Exploding atom bomb - what is the white band around the base?

[Neil9327]

http://en.wikipedia.org/wiki/Trinity_(nuclear_test)

 

On the right of the link is a photo taken a few milliseconds into the Trinity atom bomb test. You can see the smooth surface of the fireball shock wave expanding out, and you can see the rough dusty base where it (presumably) is interacting with the ground. But what is the paler band between the two?

 

Also there are some blotches on the surface of the fireball. Are these as a result of the tower or bomb casing perhaps?

[insane_alien]

reflected shockwave.

[Leader Bee]

The blotches are where the fireball is cooling faster, similar to what sunspots are (but not quite). The band at the bottom could be a reflected shockwave but i'm not quite so certain on that, it seems to blend far too well with the spherical shape of the original fireball to be a reflection of some kind, my guess would be that this is some kind of melted ground debris.

 

The sand around the trinity test site was turned into radioactive green glass and I assume this might be what it is.

 

If you're interested in the history of nuclear testing a great movie to watch is "Trinity & Beyond: The Atomic Bomb Movie" followed by Nukes in Space, Nuclear 911 and Atomic Journeys. All great Documentaries in my opinion.

Edited February 25, 2010 by Leader Bee
Further info

[williamthegreat]

..makes me shudder