It’s a common theme, and the images that pop into mind may be of early humans during the Iron Age.

But according to Professor Seohyung Kim of Inha University, the history of iron precedes the history of life, and so historians need to look back to the beginning of the universe to fully understand the way iron has shaped humankind and its environment. She gave a special lecture called “History of Iron: Universe, Life and Human,” as part of the exhibition on October 13. Professor Kim studies history from a Big History perspective, or a multi-disciplinary approach to the study of the past that combines science, geology, human history and more to get a better, bigger picture of the past, present and future.

So here’s a look back, way back, into history to see what iron has to do with the history of man.

Stars Exploded and then Iron Existed

Where did iron come from? The stars. To be exact, large, dying stars. In the beginning of the universe, there were only 2 elements in existence- helium and hydrogen. New elements are only created when protons and neutrons fuse together and this requires a lot of heat.

The temperature of a star rises when it uses up all of its hydrogen atoms, and when it uses up all of its helium atoms, it collapses, emitting even more heat. This cycle repeats itself, creating new elements in the process until finally, iron in created. Elements with greater mass than iron are created in a supernova, or the death of a really, really big star.

A piece of meteoric iron formed by the heating and collapsing of a star sits on display at the National Museum of Korea.

So, why is this important?

The variety of elements created by exploding stars are what planets are made of, including earth, and iron makes up 35 percent of the earth’s entire mass.

Humans and their Complex Brains

After the formation of the earth, simple life forms appeared, and then eventually primates and homo sapiens. Humans are the most powerful species on earth, largely due to their complex brains that allowed for the development of language and through it, collective learning.

Iron-rich red meat was an important factor in human-brain development. (Source: Omicrono)

What’s interesting is that around 2.5 million years ago, humans started eating meat rich in iron and calories. Before this change in diet, early humans spent most of their scarce energy on chewing and digesting large amounts of vegetation. With the introduction of meat, their brains got larger as it is a muscle that requires 20 times more energy than muscles in other parts of the body. When humans started cooking meat with fire around 500,000 years ago, they consumed even greater amounts of meat, meaning humans could meet their dietary iron needs, and put their larger brains to use for things like agriculture.

Agriculture and Civilization

Collective learning led to some of the most critical developments is history, including agriculture, which developed after the end of the last ice age about 11,700 years ago, as human populations increased due to the fact that they were able to cook and consume meat. Further advancements in farming tools during the Iron Age led to an abundance of food and massive civilizations.

Some iron tools that made farming easier are on display at the National Museum of Korea.

Weapons Made Stronger with Iron

However, farming tools were not the only places where iron was applied. As communities developed around abundant agricultural centers, people decided they wanted more land, labor and power. So, cities waged war on one another with iron tools and armor that were fatally strong.

The Iron Age brought forth improvements in soldiers’ armor, and can be seen at the National Museum of Korea.

One vital invention in the evolution of weapons and tools alike was the wheel. The oldest artifact of the wheel is a potter’s wheel found in Mesopotamia and dates back to about 3500 BC. Then came the wooden wheel that were attached to chariots for effective warfare. Then finally, the Celtics applied iron rims on their chariots for added strength, durability and speed. Paired with iron swords and armor, wars became vastly efficient.

Iron wheels, like this one on display at the National Museum of Korea, enhanced existing wooden wheels.

After many years, the Chinese invented gunpowder triggering a new era of warfare. Iron was used to make rifles, cannons and other gunpowder machines to wipe out massive amounts of people at a time.

The invention of gunpowder led to new weapons such as these Iron rifles on display at the National Museum of Korea.

From Iron to Steel

After centuries of iron spearheading the development of new technologies and civilizations alike, a man named Henry Bessemer introduced a process to produce pure iron with a converter in 1856, known as the Bessemer Process. This invention would lead the way to the commercialization of steel and then eventually the industrial revolution near the end of the 18th century.

The steel industry was met with a rampant rise in steel demand during the second industrial revolution nearly a century later, with the introduction of electricity, gas and oil. Steel consumption continued to thrive into the third industrial revolution as it served the foundations for electronics, computers and automated production systems. As the world enters the fourth industrial revolution, steel will continue to be the bedrock of leading innovation and technology including electric vehicles, sustainable energy facilities and smart manufacturing factories.

Automated robots are part of what workplaces will look like in the fourth industrial revolution. (Source: Business Insider)

Looking back on history, the role and value of iron and steel in human development is indisputable. And to think, it all started with the death of a star.

Cover photo courtesy of BBC.

[Iron is the Future] blog post series will explore the history of the iron and speculate on how it will unfold in the future.

Iron has had a significant impact on the advance of human civilization. Do you know how iron, which is now taken for granted and used widely, entered our lives in the first place?

Today, to kick off the first edition of [Iron is the Future] series, we have prepared the behind story of the emergence of iron on Earth, as well as, various origin theories of iron.

How is Iron, number 26 on the periodic table and the fundamental element of life forms, made?

Atomic number 26 Fe, a.k.a. iron, makes up 35% of Earth’s mass and 5.2% of Earth’s crust. The abundant metal is truly one of Earth’s essential building blocks.  As mentioned in our previous post, there are 3 grams of iron even in the human body. Let’s take a look at how it’s made.

Long, long time ago, in a galaxy far away, iron was born during a nuclear fusion reaction within a star. During the initial stages following the Big Bang, no elements that were heavier than hydrogen or helium existed. In other words, iron didn’t even exist in the very beginning.

Nonetheless, all elements have the tendency to return to the most stable state. In order to achieve this, elements continuously go through nuclear fusion and fission. Since iron is the most stable element in the universe, all elements naturally try to convert to it.

However, lighter elements require extreme heat to become iron through nuclear fusion, and to obtain such heat, extreme pressure is necessary. The only place that fulfills such requirements is within a giant star. Thus,  iron is  born when a giant star explodes into a supernova. This is why stars are nicknamed “Iron Factories in Space”.

How much iron is there in Earth?

Like we said, all elements have the tendency to turn into iron, the most stable element in the universe. Let’s see how much iron, one of the most widely used metals, makes up the Earth.

Iron accounts for a third of Earth’s mass. Most of it exists not in the crust, but within the core. It exists as a liquid in the outer core and as a solid in the inner core. In fact, 91% of the Earth’s core is made up of iron!

The iron within the outer core forms Earth’s magnetic field as it rotates along with the Earth. Though the force of Earth’s magnetic field is negligible compared to that of magnets, it nonetheless plays a very important role. The reason why have compasses to show us direction and help us tell north from south is due to Earth’s magnetic field!

Furthermore, the iron in Earth’s core makes our planet habitable by forming Earth’s magnetic field which protects us from solar wind.

Then why is it so important to not be directly exposed to solar wind?

The upper atmospheric layer of the Sun emits plasma, which is what we call solar wind. Plasma, in turn, is essentially for the flow of electrons and protons which is known as radiation. Space radiation, if exposed, could 1) alter our DNA which will lead to cancer; 2) take away the electrons from the atoms that form our bodies; or 3) be absorbed by the atoms. All three scenarios will inevitably make life unsustainable.  If there were no iron in Earth’s core, there would be no magnetic field to shield us and we wouldn’t be able to exist on Earth in the first place.

Are you curious about the various origin theories of iron? There are three theories about the birth of iron, let’s find out now!

Theory 1: A Mistake

The first theory is that the discovery of iron was, interestingly, a mistake. This theory posits that our ancestors mistook iron for chalcopyrite, an ingredient of bronze, which happened to be of similar shade and color. This theory becomes plausible when we assume that our ancestors already had the technology to manufacture bronze during the Bronze Age.

Theory 2: Wildfire

Next is the wildfire theory. This theory argues that a wildfire melted the iron ore that emerged on the earth’s surface, thus allowing our ancestors to discover iron. According to this theory, prehistoric humans took the now deoxidized and exposed iron ore and molded it into different shapes for use.

In general, the fire we use daily seldom goes over 800℃, which is insufficient heat to deoxidize iron ore. However, a wildfire in thick, prehistoric jungles could have been much larger and may have lasted for much longer, which makes the wildfire theory possible.

Theory 3: Meteorites

Last but not least is the meteorite theory. This theory posits that humankind discovered iron from fallen meteorites. In fact, many of the meteorites which landed on Earth contain abundant iron, which is called meteorite iron. Meteorites, which are an alloy of iron and nickel, are reported to contain 4~20% nickel and 0.3%~1.6% cobalt.

The most plausible of the aforementioned theories is the first one, which states that our ancestors mistook iron for bronze. According to ancient documents and ruins, humankind first began to use iron around BC 4,000 in the Asia Minor region. Also, evidence claims that iron refining technology existed around 3,000 B.C. in Mesopotamia and Egypt.

From cars to ships, planes, homes, various daily necessities, iron is indeed all around us. We hope this post provided some enlightenment around Iron. Look forward to our part 2 in the [Iron is the Future] series.