Apps so far, and whatever else I end up making. Right now that means software for people working in Korea — each with a page that says plainly what it does and what it doesn't.
From the first particles to the present, in 42 chapters.
The oldest fossils we could firmly call Homo sapiens were about 195,000 years old, from Omo Kibish in Ethiopia. Then in June 2017 remains from Jebel Irhoud in Morocco were dated to roughly 300,000 years, and our species became a hundred thousand years older in a single paper.
That is the method working, not failing. Science reports whatever nature turns out to be, so the answer moves when the evidence moves. The old number was the honest reading of everything available at the time — never a claim that nothing older existed, only that nothing older had been found. Chapter 24 carries the new date.
Smithsonian’s Human Origins Program, Our species arose at least 300,000 years ago
Science
The Primordial Soup
The universe began 13.8 billion years ago hot and dense — far too hot for anything solid to hold together. What filled it was a soup of loose quarks, gluons, and photons — the smallest pieces of matter and light, with nothing yet built from them.
RocketSTEM, Unravelling the mystery behind the Big Bang birth of the universe
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The First Building Blocks
Within microseconds the soup expanded and cooled to about a trillion degrees — hotter than any star, but cool enough for loose quarks to stick to one another. Bound together, they made the universe’s first protons and neutrons.
RocketSTEM, Unravelling the mystery behind the Big Bang birth of the universe
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The First Atoms and Light
About 380,000 years on, protons finally held on to passing electrons and the first hydrogen and helium atoms formed. Until then light had bounced off loose electrons and gone nowhere; now space turned clear and it streamed out, the oldest light we can still see.
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The Simplest Elements
Only the simplest elements came out of those first minutes: hydrogen, helium, and a trace of lithium, each needing just a handful of protons to hold together. Everything heavier — carbon, oxygen, iron — did not exist yet, and there was nowhere yet to make it.
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The Gravity Engine
Hydrogen and helium are light gases, but a cloud of them light-years across adds up to an enormous weight. Gravity pulled each cloud inward until the squeeze at its center grew hot enough to start nuclear fusion, and the first stars switched on.
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The Forge of Complex Elements
A star fuses hydrogen into heavier elements, up to iron, until it runs out of fuel. The biggest then explode as supernovae and scatter what they made across space. Heavier elements still, like gold, need something more violent — most likely the collapse or collision of dead stars.
Columbia News, A Cosmic Explosion Forged Heavy Elements Like Gold and Platinum
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The Birth of Galaxies
Stars did not form alone. Over hundreds of millions of years they gathered into enormous groups that drew on each other, merged, and settled into a spin — the first galaxies in the universe.
NASA Science, Hubble Approaches the Final Frontier: The Dawn of Galaxies
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The Milky Way Takes Shape
About 13 billion years ago small early galaxies ran into each other and merged into one — the Milky Way, ours. It has been swallowing gas, dust and smaller galaxies ever since, and that slow feeding drew out its spiral arms.
UC Davis Letters & Science Magazine, How Did the Milky Way Galaxy Form?
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The Birth of Our Solar System
Around 4.6 billion years ago a cloud of gas and the dust of dead stars fell in on itself and flattened into a spinning disk. Almost all of it piled into the middle and lit up as our Sun; what was left kept circling.
NASA Science, How did our Solar System form?
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The Formation of Earth
In the leftover ring, rock stuck to rock over tens of millions of years — dust, to pebbles, to boulders, to a planet — until Earth reached the size it is now. It began molten throughout, and cooled slowly until a crust hardened on top.
Introduction to Historical Geology (Maricopa), The Hadean Eon (4600–4000 Ma)
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The Origin of Earth’s Water
Where Earth’s water came from is still argued over. Comets and water-rich asteroids brought some, but the rock Earth was built from may have held much of it from the start. Either way, once Earth cooled, steam in the air fell as rain and filled the oceans.
Earth How, Did Earth’s First Water Come from Comets, Volcanoes or Asteroids?
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The Seeds of Life
The early air would poison anything alive today, but the new oceans could dissolve carbon-based chemicals and hold them together. Somewhere — perhaps at hot vents on the sea floor — some combined into molecules that could copy themselves. The oldest likely signs of life are about 3.8 billion years old.
Smithsonian Magazine, LUCA, the Ancestor of All Life on Earth
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LUCA, the Universal Ancestor
Every living thing on Earth descends from a single microbe: LUCA, the Last Universal Common Ancestor, which lived over 3.5 billion years ago — not the first life, but the last ancestor every survivor shares. We can tell because bacteria, trees and people all still run on the same genetic code.
Earth How, LUCA: Last Universal Common Ancestor
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The Air Turns Breathable
Some of those microbes learned to live off sunlight — photosynthesis — and gave off oxygen as waste. Over hundreds of millions of years that waste filled the oceans and then the air, killing off many of the microbes already here and leaving behind an atmosphere animals could one day breathe.
Wikipedia, Great Oxidation Event
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The Rise of Complex Life
Cells got more complicated: the eukaryotic cell keeps its DNA in a nucleus and runs on structures that were once separate microbes it absorbed. Cells like that could stick together and take on different jobs, and much later animal body plans multiplied in a rush — the Cambrian Explosion.
Exploring Our Fluid Earth (University of Hawaiʻi), Change Over Time
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The Step onto Land
Around 375 million years ago some fish in shallow water had thick jointed fins that could prop up their weight, and simple lungs for gulping air. Those that coped out of the water did better, and their descendants became tetrapods — the four-limbed line leading to amphibians, reptiles, and us.
National Geographic, Walking Towards Land
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The Age of Mammals
An asteroid struck 66 million years ago and killed the dinosaurs, birds aside, emptying nearly every role in the food chain. Mammals had been small and mostly active at night; with the competition gone they spread out, and one branch became primates — tree-living, sharp-eyed, with hands that grip.
Popular Science, The ancestor of all placental mammals survived the dino-killing asteroid
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Walking Upright
Around 6 million years ago in Africa, some primates began walking on two legs. Why is still argued: the earliest upright walkers lived among trees, not on open grassland as once thought. Walking freed their hands to carry food and young — the start of the hominin line, leading to us.
Smithsonian’s Human Origins Program, Walking Upright
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The First Toolmakers
Stone tools from Lomekwi in Kenya are 3.3 million years old, older than any known member of our genus. From 2.6 million years ago, Oldowan flakes, later linked to Homo habilis, became common. They did what teeth and nails could not: open a carcass, strip meat, crack bone for marrow.
Smithsonian’s Human Origins Program, Homo habilis
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Homo Erectus Keeps a Fire
Roughly a million years ago Homo erectus was keeping fire — the earliest firm evidence of a hominin controlling it, though it may have started much earlier. Fire meant warmth, light and safety at night, and it meant cooking: heat breaks food down before it ever reaches the mouth.
Harvard Gazette, Invention of cooking drove evolution of the human species, new book argues
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Cooking and the Growing Brain
Cooking saves the body a great deal of work — less chewing, less digesting, more calories out of the same meal. The brain is the most expensive organ to run, and that spare energy is thought to be part of what paid for hominin brains getting bigger.
Scientific American, Cooking Up Bigger Brains
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Softer Food, Bigger Skulls
One idea points at the temporalis, the jaw muscle that wraps over the skull and presses on it as a child grows. A mutation in the MYH16 gene, about 2.4 million years ago, shrank it — and a looser grip may have left the skull free to grow larger.
National Geographic, Chew On This
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The Teeth That No Longer Fit
Human jaws kept getting shorter, but the tooth count did not follow. The third molars — wisdom teeth — are left over from ancestors with room for them; in a modern jaw they often arrive sideways or stay trapped under the gum, which is why having them pulled is so ordinary.
Pitt Med Magazine (University of Pittsburgh), Tween science: Why do we have wisdom teeth?
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The Emergence of Homo Sapiens
Around 300,000 years ago in Africa, Homo sapiens appeared: a large brain, and hands and tools much like ours. What sets the species apart is language — it let what one person learned outlive them, so each generation could start where the last left off.
Smithsonian’s Human Origins Program, Our species arose at least 300,000 years ago
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Out of Africa
From around 70,000 years ago, groups of Homo sapiens walked out of Africa in waves — into Asia, then Europe, then everywhere people now live. It is called the Out of Africa account, and it means every person alive outside Africa descends from those few travelling groups.
Smithsonian Magazine, The Great Human Migration
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Meeting Our Ancient Cousins
Sapiens were not alone out there. In Europe and Asia they met Neanderthals, and further east Denisovans, and had children with both — which is why most people outside Africa still carry a little of their DNA, and why those cousins are gone as separate peoples but not gone completely.
Smithsonian’s Human Origins Program, Ancient DNA and Neanderthals
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The Rise of Civilization
Around 10,000 BCE the last Ice Age ended, and in the warmer climate some groups stopped following their food and began growing it — wheat, barley, herded animals. A field has to be stayed with, so people stayed, and settlements that could store a surplus became the first cities.
Britannica, Neolithic Revolution
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The Dawn of History
Around 3200 BCE the Sumerians of Mesopotamia pressed wedge-shaped marks into wet clay: cuneiform, one of the two oldest writing systems we know of, with Egypt’s. It started as accounting — who owed what — and ended up holding laws, letters and stories. Recorded history starts here.
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Gods and the Rise of Religion
The early cities worshipped many gods, each tied to something a farming life depended on — the sun, the river, the harvest. Later some turned to a single god: Akhenaten tried it in Egypt and it died with him; in Judaism it held, and Christianity and Islam grew from there.
World History Encyclopedia, Monotheism in the Ancient World
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The First Empires
Around 2334 BCE Sargon of Akkad took the Mesopotamian city-states one at a time and ruled them as one state — the Akkadian Empire, usually counted as the first. The new part was not conquering but holding: one army, one law, one tax, over people who had never been one people.
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Law Written in Stone
Around 1754 BCE the Babylonian king Hammurabi had 282 laws cut into a stone pillar and set it up in public — theft, wages, marriage, medicine, all of it. Putting the penalties where anyone could read them is the point: the rule stops being whatever a judge feels that day.
World History Encyclopedia, Code of Hammurabi: The Most Influential Law Code of the Ancient World
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The Invention of Currency
Around 600 BCE the kingdom of Lydia, in what is now Turkey, stamped the first coins: lumps of electrum, a natural mix of gold and silver, each made to a set weight. The stamp was the invention — take the value on trust, instead of weighing and testing every payment.
World History Encyclopedia, The Invention of the First Coinage in Ancient Lydia
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The Birth of Philosophy
From about the 6th century BCE, thinkers in Greece — Thales, then Socrates, Plato, Aristotle — asked what the world is made of, what a good life is, and how anyone knows anything, without answering “the gods did it”. Demanding a reason rather than a story is where science starts.
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Empires of Antiquity
Between the 6th century BCE and the 5th century CE, a run of empires — Persian, then Alexander’s, then Rome — put Europe, Asia and North Africa under shared roads, coinage and law. Goods and ideas moved further than a person ever had, and so did religions, languages and disease.
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The Fall of Rome
In 476 CE the Germanic leader Odoacer removed the last western Roman emperor, Romulus Augustulus. The date marks the fall more than it caused it — the west had been coming apart for a century — and after it western Europe was a patchwork of small kingdoms instead of one empire.
Britannica, Roman Empire: Height and decline of imperial Rome
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The Printing Press
Around 1440 in Germany, Johannes Gutenberg printed using movable metal type, so a book could be run off in numbers instead of copied out by hand. Books got cheap, reading spread, and an idea could now travel faster than the people who wanted to stop it.
Britannica, Johannes Gutenberg
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The Scientific Revolution
In the 16th and 17th centuries Copernicus, Galileo and Newton showed that the Earth goes around the Sun, and that the same few equations govern a falling apple and an orbiting moon. The method was the real result: make a claim, then test it, and let the test decide.
Britannica, Scientific Revolution
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The Industrial Revolution
From about 1760 in Britain, steam engines gave machines power that needed no muscle, water or wind. Work moved out of homes and fields into factories and people moved with it into cities — within two generations most of the country lived a life its grandparents would not recognize.
Britannica, Industrial Revolution
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Electricity and the Modern World
In the late 19th century Edison, Tesla and Westinghouse worked out how to generate electricity and send it down wires — first to lamps and motors, then to whole cities. Electricity is not one invention but the thing almost every later invention runs on, computers included.
HISTORY, How Edison, Tesla and Westinghouse Battled to Electrify America
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The Computer Age Begins
In the 1940s machines like ENIAC became the first general-purpose electronic computers, built in wartime to work out artillery tables. What set them apart was that changing the program changed the job, and over the following decades they shrank from filling a room to sitting on a desk.
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The Internet Connects the World
In 1969 the U.S. military-funded ARPANET sent its first message between two computers; it crashed on the third letter of “LOGIN”. That network grew into the internet, and in the 1990s the World Wide Web put a readable page on top of it, which is what reached ordinary people.
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The Rise of Artificial Intelligence
The term was coined in 1956, and for fifty years the results stayed thin. Then in the 2010s enough data and computing made neural networks work — machines shown examples until they find the pattern, rather than told the rules. Atoms from the Big Bang, arranged into something that learns.
IBM, The History of Artificial Intelligence
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