In 1945 two atomic bombs were dropped on Hiroshima and Nagasaki, killing 50,000 people each and
unleashing 20 kilotons of TNT. These were the only nuclear bombs used against civilian populations,
but the ensuing arms race would see the United States and Soviet Union developing ever more
powerful weapons of mass destruction. The culmination of this work was the Tsar Bomba,
the most powerful nuclear bomb ever detonated. With an explosive force of 50 megatons of TNT
(that's 50 million tons of TNT) and 10 times more powerful than every bomb and bullet used
during World War Two combined. The bombs dropped on Japan decimated entire cities, but the Tsar
Bomba is 1,570 times more powerful. Since WW2 cities have only denser and more populated, so
it’s worth asking, what would an explosion of that size be due to some of today’s largest cities?
In its original testing, the Tsar Bomba was detonated at 11:32,
Moscow time over Novaya Zemlya island. In a flash,
the bomb created a fireball five miles wide that could be seen from 600 miles away [1,000km] away.
The bomb’s mushroom cloud soared to 40 miles [64km] high, nearly touching the edge of space,
with its cap spreading outwards until it stretched nearly 63 miles [100km] from end to end.
Just as a size comparison, that’s an area larger than Delaware for my
American viewers or just a bit smaller than American egos for my international viewers.
A village on the island 34 miles [55km] was completely destroyed.
Shock waves shook buildings and blew out windows at the Dikson settlement 730 miles [700 km] away.
And because of atmospheric focusing, the blast was able to damage windows in Norway
and Finland. Despite being detonated 4.2 km above ground, its produced a magnitude 5 earthquake, and
the blast wave through the atmosphere was so strong it hit sensors nearby,
wrapped around the Earth, hit them again, wrapped around the Earth, hit them again,
then wrapped around the Earth and hit the sensors again [three encirclements of the earth].
But enough background on the bomb, let’s get to blowing up cities! Like King Kong, first we’ll
focus on New York City. What if the Tsar Bomba was detonated above the streets of the Big Apple.
Anyone within 3 km (21 km^2) would receive an instantly lethal dose of radiation,
although that wouldn’t matter much because anyone within a 4 and a half km range (67 km^2) would be
consumed in a nuclear fireball. Going out as far as 9 km (249 km^2) the force of the blast
would be so intense that virtually every building would be demolished within a fraction of a second.
More than 3 million people [3.19 million] live in this area alone. And for comparison
remember the bombs dropped on Japan only killed 50,000 people each.
Going out to 21 km [1350 km^2] buildings, trees, and even clothing would quickly
catch on fire from intense ionizing radiation, leaving most people would be heavily injured.
Going as far out as 54 km [9270 km^2] all windows would be shattered, and given the
shockwave moves at the speed of sound, people would see the flash of the bomb nearly two
minutes before the shockwave got to them. And because humans love staring straight at danger,
this means up to 12 million people could be looking out the windows
at the fiery explosion when glass comes shattering in from the shock wave.
And if you were unlucky enough to be outside when the bomb went off, as far
as 60 km away (11,300 km^2) you could expect 3rd degree burns from the heat of the blast.
All told just in the immediate aftermath of the blast you’d be looking at more than 7 and a half
million dead and more than 4 million critically injured. But the majority of those 4 million
would likely pass away. Those 4 million critically injured people are 16 times
more than the total hospital capacity of the US, and that’s before thinking about all the
people with more minor injuries like cuts and broken bones. Without immediate treatment
many of these people would succumb to infections from their wounds.
The casualties from just this one bomb would be 7 times more than the deaths of every
US service member in every war combined, and remember, America has fought in a lot of wars.
Luckily for New Yorkers, by land area, more of New Jersey would actually be destroyed than New York.
Radioactive particles would linger in the air, but surprisingly radioactive fallout isn’t as
much of a concern as you might think. Radioactive particles from the blast would quickly decay.
Seven hours after the blast residual radioactivity would have fallen by more than 90%,
by 48 hours it would be less than 1%. Still a problem for anyone seeking immediate medical
attention, but most survivors could avoid the radiation camping out in their homes.
So the only people in real danger are those immieadelty upwind of the blast,
mostly all across Connecticut.
Blasts across major cities would have similarly disastrous effects. Moscow nearly 10 million dead,
Paris 8, Tokyo, with one of the highest population densities in the world,
16 million people, and Hawaii, well, let’s just say we’d be back to 49 states.
But that’s if you detonated the bomb above a city. What if it was underground.
Well, that really depends on how deep you bury it. Bury a body six feet deep,
and it won't be found. Bury the tsar bomba six feet underground and it’s like you did nothing.
If the bomb isn’t deep enough you’ll be left with a crater and radiation shot into the atmosphere.
The exact distance you need to bury a nuclear bomb depends on the rock it's buried in,
but generally speaking to contain the explosion the burial depth in meters divided by the cube
root of the yield in kilotons needs to be at least 100. The Tsar Bomba had an explosive force
of 50,000 kilotons, so plugging that into our equation means the world's most powerful bomb
would have to be buried at least 3,684 meters or 2.3 miles. The only man-made hole ever dug
that deep was the Kola Superdeep Borehole in Russia stretching 7.5 miles into the Earth,
but it was only 9 inches in diameter, so you won't be fitting a bomb down there anytime soon.
The energy of the nuclear explosion is released in one microsecond
with temperatures of several million degrees and pressures of several million atmospheres
Within milliseconds of exploding, a bubble of high-pressure gas and steam would form
vaporizing the surrounding rock. The explosion would create a cavity in the rock
1.2 km or three quarters of a mile across.
The Limited Test Ban Treaty signed between The United States, Soviet Union, United Kingdom,
and eventually 105 other countries banned nuclear testing in the atmosphere, in space,
and underwater, but specifically excluded underground tests from the list,
because the Soviet Union feared this would necessitate on site inspections to investigate,
and they didn’t want Americans peeking their head around Soviet nuclear facilities.
As of today, the largest underground nuclear explosion was project Cannikin, by the United
States. On November 6th, 1971 a 5 megaton bomb was detonated along the Aleutian Islands,
Alaska's long tail of island chains. This was still within the 20 biggest
nuclear devices ever detonated, but the Tsar Bomba would still be 10 times more powerful.
And the go to question everyone always asks, what if we detonated the bomb in space.
Well, in space the physics of nuclear weapons changes dracstilaally.
First, in the absence of an atmosphere, the blast disappears completely. Second, thermal radiation,
that caused everything to light on fire here on earth, also disappears. There is no longer any
air for the blast wave to heat and so the weapon emits a much higher frequency of radiation..
Third, and most importantly, here on Earth, the atmosphere dulls explosions.
Think about trying to scream to someone underwater, sure it’s possible for them
to hear you, but they have to be a lot closer than they would outside the pool.
The atmosphere dampens the explosive force, but without it in space, the range of a nuclear
explosion would be 10 to 30 times larger than on Earth. While the bomb released lethal radiation
for 37 miles [60 km] on earth, in space that would be more than 600 miles or 1000 km.
There aren’t many people in space, but this would have effects across the globe. One of
the most noticeable here on the ground, ribbons of lights would danse across the night sky. Think of
northern lights for days as radiation from the blast reacts with the Earth’s magnetic field.
On July 9, 1962, the United States detonated a 1.4 megaton nuclear bomb in space above the Johnston
Atoll in the Pacific. The goal was to study the effects of nuclear explosions in space,
because why run simulations when you can just do the real thing amiright. The explosion,
only 3% as strong as the Tsar Bomba generated an aurora for 1000 miles, Hawai
9 miles away suffered a complete power outage, and satellites were damaged tens of miles away.
The explosion destroyed 6 satellites. In 1962 there were only about 250 satellites
in space, but today there are 6,105 satellites orbiting the earth and 2,787 are operational. An
explosion the size of the Tsar Bomba would destroy 100’s of satellites, and besides
being able to cripple an entire country could force some of you to actually go outside.
But dont worry too much, it's been more than 50 years since a nuclear device was detonated in
space. Want to change that? Well check out our video on how to build an at home nuclear bomb,
and maybe you could change that. And remember, there is always more to learn.