Did Wyatt Earp have the law on his side at the OK Corral? A lot of people at the time might have disagreed, but Wyatt Earp acted legally during the Gunfight at the OK Corral.

The Gunfight at the O.K. Corral happened on October 26, 1881, in Tombstone, Arizona. Wyatt Earp, his brothers Virgil and Morgan, and their friend Doc Holliday confronted a group of men associated with an outlaw gang called the Cowboys. The resulting gunfight lasted approximately 30 seconds, during which around 30 shots were fired. Three Cowboys were killed, while Virgil Earp, Morgan Earp, and Doc Holliday were wounded. Despite its famous name, the gunfight didn’t actually happen inside the O.K. Corral. It took place in a narrow vacant lot nearby.

The town of Tombstone was only a few years old when Wyatt Earp arrived. It had been founded in 1879 by a United States Army scout who was hunting for silver. His name was Ed Schieffelin, and he found a long vein of silver in the area in 1877. He settled down to mine the vein and, as with the gold rush, more people gradually joined him. The town started out as tents but slowly grew. It was founded in 1879, and by 1880, it had a hotel and several other buildings. The population grew as well. By 1881, there were 6,000 people living in Tombstone.

Just like most frontier towns, there was a mix of people, but there were more men than women, and there were a lot of criminal elements. These criminals made money by theft, intimidation, or even murder. Wyatt Earp suggested that 3% of Tombstone were criminals like this. They were members of a gang called the Cowboys that spread across southeastern Arizona and northern Mexico.

The silver mines were profitable, and there were middle-class and wealthy people in the town. They didn’t like all of the crime, so towns like theirs often hired gunmen to protect them. Tombstone had its own lawmen, including Virgil Earp, who had arrived in 1879 as a deputy U.S. marshal and later became the town’s chief of police. His brothers Wyatt and Morgan also worked in law enforcement at various times. Wyatt’s friend Doc Holliday, a dentist and gambler, became closely associated with the Earps. Virgil was strict and enforced a “no guns” in the town policy. He arrested about 60 people a month, and his no guns policy was to stop a simple fight from turning into a murder.

The town ended up split along two lines. There were the merchants, the Earps, and the mayor on one side. And the cattle rustling cowboys with the county sheriff on the other. Things were not friendly, and the two factions had several confrontations. However, things became worse after the spring of 1881. A group of the Cowboys held up a stagecoach and killed its driver and passenger. The Clantons and McLaurys were not involved, but they knew who was. It seems that Wyatt Earp offered Ike Clanton half of the reward money if he told who killed the two people. I don’t know if Ike did give up the person, but by October he had become convinced that Wyatt Earp had told Doc Holliday Ike was a rat. Things came to a head on October 25^th, the day before the gunfight, when Doc Holliday and Ike Clanton had a blazing row. The Clantons threatened the lives of Holliday and the Earps.

On the day of the gunfight, Ike Clanton had been drinking in the town all night and making threats. He was threatening to kill the Earps. Virgil Earp physically took it from him, which was a humiliation for Ike, and arrested him. Ike was soon released and went to a gun shop to get a new gun, and he met some other Cowboys. Wyatt Earp had pistol-whipped one of those cowboys, Tom McLaury, earlier in the day. The Earps were law officers, but they were also personally involved in the dispute. All of the cowboys ended up in the empty lot behind the OK Corral. Virgil went with his brothers and Doc Holliday to disarm all of the men. They knew there would probably be a confrontation.

The four lawmen faced off against the six cowboys. Who fired first and where everybody was standing is not known for certain because witness statements differ. Virgil Earp said he was there to disarm the cowboys, and then somebody shot. Within 30 seconds, Morgan Earp was shot; although he survived, five of the cowboys were killed, and Ike Clanton had run away.

The county sheriff tried to arrest the Earps and Doc Holliday, but they didn’t let him. Following the gunfight, Ike Clanton accused the Earps and Doc Holliday of murder. A preliminary hearing lasted about a month, during which numerous witnesses gave conflicting accounts. The judge, Wells Spicer, ruled that there was insufficient evidence to send the men to trial. He criticized some of Virgil Earp’s decisions, but concluded that he had been acting within his authority as a law officer. The charges were dismissed. The judge had ruled that Wyatt Earp and the other men had been legally justified, although the decision remained controversial. Many Tombstone residents continued to believe that the Earps had used unnecessary force or deliberately provoked the confrontation. Whatever public opinion, they had acted lawfully.

However, the violence didn’t end with the hearing. In December 1881, Virgil Earp was ambushed and seriously wounded, leaving him with a permanently disabled arm. Then, in March 1882, Morgan Earp was shot and killed while playing billiards. Wyatt believed the Cowboys were responsible, and he assembled a group to hunt down the men he blamed for the attacks. Several men were killed during what became known as the Earp Vendetta Ride. Unlike the gunfight at the O.K. Corral, these killings led to warrants for Wyatt and members of his group. Wyatt eventually fled to Colorado, where the governor refused to extradite him to Arizona. He never returned to Tombstone. And this is what I learned today.

Sources

https://www.okcorral.com/history

https://en.wikipedia.org/wiki/Gunfight_at_the_O.K._Corral

https://www.history.com/articles/gunfight-ok-corral

https://en.wikipedia.org/wiki/Tombstone,_Arizona

https://en.wikipedia.org/wiki/O.K._Corral_hearing_and_aftermath

https://en.wikipedia.org/wiki/Wyatt_Earp

image’ By unattributed – Heritage Auction Gallery – Constable Wyatt Earp Lamar Missouri summons, Public Domain, https://commons.wikimedia.org/w/index.php?curid=17195693

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Was the Iron Maiden ever actually used? Despite its terrifying reputation, there is no credible evidence that the iron maiden was used as a medieval torture device. The familiar spiked cabinet appears to have been invented much later, during the 19th century.

The iron maiden is probably one of the most famous medieval torture devices of all time. So, it might surprise you to learn that it was never actually used in the Middle Ages. It was supposed to be a metal cabinet, slightly larger than a person. It was said to be cast in the shape of a woman, hence the term “maiden”. Inside were purported to be long spikes. As an item of torture, the victim was said to be locked inside the casket. It was too small to allow them to sit down, and they had to remain upright, but the spikes meant they couldn’t lean against the sides without being impaled. If left inside for long enough, the victim could die. Some versions were said to have spikes that could be extended to kill the victim.

The only problem with all of this is that such a device never existed in the Middle Ages. The first mention of the iron maiden comes from a mid-18th-century writer called Johann Georg Keyssler, a German polymath and travel writer. He travelled widely and wrote travelogues as a series of letters. They were heavily censored because of the political climate at the time, but they were published in several volumes. It is in his volume, “Travels through Germany, Bohemia, Hungary, Switzerland, Italy and Lorraine,” that he makes reference to the iron maiden. His travel accounts were first published in German in 1740 and 1741 and later translated into English in 1756 and 1757. He talked about a device called an iron maiden in Plassenburg Castle in Germany and the White Tower in Prague. However, he hadn’t seen the device, and he didn’t believe it existed. He said there was no evidence of it.

Another account appeared in a historical collection called Materials for the History of Nuremberg, published beginning in 1792. The collection was compiled by a German scholar named Johann Christian Siebenkees, although the iron maiden story is sometimes attributed to his cousin, Johann Philipp Siebenkees. The device that Siebenkees described, though, is a little different from the idea of the iron maiden that we have today, and he was probably confusing the purpose of a contraption that did actually exist. The device he describes is a metal cabinet that the person is put into. The person is then cut with swords, which is where the spikes idea comes from. He may have been writing about a device called a Schandmantel, or cloak of shame, that actually did exist. It was a wooden, barrel-like structure that people were trapped in and displayed. They were used for public humiliation more than torture, in the same way the stocks were. They had no spikes in them. However, Siebenkees also didn’t completely believe the account he read.

So, if the two people who wrote about the iron maiden in the 18^th century didn’t really believe it, where did we get the idea that the iron maiden was a medieval torture device from? In the late 18^th and early 19^th centuries, there was a growing interest in Gothic fiction, mysterious castles, secret tribunals, and gruesome medieval punishments. People loved reading about them, and they loved going to see them. There was a new Gothic tourism, and various collections and displays emerged to meet this market. And this seems to be where the first iron maiden came from. The medieval crime museum in Rothenburg has an iron maiden that appeared to be from the 15^th century. However, when they examined it more closely, they discovered it was a real Schandmantel with French bayonets from the Napoleonic era attached to the inside. This proved that the deadly spikes were a much later addition. The original device had been used for public humiliation, but someone had subsequently transformed it into an apparent instrument of torture.

In the 1850s, an antiques dealer and collector named Georg Friedrich Geuder assembled a collection of historical punishment instruments, including an iron maiden, which he displayed in Nuremberg Castle. The exhibition helped establish the iron maiden’s reputation as an authentic medieval device. Later, other iron maidens appeared in collections and exhibitions across Europe and beyond. In 1893, a collection of supposed torture instruments from Nuremberg Castle was exhibited in America, complete with an iron maiden. A year later, Bram Stoker, the author of Dracula, published a short story called The Squaw, in which an iron maiden played a central role. The device had become firmly established in the public imagination. And this is what I learned today.

Sources

https://en.wikipedia.org/wiki/Iron_maiden

https://www.history.co.uk/articles/the-iron-maiden-medieval-torture-device-or-modern-myth

https://allthatsinteresting.com/iron-maiden-device

https://en.wikipedia.org/wiki/Johann_Philipp_Siebenkees

https://en.wikipedia.org/wiki/Johann_Georg_Key%C3%9Fler

image By epbechthold – de.wikipedia epbechthold, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=790235

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Why do some chemical reactions give off heat and others don’t? The answer depends on the amount of energy absorbed when chemical bonds are broken compared with the amount released when new bonds are formed.

There are two types of chemical reactions: endothermic and exothermic. Endothermic reactions are those that require energy, and exothermic reactions are those that release energy. Both words are made by combining the Greek word “therme”, which means “hot,” with “endon”, meaning “within”, or “exo” meaning “outwards”.

An endothermic reaction is a chemical process that needs energy, so it absorbs heat from the surroundings. This is because a chemical bond is being broken. When two atoms are bonded, they are in a low-energy, stable state. To pull them apart, you have to overcome the electrical attraction that is holding them together. That requires adding energy, and depending on the element, it can take a lot of energy. Endothermic reactions reduce the thermal energy in the surrounding environment because it is being absorbed by the reaction.

An exothermic reaction is the opposite. It is a chemical process that releases energy, so it expels heat into its surroundings. This happens because chemical bonds are forming. When two atoms come together, two hydrogen atoms, for example, they each have one positively charged proton and one negatively charged electron. As the atoms get closer, each electron is attracted to the other atom’s proton, and once they get close enough, the atoms settle into a stable arrangement, sharing electrons. The new bonded atoms have less energy than the two atoms had on their own, and this excess energy is released as heat.

Endothermic and exothermic reactions can be seen in the cold packs and hot packs you can buy in shops. A cold pack is one where you press an activator on it, and it very rapidly becomes cold. You can use it if you are too hot, or if you need to ice a muscle injury. It works because of an endothermic process. Inside the cold pack is usually water and a plastic bag or tube containing a chemical reactant. Usually something like ammonium nitrate, urea, or calcium ammonium nitrate. When you activate the pack, the chemical reactant comes into contact with the water, and the water starts to dissolve it. Ammonium nitrate consists of positively charged ammonium ions and negatively charged nitrate ions held together in a crystal structure. The water molecules surround the ammonium nitrate molecules, and the positive end of the water molecule (the hydrogen) is attracted to the negatively charged nitrate ions, and the negative end of the water molecule (the oxygen) is attracted to the positively charged ammonium ions. These attractions pull the ions away from the crystal structure and keep them separated in the water. Separating the ions requires more energy than is released when the water molecules surround them. This difference in energy is absorbed as heat from the water and its surroundings, and the pack very quickly gets cold. It stays cold until the reaction finishes.   

A heat pack works in the opposite way, and it uses an exothermic reaction. There are different kinds of hand warmers, but the cheapest ones are the disposable pouch type. They come in a sealed plastic bag, and they start to get warm as soon as you open the bag. They can stay warm for several hours. They work because they contain iron powder, which reacts with the oxygen in the air. These pouches contain cellulose, iron powder, activated carbon, vermiculite, and salt. When you open them, air enters the pouch through holes in its covering. The oxygen and water in the air react with the iron to produce rust. When you open the packet, oxygen from the air enters through tiny holes in its covering and begins reacting with the iron powder. The salt and water help speed up the process. The iron reacts with oxygen to produce iron oxides, commonly called rust. The products have less chemical energy than the original iron and oxygen, and the difference is released as heat. You might wonder why oxygen reacting with iron to produce rust becomes so hot when your bicycle left in the front garden for six months never warms up. The reason is down to the speed of the reaction. The rust appearing on your bicycle is producing heat, but it is doing it in such small amounts and so slowly that you never notice. A hand warmer reaction is much faster. The iron in a hand warmer is a fine powder, giving it an enormous surface area exposed to oxygen. This allows much more iron to react at once, releasing enough heat for us to feel. And this is what I learned today.

Sources

https://www.bbc.co.uk/bitesize/articles/zb7wwnb#zjynn9q

https://en.wikipedia.org/wiki/Exothermic_process

https://en.wikipedia.org/wiki/Endothermic_process

Image Public Domain, https://commons.wikimedia.org/w/index.php?curid=642519

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What is Göbekli Tepe? Göbekli Tepe is one of the world’s oldest temples and megalithic sites. It was built in roughly 9500 BC, over eleven thousand years ago. It is in the south of the modern country of Turkey, not far from the border with Syria. It is the first human-built holy place in the world, telling experts a lot about what early people did. The name Göbekli Tepe means belly hill in Turkish because of the shape of the hill the site is built on.

When people think of the most ancient monuments in the world, they probably think of the Great Pyramids, or possibly stone circles like Stonehenge. However, when Stonehenge was built, Göbekli Tepe was already six and a half thousand years old, and when the pyramids were built, it was celebrating its seven thousandth birthday. It is truly ancient, and the remarkable thing is, it was built just as humans were starting to settle down.

The site is located high on the edge of the Germus Mountains, giving it panoramic views across the plains. Today, the area is very dry and brown, but when Göbekli Tepe was built, it was much wetter, and the plains would have been full of grassland, wild cereals, and herds of grazing animals. It was the plentiful food source that kept hunter-gatherers alive.  

The whole site hasn’t been completely excavated yet. There are monumental buildings with stone walls and standing stones arranged in circles. On the hillside, there are four more rings of partially excavated pillars. There are two large stone T-shaped pillars in the center of each circle, with a circle of slightly smaller stones around them facing inwards. The tallest pillars are about 5 meters tall. Some of the pillars have no designs, while others are covered in carvings of foxes, lions, scorpions, snakes, boars, birds, leopards, and vultures. Lions might surprise you, but up until fairly recently there were wild lions in Turkey. Ground-penetrating radar surveys have shown that there are at least another 16 stone rings buried around the site. The currently excavated objects only account for about 5% of the whole site.  

All of the stones are made from limestone, which is readily available in the surrounding mountains. The builders and stonemasons were working in the Stone Age, and they did not have access to any metal tools. The Bronze Age wouldn’t happen for several thousand years. They built and carved all of the stones using flint tools.

Göbekli Tepe has been called a holy site, but it probably wasn’t used in the same way as modern holy sites. The pillars may have represented human figures and could have been used to honor ancestors, supernatural beings, or other important figures from whatever mythology they believed. They could have made offerings at the pillars. They may have held communal feasts. Large quantities of animal bones have been found, including the tools used to grind cereals. Perhaps it was a place where lots of tribes came together to celebrate. They may have used it as a place to perform ceremonies for the dead. Archaeologists have found skulls with strange marks carved in them, or holes drilled in them. The skulls may have been suspended as part of a ritual. Several burials have also been discovered. Small stone masks and animal carvings have also been found. Archeologists can speculate about what happened and what the site was used for, but it would be very difficult to actually prove anything.

The most interesting thing about the Göbekli Tepe site is what it represents in the shift from hunter-gathering to farming. When the site was first discovered, archeologists thought that hunter-gatherers came together at this location and built the enormous monuments for their ceremonies. More people came, which meant they needed to feed more people, and eventually farming developed as a way to feed these people. However, newer evidence has shown that settling down and building the monument probably came at the same time. Among the monuments, smaller buildings that seem to be houses, evidence of domestic activities, water storage facilities, and human burials have been found. All of this seems to indicate that people were living there while they were building. So, the interesting question is, when did they start to farm?

Were the people at Göbekli Tepe farmers? Surprisingly, there is very little evidence that they were. The people at Göbekli Tepe hunted wild animals and gathered wild cereals. They may have begun experimenting with growing plants, but there is no convincing evidence that they were raising domesticated animals or practicing fully developed agriculture.

This raises an interesting question. Did people begin farming because they had settled down, or did they settle down because they had begun farming? Göbekli Tepe suggests that at least some hunter-gatherers were establishing settlements and building enormous monuments before agriculture became their main source of food. Perhaps settling down, building monuments, and developing farming were all parts of the same gradual process. We still don’t know exactly how it happened, but Göbekli Tepe is helping archaeologists rethink one of the most important changes in human history. And this is what I learned today.

Sources

https://en.wikipedia.org/wiki/G%C3%B6bekli_Tepe

https://www.smithsonianmag.com/history/gobekli-tepe-the-worlds-first-temple-83613665

https://whc.unesco.org/en/list/1572

Image By Teomancimit – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=17377542

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Why are lemons sour when other fruits are sweet? Lemons are sour because they contain a lot of citric acid. We also need to remember that there are a huge variety of lemons, some very sour and some not so much. We need to break this question down into a few parts. Why does citric acid taste sour? How do lemons cope with so much citric acid? Why did they evolve to have citric acid? And how and why did we breed them to be so sour?

Let’s look at why citric acid tastes sour first of all. Most acids taste sour, although some taste more sour than others. And some acids, such as hydrochloric acid, is not something you should ever try to taste. They taste sour because acids release hydrogen ions, which interact with the taste cells on our tongues. We have type III taste receptor cells inside the taste buds on our tongues, and they detect acidity using a protein called OTOP1. This protein lets hydrogen ions pass through a cell membrane, where they form an electrical signal that travels to the brain. The amount of hydrogen ions changes the level of sourness. On the low end, sparkling water is carbonated, which means it contains carbonic acid, and that has a very slight sour taste. And on the top end, we have citric acid and acetic acid (vinegar), which are extremely sour.

So, how can lemons cope with so much citric acid? All acids are corrosive. You can tell how corrosive citric acid is because if you drink a lot of lemon juice, it can damage your teeth, and they might feel slightly painful. The acid strips away calcium and phosphate minerals in tooth enamel, making it temporarily porous and exposing the nerves. Your saliva can replace some of those minerals, but if you constantly drink lemon juice, it can cause irreversible damage. So, if citric acid is so corrosive, how do lemons survive? They can survive because they store most of the acid inside special compartments called vacuoles. These have membranes that separate the acid from the rest of the cell. The vacuoles can have a pH as low as 2, but the surrounding cell stays close to a neutral 7. Lemons use something called a proton pump to accomplish this. The proton pump uses energy to push hydrogen atoms from the cytoplasm into the vacuole, making it more acidic. The vacuole has a special membrane which keeps the acidic contents away from the rest of the cell.   

Why have lemons evolved citric acid? Well, lemons are not the only fruit that have evolved citric acid. Some fruits that are sweet also contain it. Oranges, pineapple, strawberries, cherries, mangos, and apples all contain citric acid. They also contain a lot more sugar than lemons do, which is why they taste sweet to us and not sour. But we all know that fruit like pineapple is sweet, but they have a certain tartness. That comes from the citric acid. All of these plants have evolved to develop citric acid because it can protect the fruit against microbes. High acidity creates a very harsh environment for bacteria and fungi. Citric acid can also deter many pests, birds, and herbivores. A lot of fruits are sour until they are ripe. This deters animals from eating them until their seeds are ready to be dispersed.

So, why have lemons become as sour as they have? The very sour lemons that we have have become that sour through selective breeding, just like the sweet fruits we have have become much sweeter. Modern lemons are a hybrid of citron and sour orange fruits, both of which can be very acidic. The citron has a very thick rind and is used for its scent more than as a food. Some other citrus varieties developed mutations that reduced their acidity, making their natural sugars more noticeable. Humans then selected the type of citrus fruit they wanted and cultivated them accordingly. Sweet oranges were useful for eating, and people wanted sweeter ones. Sour lemons were useful for flavoring food and making drinks. There are far more cultivated varieties of citrus fruit around today than there used to be. We took the quality of a fruit we liked and “improved” on it. You can even get lemons that don’t have much citric acid. They can be eaten like oranges and are very popular in drinks in India, Pakistan, and the Middle East. And this is what I learned today.

Sources

https://cen.acs.org/biological-chemistry/biochemistry/Lemons-sour-s/97/web/2019/03

https://www.aip.org/inside-science/the-genetic-reasons-why-citrus-fruits-taste-so-sour

Photo by L. Lum: https://www.pexels.com/photo/fresh-lemons-with-vibrant-green-leaf-35926707/

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How did we discover stem cells? Stem cell were discovered by accident in the 1960s by James Till ad Ernest McCulloch. Despite the enormity of the discovery, they never won a Nobel Prize for it.

Most cells in our bodies have a specific job. Skin cells, nerve cells, and liver cells all perform different functions. Stem cells are unusual because they can make copies of themselves and develop into other types of cells. Some stem cells can become almost any type of cell in the body, while others can only produce certain types. For example, stem cells in our bone marrow continually produce new blood cells. They are unique. When we begin to develop in the womb, we have a lot of stem cells. Once we reach adulthood, the majority of our cells have settled down and we only have a few places in our bodies that produce stem cells. A lot of research is going in to creating stem cells because if we can create them, we can potentially fix a lot of injuries and illnesses that plague us. For example, they could potentially repair damaged nerve tissue in paralyzed people and, although not fix them, restore some movement and feeling. Finding a way to make stem cells is the holy grail.

So, how were stem cells discovered? Well, first we need to look at the discovery of cells. Robert Hooke was the first person to name cells. He used a compound microscope that had been invented in 1590 and in 1665 he looked at slices of cork. He saw that it was made up of lots of tiny compartments that reminded him of monks’ rooms, so he called them “cells”. Ten years later, Antonie van Leeuwenhoek was able to see microscopic living organisms in water. He called them animalcules. He was able to see them because of further developments in the microscope. In 1831, Robert Brown identified the nucleus in plant cells, and then in 1838, Matthias Schleiden put forward the idea that plants were made mainly of cells. In 1839, Thedor Schwann showed that animals were also made of cells and in 1852 Robert Remak was able to show how cells divide and reproduce. It was only with the invention of the electron microscope in 1931 that it became possible to see the fine cellular structures. It was known that new cells came from existing cells but no one knew that there was a type of cell that can develop into all cells.

The term “stem cell” was introduced in 1868. A German biologist called Ernst Haeckel used the term to refer to an ancestral cell in evolutionary history. The cell that all cells come from. He then used the term to apply to a fertilized egg. Then, in the 1890s, scientists put forward the idea that some cells could give rise to reproductive cells. It was only an idea. In 1908, Alexander Maximow and several other scientists developed the idea that blood cells come from a single type of cell. This led to the idea that problems with blood cell production in people could be cured with a bone marrow transplant. The Bone marrow contained the blood stem cells, which grew new blood cells, but nobody knew why.

In 1960, two scientists working in Canada, James Till and Ernest McCulloch, were studying how radiation affected bone marrow. They wanted to know if a bone marrow transplant could offset the problems caused by radiation. They exposed mice to lethal doses of radiation and then injected each mouse with a different number of bone marrow cells to observe what happened. One day, James Till and Ernest McCulloch were examining the spleens of the mice when they noticed small lumps. The number of lumps was directly proportional to the number of bone marrow cells that had been injected. The lumps were colonies containing millions of newly produced blood cells. The injected bone marrow cells traveled through the mice’s bloodstreams, and some settled in their spleens. The spleen can produce blood cells under certain conditions, so these cells began to multiply. Within ten days, they had produced small lumps containing millions of cells. The scientists noticed that the more bone marrow cells they injected, the more lumps appeared. This suggested that each lump had grown from a single special cell. Further experiments showed that these cells could produce different types of blood cells and make copies of themselves. The scientists had found experimental evidence of stem cells.

They published their discovery in 1961, but they hadn’t yet proved what they had discovered. That would take them another two years. In 1963, with other colleagues, they were able to show that these cells could produce other cells. They were stem cells.

The discovery of stem cells opened up an entirely new field of research. In 1981, scientists managed to isolate and grow embryonic stem cells from mice. Then, in 1998, James Thomson and his colleagues successfully grew human embryonic stem cells in a laboratory. These cells could develop into almost any type of cell in the body. However, perhaps the most remarkable discovery came in 2006, when Japanese scientist Shinya Yamanaka found a way to turn ordinary mouse cells back into stem-cell-like cells. A year later, scientists achieved the same thing with human cells. Suddenly, researchers had a way to produce versatile stem cells without obtaining them from embryos. Yamanaka received the Nobel Prize in Physiology or Medicine in 2012, alongside John Gurdon, for discoveries about reprogramming mature cells. However, Till and McCulloch, whose experiments had helped establish the existence of stem cells, never received a Nobel Prize. And this is what I learned today.

Sources

https://www.mayoclinic.org/tests-procedures/bone-marrow-transplant/in-depth/stem-cells/art-20048117

https://en.wikipedia.org/wiki/Stem_cell

https://bioinformant.com/who-discovered-stem-cells

https://news.usask.ca/articles/research/2018/the-accidental-discovery-of-stem-cells.php

Photo by Lidija Ostojić: https://www.pexels.com/photo/organism-under-miscroscope-16598692/

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Why do spacesuits pick up so much static electricity on the Moon? Static electricity builds up on spacesuits for some of the same reasons it builds up on our clothes on Earth. As astronauts walk and move, their suits rub against other materials, allowing electrical charges to build up. However, conditions on the Moon make it much harder for those charges to dissipate. Spacesuits themselves also contribute to the problem because they contain layers of insulating materials. And there is another source of electrical charging on the Moon: the Sun. Even if you wore ordinary clothes, static electricity would still be a problem. However, if you walked on the Moon in jeans and a T-shirt, static electricity wouldn’t be your most pressing concern. It is worth noting that everything on the Moon builds up static electricity, not just spacesuits.

Static electricity on the Moon can cause two serious problems. The first is that astronauts can accumulate significant electrical charges. When they return to their spacecraft, these charges could produce sparks that might damage sensitive electronics or ignite combustible materials in an oxygen-rich environment. The second problem is lunar dust. Electrically charged spacesuits can attract enormous amounts of dust, which can interfere with their equipment and be carried back into the spacecraft.

So, why is static electricity such a problem on the Moon? Static electricity produced when two materials come into contact and separate is called triboelectric charging. Electrons can transfer from one material to another, leaving one positively charged and the other negatively charged. This happens on Earth as well. However, we have several ways for electrical charges to dissipate on Earth. Moisture in the air and on surfaces can help charge leak away, and contact with conductive materials can allow electricity to flow into the ground. We have looked before at why static electricity is more common in dry rooms than humid ones.

The Moon is different. It has virtually no atmosphere, no moisture, and a surface covered in extremely dry dust and broken rock called regolith. This regolith is a very poor electrical conductor. That means electrical charges cannot easily flow away through the ground. Spacesuits make the problem more complicated because they contain several layers of different materials, many of which are electrical insulators. Charges can accumulate on different parts of the suit without an easy way to remove them.

There is also another source of electrical charging: space itself. Unlike Earth, the Moon has no substantial atmosphere or global magnetic field to protect its surface from the Sun. Ultraviolet radiation can knock electrons out of lunar dust, leaving the dust positively charged. At the same time, the solar wind carries electrically charged particles that can deposit electrons on the surface. In areas without sunlight, the surface can become negatively charged. Astronauts and their equipment are exposed to this electrical environment as well.

All of this makes lunar dust an enormous problem. If you have ever tried to refill a beanbag with tiny polystyrene balls, you will know what happens. They stick to everything because of static electricity. Lunar dust behaves in a similar way, although static electricity isn’t the only reason it sticks. The particles are also extremely fine, sharp, and abrasive. During the Apollo missions, astronauts discovered that the dust was incredibly difficult to brush off their spacesuits. It could scratch surfaces, interfere with moving parts, and get inside the lunar module.

NASA is developing several ways to deal with this problem. One of them is called an Electrodynamic Dust Shield. This uses a series of electrodes to create changing electric fields that move dust particles across a surface and remove them. The technology could eventually be used on spacesuit visors, boots, and other equipment. In March 2025, NASA successfully demonstrated the technology on the Moon using a robotic lander. However, removing accumulated electrical charges from an entire spacesuit remains a difficult problem, and NASA is still looking for solutions. They need to find a way to bleed the static electricity from the astronaut before they touch the ladder to the lander or get into the airlock. It is such a tricky problem that they are offering a significant prize. And this is what I learned today.

Sources

https://www.universetoday.com/articles/static-electricity-in-space

https://ntrs.nasa.gov/api/citations/19700004167/downloads/19700004167.pdf

https://ttu-ir.tdl.org/server/api/core/bitstreams/3c3f160c-4b29-49a3-a6fc-6878d740ab64/content

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Why did the USA invade Canada in 1812? The United States invaded Canada as part of its war against Britain. Some Americans hoped to make Canada part of the United States, while others believed that conquering it would force Britain to negotiate. Either way, they expected a much easier victory than they actually achieved.

In 1812, Britain and the USA were at war. Britain was also at war with Napoleon’s France. The United States had declared war on Britain on 18 June 1812. They had several reasons for wanting to go to war. The first was that Britain was preventing America from trading with France. In order to bring the war in Europe to a close as fast as they could, Britain tried to cut off all trade with France. That meant turning back American ships. The problem was, America was an independent country and felt that it had the right to trade with whichever country it chose. The second reason was that Britain was stealing sailors off the American vessels and forcing them to join the British Navy, a process called impressment or press-ganging. The third reason was that Britain was trying to prevent American expansion westward by helping the indigenous people. Britain wanted to protect the fur trade, hold back the Americans, and keep a buffer zone between the United States and Britain’s territories in Canada. Britain offered some concessions and had already decided to repeal some of its trade restrictions, but news traveled so slowly across the Atlantic that the decision reached America too late to prevent the declaration of war..

About a month after declaring war, American forces headed north for Canada. The United States had little chance of defeating the powerful British Navy, so American leaders decided to attack Britain’s territory on land instead. They hoped that capturing Canada would force Britain to negotiate. Some also wanted to take the territory permanently, removing British influence from northern North America. Because Canada had such a small population, only 600,000 compared to almost 8 million in the USA, people like Thomas Jefferson thought it would just be a case of marching in. Many of the inhabitants of Canada used to be Americans, and they thought many Canadians would welcome them as liberators. However, that is not what happened.

The American army marched across the Detroit River into Upper Canada in July of 1812. They ended up retreating, and they lost the fort at Detroit. They crossed again in October, but they had to turn back again. In 1813, they managed to get further, and they captured York (now Toronto) and burned the government buildings. They won victories on Lake Erie and at the Battle of the Thames, but that was as far as they could get, and they realized they wouldn’t be able to control Canada. Their attempt to capture Montreal failed in late 1813, and although fighting continued in 1814, American forces never succeeded in conquering Canada.

So, why couldn’t the American army take control of Canada? There were several reasons. The American army was not as well prepared as it could have been. The USA had a relatively small standing army at the time, and many of the soldiers were inexperienced. Some of the commanders were elderly or ineffective. The British forces were better trained than the Americans had thought they would be. The USA thought Britain would have saved all of its capable soldiers for the fight in Europe, but they still had experienced professional soldiers stationed in Canada. These troops were generally better trained than the inexperienced American forces. The Americans were also hindered because when they crossed into Canada, a lot of the soldiers refused to go. They thought their job was to defend their own states and not invade another country. However, the two biggest things that stood against their invasion were the size of Canada and the Canadians and indigenous people. Canada is an enormous country, and the forests, rivers, lakes, and severe winters made supplying the American soldiers extremely difficult. They also expected to be welcomed into Canada as liberators. Many Canadians had no desire to join the United States. Some were descendants of Loyalists who had left America during or after the Revolutionary War because they wanted to remain under British rule. Others were French-speaking Canadians who had their own reasons for resisting American control. They were not sympathetic to America’s cause. The indigenous people also feared what America would do if they managed to capture the territory, so they fought as well. Their knowledge of the region allowed them to disrupt American operations, which could sometimes sway a whole battle.

The United States had underestimated both the difficulty of invading Canada and the determination of the people defending it. In 1814, Britain and America began negotiating an end to the war. The Treaty of Ghent was signed in December 1814, and the war officially ended in February 1815. Neither country gained any territory, and Canada remained under British control. Although there would be further disputes and raids along the border, Britain and the United States would never fight another war against each other. And this is what I learned today.

Sources

https://en.wikipedia.org/wiki/War_of_1812

https://www.history.com/articles/how-u-s-forces-failed-to-conquer-canada-200-years-ago

Photo by Bogdan Krupin: https://www.pexels.com/photo/canadian-flag-on-a-flagpole-16920248/

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Why are some elements rarer than others? Some elements are rarer than others because lighter elements are easier to make, and heavier elements require a huge amount of energy. Also, elements with even atomic numbers are more common than those with odd numbers. And some elements are destroyed inside stars.

This is an interesting question because it isn’t the case that all of the lighter elements are common and all of the heavier elements are rare. Some of the light elements are rare. We should also mention that rare earth metals on Earth are not technically rare; they are just very hard to process. And it is also worth mentioning that some elements are rare on Earth without being rare in the universe.

Let’s begin by looking at why lighter elements are easier to make than heavier elements. The atomic number of an element is the number of protons it contains. Hydrogen has one proton, helium has 2, carbon has 6, iron has 26, and gold has 79. The heaviest element, which is synthetic, is Oganesson, and it contains 118 protons.

Protons have a positive electrical charge, and because like charges repel, they push each other apart. There is another force, called the strong force, which can hold neutrons and protons together when they are extremely close. However, to get the protons close enough together so that the strong force takes over requires a lot of energy. Think of it like two magnets with superglue on them. If you face the south and south ends of the magnets together, you will have a lot of trouble getting them to touch, but if you can push them hard enough, they will touch, and then the superglue will hold them. Because it takes so much energy to bring more than one proton together, heavier elements are only fused in the stars with the highest temperatures and pressures. This is why there are far more lighter elements than there are heavier ones.

Just after the Big Bang, the universe was filled with protons and neutrons. As it cooled, some of these particles combined to form helium nuclei, but most of the protons remained as hydrogen. Within a few minutes, the universe contained mostly hydrogen, a substantial amount of helium, and tiny traces of lithium. Millions of years later, stars formed from these elements. Inside the stars, hydrogen nuclei began fusing into helium, releasing enormous amounts of energy. This is why stars shine. Once all of the hydrogen has been made into helium, if the star is big enough, it will start to fuse helium together and make carbon. In sufficiently massive stars, fusion can continue creating heavier elements, including carbon, oxygen, and silicon. Eventually, the star may develop a core rich in iron-group elements. However, they have to stop when they get to iron. Up to the point of iron, fusing elements together always produces energy, which stops the star from collapsing under its own weight. Fusing iron doesn’t work, though, because it takes energy to fuse iron, rather than produce it. When some massive stars develop iron-rich cores, their cores can collapse, triggering enormous explosions called supernovae. These explosions scatter elements into space. Other types of supernovae also produce large quantities of iron.

We obviously have elements that are heavier than iron, so something must have fused them. Many elements heavier than iron are formed through a different process. Atomic nuclei absorb neutrons, some of which eventually change into protons, creating new elements. This can happen inside aging stars, but the heaviest elements, including gold and platinum, can also form during extraordinary events such as the collision of two neutron stars. Neutron stars don’t collide very often, which is why the really heavy elements are so rare.

However, there is another reason why there are more of some elements than others. We have to look not only at how elements are made, but at how they are destroyed as well. Some surprisingly light elements, including lithium, beryllium, and boron, are relatively rare because nuclear reactions inside stars can easily destroy them. They can react with protons at lower temperatures than many heavier elements. For example, lithium-7, which contains three protons and four neutrons, can absorb another proton and briefly become unstable beryllium-8. This almost immediately splits into two helium nuclei. Stars also don’t produce enough of these elements through ordinary fusion to replace what they destroy.

Another interesting pattern is that elements with even atomic numbers are more abundant than elements with odd atomic numbers. This is partly because protons become more stable when paired inside atomic nuclei. It is also because stars can build heavier elements by adding helium nuclei, each containing two protons and two neutrons. This naturally favors elements with even numbers of protons. Scientists call this the Oddo–Harkins rule, after the two researchers who identified the pattern in the early 20th century.

Some elements are extremely common in the universe but relatively rare on Earth. Helium is a good example. It is the second most abundant element in the universe, but Earth’s supply is limited. Helium is extremely unreactive, so it rarely becomes chemically trapped in minerals. Because its atoms are so light, helium can also escape from Earth’s atmosphere into space. Most of the helium we use comes from underground natural gas deposits, where it has accumulated over millions of years. Once released into the atmosphere, it is very difficult to recover. And this is what I learned today.

Sources

https://en.wikipedia.org/wiki/Oganesson

https://www.iflscience.com/why-are-the-universes-most-common-elements-so-rare-on-earth-75500

https://frisellagiuseppe.medium.com/why-are-the-most-common-elements-in-the-universe-so-common-892a1b2fc75d

https://www.dongascience.com/en/news/76372

https://en.wikipedia.org/wiki/Abundance_of_the_chemical_elements

Photo by Malcoln Oliveira: https://www.pexels.com/photo/close-up-of-iron-ore-texture-in-minas-gerais-34045315/

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Why did executioners live on the edge of town? Executioners were forced to live on the edge of town for the rather odd reason that, even though they were killing legally for the state, they were considered to be unclean.

The practice of executing people has probably existed for as long as people have lived together in groups. The idea of punishment for crimes is one of the things that make us human. There are some animals that punish members of their own species, but that appears to be an evolved response which stops certain behaviors and benefits the group. I suppose you could say that human punishment is also a behavior that benefits the whole group, but we are the only species that decide what punishment fits a crime, and we are the only species that think some crimes deserve the ultimate punishment. We are the only species that kill after a crime has happened and not in defense or for food.

Because the majority of us don’t want to kill people, if a state is going to have executions, it also needs to have executioners. Early civilizations, such as Ancient Egypt and Ancient Mesopotamia, had elaborate legal systems that carried a sentence of death for many offenses. They may have had professional executioners, but that is difficult to find evidence for. It is possibly more likely that they used soldiers or prison guards to carry out the deeds.

The Ancient Greeks are the first civilization where evidence of professional executioners can be found. Athens employed public executioners who were often enslaved people owned by the state. They operated under a group of eleven officials who were responsible for prisons and executions. One of their duties was preparing and administering the hemlock used to kill people. Socrates, the famous philosopher, was executed by hemlock poisoning in 399 BC, and maybe it was one of these slaves who administered it to him.

Rome also had public executioners, who were known as carnifices. They were in charge of condemning people, in particular slaves and non-citizens, administering torture, and executing them. This is one of the first civilizations where we can see that the role of executioner was considered to be deeply dishonorable. They were prohibited from living inside the city of Rome and had to live beyond the city boundaries in a specific place associated with executions and punishment.

Things changed in the Middle Ages because the law, courts, and systems became much more sophisticated. In the early days, executions were carried out by a lord’s servant, a soldier, an official, or someone else commanded by the system, but as the courts and governments became more organized, the paid occupation of executioner evolved. This became particularly common after the 13^th century. By the later Middle Ages, many European towns had a professional executioner.

However, despite being employed by the state to carry out legal executions, these people were considered unclean and dishonest. This came from the belief that handling corpses, blood, or other impure things could contaminate the person handling them. Because of this, many executioners were excluded from trade guilds, citizenship, public office, and other social activities. They were also often forced to live outside of the town walls. Often, they were housed in neighborhoods with other people who were thought of as unclean, such as slaughterhouses, brothels, and hospitals for people with infectious diseases.

Very few people wanted the job for obvious reasons, so they were sometimes forced into it. There is a famous story of a German woodsman called Heinrich Schmidt who was ordered by his local lord to execute three men or face hanging himself. He did it and was ostracized. The stigma affected his family, and his son Franz ended up becoming not just an executioner himself, but one of Germany’s most famous executioners.  

Executioners received a salary and sometimes free housing, but it wasn’t a lot of money. Many executioners managed to make ends meet, and sometimes become quite wealthy, by embracing their unclean status and doing the jobs that other people wouldn’t do. They might dispose of dead animals, clean waste, and administer corporal punishment. Some executioners controlled the brothels they lived near and gaming houses, which were also outside the city. Several executioners also worked as healers as well. They needed to know about anatomy to torture and execute people, which they could use to heal as well. And this is what I learned today.

Sources

https://en.wikipedia.org/wiki/Executioner

https://historymedieval.com/the-executioner-life-on-the-edge-of-medieval-law

https://www.battlemerchant.com/en/blog/executioners-in-the-middle-ages-between-myth-and-reality

https://en.wikipedia.org/wiki/Trial_of_Socrates

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