?

I mean, there is a big burst of radiation at detonation and later on fallout may land on you and irradiate you from short range, but after the bang itself, is the mushroom cloud itself a radiation hazard if viewed from a reasonable distance like all those soldiers we see in 1950's footage walking around at nuclear test sites with the mushroom cloud hovering in the background?

Oh, so this isn't a thread about drug abuse!

Given that the cloud is probably full of radioactive particles that are probably still radiating then I would say possibly yes - although of course the question of whether the intensity of the remaining radiation is enough to be signficantly hazardous at some distance is another matter.

 

[Badly Shaved Monkey]

Re: Re: Looking at the mushroom.

Oh, so this isn't a thread about drug abuse!

Nope, but I got you to read it, so the title worked!

Still not sure I have an answer. I think that after the initial flash, the answer must depend on how many radionuclides are in the mushroom and how energetic they are. If all they release is beta and alpha then there is no risk at all at a distance, but if there is a lot of gamma emitters then presumably that would be bad.

 

[Rob Lister]

Re: Re: Re: Looking at the mushroom.

Nope, but I got you to read it, so the title worked!

Still not sure I have an answer. I think that after the initial flash, the answer must depend on how many radionuclides are in the mushroom and how energetic they are. If all they release is beta and alpha then there is no risk at all at a distance, but if there is a lot of gamma emitters then presumably that would be bad.

I not only look at mushroom clouds, I specifically look for mushroom clouds with little purplish spots or a purple tint.

 

[Soapy Sam]

They're the ones that are safe to eat, right?

 

[CyCrow]

The relative damaging effect of different wavelengths of radiation varies with distance, and thus at a surviveable distance it depends on the size of the weapon. Megaton size blasts do most of their initial damage as thermal radiation, while small (kiloton) blasts have a lethal-radiation-dose radius that is larger than the blast/thermal lethal radius. Think neutron-bomb. Most modern warheads are in the 100kt-1Mt range, because that is the most efficient size for most targets. As for the mushroom cloud, after the fireball has died down (takes longer the larger the weapon), I really doubt it contributes much to direct radiation. In fact, gamma radiation is mostly absorbed by the atmosphere, the fireball is made of air that is superheated by the initial radiation, so much that it emmits a lot of X-ray and UV. As noted above, alpha and beta will not go far from the source.

So as long as you stay out of the fallout, you should be pretty safe if you are already at a safe distance from the explosion. Also, the danger level of the fallout is very dependent on protection gear, neither alpha or beta can penetrate clothing. Even if it seems silly today, the old training films do give good advice about fallout, don't breathe the dust, get a shower, and don't eat contaminated food. From a military standpoint, any radiation dose below radiation-sickness level doesn't affect a soldiers ability to fight, and during the 50s limited nuclear battlefield use was not out of the question. Fortunately, it never happened.

// CyCrow

 

[Nex]

Re: Re: Looking at the mushroom.

Oh, so this isn't a thread about drug abuse!

Funny, I thought it was a thread on mycology. I was looking forward to an interesting discussion of puffballs.

 

[TillEulenspiegel]

"Funny, I thought it was a thread on mycology"

Three words:
Rain, cow poop.

 

[Badly Shaved Monkey]

The relative damaging effect of different wavelengths of radiation varies with distance, and thus at a surviveable distance it depends on the size of the weapon. Megaton size blasts do most of their initial damage as thermal radiation, while small (kiloton) blasts have a lethal-radiation-dose radius that is larger than the blast/thermal lethal radius. Think neutron-bomb. Most modern warheads are in the 100kt-1Mt range, because that is the most efficient size for most targets. As for the mushroom cloud, after the fireball has died down (takes longer the larger the weapon), I really doubt it contributes much to direct radiation. In fact, gamma radiation is mostly absorbed by the atmosphere, the fireball is made of air that is superheated by the initial radiation, so much that it emmits a lot of X-ray and UV. As noted above, alpha and beta will not go far from the source.

So as long as you stay out of the fallout, you should be pretty safe if you are already at a safe distance from the explosion. Also, the danger level of the fallout is very dependent on protection gear, neither alpha or beta can penetrate clothing. Even if it seems silly today, the old training films do give good advice about fallout, don't breathe the dust, get a shower, and don't eat contaminated food. From a military standpoint, any radiation dose below radiation-sickness level doesn't affect a soldiers ability to fight, and during the 50s limited nuclear battlefield use was not out of the question. Fortunately, it never happened.

// CyCrow

Ah, ha! An actual answer.

Fungi may now be discussed freely.

 

[Skeptical Greg]

Re: Re: Looking at the mushroom.

I have a family friend, who during the cuban missile crisis, sat in a fighter jet, with the engine running, in shifts. He wore a lead patch over one eye, so that if the flash destroyed his other eye, he could take off the patch and still see to complete his mission.

If there was an Atomic explosion, close enough to destroy his eye, exactly what would have been the resulting mission?

All I can come up with is " Get the hell out of Dodge .. "

 

[RussDill]

Re: Re: Re: Looking at the mushroom.

If there was an Atomic explosion, close enough to destroy his eye, exactly what would have been the resulting mission?

All I can come up with is " Get the hell out of Dodge .. "

I'm sure someone had thought that far along, I just don't know the answer.

 

[teddygrahams]

Re: Re: Re: Re: Looking at the mushroom.

I'm sure someone had thought that far along, I just don't know the answer.

And if he was just sitting there, why not patches on both eyes ?

 

[Badly Shaved Monkey]

Re: Re: Re: Re: Re: Looking at the mushroom.

And if he was just sitting there, why not patches on both eyes ?

He needed to be able to see the bombs going off, silly! If he had both eyes covered and just felt the plane shaking he might just assume the copilot had eaten too many beans again.

 

[RussDill]

Re: Re: Re: Re: Re: Looking at the mushroom.

And if he was just sitting there, why not patches on both eyes ?

Because he needs to be able to fly. The eye patch is not for just waiting, it is also for once he takes off. Also, it probably important to keep an eye on the gauges on the plane while it is running.