Photo of a Nuclear Explosion Less than 1 Millisecond After Detonation

There's also the National Atomic Testing Museum in Las Vegas http://www.nationalatomictestingmuseum.org/

Something to do with the electromagnetic heating of the wire being quicker than the energy capture and incandescence of the air?

Thanks for the pointer - in case people want to see it and comment on it, now submitted over here:

http://news.ycombinator.com/item?id=4759908

Implosion-type nuclear bombs (which are nearly all of them) use a mind-bogglingly precise sphere of fissile material. If you put a drop of thin oil on top and came back a few hours later, the oil would coat the sphere evenly.

The mottling is apparently from the bomb casing.

(http://www.damninteresting.com/rapatronic-nuclear-photograph...)

> The resulting extraordinary photographs revealed intricate details of the first instant of an atomic explosion, including a few surprises such as irregular “mottling” caused primarily by variations in the density of the bomb’s casing. It also showed the detail of the “rope trick effect,” where the rapid vaporization of support cables caused curious lines to emanate from the bottom of an explosion.

The camera is interesting - using an electronic not mechanical shutter. This was around 1944. (Bell Lab's transistor was around 1947.)

This is what impresses me so much about this photo. I think of nuclear bomb fissile materials as being one of the most precise things ever humans have ever made, yet the the fireball is so incredibly irregular.

It reminds me of when I first learned that irregularity in the early universe is what enabled material to condense (probably not the best word) and eventually form gas clouds.

Edit: I was wondering if there was some connection between the two, but thanks to DanBC's comment, it seems like the actual cause is a lot less mysterious.

While it is somewhat due to the makeup of the bomb and the environment at the time, fusion physicists are discovering that such instabilities in the explosion are extremely difficult to get rid of. Even in the NIF, which is a controlled environment with no air and a perfectly symmetric fusion target, they'se seeing images that look creepily similar to this one. Unfortunately, that means that creating an efficient fusion reactor is...more challenging that expected.

The way the explosion works isn't exactly a single, expanding nucleus of hot material. It's pretty complicated, but what's going on at this point is that the bomb is giving off x-ray radiation, which is absorbed the air, heating it up. As a consequence of air absorbing the radiation, air further from the bomb is shielded from the radiation. The sphere that you see is, approximately, the air close enough (un-blocked enough) to absorb enough heat to glow in the visible spectrum.

The upshot of this is that the entire sphere that you see comes into existence in a roughly simultaneous fashion, not in an expanding fashion. If you watch slow-motion videos, you will see that sphere stay at the same size and transition from dark to light, rather than start light and transitioning from small to large.

The explosion itself comes later, as that air (which is around 9000F) obeys basic gas laws, and tries to expand.

Yes, that was pointed out by aw3c2 here: http://news.ycombinator.com/item?id=4759809

It's too late, but I have submitted that link here:

http://news.ycombinator.com/item?id=4759908

Doesn't do any good, the discussion is here already, and there's no way to merge or migrate.

Excellent link. I had my curiousity raised about the techniques of the image capture, which this article provides some direction towards. Thank you for posting it.

it's been a long time since i've studied physics and physical chemistry so i could be wayyyy off but ...

how i understand it is two-fold. first, heat density. the surface area of the explosion is significantly smaller than the sun, and so the energy in the explosion is condensed to a smaller area and thus creates a higher temperature. as it expands it will, therefore, "cool" (relatively speaking) and by the time it reaches 7 miles away it wont melt the piss out of the camera (it obviously survived).

second is the spread of heat from the explosion to the camera. heat transfer is not instantaneous, and so the camera was just fine at this point. again, by the time it spreads to the camera it's dissipated so much energy that the heat will be relatively cooler.

finally i imagine the camera was pretty well protected to withstand the various forces of the explosion.

It's rather smaller than the Sun, so the total energy output is rather less.

I am also wondering how we can blow up something 3 times hotter than the surface of the Sun so close. Then again, the "surface" of the Sun is orders of magnitudes cooler than its center. The "surface", which is kind of hard to define, is about 5778K, but the centre is about 1.571 x 10^7 K. [1]

[1] http://nssdc.gsfc.nasa.gov/planetary/factsheet/sunfact.html

EDIT: If it was 3 times hotter than the centre of the Sun...yeah, the Earth might be done for at that point.

You do get toasted! But only when the fireball gets to you. I'm pretty sure clever design could get the film into a safe place by then.

The intensity of that heat is going to drop off rapidly with distance. I'm no physicist, but I'd bet it follows the Inverse-Square Law (https://en.wikipedia.org/wiki/Inverse-square_law) just as light does.

Meaning that at 20m from the center of the explosion (the fireball was 20m diameter, or 10m radius) it should already be at 1/4 the intensity, already less than the surface of the sun. At 7 miles or 11200m, you're talking 1/(1120^2) or 7.97e-7 of the original intensity - effectively zero - if I've done that math right.

It doesn't maintain the temperature for very long, so there's surprisingly little total heat energy transferred over that time. If the camera were behind a barrier and took the picture in a mirror (as is often done with explosions), it could be within 2 miles of a large-ish atom bomb without taking much damage. http://www.nebraskastudies.org/0900/frameset_reset.html?http...

I don't think there is a current Edgerton exhibit at the MIT Museum although there may be some photos. Strobe Alley (fourth floor of Building 4) does however have a permanent exhibit of photographs and some other things.

(For others, the context here is that in addition to his work photographing and filming nuclear explosions, Edgerton also developed the electronic strobe along with developing lots of other interesting things, and going on Jacques Cousteau expeditions. (Also a wonderful teacher and person.)

That (very nifty) technique only works for periodic phenomena, so it seems hard to apply here.

I might be wrong but I think it's this: http://en.wikipedia.org/wiki/Planck_time

...which if my math is right, comes out to 1/100,000,000,000,000,000th of the amount of time post explosion of this photo...

I don't think it would like much!

That would be a Planck time, but 1) we can't measure with a precision anywhere remotely close to that, and 2) if we could time things that finely, we couldn't take a photograph of it because there isn't enough time for the photons to hit your receptor. For perspective, this photo took more than a decillion Planck times.

(Disclaimer: I'm not a physicist of any sort, but I'm pretty sure this is all right.)

See also: http://en.wikipedia.org/wiki/Greisen%E2%80%93Zatsepin%E2%80%...

http://www.technologyreview.com/view/429561/the-measurement-...

http://arxiv.org/abs/1210.1847

http://www.deepdyve.com/lp/hindawi-publishing-corporation/a-...