Ferrari Mailing List: Re: Fwd: Cool Pix

[JAshburne (JAshburne]

Todd
 
Simply amazing photos and, as Bubba said, like looking directly into  hell.  
Thanks for posting the link.
 
John
 
 
In a message dated 12/3/2008 11:07:37 P.M. Eastern Standard Time,  
racertod [at] racertodd.com writes:

Ferrari  Bubba wrote:
>Reminds me of one of the most terrifying and evil photos  that I've ever 
>seen. It was a shot of the beginning of the  actual?explosion when we set 
>off an H-Bomb. I don't know how many  milli-seconds after the device was 
>detonated the shot was taken, but  the actual explosion was no more than 50 
>feet across. To me, it was a  glimpse straight into hell. How the camera 
>survived is a mystery to me  too.

I'm guessing you are referencing  the photos taken by Harold 
Edgerton of atomic tests in Nevada.   Edgerton perfected stroboscopic 
photography using strobes that fire pulses  of light a millionth of a second 
long.  If you've seen photos or  video of a balloon bursting, a drop of milk 
hitting the table or a bullet  slicing a card in half - you've seen his work.
To photograph the atomic tests, he used his rapatronic  camera.  To 
overcome the speed limitation of a conventional camera's  mechanical 
shutter, the rapatronic camera uses two polarizing filters and  a Kerr cell. 
The two filters are mounted with their polarization angles at  90° to each 
other, to block all incoming light. The Kerr cell between the  filters, 
which changes the polarization of light passing through it when  energized, 
acts as shutter when it is energized at the right time for a  very short 
amount of time, allowing the film to be properly  exposed.
For a film-like sequence of  high-speed photographs, as used in the 
photography of nuclear and  thermonuclear tests, arrays of up to 12 cameras 
were deployed, with each  camera carefully timed to record a different time 
frame.  For these  pictures he built a special lens 10 feet long for the 
cameras which was  set up in a bunker 7 miles from the source of the 
blast.  The camera  took exposures at one-billion of a second long.

Several of the pictures are here.  These are from the  Operation 
Tumbler-Snapper series of tests at the Nevada Proving Ground in  May and 
June of  1952.
http://www.yellowswordfish.com/257/1000000000th-of-a-second/

This one shows the fireball at about 20 meters in  diameter.  The 
spikes at the bottom of the fireball are known as the  "rope trick effect".
The cause of the  "rope trick" is the absorption of thermal 
radiation from the fireball by  the rope. The fireball is still extremely 
hot (surface temperature around  20,000 degrees K at this point, some three 
and a half times hotter than  the surface of the sun; at the center it may 
be more than ten times  hotter) and radiates a tremendous amount of energy 
as visible light  (intensity over 100 times greater than the sun) to which 
air is  (surprise!) completely transparent. The rope is not transparent 
however,  and the section of rope extending from the fireball surface gets 
rapidly  heated to very high temperatures. The luminous vaporized rope 
rapidly  expands and forms a spike-shaped extension of the  fireball.
<http://upload.wikimedia.org/wikipedia/commons/e/e9/Tumbler_Snapper_rope_trick
s.jpg>


Todd
Seattle,WA
'86  GTI, Red of course. (exciting racey car) 268,000 miles
'01 Golf TDI,  silver.   (new work car)       186,000  miles
'87 Golf, Polar Silver. (retired work car)   654,000 miles  <- Gone to a new 
home :(
http://www.pureluckdesign.com <-Ferrari  & VW  stuff


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