7+ explosive facts about atomic bombs and other nuclear weapons

Find out all you need to know about the atomic bomb and nuclear weapons.
Christopher McFadden
Nuclear explosion
Nuclear explosioncelafon/iStock

 "Now I am become Death, the destroyer of worlds" was J. Robert Oppenheimer's infamous response to seeing the first atomic bomb test detonation in 1945. This single event ushered in the so-called "Atomic Age" that saw the beginning of the age of harnessing of the power of the atom, for good and bad. 

While no nuclear weapons have been used in anger since WW2, there are now thousands of nuclear warheads whose combined power would probably cause the collapse of all human civilization if ever unleashed en masse. 

Let's take a closer look at these most destructive of human inventions. 

What are the differences between a hydrogen bomb and an atomic bomb?

Nuclear weapons come in a variety of forms, but atom and hydrogen bombs, while related, are about as similar as chalk and cheese. Both chalk and cheese have calcium in them, but they are very different things.

7+ explosive facts about atomic bombs and other nuclear weapons

In essence, a hydrogen bomb employs fission to fuel a fusion process, whereas an atomic bomb is solely a fission-based weapon. In other words, a hydrogen bomb is set off by an atomic bomb.

To better understand this, it is probably worth giving a quick overview of each.  

An atomic bomb, or A-bomb for short, is a form of nuclear weapon that detonates as a result of the tremendous energy unleashed by nuclear fission. Because of this, this kind of bomb is also often referred to as a fission bomb. 

A material capable of fission (fissile material) is given supercritical mass, which is the point at which fission occurs — the nuclear breaks apart. This can be done by either firing one portion of a sub-critical mass into another or by compressing the sub-critical material with conventional explosives.

This material usually consists of either enriched plutonium or enriched uranium. The fission reaction is incredibly powerful. Atomic bombs are measured in kilotons, with each unit equal to the explosive force of 1,000 tons of TNT. The  atomic weapon which leveled Hiroshima in 1945 had a yield of around 15 kilotons; or the explosive power of 15,000 tons of TNT.

A single atomic bomb can produce between around a ton and 500 kilotons of the explosive TNT. Additionally, radioactive fission fragments are released by the bomb as a result of the heavier nuclei splitting into smaller ones.

When detonated, fission fragments make up the majority of nuclear fallout.

Hydrogen bombs, or H-bombs for short, are also a type of nuclear weapon, which detonate as a result of the enormous energy produced by nuclear fusion. This is usually achieved through the use of deuterium and tritium (two hydrogen isotopes) that fuse to provide energy.

In a hydrogen bomb, the energy created during a fission reaction is used to heat and compress the hydrogen in order to start a fusion reaction, which can then lead to more fission reactions. About half of the output of a big thermonuclear device is produced by the fission of depleted uranium.

7+ explosive facts about atomic bombs and other nuclear weapons

Although the fusion reaction doesn't actually contribute to fallout, H-bombs produce at least as much of it as atomic bombs do since the process is started by fission and leads to more fission. In comparison to atomic bombs, hydrogen bombs have a far larger yield that is comparable to megatons of TNT. The greatest nuclear explosion ever created by humans, the 50 megaton yield Tsar Bomba, was an example of a hydrogen bomb (1 megaton has the energy equivalent of 1 million tons of TNT). 

Both types of nuclear bombs emit radioactive fallout and unleash enormous amounts of energy from a relatively small amount of material.

But, while the yield of the hydrogen bomb is much larger, building one is a lot trickier. This is impressive enough, but these are not the only kinds of nuclear bombs that exist. 

7+ explosive facts about atomic bombs and other nuclear weapons

Who dropped the first atomic bomb and when?

Mercifully, to date, the only nation to ever use an atomic weapon in war is the United States of America. They unleashed not one, but two, atomic weapons on two cities in Japan at the end of World War II. 

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The first of these two unlucky targets was the Japanese city of Hiroshima, which was bombed on August 6, 1945, by an American B-29 bomber. An estimated 80,000 people perished in the explosion directly, while tens of thousands more perished from radioactive exposure. An additional A-bomb was detonated on Nagasaki three days later by a second B-29, killing an estimated 40,000 people.

In a radio address on August 15, Japan's Emperor Hirohito declared Japan's surrender and cited the devastating impact of "a new and most merciless/cruel bomb."

But what was the rationale for unleashing the power of the atom on these cities? 

To fully understand this, it is necessary to understand the state of affairs leading up to the dropping of the two bombs. 

In 1945, by the time of the Trinity test as part of the Manhattan Project, the Allied powers had already vanquished Germany (the Trinity test took place on July 16, and Germany had surrendered on May 7). 

7+ explosive facts about atomic bombs and other nuclear weapons
Source: estt/iStock

Despite obvious signs (as early as 1944) that they had little prospect of prevailing, Japan had signalled that they were willing to fight to the final end in the Pacific. In fact, between mid-April 1945 (when President Harry Truman assumed office) and mid-July, Allied deaths in the Pacific Theater totalled almost half of all those sustained in three full years of fighting, demonstrating that Japan was not slowing its attacks, even while facing defeat.

The Potsdam Declaration, calling for Japan's unconditional surrender and  threatened the Japanese with "prompt and utter devastation" if they refused to surrender, was rejected by Japan's militarist leadership in late July.

Top military leaders, including General Douglas MacArthur, advocated extending the current conventional bombardment of Japan and then launching a large invasion known as "Operation Downfall." However, they warned Truman that such an invasion may result in up to 1 million American casualties if the Japanese decided to fight city-by-city and house-to-house.

Over the moral objections of Secretary of War Henry Stimson, General Dwight Eisenhower, and a number of the Manhattan Project scientists, Truman decided to deploy the atomic bomb in an effort to hasten the conclusion of the war. The reasoning was that the bomb would ultimately lead to fewer casualties than prolonging the war for several more months or years. 

James Byrnes, Truman's secretary of state, and other A-bomb proponents also reasoned that the weapon's catastrophic force would not only end the war but also place the United States in a dominant position to shape the postwar world. Part of this reasoning was that the bombs would serve as a warning to the Soviet Union, an ally during WWII, but already turning into an enemy.

How many atomic bombs are in the world?

According to some sources, there are thought to be somewhere in the order of 12,705 nuclear weapons in existence right now. Although this number is considerably lower than either the United States or Russia had at the height of the Cold War, it is noteworthy that there are now more nuclear-armed nations than there were 30–40 years ago.

With an estimated 6,257 total warheads, Russia has the most nuclear weapons in existence to date. The New START treaty currently limits both the United States and Russia to a total of 1,550 weapons deployed on ICBMs, SLBMs, and heavy bombers. Of these, somewhere around 1,458 are thought to be currently deployed, around 3,039 are dormant but might be activated, and approximately 1,760 are retired and awaiting dismantlement. With about 5,428 nuclear weapons in total— including around 1,708 warheads, of which about 1,744 are deployed, approximately 1,964 are held in reserve and around 1,720 are retired and scheduled for destruction—the United States is not far behind Russia in terms of the nuclear stockpile.


7+ explosive facts about atomic bombs and other nuclear weapons
Source: rusm/iStock

At present, there are 9 nuclear-armed nations. These are: -

Facts about the atomic bomb

So, you should now have a good grounding as to what an atomic bomb (and other nuclear weapons) are. But, if you are hungry for more information, here are some interesting facts about these incredibly potent weapons. 

1. The first atomic bomb(s) were developed by a diverse team

7+ explosive facts about atomic bombs and other nuclear weapons
Source: KREMLL/iStock

The "Father of the Atomic Bomb," theoretical physicist J. Robert Oppenheimer, oversaw much of the work on the Manhattan Project in Los Alamos, New Mexico. The Trinity Test, the first atomic bomb to be successfully detonated, took place on July 16, 1945, in a remote desert location close to Alamogordo, New Mexico. It brought about the Atomic Age and produced a massive mushroom cloud that reached a height of 40,000 feet.

Many refugees joined the Manhattan Project in England and America. Among the scientists who fled Europe at the outset of the war, or just before, and contributed to the development of the bomb were Albert Einstein, Hans Bethe, John von Neumann, Leo Szilard, James Franck, Edward Teller, Rudolf Peierls, and Klaus Fuchs.

2. Nagasaki was an unfortunate victim of circumstance

7+ explosive facts about atomic bombs and other nuclear weapons
You'd never guess Nagasaki was effectively destroyed during WW2 today. Source: Tomio344456/Wikimedia Commons

While Nagasaki was made famous for the unfortunate events of the Second World War, it was never initially selected as a potential target. 

The initial list of potential targets included Kokura (present-day Kitakyushu), Hiroshima, Yokohama, Niigata, and Kyoto. According to legend, Kyoto was spared by US Secretary of War Henry Stimson, who argued that the city's vast cultural heritage should be spared destruction. When the military insisted on the city's inclusion, Stimson pled with Truman, and pointed out that destroying Kyoto would lead to lasting bitterness that could lead the Japanese to turn towards the Soviets.

On the morning of August 9, 1945, the B-29 carrying the “Fat Man” bomb took off for Kokura, home to a large Japanese arsenal. However, on finding Kokura obscured by cloud cover, the bomber’s crew decided to head to their secondary target, Nagasaki.


3. The bombs that were dropped on Nagasaki and Hiroshima were very different designs

7+ explosive facts about atomic bombs and other nuclear weapons
Replicas of "Little Boy" (foreground) and "Fat Man" (background). Source: Larry Lamsa/Flickr

Did you know that the only two nuclear weapons ever used in combat were actually different designs

The first, “Little Boy”, that was dropped on Hiroshima was made of highly enriched uranium-235 and was a kind known as a gun-type assembly. While the second, “Fat Man”, that was dropped on Nagasaki was made of plutonium and was an implosion assembly type of atomic bomb. 

Of the two, "Fat Man" was regarded as a more complex design.

4. Despite their power, the atomic bombings of Japan were not the most destructive of the war

7+ explosive facts about atomic bombs and other nuclear weapons
A section of Tokyo showing the aftermath of the campaign. Source: 米軍撮影 /Wikimedia Commons

While the destructive power of nuclear weapons is without question, their use was not the most destructive bombing event of the war. Far from it, in fact. 

The European Theatre had some very serious bombing campaigns, with some events, like the Blitz or bombing of Dresden, now burned (literally and figuratively) into the memories of those nations. However, there was a far more devastating bombing event in the Japanese Theatre; "Operation Meetinghouse". 

The US firebombing of Tokyo on March 9, 1945, known as "Operation Meetinghouse", is widely regarded as the worst bombing raid in history. "Meetinghouse" was a napalm strike by 334 B-29 aircraft that claimed well over 100,000 lives, left 1,000,000 people homeless, and destroyed more than a quarter million buildings and homes.

5. There have been a few "close calls" since WW2

7+ explosive facts about atomic bombs and other nuclear weapons
CIA reference photograph of Soviet medium-range ballistic missile. Source: CIA/Wikimedia Commons

Since World War II, there have been several situations where nuclear weapons could have been used again. But, of these, the two "closest calls" were as follows. 

The first is the famous "Cuban Missile Crisis". 

In October 1962, it seemed as though a nuclear war was about to break out. Only 90 miles from the coast of the United States, the Soviet Union had placed nuclear-armed missiles on Cuba. This led to the Cuban Missile Crisis, a 13-day military, and political standoff.

In order to defuse the perceived danger, President John F. Kennedy imposed a naval blockade around Cuba and made it apparent that the US was ready to use force if necessary.

When the United States accepted Nikita Khrushchev's offer to withdraw the Cuban missiles in exchange for a commitment from the United States not to invade Cuba (and to remove the US nuclear missiles from Turkey), disaster was averted.

The second, less well-known event, occurred in the September of 1983. Several weeks after the downing of Korean Air Lines Flight 007 over Soviet airspace, a satellite early-warning system near Moscow reported the launch of one American Minuteman ICBM.

It announced shortly after that five missiles had been fired. Lieutenant Colonel Stanislav Petrov of the Air Defense Forces refused to report the threat or acknowledge it as legitimate and persisted in persuading his superiors that it was a false alarm until this could be verified by ground radar, because he believed a true American offensive would involve many more missiles. In fact, the system had mistaken the sun’s reflection off clouds for the missiles.

This act, in effect, saved millions of innocent lives!

6. There are enough warheads to destroy every city on Earth

7+ explosive facts about atomic bombs and other nuclear weapons

There are more than 12,000 nuclear weapons on Earth, as we previously mentioned. To date, depending on how you define a city, there are approximately 10,000 cities on Earth. However, most of these are relatively small, and only around 440 have populations between 1 and 5 million people. 

Each of these cities would only need between one and three nuclear warheads to be destroyed, so we can probably safely say that there are enough warheads to completely decimate every major city on Earth (assuming they reach their targets without being intercepted). 

The energy of this many warheads is comparable to several billion tons of TNT and many times that of the Krakatoa volcano, which erupted with the greatest amount of force ever recorded.

If all these bombs were concentrated in one place, the combined explosion would produce a blaze that was 50 km across and a blast wave that would destroy anything within a 3,000 km radius. The pressure wave that followed the explosion traveled the globe for several weeks and could be heard everywhere.

The mushroom cloud would reach close to space and would extend to the farthest reaches of the Earth's atmosphere. An explosion in the Amazon Rainforest of South America would start a fire that would destroy almost the entire continent.

Everything in the blast radius would die from radiation, and the area surrounding it for hundreds of kilometers would be uninhabitable. The world's ecosystem would be very radioactive and the Amazon Rainforest be entirely destroyed, and it would likely eradicate humanity.

What a lovely thought. 

7. While only two have ever been used in combat, thousands more have been detonated

7+ explosive facts about atomic bombs and other nuclear weapons
Still of the "Baker" explosion on Bikini Island. Source: United States Department of Defense/Wikimedia Commons

Although there have only ever been two instances of nuclear weapons being used in hostilities, there have been over 2,000 nuclear tests over the interim decades since. Many of them released enormous amounts of radiation into the atmosphere and have rendered some areas of the world uninhabitable for many years to come.

But, not all.

8. Modern weapons are orders of magnitude more powerful than "Fat Man" or "Little Boy"

Around 5 square miles (13 square kilometers) of the Japanese city of Hiroshima were destroyed by the 15 kiloton bomb that was unleashed on it in 1945. Several million degrees Celsius were achieved at the explosion's center. Around 70% of the city's structures were destroyed or damaged, and everyone within half a mile of the blast's epicenter died.

Approximately 75,000 people died right away, but many more perished from radiation sickness. The number of fatalities reached 200,000 by the end of the 1950s.

Three days later, 40,000 people were killed by the Nagasaki bomb, and by 1950, 140,000 had perished from the effects. 


But, nuclear weapons today are significantly more powerful than those used to attack Japan. The combined populations of Britain, Canada, Australia, Aotearoa/NZ, and Germany, totaling 200 million people, could all be killed by just 50 modestly-sized warheads. 

9. There is no proven defense against nuclear attack, as yet

7+ explosive facts about atomic bombs and other nuclear weapons

Despite numerous attempts over the years, there is no real defense against a nuclear assault. Instead, states use a strategy called "Mutually Assured Destruction," or MAD, which effectively threatens an apocalypse that would wipe out everyone, and thus serves as a deterrent.

While some argue the merits of this stance, it may be the main reason that no nuclear warheads have been used in anger since the Second World War. Various initiatives have been experimented with in the past to intercept incoming nuclear weapons, but, to date, none have proved fruitful. 

However, advances in space-based weapons and hypersonic missiles may provide some hope if way can be found to scrapping all nuclear arsenals. Although hypersonic missiles can, of course, be extremely destructive as well. 

And that, atomic bomb addicts, is your lot for today. 

The invention, and initial use, of the atomic bomb, has, undoubtedly, significantly changed the history of our species. For better or worse, these weapons now exist and can be deployed at any time. 

Depending on your point of view, this has either made the world a more dangerous or a safer place. 

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