Since then, the global nuclear stockpile has multiplied, and when geopolitical tensions rise, the idea of a nuclear apocalypse understandably causes widespread concern. But despite their catastrophically large effects, the science of how nuclear weapons work is atomically small.
The Atomic Science of Nuclear Weapons
All matter is composed of atoms, which host different combinations of three particles—protons, electrons, and neutrons. Nuclear weapons work by capitalizing on the interactions of protons and neutrons to create an explosive chain reaction. At the center of every atom is a core called the nucleus, which is composed of closely-bound protons and neutrons. While the number of protons is unique to each element in the periodic table, the number of neutrons can vary. As a result, there are multiple “species” of some elements, known as isotopes. For example, here are some isotopes of uranium:
Uranium-238: 92 protons, 146 neutrons Uranium-235: 92 protons, 143 neutrons Uranium-234: 92 protons, 142 neutrons
These isotopes can be stable or unstable. Stable isotopes have a relatively static or unchanging number of neutrons. But when a chemical element has too many neutrons, it becomes unstable or fissile. When fissile isotopes attempt to become stable, they shed excess neutrons and energy. This energy is where nuclear weapons get their explosivity from. There are two types of nuclear weapons:
Atomic Bombs: These rely on a domino effect of multiple fission reactions to produce an explosion, using either uranium or plutonium. Hydrogen Bombs: These rely on a combination of fission and fusion using uranium or plutonium, with the help of lighter elements like the isotopes of hydrogen.
So, what exactly is the difference between fission and fusion reactions?
Splitting Atoms: Nuclear Fission
Nuclear fission—the process used by nuclear reactors—produces large amounts of energy by breaking apart a heavier unstable atom into two smaller atoms, starting a nuclear chain reaction. When a neutron is fired into the nucleus of a fissile atom like uranium-235, the uranium atom splits into two smaller atoms known as “fissile fragments” in addition to more neutrons and energy. These excess neutrons can then start a self-sustaining chain reaction by hitting the nuclei of other uranium-235 atoms, resulting in an atomic explosion. Atomic bombs use nuclear fission, though it’s important to note that a fission chain reaction requires a particular amount of a fissile material like uranium-235, known as the supercritical mass.
Merging Atoms: Nuclear Fusion
Hydrogen bombs use a combination of fission and fusion, with nuclear fusion amplifying a fission reaction to produce a much more powerful explosion than atomic bombs. Fusion is essentially the opposite of fission—instead of splitting a heavier atom into smaller atoms, it works by putting together two atoms to form a third unstable atom. It’s also the same process that fuels the Sun. Nuclear fusion mainly relies on isotopes of lighter elements, like the two isotopes of hydrogen—deuterium and tritium. When subjected to intense heat and pressure, these two atoms fuse together to form an extremely unstable helium isotope, which releases energy and neutrons. The released neutrons then fuel the fission reactions of heavier atoms like uranium-235, creating an explosive chain reaction.
How Atomic and Hydrogen Bombs Compare
Just how powerful are hydrogen bombs, and how do they compare to atomic bombs? The bombs Little Boy and Fat Man were used in the atomic bombings of Hiroshima and Nagasaki in 1945, bringing a destructive end to World War II. The scale of these bombings was, at the time, unparalleled. But comparing these to hydrogen bombs shows just how powerful nuclear weapons have become. Castle Bravo was the codename for the United States’ largest-ever nuclear weapon test, a hydrogen bomb that produced a yield of 15,000 kilotons—making it 1,000 times more powerful than Little Boy. What’s more, radioactive traces from the explosion, which took place on the Marshall Islands near Fiji, were found in Australia, India, Japan, U.S., and Europe. Seven years later, the Soviet Union tested Tsar Bomba in 1961, the world’s most powerful nuclear weapon. The explosion produced 51,000 kilotons of explosive energy, with a destructive radius of roughly 60km. Given how damaging a single nuke can be, it’s difficult to imagine the outcome of an actual nuclear conflict without fear of total annihilation, especially with the world’s nuclear arsenal sitting at over 13,000 warheads. on Even while political regimes across these countries have changed over time, they’ve largely followed a few different types of governance. Today, every country can ultimately be classified into just nine broad forms of government systems. This map by Truman Du uses information from Wikipedia to map the government systems that rule the world today.
Countries By Type of Government
It’s important to note that this map charts government systems according to each country’s legal framework. Many countries have constitutions stating their de jure or legally recognized system of government, but their de facto or realized form of governance may be quite different. Here is a list of the stated government system of UN member states and observers as of January 2023: Let’s take a closer look at some of these systems.
Monarchies
Brought back into the spotlight after the death of Queen Elizabeth II of England in September 2022, this form of government has a single ruler. They carry titles from king and queen to sultan or emperor, and their government systems can be further divided into three modern types: constitutional, semi-constitutional, and absolute. A constitutional monarchy sees the monarch act as head of state within the parameters of a constitution, giving them little to no real power. For example, King Charles III is the head of 15 Commonwealth nations including Canada and Australia. However, each has their own head of government. On the other hand, a semi-constitutional monarchy lets the monarch or ruling royal family retain substantial political powers, as is the case in Jordan and Morocco. However, their monarchs still rule the country according to a democratic constitution and in concert with other institutions. Finally, an absolute monarchy is most like the monarchies of old, where the ruler has full power over governance, with modern examples including Saudi Arabia and Vatican City.
Republics
Unlike monarchies, the people hold the power in a republic government system, directly electing representatives to form government. Again, there are multiple types of modern republic governments: presidential, semi-presidential, and parliamentary. The presidential republic could be considered a direct progression from monarchies. This system has a strong and independent chief executive with extensive powers when it comes to domestic affairs and foreign policy. An example of this is the United States, where the President is both the head of state and the head of government. In a semi-presidential republic, the president is the head of state and has some executive powers that are independent of the legislature. However, the prime minister (or chancellor or equivalent title) is the head of government, responsible to the legislature along with the cabinet. Russia is a classic example of this type of government. The last type of republic system is parliamentary. In this system, the president is a figurehead, while the head of government holds real power and is validated by and accountable to the parliament. This type of system can be seen in Germany, Italy, and India and is akin to constitutional monarchies. It’s also important to point out that some parliamentary republic systems operate slightly differently. For example in South Africa, the president is both the head of state and government, but is elected directly by the legislature. This leaves them (and their ministries) potentially subject to parliamentary confidence.
One-Party State
Many of the systems above involve multiple political parties vying to rule and govern their respective countries. In a one-party state, also called a single-party state or single-party system, only one political party has the right to form government. All other political parties are either outlawed or only allowed limited participation in elections. In this system, a country’s head of state and head of government can be executive or ceremonial but political power is constitutionally linked to a single political movement. China is the most well-known example of this government system, with the General Secretary of the Communist Party of China ruling as the de facto leader since 1989.
Provisional
The final form of government is a provisional government formed as an interim or transitional government. In this system, an emergency governmental body is created to manage political transitions after the collapse of a government, or when a new state is formed. Often these evolve into fully constitutionalized systems, but sometimes they hold power for longer than expected. Some examples of countries that are considered provisional include Libya, Burkina Faso, and Chad.
