“We knew the world would not be the same. A few people laughed, a few people cried, most people were silent. I remembered the line from the Hindu scripture, the Bhagavad Gita…’Now, I am become Death, the destroyer of worlds’.” – J. Robert Oppenheimer
The above quote by Oppenheimer, who some call the father of the atomic bomb, really captures the awe inspiring power of these weapons. On the one hand, nuclear weapons show off the fascinating science that exists at the smallest and most fundamental aspects of nature. But on the other hand they represent terrifying death, destruction, and potential apocalypse. Although these weapons were only ever used twice in warfare (in 1945), the recent struggles with North Korea have kept the significance of nuclear bombs in our minds. So in this episode we explored this fascinating topic over some craft beers (to keep it from getting too heavy) and got into everything from the science of these weapons to their usage in World War II and to their significance on current world politics. Listen to the episode below, and read further on for a few more details about the science and politics of nuclear weapons.
Without going into too much detail about the workings of nuclear reactions (as if I could…), I want to describe the basics of how it works. We can start with one of the most famous equations that I’m sure you have heard of: E= mc2 (check out the details here). This equation, derived by Einstein in 1905, is what describes just how much energy can be released from the nucleaus of an atom. The basic principle behind his equation is that it equates energy (E) and mass (m). The concept alone is pretty mind blowing because, much like the linking of the dualities of electricity and magnetism or of time and space (check out more here), it means that energy and mass can be thought of as two sides of the same coin. Mass can become energy and vice versa. During a nuclear fission reaction of uranium, the combined mass of the resulting atoms is slightly less (1/5 the mass of a proton in fact) than the mass of the original atom from which they came. The missing mass gets converted into energy. The energy from such a small change in mass is so enormous because of the speed of light. The speed of light (represented by c in the equation) is 299,792 kilometers per second. This massive number (even more massive because it’s squared in the equation) allows for a reasonably small amount of mass to convert into an insanely large amount of energy. This nuclear energy dwarfs that from chemical energy (oil, coal, TNT etc); nuclear fuel contains approximately ten million times more energy than the same mass of chemical fuel.
A nuclear reaction can either smash atoms apart (fision) or fuse them together (fusion). Our sun, for example, has been producing it’s energy through nuclear fusion for well over four billion years. But it was not until the 1940s that humans figured out the crucial details needed to create chain reactions of nuclear fission. By July of 1945 this reaction was successfully implemented into an atomic bomb which was exploded in the New Mexico desert as a test. About one month later two of these atomic bombs, separated by three days, were dropped on Hiroshima and Nagasaki.
The splitting apart of an atom to become two different atoms, known as fission, is something that can actually occur naturally. This is known as radioactive decay or spontaneous fission. Most nuclear fuels undergo this spontaneous fission extremely slowly (like over thousands and thousands of years) which doesn’t create usable energy. However a fission reaction can be induced by bombarding a heavy element with a neutron. Because a neutron has a neutral charge, it can pass directly into the center (nucleus) of an atom. When a neutron collides with the nucleus, it can smash it apart into smaller pieces. With a heavy element like uranium or plutonium, each smash releases energy and more neutrons. The new neutrons can then crash into more atoms, releasing more energy and more neutrons and creating a chain reaction. This chain reaction can happen in a controlled environment (nuclear power plants) or in a sudden and uncontrolled manner (nuclear weapons). Critical mass is having enough uranium so that the chain reaction produces enough neutrons to smash apart every uranium atom present. As noted above, each split results in two different atoms with slightly less mass then the original atom. The missing mass, of course, becomes energy.
The opposite of fission is fusion. Unlike splitting apart heavy elements, fusion smashes together light elements. The nuclei of light elements repel each other and won’t bind together unless they collide at very high energies (ie high temperatures). Such high energies are found in the core of stars where hydrogen gets fused into helium and releases massive amounts of energy. When the hydrogen runs out, the fusion will continue to take place making heavier and heavier elements ( hydrogen»helium»lithium»carbon»neon»oxygen»silicon etc). So all the heavier elements in the universe, like the elements for life (carbon,nitrogen, and oxygen etc) were fused together inside the core of a star. In fact the atoms that make up your very brain reading this sentence were fused together in the core of a star billions of years ago. (cue mind blowing video). The star begins to die once it begins to fuse iron. The fusion of iron produces a net loss of energy and kills the fusion reactions in the core of the star. In fact iron is the element on the periodic table that exists at the boundary between fusion and fission.
How does this all relate to nuclear weapons? Well by 1952 the United States tested the first ever thermonuclear weapon, also known as a hydrogen bomb. This type of bomb utilizes fission as well as fusion. In order to create enough heat to fuse the hydrogen together, a small fission bomb is first exploded as the primary stage, followed by the secondary fusion stage. The energy released from such a fusion bomb is far greater than the fission bombs like those that were dropped on Japan. The 1952 test of the hydrogen bomb , for example, was 450 times more powerful than the bomb dropped on Nagasaki. Far more powerful than that was the Soviet Union’s Tsar Bomba, which was tested in 1961. The tsar bomba remains the world’s most powerful nuclear weapon ever created (see video of it here). It was over 3000 times more powerful than the Little Boy bomb that was dropped on and leveled Nagasaki.
There are currently nine countries with nuclear weapons that total to approximately 16,000. They are United States, Russia, the UK, France, China, North Korea, India, Pakistan, and Israel. The United States and Russia possess most of these weapons at around 7,000 each. Although this may seem like a large number, this is nothing compared to the past. At the peak of the Cold War there was an estimated 70,000 nuclear weapons. Considering that only 100 or so nuclear explosions over cities could cause a global disaster (nuclear winter), it’s hard to imagine why so many weapons were built. But it is not hard to imagine why countries seek possession of nuclear weapons. Once you are armed with nukes, it makes you a serious force to be reckoned with on the world stage. Even if a country is completely invaded, there are nuclear armed submarines and hidden underground missle silos that could retaliate with a nuclear strike. This is called mutually assured destruction, and it really makes the concept of full scale war between nuclear armed countries implausible. It has created a situation in current politics where big countries will only fight with each other through proxy wars (like the U.S. and Russia in Syria).
The concept of nuclear deterrence is what prevented the cold war from becoming hot. Because of the intricate systems in place, retaliation strikes can be ordered and accomplished within minutes, and they cannot be stopped once the signal to launch has been ordered. Check out this Veritasium video to see the inside of a nuclear missle silo and watch how the launch sequence works.
Lastly I’d like to mention Stanislav Yevgrafovich Petrov, who we also talked about on the podcast. Put yourself in the position of being in one of these nuclear silos with your finger on the button. Do you push it when the order comes through? Despite the fact that Soviet warning systems were indicating incoming missiles (a malfunction it turned out), Petrov decided not to follow protocol and because of this is known as “the man who single-handedly saved the world from nuclear war”.
So nuclear weapons are definitely a weird mix of fascinating and terrifying. As such it made for a good topic to explore while cracking open a few craft beers.
Thanks for reading and listening!
Cheers ￼ 🍻–Luke from Thunk Tank Podcast