For not so long ago (that'll be a couple of years ago =D), I watched this TV program about nuclear explosions and effects. I must say I was facinated and slightly astonished to hear how powerful these nukes actually were. I mean, have you guys any clue of how much a minor nuke (20 kilotons) can destroy and desolate?
The atomic bomb which was dropped over Hiroshima in 1945, had a yield of about 13 kilotons (13 kilotons equals 13,000 tons (1 kiloton = 1,000 tons TNT)). Even though this atomic bomb which was named "Little Boy", was one of the most minor ones (the reason it got this name), it destroyed 2/3 of the city. Hiroshima at that time had a population of about 250,000 people (pretty similar to that of the city I live in, Bergen), and if I remember correctly, over 70,000 people got killed and over 100,000 people got injured.
Before I knew as much about nuclear effects as I do now, I just couldn't conceive how one single explosion could weap out a whole city. I began researching on the internet and reading books about it, and my facination for nukes increased.
What I think is so mind-blowing is the amount of area one single nuke can flatten. All the nuclear effects interest me.
It's not only the bomb itself which destroys, but also the chain reactions after a nuke has been fired.
The Nuclear Effects of an A-Bomb (1 megaton)
There are several ways of detonating a nuclear device. You can either detonate an a-bomb in the air ("airburst"), under water ("underwater burst"), under the ground ("sub-surface burst") or on the ground ("surface burst"). The most common way of detonating a nuclear weapon is the airburst, which usually is about 500 - 1,000 feet above groundlevel.
Let's say a nuclear bomb detonates about 1 mile above the surface. The bomb itself explodes in about 200 milliseconds -- way too fast for human eyes to observe. The moment the bomb explodes, a magnificent amount of light is emitted, lighting up the desert thousands of miles away. The short period this light is "on", great amounts of thermal radiation is also emitted with the light, causing the most nearby objects like plants, insects, and even some sorts of rock to vaporise. At a furthur distance, plants, etc., catch fire.
After about 2 seconds after the detonation, the brightness of the light decreases, including the heat. Because of the sudden expansion of extremely hot gasses in the fireball (several million degrees F), a hazarous shock or blast wave front expands outwards from the fireball.
After a few more seconds, the shock wave strikes the ground, resulting a second shock wave to form, reflected from the frist one. The first shock front and the secind one "melt" together to form a Mach front. A Mach front is an expanding sphere with thin walls of higly pressurized gasses. It strikes all objects around the epicenter. The closer for instence a house is to the epicenter, the more it will get destroyed, both by the heat and the pulverising shock wave.
Immidiately after the Mac front has passed by with an extremely high speed (600-1200 mph), superfast hurricane-like winds immidiately strikes, blowing away all the remains of a building. To meassure these winds, we use PSI (pounds per square inch). The closer a building is the epicenter of the explosion, the higher rate of Psi it's revealed to.
16 psi = 16 pounds per sqaure inch
A wall with an area of 1x1 meter (62.75x62.75 inches) would be strook by a wind with a forse of 28.5 tons (16 psi)!
Even buildings over 9 miles away from the epicenter will have their windows shattered by the shock wave front, which its forse at this distance has decreased to 1 psi.
Many people wonder why the nuclear explosions always have the mushroom-shadped forms. As the bomb explodes, a fireball is rapidly created. As I mentioned before, it releases a shock wave which strikes the ground, and partly reflects back up where it came from. When the shock wave front strikes the fireball, it distorts it, and the fireball flattens at the "bottom" of it. Because of the intense heat, the fireball starts ascending up into the sky. As it ascends in about 250 mph, it creates a sort of suction underneath it. The loose soil and dust underneath gets sucked up into the fireball, forming a stem consisting of these things..
Here are some links to short video clips of nuclear tests. I recommend you to take a look at this! (No spam, honestly). These were found on Google Video searching engine.
http://video.google.com/videoplay?docid=7278951069225366106& amp; amp;q=atomic+bomb
http://video.google.com/videoplay?docid=2552156377245852199& amp; amp;q=atomic+bomb
Thank you so much for reading my post. I hope you found some of this interesting.
Edited by Zonic Blazer