The goal of this blog is to create a list of super facts. Important facts that are true with very high certainty and yet surprising, misunderstood, or disputed by many. This blog aims to be challenging, educational, and fun, without it being clickbait. I determine veracity using evidence, data from reputable sources and longstanding scientific consensus. Prepare to be challenged (I am). Intentionally seek the truth not confirmation of your belief.
Superfact 118: There are more than 100 million forcibly displaced people in the world, including more than 30-40 million refugees, 9 million asylum seekers, and more than 70 million internally displaced persons. The number of refugees in the world has almost tripled since the year 2000 and the number of internally displaced persons is estimated to have more than ten doubled since the year 2000.
Drone footage of thousands of Afghan refugees returning from Pakistan, Pakistan border, refugee camp, Torkham Border. Nangarhar, Afghanistan 8 November 2023. Shutterstock asset id: 2385658471 by Waheedullah Jahesh.
According to Wikipedia the number of refugees is 41.6 million worldwide, 72.1 million internally displaced persons, 8 million asylum seekers and 122.6 million forcibly displaced people in total globally. The number of refugees in the year 2000 was 12,129,600 and the number of internally displaced persons in the year 2000 was 5,998,500.
According to the refugee council of Australia there were 117.8 million forcibly displaced persons in 2025 including 34.4 million refugees, 9 million asylum seekers, and 73.5 million internally displaced persons. According to Our World in Data a record 83 million people globally were living in internal displacement at the end of 2024.
Internally displaced children from other parts of Ukraine in the Zakarpattia Oblast of western Ukraine. UNICEF Ukraine from Kyiv, Ukraine, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0>, via Wikimedia Commons.
I should explain that a refugee is someone who has been forced to flee their home country to escape war, violence, or persecution. A refugee who acquires a new citizenship or returns to his country stops being a refugee. An internally displaced person is an individual who was forced to leave their home or place of residence but did not cross an international border.
It should be noted that World War II was the largest forced displacement event in recorded human history. 65 million people were forcibly displaced in Europe alone according to the Imperial War Museum. The partition of India and Pakistan in 1947 resulted in 12-20 million people being forcibly displaced according to this article. The Afghanistan war resulted in around 10 million people being forcibly displaced according to this article. Today most refugees (65%) come from just five countries Syria, Venezuela, Ukraine, Afghanistan, and Sudan.
Having tens of millions of refugees and forcibly displaced persons is nothing new. What may come as a surprise to many is first of all the size of the numbers and the fact that despite the reduction of causalities from wars in the 21st century compared to previous centuries; the refugee and forcibly displaced persons problem has grown significantly larger over the last couple of decades. Since this is an important but surprising reality, I consider it a super fact.
Where Are the Internally Displaced Persons ?
Internally displaced people, 2024. Internally displaced people had to leave their homes because of violence or disaster and have not crossed an international state border. This counts all individuals who are currently displaced, regardless of how many times they have been displaced. Data source: Internal Displacement Monitoring Centre (2026) OurWorldinData.org/migration | CC BY
You may wonder how come there are internally displaced people in countries such as Japan and the United States. The reason is that natural disasters can also be a source of internal displacement. In fact, my in-laws were internally displaced persons after a tornado devastated our neighborhood in Dallas in October 2019. Notice that the Africa is where you have most of the internally displaced persons.
Where are the Refugees ?
Refugees by country of asylum, 1951 to 2024. People who fled their country of origin because of serious threats against which the authorities of their home country cannot or will not protect them. This includes all refugees, not just those who arrived that year. Data source UNHCR (2025). OurWorldinData.org/migration | CC BY
The three countries with the most refugees are Iran (3.49 million), Turkey (2.94 million) and Germany (2.75 million). Next comes Uganda, Pakistan, Chad, Poland, Ethiopia, all Bangladesh, all with more than one million refugees. Iran has a lot of refugees because of the refugees from Afghanistan pouring into the country, and Turkey has a lot of refugees because of the refugees from Syria, and Germany has a lot of refugees because of their generous immigration and refugee policy. The big spike in the number of refugees in Iran around 1991 was due to the Gulf war and the Afghanistan war.
As for other Western countries, France has 722 thousand refugees, United Kingdom 516 thousand refugees, the United States 435 thousand refugees, and Spain 429 thousand refugees. By clicking here, you can play around with the graphs and compare all countries in the world.
Since it is Halloween I thought I’d make a fun post (not a super fact) about Scandinavian Mythology or folklore. I live in Texas, but I am originally from Sweden so the various beings I’ll describe or mention below are beings that I grew up hearing about. When I was a kid, we kids used to scare each other with stories about these beings.
I should also point out that it is not ancient Viking mythology but more recent folklore that some people still believe in. I am focusing on Swedish folklore and Norwegian folklore since it is similar to Swedish folklore. Danish folklore is a little bit different, but it has many similarities to Swedish and Norwegian folklore. Denmark is a Scandinavian country, but the post would be too long if I included folklore that is specifically Danish.
I am providing one or more pictures for each being. These pictures are either in the public domain, for example via Wikipedia, or shutter-stock pictures (I have a subscription), or pictures I generated with the help of ChatGPT with varying success. The beings covered are Tomte, Vittra (Vitter folk), Elf, Skogsrå/ /Tallemaja/Huldra, Näcken/Fossegrim, Troll, Myling, Storsjö odjuret (the north Swedish equivalent of the Loch Ness monster), Kraken, and Skvader. Finally, Blodstämmare is not a being but a north Swedish magical practice that you use to remotely stop the blood flow in a person.
Tomte
Tomtar (plural of Tomte) or Nisse in Norwegian is a type of small magical people, or gnomes, related to Vitter folk (described below). They are friendly and is the inspiration behind the Swedish version of Santa Claus, which is therefore a bit different from the Disney version of Santa Claus that has become so popular.
For one thing, the Disney version of Santa Claus works alone while delivering presents and therefore needs to move faster than the speed of light to cover all the good children. A Tomte may help you with your projects and duties if you are nice to them. They may help you with your farm and your animals, warn you of danger, and bring you gifts for Christmas if you in return put out food for them, such as porridge. As mentioned, there are many Tomtar, often one Tomte per house.
An illustration of a Tomte. Shutterstock ID: 2060057882 by PLIMPLUM.A Tomte or a Nisse, about as big as a cat, Erik Werenskiold, Public domain, via Wikimedia CommonsTomte generated by ChatGPT
Vittra
Vittra or Vitterfolk are supernatural spirits or small invisible people who have a lot in common with people as well as Tomtar. They own cattle and they sometimes interact with people. Usually, they stay out of your way, but if you hurt them, for example by throwing hot water out the window without warning them first, they may take revenge on you and burn down your house. Vittra are not evil but not friendly either.
The belief in Vittra is especially prevalent in northern Sweden. On the Swedish island of Gotland, they are often referred to as “Di små undar jordi” in the Got/Goth dialect, or “De små under jorden” in proper Swedish, or “the small ones below ground” in English. They are sometimes depicted as looking similar to Tomtar, gnomes or elves, and sometimes as invisible, or near invisible little spirits. Below are some depictions of Vitter folk.
A Vitter and his mini calf. Generated with the help of ChatGPT
Elf
An elf, or elves in plural, is a type of human like supernatural being in Germanic folklore and especially Nordic/Scandinavian folklore. Since elves have been popularized around the world it is a well known being. In Scandinavian mythology they were initially often considered bad news but because of popular culture, such as Tolkien’s books, they have been redeemed into something positive. The first picture below is from a Swedish children’s book written in 1910. I read this book when I was a child. The wispy creatures are elves and the small kids with mushroom hats are Tomte children. In this book the elves are depicted in a Nordic pre-modern fashion, but they are nice.
Little älvor, playing with Tomtebobarnen. From Children of the Forest (1910) by Swedish author and illustrator Elsa Beskow. Elsa Beskow, Public domain, via Wikimedia CommonsÄngsälvor (Swedish “Meadow Elves”) by Nils Blommér (1850). Nils Blommér, Public domain, via Wikimedia Commons.A female elf that I generated with the help of ChatGPTFour elves (one male, three females) standing in a forest glade. I generated this picture with the help of ChatGPT.
Skogsrå, Tallemaja, Huldra
Skogsrå or Tallemaja in Swedish folklore is a seductive female creature who lures men with her beauty or beautiful singing and then kills the men. The Skogsrå / Tallemaja typically has a tail and a hollowed out back, which you can’t see if you are facing each other. In Norwegian this creature is called Huldra (Hulder in plural).
It should be noted that I read that if you meet a Huldra in the forest and you treat her with respect she will not kill you. She would just enjoy your company for a while, talk to you, sing to you, show you the beauty of the forest, and then she would let you go. It is only the rude and selfish men who don’t respect her boundaries whom she kills.
Imagining how a Huldra would look like. Stock AI-generated image ID: 2400845203 by Shutterstock AI Generator.Huldra’s Nymphs (1909) by Bernard Evans Ward, Public domain, via Wikimedia CommonsA Skogsrå, Tallemaja or Huldra that I generated with the help of ChatGPTAnother picture of a Skogsrå, Tallemaja or Huldra that I generated with the help of ChatGPT.A Tallemaja that I generated with the help of ChatGPT.
Last summer (a bit more than one year ago) we visited Sweden and Norway. One day we took a tour into the Norwegian mountains and fjords. We took a two-hour cruise on Sognefjord and after the cruise we took a train to the top of the surrounding mountains. Along the way we encountered a Huldra by a waterfall. She sang to us in her beautiful voice, and she seduced us all, both men and women, to take photos of her with our phones and posting them on social media. It was a tourist ploy of course. You can read more about our trip here .
My photo of the Huldra (in red) by the waterfall in the Norwegian mountains. She seduced us all into taking photos of her for Facebook. Her seductiveness was feared in medieval times, but in modern times we refer to the seductiveness of the Huldra as a “tourist trap”.A close up of the Huldra we encountered. Sorry, my phone camera is the best and it was at a distance.
Näcken, Fossegrim
Näcken, Strömkarlen, or Fossegrim in Norwegian is a male creature who lives by the water, creeks, rivers, ponds and lakes. He plays a harp or a violin He lures children and others to their death. In southern Sweden (Scania) he seduces people by skillfully playing a violin thus creating irresistible music.
Troll, or Trolls in plural, are large ugly creatures with magical powers. They typically live in caves and sunlight is dangerous to them. They are typically hostile to humans and may kidnap people, including children, to work in their mines. Trolls are called Trolls in both Swedish and Norwegian.
Look at them, troll mother said to the elf girl. Look at my sons! You won’t find more beautiful trolls on this side of the moon. (1915) by John Bauer. John Albert Bauer (4 June 1882 – 20 November 1918) was a Swedish painter and illustrator. wikipedia public domain.A picture of a troll that I generated with the help of ChatGPTAnother picture of a troll that I generated with the help of ChatGPTA picture of a troll, a slightly different style, that I generated with the help of ChatGPT
Myling
Before modern contraception, infanticide was one way for parents to limit the number of children they had. Unwanted and out of wedlock children were often killed. It is part of our human dark history. These babies were not baptized and in old Scandinavian mythology they became restless spirits seeking revenge on the mother or both parents. Alternatively, they caused mischief until they could convince someone to at least bury them properly. These restless baby spirits are referred to as myling or mylingar in plural.
A picture of a myling that I generated with the help of ChatGPT
Storsjö odjuret
Storsjöodjuret is a large sea serpent like Swedish lake monster like the Loch Ness monster. It resides in a lake in northern Sweden. The English translation of Storsjö odjuret is the monster of the Great Lake. Storsjö / Great Lake is not far from where I grew up. I should say this monster has been hundreds of times since 1635 and seems to have been depicted on a rune stone from the 11th century.
The Frösö Runestone from the mid-11th century. Frösö is an island located in the middle of Storsjö. In the legend from 1635 Storsjöodjuret is said to be the serpent depicted on the stone. Andreaze, Public domain, via Wikimedia CommonsA picture of storsjoodjuret that I generated with the help of ChatGPT
Kraken
Kraken is a gigantic octopus that can bring down entire ships. It is more of a Norwegian creature but also Swedish.
Pierre Denys de Montfort (1766–1820) / Étienne Claude Voysard (1746–1812.), Public domain, via Wikimedia Commons
Skvader
The skvader is a Swedish fictional creature that looks like a mix of a wood grouse and a hare. It started with a taxidermist creating a mixture of the two animals, taking a photo, and a rumor spread that it was real. I am remember watching debates on Swedish TV on whether the creature was real or not. People love to believe strange things. Yet another reason we scientifically valid evidence.
Unknown photographer, Copyrighted free use, via Wikimedia Commons
Blodstämmare
This is not a creature but a very common superstition in northern Sweden. There are people, blodstämmare, who can stop the flow of blood by uttering magical phrases while focusing their minds on the person in question. This power is usually used for helping people who are bleeding. It can also be used for evil, like black magic, to stop the blood flow in someone’s heart. This superstition is based on Sami (indigenous north Scandinavian people) Shamanism and north Swedish Christian fundamentalism (Laestadians). It is respected enough that some north Swedish hospitals have used blodstämmare in emergency situations.
The father of a close friend of mine called a blodstämmare when he had a bad nosebleed, and it worked. I know anecdotes are not valid scientific evidence. It is just a good story.
Super fact 48 : Since 1945 we have set off more than 2,000 Nuclear Bombs corresponding to a yield of an estimated 42,000 times that of the Hiroshima Bomb.
According to the Arms Control Association there’s been 2,056 nuclear bomb tests. According to the UN there’s been more than 2,000 nuclear bomb tests, and according to Wikipedia there’s been 2,121 nuclear bomb tests, totaling 635 Megaton. Using the typical yield estimate for the Hiroshima bomb of 15 Kiloton that corresponds to more than 42,000 Hiroshima bombs. I think most of us know about the Hiroshima and Nagasaki bombs and we know about nuclear testing. However, I think the number of tests and the large total yield will come as a surprise to many, at least it was a surprise to me. That is why I consider this a super fact.
Nuclear bomb dropped on a big city. Shutterstock, asset id: 2188083835 by CI Photos.
Nuclear Landscaping
It may also come as a surprise that many of these tests were not for military purposes. Another usage for nuclear bombs is nuclear landscaping. Towards the end of the 1950’s the existing Panama Canal was thought to be insufficiently large and some people, including Edward Teller, the father of the Hydrogen bomb (Thermonuclear bomb), suggested that a new wider and deeper canal could be built simply by using nuclear bombs to blow multiple huge holes across Panama. The US was also interested in creating a new harbor in Alaska using nuclear bombs.
Thus, Project Plowshare was created to achieve this. As part of the Project Plowshare 35 nuclear warheads were detonated. The Soviet Union also had a similar program named “Nuclear Explosions for the National Economy” that included 124 nuclear bomb tests. Due to concerns over radioactive fallout the nuclear landscaping projects were eventually put to rest. The last Plowshare detonation was on May 17, 1973. The book Atomic Awakening by James Mahaffey recounts the history of nuclear testing and nuclear landscaping in greater detail.
Hydrogen bomb test by Alones Shutterstock Asset id: 2194195335.
Project Orion
Another non-military use of nuclear bomb testing was Project Orion. Project Orion was a study conducted from 1956 to 1964 by the US Air Force, NASA, and DARPA into the viability of a nuclear pulse spaceship that would be directly propelled by a series of atomic explosions behind the craft. A thick steel pusher plate would catch the blast and accelerate the ship forward.
The “Pascal B” shot in Operation Plumb Bob in 1957 was the first nuclear weapons test of the pusher concept. The Limited Test Ban Treaty of 1963 made it difficult to continue with the project. According to the book Atomic Awakening, if the design had been successfully completed, we could have created an interstellar spaceship that could have taken a crew and a large load to other planets and stars.
I can add that According to Atomic Awakening, in addition to Nuclear Landscaping and Project Orion, Nuclear Blasts were a tourist attraction.
Number of Nuclear Tests by Country
Below is a list of countries and the number of nuclear tests that they’ve performed according to the Arms Control Association and Wikipedia.
The United States – 1,030 – According to Wikipedia – 1,032
The USSR/Russia – 715 – According to Wikipedia – 727
France – 210 – According to Wikipedia – 215
United Kingdom – 45 – According to Wikipedia – 88
China – 45 – According to Wikipedia – 47
North Korea – 6 – According to Wikipedia – 6
India – 3 – According to Wikipedia – 3
Pakistan – 2- According to Wikipedia – 2
However, it should be noted that partially due to nuclear arms control legislation such as; the Limited Test Ban Treaty (LTBT): Signed in 1963, the Threshold Test Ban Treaty (TTBT): Signed in 1974, and the Comprehensive Nuclear-Test-Ban Treaty (CTBT) opened for signing in 1996, the number of nuclear tests have been significantly reduced. This is illustrated by the graph below from Our World in Data. The last nuclear test was done by North Korea in 2017.
The biggest nuclear bomb ever exploded was RDS-220, or AN602, or Tsar Bomba. It was detonated by the Soviet Union on October 30th, 1961, on the arctic island of Novaya Zemlya, and yielded more than 50 Megaton. In other words, it was 3,300 times more powerful than the Hiroshima bomb. According to Atomic Awakening, windows in Finland 1,900 kilometers (1,180 miles) away shattered. There are no cities large enough to match the size of the explosion. This is the kind of bomb that could obliterate states or small countries.
Tsar Bomba was a so-called thermonuclear device, or a hydrogen bomb as they are typically called. Hydrogen bombs are much more powerful than fission bombs, such as Uranium bombs or Plutonium bombs. To read my related post called “Ukraine Gave up Thousands of Nuclear Warheads” click here.
This is an illustration of the Tsar Bomba explosion by by mbafai Shutterstock Asset id: 2208486661. To see a photo of the actual Tsar Bomba explosion click here (it is copyrighted).
Would you pay to watch a Nuclear Bomb Test? (Nuclear Bomb Test Tourism)
Today, June 6 is the National Day of Sweden (or the Independence Day of Sweden). Gustav Vasa, or Gustav I, Sweden’s hero king and the father of modern Sweden, was elected king of Sweden on June 6th, 1523. This was after the Swedish War of Liberation from Denmark 1521 to 1523. Gustav rose to lead the Swedish War of Liberation following the Stockholm Bloodbath, where his father was executed. Gustav Vasa or Gustav I was King of Sweden from 1523 until his death in 1560. Since I am originally Swedish (now living in Texas) June 6 is a significant date for me.
This picture is how I imagine Gustav Vasa at his coronation. BTW this is a submission for Kevin’s No Theme ThursdayThis is how I imagine Gustav Vasa’s marriage to Catherine of Saxe-Lauenburg on September 24th, 1531. This picture is also from Kevin’s No Theme Thursday
Depictions of Gustav Vasa
Kevin’s pictures above were, like I said, how I imagine Gustav Vasa. The depictions below might be closer to the truth.
Painting of Gustav I Vasa. Fashion was somewhat different back in the day.Portrait of Gustav Vasa (from Wikipedia Commons).
The Kalmar Union
In 1397 a union was formed between Denmark, Norway and Sweden called the Kalmar Union (Kalmar is a city a Sweden). The Kalmar Union came to be dominated by Denmark and there were occasional rebellions. During Gustav’s childhood, parts of the Swedish nobility tried to make Sweden independent. Gustav’s father Erik Johansson Vasa was part of that nobility.
After some problematic interactions with Denmark and the Danish King Christian II, King Christian massacred 100 Swedish nobles, November 7-9, 1520, on Stortorget in Stockholm, including Gustav’s father. In 1521 Gustav led a rebellion (or a civil war) against Denmark, which ended in the deposition of King Christian II from the throne of Sweden, effectively ending the Kalmar Union. I can add that King Christian is called Christian the Tyrant in Sweden and Christian the good in Denmark.
Sweden and Denmark has had a complicated history that included a lot of hostilities and eleven wars, but you wouldn’t know it if you looked at the situation today. There hasn’t been a war between Sweden and Denmark in more than 180 years and Swedes and Danes get along very well. However, it is best not to bring up the past. That is probably true for marriages as well.
Denmark vs Sweden. The yellow and blue flag is the Swedish flag. Red and white is the Danish. Shutterstock Stock Photo ID: 1114320377 by Hasanov Jeyhun.
Gustav Vasa’s Burial Place
Gustav Vasa died on September 29, 1560, and is buried together with three of his wives (while only two are engraved) in the Cathedral of Uppsala. Uppsala is an old city north of Stockholm famous for its Viking graves/mounds. During the Viking era Uppsala was the religious center of Sweden. Later as Sweden became Christian it remained the religious center of Sweden, however, the Viking temple in old Uppsala was replaced by a Christian church. Uppsala hosts one of the most prominent Universities in the world and it also happens to be where I studied Engineering Physics.
The largest cathedral in Sweden, Uppsala Domkyrka. This is where Gustav I Vasa is buried. Gustav I is arguably Sweden’s most prominent king.Inside Uppsala Domkyrka.The tomb of Gustav I Vasa in Uppsala Domkyrka. In the background is my son and his wife.
Photos from Sweden
I am a fan of Leonberger dogs, and this is a photo of the only Swedish Leonberger I met personally. Her name was Amie. We met her at an interesting place, at the top of a north Swedish mountain called Skule Mountain (Skull Mountain).One of the interesting tourist attractions in northern Sweden is the Ice Hotel in Jukkasjärvi . The ice hotel in Jukkasjärvi is the first/original and largest ice hotel in the world. My kids at the lobby of the ice hotel in northern Sweden.
Sweden has a king (Carl XIV), and he owns a couple of big castles. This is my kids with the guard in front of the Winter Castle in Stockholm.Drottningholm, one of the Royal Palaces in Sweden. It was built in the 1660’s and inspired by Versailles.A photo of the Vasa ship from the bottom floor. My son is standing on the right in a green and black shirt.The Swedish Royal family. The two people in the middle are Queen Silvia and King Carl XVI Bernadotte. To the right of the king is the future monarch of Sweden princess Victoria and to the left of Queen Silvia is her husband. The others are their other two children and their spouses.Finally, the Swedish Flag (Wikimedia Commons). All other photos above are mine
Super fact 47 : In 1991, after the dissolution of the Soviet Union, Ukraine became the third largest nuclear power in the world after Russia and the United States. Ukraine held about one third of the former Soviet nuclear weapons and delivery systems. Ukraine agreed to transfer these weapons to Russia for dismantlement in exchange for economic compensation and assurances to respect Ukrainian independence and borders.
In 1994, Ukraine agreed to transfer these weapons to Russia for dismantlement in exchange for economic compensation and assurances from Russia, the United States and the United Kingdom to respect Ukrainian independence and sovereignty within its existing borders. These political agreements are referred to as the Budapest Memorandum.
These events are relevant to what is happening in Ukraine today, and yet it is seldom discussed, and many people are unaware of or have forgotten about this history. It also comes as a surprise to many that there are nuclear states who have relinquished their nuclear weapons. This is why I call this fact a super fact.
Nuclear bomb dropped on a big city. Shutterstock, asset id: 2188083835 by CI Photos.
Nine Nuclear States
There are nine nuclear states in the world as of 2025 according to the Federation of Atomic Scientists. There are 12,331 nuclear warheads including 9,600 in active military stockpiles.
Russia – 5,449 warheads
The United States – 5,277 warheads
China – 600 warheads
France – 290 warheads
United Kingdom – 225 warheads
India – 180 warheads
Pakistan – 170 warheads
Israel – 90 warheads
North Korea – 50 warheads
There are also countries that are hosting nuclear warheads owned by other countries.
Italy (the United States) – 35 warheads
Turkey (the United States) – 20 warheads
Belgium (the United States) – 15 warheads
Germany (the United States) – 15 warheads
Netherlands (the United States) – 15 warheads
Belarus (Russia) – ? warheads
Four missiles aimed at the sky at sunset. Shutterstock, asset id: 2131803989 by Hamara
Four nations that relinquished their nuclear weapons programs
The four nations that relinquished their nuclear weapons programs are Belarus, Kazakhstan, South Africa, and Ukraine. Belarus, Kazakhstan, and Ukraine returned their inherited nuclear weapons to Russia after the dissolution of the Soviet Union. However, it should be noted that in 2023 Russia began deploying tactical nuclear weapons to Belarus. However, Belarus does not currently possess its own nuclear weapons. South Africa voluntarily dismantled its nuclear weapons program in 1991.
In 2023 Russia began deploying tactical nuclear weapons to Belarus.Russia (green) and Ukraine (brown) map on a world map. Ukraine is about the size of Texas. Russia is about twice the area of the United States. Belarus is the country located immediately to the north of Ukraine and Kazakhstan is the big country immediately to the south of Russia and east of Ukraine. Shutterstock Asset id: 2121271067 by buraktumler
How to Build a Nuclear Bomb
This section is just some extra reading that is only somewhat related to the topic. However, since it is an interesting topic somewhat related to the topic I might as well explain how to build a nuclear bomb. Don’t worry I will not present any engineering details, only general principals, which is all I know, and which are already all over internet. Besides if I were to give detailed engineering instructions some peacenik hippie might have a hissing fit and swear in the comment section (that was a joke).
Anyway, the main idea behind a nuclear fission bomb is to achieve a runaway chain reaction. A fusion bomb, or a so-called hydrogen bomb is different. To create a fission bomb you are not looking for the most radioactive materials there are. You are looking for a fuel which you can use to create a runaway chain reaction, and which is also stable enough to make a bomb possible, in other words not too radioactive. Basically, the fuel must be just right. The primary fuels used in fission bombs are uranium-235 and plutonium-239. These isotopes undergo fission when struck by neutrons, releasing a massive amount of energy in a chain reaction.
Uranium-235 and Uranium-238 are both not very radioactive and can be used for radiometric dating that stretches millions and billions of years. Uranium-235 is also the “just-right” uranium isotope that can be used for bomb making. Shutterstock Vector ID: 2417370135 by grayjay
I should explain, isotopes are different forms of an element. For example, hydrogen comes in three different forms, a nucleus with just a proton, a nucleus with one proton and one neutron (deuterium), and a nucleus with one proton and two neutrons (tritium). Isotopes for the same element are chemically identical but have different atomic weight and they may or may not be radioactive.
The three isotopes of Uranium are uranium-234, uranium-235, and uranium-238. The one we need is uranium-235, which has 92 protons and 143 neutrons in the nucleus. The isotopes of Plutonium include Pu-238, Pu-239, Pu-240, Pu-241, and Pu-242 but there are others. The one we need is plutonium-239, which has 94 protons and 145 neutrons in the nucleus. There are more than 3,500 known isotopes of which 3,000 are radioactive.
During Uranium-235 fission, an average of 2.5 neutrons are released. Specifically, the fission of U-235 typically releases 2 or 3 neutrons, with the average being close to 2.5. During the fission of plutonium-239, an average of 2.9 neutrons are released (depending on the energy of the incident neutron). The important thing for bomb making is that one atom/nucleus releases enough neutrons so that the neutrons from one nucleus cause more than one fission. For example, a nucleus releases three neutrons and two of those neutrons cause two more fission events, which in turn cause four fission events, etc. 2, 4, 8, 16, 32, 64, a trillion…
Illustration of nuclear chain reaction. Uranium-235 fission. Unfortunately, the picture has an error in it. It is 92 protons not 95 in a U-235 isotope. – Shutterstock asset id: 73714504 by Mpanchenko.
By putting together enough U-235 you can make it so that one fission event will result in more than one additional fission event. This is called the critical mass. The critical mass for U-235 is 47 kilograms (104 pounds). Theoretically, you can achieve this by taking a 24-kilogram half sphere of U-235 in your right hand and a 24-kilogram half sphere of U-235 in your left hand and bring them together. You will achieve a limited chain reaction for a nano second, but you will just blow the two halves apart and kill yourself, but your city will survive. This is called a fizzle. To make most of the 48-kilogram mass undergo fission you have to force them together long enough for the chain reaction to complete (or almost complete). This requires force and precise calculations. See the illustration below.
Components Inside of Uranium Nuclear Fission Bomb illustration – Shutterstock asset id: 2271462995 by BlueRingMedia.
Another difficulty is obtaining nearly 100% U-235 from natural uranium. 99% of the Uranium you find in nature is U-238. U-235 and U-238 chemically identical so extracting U-235 from natural uranium is difficult. However, U-235 is slightly lighter than U-238 so you can use centrifugal separation as you do to separate cream from milk. What is typically done is using a uranium compound, uranium hexafluoride, heat it into gaseous form and then utilize centrifugal separation to extract the uranium hexafluoride with U-235 isotopes. After that you can chemically extract the uranium, which is now U-235.
Super Facts 