Every cloud

has a silver lining.

Except nuclear mushroom clouds, which have a lining of Strontium-90,

Caesium-137 and other radioactive isotopes.

Upon detonation, atoms are literally gutted

and glutton at temperatures exceeding that of the surface

of our Sun. In the 1950s, Harold Edgerton's

rapatronic camera caught nuclear fireballs less than a

thousandth of a second after detonation. Using a special magnetic shutter,

each exposure lasted only a billionth of a second and captured

an other-worldly creature, its energy vaporising the metal wires

supporting its tower into stringing legs

of plasma. Watch the target

on the ground. Now, roughly visualized, here is a conventional

TNT explosion. Now, on the same spot,

a similarly sized bomb that uses nuclear

fission.

When 'Little Boy' was detonated over

Hiroshima only 1.38% of its uranium

actually fissioned. The rest was blown away before

that could happen, which means, as Eric Schlosser points out, the

fission of merely 0.7 grams

of uranium, that's less than the weight of a banknote, was enough to kill

80,000 people and destroy two-thirds

of city's buildings. When a country has tens of thousands of nuclear weapons

ready to go,

accidents are a possibility.

This was a problem during the Cold War and it still

is a problem. What if there is a fire or a miscommunication or a rogue

officer decides to

set one off. Or what if someone just drops

a warhead? How much risk

is too much, I asked Schlosser.

The acceptable probability of a nuclear weapon

accident? What is it now?

The acceptable probability

of the detonation of a nuclear weapon in an accident is one in a million.

In 2012, the odds of your dying

in a commercial airliner accident were about one in forty

million. So that's even more remote than the accidental detonation of a nuclear weapon.

There have been 'oopsie daisy' moments with nuclear weapons

on US soil. Luckily, none that resulted in critical mass

but accidents nonetheless. Just like when you

pee your pants, except your pants are the entire planet

and the "P" stands for Plutonium.

Eureka comes from ancient

Greek, meaning "I have found it!" And in

Eureka, North Carolina you can find

it. A giant sign that says

"Nuclear mishap". On my birth date

the year my father was born, a US B-52 bomber carrying

two 4 megaton thermonuclear bombs

over North Carolina tumbled

from the sky. A loose lanyard in the cockpit snagged the bomb release

switch. Each bomb contained a greater explosive yield

than all munitions ever detonated by mankind

combined. Lieutenant Jack ReVell discovered that only

one safety mechanism didn't fail that day.

A single low voltage arming switch remained

untouched during the crash. And that one switch is why,

he explained in 2011, we don't have

a bay where North Carolina is today.

The bombs were recovered... mostly.

The uranium-rich Secondary of one of the bombs was

never found. To this day it remains buried

underground in North Carolina. Here's something you can try

at home.

Build a nuclear reactor.

In 1994, a 17-year-old David Han attempted to build

a nuclear reactor in his mother's backyard

in Michigan. It wasn't that difficult. For instance,

common everyday smoke detectors contain small amounts of

radioactive Americium. And old glow in the dark paint

contains Radium. His reactor never reached critical mass but it did succeed

in exposing his neighborhood

to 1000 times the regular dosage

of background radiation. It was declared a Superfund hazardous materials cleanup

site

and all of his work was confiscated by authorities and buried

in Utah. It didn't end

there. In 2007 David Hahn was

arrested for stealing smoke detectors from an apartment building.

His face was covered with sores believed to be caused by constant exposure to

radioactive materials.

Three days after Little Boy was dropped on Hiroshima by the Enola Gay

Charles Sweeney was ordered to drop Fatman

on Kokura. He flew boxcar over the city for nearly an

hour with the bomb bay doors open, but it was cloudy.

Sweeney couldn't achieve visual confirmation of the target and was

forced

to go to the secondary target - Nagasaki,

where 75,000 people died instead.

Kokura was spared because of the clouds.

We can build a weapon

that mimics the furnace of our Sun and the winds of Neptune but yet we can't

predict the weather more than a few minutes ahead of time.

During World War 2 Japanese soldiers spot for their

emperor in ways that made allied troops speechless.

Kamikaze planes and torpedoes, driven by a single pilot,

lost after use. When outnumbered,

without hope, Japanese soldiers were reported to have thrown themselves

off clips or swam out to sea to drown

rather than surrendered. Even after two

atomic bomb attacks, the Japanese Minister of War

urged his people to continue fighting.

But on August 14th, 1945, the Emperor of Japan

overruled that decision and unconditionally

surrendered. Men had leapt of off cliffs

for him, but in his own words, the enemy has for the first time

used cruel bombs.

The heavy casualties are beyond measure.

Richard Feynman received the Nobel Prize in Physics

in 1965. He also helped develop the first atomic bomb

at Los Alamos. In "The Meaning of It All," he wrote

"Is science of any value?"

And below that, "I think a power to do something

is of value." He elaborates by talking

about keys. Everything we learned about the universe, everything we invent or

discover within it,

is a key to the gates of heaven.

But the same key will

also open the gates to hell.

The Titan II Missile is great for delivering

lethal nuclear warheads.

But it also sent Gemini astronauts to space,

preparing us for a mission to the Moon.

Science doesn't tell us how to use

keys. It finds them or predicts them.

How we use keys is up to us.

And as always,

thanks for watching.