Kurzgesagt - In a Nutshell

Fat is not just stored energy, it’s a complex organ that controls crucial hormones and communicates with your brain, immune system, and metabolism. It's one of the most powerful organs, but it can be one of the most dangerous ones, as well. When there’s too much of it, fat can trigger inflammation, disrupt hormonal balance, increase your risk for nearly every major disease, and significantly shorten your life. What is fat really, and how does it function? When does it become dangerous and can the damage caused by excessive amounts of fat be reversed?

Stress is a biological superpower that helped your ancestors outrun predators, fight off enemies, and survive extreme situations. In the past, it helped us survive, but today, it’s quietly damaging millions of lives. What exactly is stress, how did it evolve, and is it even possible to use it in a healthy way

Weed is often seen as harmless, and in some cases, even helpful. But for many people, it can slowly become a serious problem, especially as they approach their twenties or thirties. Today, we take a closer look at how long-term daily use can affect your relationships, motivation, mental health, and life in general. Can it really be used safely? How easy is it for weed to turn into an addiction?

AI-generated content is flooding the internet, from videos and music to news and books. On top of that, generative AI is making false information look more convincing than ever. We're entering a new era of information overload, and figuring out what's real and what's not is becoming more and more of a challenge. While AI slop is slowly changing the internet as we know it, one thing is certain: kurzgesagt videos will always remain human-made.

Can we survive the heat death of the universe? One day, the last star will die, galaxies will dissolve, and black holes will evaporate. The universe becomes a cold, empty void where nothing happens. Forever. But there might be a loophole that lets life keep going.

Pregnancy is not gentle. Babies begin as invaders, growing a brand-new organ inside another human. For months, they sap energy, hack the immune system, and fight for survival. Out of this struggle emerges the most magical thing there is: new life. This is the brutal and beautiful story of how you and all of us came to be.

Some killer asteroids were found only days before flyby. If they had struck Earth, the power of thousands of nuclear bombs would have flattened cities and killed millions. What if we spotted a 100-meter asteroid just two weeks before collision? Can humanity be saved?

The ocean sunfish, or Mola, is one of the strangest animals alive. A massive, flat, derpy giant that eats jellyfish, drifts aimlessly, and carries parasites that even have smaller parasites of their own. Somehow, this awkward creature that feels like evolution’s inside joke doesn’t just survive in the world’s oceans… it thrives. But how? Like actually how?

From study sessions to dance floors, amphetamines can feel like a shortcut to superhuman focus and energy. Why do they work so well? What happens to your body once you take them? And what toll does it take on your health?

Alcohol kills more people each year than wars, terrorism, homicides, and car accidents combined. It destroys bodies, relationships, and lives. Yet we toast with it at weddings, sip it at parties, and unwind with it after work. Why do we cling to something so harmful?

No matter how likely your death is, there will always be a version of you that survives. At least according to one of the most bizarre interpretations of quantum mechanics, known as Quantum Immortality. Can science prove that you are unkillable? And does this mean our reality is split into an endless number of copies?

What happens when the immune system meant to protect you becomes your worst enemy? This is the betrayal of autoimmune diseases like Type 1 diabetes, multiple sclerosis, celiac disease, lupus, Crohn’s disease, and many others. What exactly goes on in your body and why does it happen in the first place?

A war has been raging for decades in the jungles of Panama, as we fight one of the most terrifying parasites on Earth. It is so relentless that our best defense is to drop 100 million radiation-blasted, flesh-eating flies from the sky – every week. It’s one of the most successful biological campaigns in history, but it’s a war we can never stop fighting… and one we can’t afford to lose.

Fentanyl is the deadliest illegal drug in US history by far. It’s often described as the ultimate high, but it’s actually an inferior, short-lived, and brutally addictive version of heroin. In this video, we explore what opioids do to your brain and body, what it feels like to take them, and why so many people are dying from Fentanyl overdoses without ever choosing to take it.

Can jellyfish power Tokyo? What would happen if it rained bananas for a day? We're taking two of your most absurd (and brilliant) questions and answer them with real science.

What happens when your time machine breaks and you end up stranded millions of years ago? You’ve landed in a world that’s nothing like today, facing deadly storms and unbearable heat, breathing toxic air. How can you survive long enough to make it back home?

South Korea is heading toward a demographic collapse unlike anything the world has seen before. With the lowest fertility rate ever recorded and a rapidly aging population, the country faces a future of economic decline, shrinking cities, cultural erosion, and a vanishing workforce. By 2060, nearly half of South Koreans could be over the age of 65, and entire regions may be abandoned as the population continues to shrink. How did South Korea reach this point? Why might it no longer be possible to reverse the trend? And what does this mean for other countries on a similar path?

Reality is not real. Your world is a prediction. Every sight, sound, and touch you experience is the result of calculations your brain makes before reality even reaches you. It fills in gaps, fabricates details, and even alters time itself so you feel like you’re in control. But if everything you know is an illusion… what does that say about you? What does it mean for your choices? Is there even free will?

Most of us love animals but also eat meat. Unfortunately, most animals we eat live in truly horrible conditions. We don’t torture them for better meat, just for cheaper meat. If we all paid just a bit more, we could avoid most animal suffering – often just for a few cents per meal. What would it truly cost us to avoid animal torture and still eat meat?

Humans assume aliens look human. But why would they? Let's explore what life might actually look like in strange, distant worlds.

Cannabis is finally being decriminalized in more and more places around the world. And for very good reasons! Compared to other legal drugs such as alcohol, cannabis is pretty mild and most users enjoy it without issue. But there’s a dark side for some. So let’s take an honest look at some of the latest research together.

At the height of the Cold War, a terrifying concept emerged: a bomb so powerful it wouldn’t need to be dropped. Known as Project Sundial, this doomsday device would have left a 400-km radius in flames and plunged the world into darkness. It was a bomb that would destroy everything – not a weapon, but an apocalypse. How close did we come to pressing the button?

“Your blood vessels stretch a staggering 100,000 kilometers, enough to wrap around Earth twice!" Sounds amazing, right? We spent over a year trying to confirm this claim, and let's just say – things aren't as they seem. Join us on our year-long journey that uncovered outdated science, speculation, and a lot of dead ends.

Being a human in the 21st century often feels frustrating. We are clearly at the high point of our species, while at the same time life is incredibly hard! We are divided, unable to solve our problems while creating new ones, destroying our world in the process. In many ways the vibe is that we live in dark times. But as Terry Pratchett said, we are the storytelling ape, we think in narratives and live in a network of stories that make up our world. So without minimizing the darkness, we want to add a story that we find helpful for dealing with the world.

We’ve found a new planet, home to octillions of the most extreme beings living in the most absurd and deadly hellscape. In absolute darkness, crushed by the weight of mountains, starved of oxygen, cooked alive, bathed in acid, salt or radiation. And yet, they live for thousands, perhaps millions of years! It turns out, this planet is not in space – it is inside the crust of Earth! This is the deep biosphere and we basically learned that it exists yesterday. Its volume is at least twice as large as all the Earth’s oceans, home to more microbes than the rest of the entire planet.Their total biomass is more than 20 times greater than all humans, livestock, and animal wildlife. Let’s descend into this mad, deadly world where none of the rules we thought are mandatory for life apply.

58 of you watching this video right now will not be alive next week. And it’s not because of some freak accident or rare disease. It’s because of everyday actions you probably think are harmless. Let’s save your life today by looking at what is most likely to kill you next week – so you can avoid it.

You’ve got trillions of viruses inside you – right now! But these aren’t the viruses you fear. Some of them are your body’s secret protectors, keeping deadly bacteria in check and even killing cancer cells. But what happens when they turn against you? Let's look at the wild world of the human virome.

Exercising doesn’t help you lose weight. In fact, it barely changes your daily calorie burn. Welcome to the workout paradox! Let’s dive into the science of how your body actually handles calories and sabotages your best efforts to burn them.

Time travel is possible. In fact, you’ve been doing it since the day you were born. But what if we told you there’s a way to hack the universe and manipulate time itself? We just have to do two simple things to make it happen: 1. Make a lot of physicists grumpy. 2. Shoot one twin through space against their will, while the other chills on Earth. Let's go!

Fever feels bad. So we take medication to suppress it – but is this a good idea? It turns out fever is one of the oldest defenses against disease. What exactly is a fever, and how does it make your immune defense stronger? Should you take a pill to combat it?

Humans rule Earth without competition. But we are about to create something that may change that: our last invention, the most powerful tool, weapon, or maybe even entity: Artificial Super intelligence. This sounds like science fiction, so let’s start at the beginning.

The white death has haunted humanity like no other disease following us for thousands, maybe millions of years. In the last 200 years it killed a billion people – way more than all wars and natural disasters combined. Even today it’s the infectious disease with the highest kill count. But what is this horrible disease?

You may think you have free will and can choose what you do, but this might be an illusion. Your body is made up of particles that blindly follow the laws of physics, with every outcome already predetermined. So, you might not have any free will at all. Is free will an illusion, or does it exist? Which philosophical camp is right?

Black holes might create infinite universes while destroying time and space. Everything in existence could be black holes, all the way down. We might live inside a black hole that is inside a black hole, that is inside a black hole. But let’s start at the beginning and build a black hole out of air.

We need to have an honest conversation about smoking: The problem with smoking is that it is way more than just a physical addiction. Smoking creates a temporary problem and offers an instant solution. Once your brain is used to nicotine, for up to 72 hours you are itchy,nervous and stressed – but one drag and instantly, you feel really good. It also helps you focus and take breaks during work, while suppressing your appetite. So why is it such a bad idea?

We often assume that advanced technology will make it easy for aliens to colonize space. But what if space exploration is always difficult, no matter how advanced you are? Let’s travel back in human history, to the colonization of Oceania over 5000 years ago, to find parallels between ancient explorers and extraterrestrial civilizations.

A ruthless murder was committed! Someone killed the dinosaurs and we have the murderer! Witnesses say that an Everest-sized asteroid hit Earth, devastated the planet and caused a mass extinction. A simple, fascinating and convincing explanation. Or… is it?

What is outside of the universe? We know that the universe had a beginning 14 billion years ago and that it has been expanding ever since. But something that is expanding should also have an edge, right? What would you see if you went there?

A nuclear bomb is the most devastating explosion ever created. One bomb can end tens of thousands of lives immediately and hundreds of thousands through the radioactive aftermath. However, the worst part comes afterward: a nuclear winter that might kill billions, potentially leading to the complete collapse of our civilization. In a nuclear winter, there are no winners – only starving losers. How exactly does it work and what would it look like?

Is your future already written? Do your past, present, and future all exist right now? Surprisingly, the answer could be yes. Let's take a look at what time is and how it works – in our first video of the year!

The universe today is happy and healthy, with exciting things going on – but at some point the night will turn dark. Everything that once was, will peacefully sleep forever. But what is the last thing that will ever happen? Let's travel to the end of the universe…

Could aliens destroy us from light years away? Another day at Kurzgesagt Labs, where we answer the most important questions with science. Today: how might civilizations wage war across light years? What kind of devastating weapons could they use and what would they look like?

Earth is 4.5 billion years old - which is approximately the same amount of time it took us to create this video. We’ve scaled the complete timeline of our Earth’s life into our first animated movie! Every second shows about a million years of the planet’s evolution. Hop on a musical train ride and experience how long a billion years really is. It’s the perfect background for your next party, a great way to take a break from studying, or a fascinating companion while you’re on the go … and our celebration of 10 years of kurzgesagt.

Life has existed on one planet for about 4 billion years, for all we know. But it might have started right after the Big Bang, when the universe was much stranger and more fantastic than today. A universe that might have allowed life to develop absolutely anywhere. The cosmos might be full of the seeds of life, sleeping in a dead desert, waiting for a few drops of rain to explosively bloom and grow. Tiny and not so tiny aliens might be everywhere.

Every two years one million Japanese disappear, China’s population will halve by the end of the century, the median age in Italy has reached 48. All around the world birth rates are crashing – Is humanity dying out? What is going on and how bad is it?

Absolutely everything you think about yourself and the universe could be an illusion. As far as you know, you are real and exist in a universe that was born 14 billion years ago and that gave rise to galaxies, stars, the Earth, and finally you. Except, maybe not.

Mr. President! Nuclear missiles will strike our country in 14 minutes. I know it’s your first day in office so I’m going to walk you through it, but you’re the only one who can authorize our nuclear retaliation in response and you’ve only got a few minutes to make a decision!

Black holes can destroy everything – but can they be destroyed? What happens if we push physics to the absolute limits, maybe even break it and the universe in the process? Let’s create a tiny black hole, about the mass of our moon, in the Kurzgesagt Labs and try to rip it apart.

Few of the monsters that evolution created have been so successful at hurting us as the variola virus, responsible for smallpox. The carnage it caused was so terrible and merciless that it compelled humankind, for the first time, to act truly globally. It was one of the greatest wins of our species over the ancient powers of nature, all made possible by… cows.

A breathtaking scientific revolution is taking place – biotechnology has been progressing at stunning speed, giving us the tools to eventually gain control over biology. On the one hand solving the deadliest diseases while also creating viruses more dangerous than nuclear bombs, able to devastate humanity. What is going on?

An undead city under siege, soldiers and police ruthlessly shooting down waves of zombies that flood from infected streets, trying to escape and infect more cities. This is what happens when your body fights cancer, more exciting than any movie. How does this battle for survival unfold?

The universe isn't just a vast empty ocean sprinkled with galaxies – most of the atoms are actually drifting in between, in the intergalactic medium. If we look closely, we can see who is in charge here: Quasars, the single most powerful objects in existence. As small as a grain of sand compared to the amazon river, they reside in the centers of some galaxies, shining with the power of a trillion stars, blasting out huge jets of matter, completely reshaping the cosmos around them. They are so powerful that they can kill a galaxy. What are they, and how do they mold the structure of the universe at their whim?

Somewhere in your body, your immune system just quietly killed one of your own cells, stopping it from becoming cancer, and saving your life. It does that all the time. The vast majority of cancer cells you develop will be killed without you ever noticing. Which is an incredibly hard job because of what cancer cells are: parts of yourself that start to behave as individuals even if it hurts you. What is cancer and how does your body kill it all the time?

The universe is magnificent and vast. Hundreds of billions of galaxies, trillions of stars, and even more planets. If even the tiniest fraction are habitable, then the Universe should be teeming with life. And yet we see nothing, only vast emptiness. Where is everyone else? The answer to this riddle could be as exciting as it is creepy: we are early, born before almost all other life – but very soon this may change. Not only might aliens appear, they could quickly surround us. An irreversible competition for the universe might be about to begin.

In 2023, Kurzgesagt has existed for 10 years (which is insanely long in internet years). We are among the largest sciencey channels on Youtube and still a bit of a black box to people. So let us talk about ourselves in three parts: Our backstory, how we finance our work, and the values of Kurzgesagt!

There is this idea floating around that what doesn’t kill you, makes you stronger. That surviving a disease leaves you better off. And it seems to make sense because we have all experienced this. When you go through hardship, often you come out more resilient, more ready to face a difficult situation in the future. But it turns out that sometimes, what doesn’t kill you makes you weaker. So, what happens when you get sick?

You are cells. Your muscles, organs, skin and hair. They are in your blood and in your bones. Cells are biological robots. They don’t want anything, they don’t feel anything. They are never sad or happy. They just are, right here, right now. They are as conscious as a stone or a chair or a neutron star. Cells just follow their programming that has been evolving and changing for billions of years, molded by natural selection. They are impossible machines and yet, here they are, driven entirely by the fundamental forces of the universe. The smallest unit of life, right at the border where physics becomes biology. Sometimes, to get a truer understanding of how amazing something is, you need to hold your breath and dive in really deep. So, what are cells and how do they work?

Here in the Kurzgesagt labs we test very important ideas to see what happens when you blow things up or play with black holes. Many of you suggested that we look into an idea that sounds reasonable: Shooting nuclear waste into space. It is one of those concepts that seems like an easy fix for one of the main problems with nuclear energy. But it turns out this idea is not just bad but horribly bad and it gets worse the longer you think about it.

The Earth is a gigantic ball of semi-molten rock, with a heart of iron as hot as the surface of the Sun. Titanic amounts of heat left over from its birth and the radioactive decay of trillions of tons of radioactive elements find no escape but up. Currents of rock spanning thousands of kilometers carry this energy to the surface. Earth’s crust is the only thing in their way. It feels solid to us, but it is only a fragile barrier, an apple skin around a flaming behemoth. True apocalypses can break through and unleash eruptions tens of times more powerful than all of our nuclear weapons combined, subjecting the climate to centuries worth of change in a single year, while drowning continents in toxic ash and gases: supervolcanoes. How big can they get? And will they put an end to humanity?

The universe is pretty big and very strange. Hundreds of billions of galaxies with sextillions of stars and planets and in the middle of it all there is earth, with you and us. But as enormous as the universe seems looking up, it seems to get even larger when you start looking down. You are towering over worlds within worlds, within worlds – each in plain sight and yet hidden from your experience. Let’s go on a journey – we’ll start in a park, about a thousand meters long, enough for a 15 minute walk. Every time we click a magic button, we’ll become a thousand times smaller. Ready? Let’s go.

Friends make life good. They provide the scaffolding that makes it not just bearable but fun. They give us a sense of meaning and purpose and are a source of security, self esteem and happiness. Almost nothing predicts how happy you will be as how connected you feel and a lack of social connection is associated with a number of diseases and a shorter life. But maybe you have scrolled through your phone, unsure who to call to go to a movie with, to celebrate with or ask for comfort. You may realize that you don’t have enough friends and feel lonely. And it is not just you. Disconnectedness and loneliness are widespread. Many people want more close friends but don’t know how to get them.

At its height, the Roman Empire was home to about 30 % of the world’s population, and in many ways the pinnacle of human advancement. Rome became the first city in history to reach one million inhabitants and was a center of technological, legal, and economic progress. An empire impossible to topple, stable and rich and powerful. Until it wasn’t anymore. First slowly then suddenly, the most powerful civilization on earth collapsed. If this is how it has been over the ages, what about us today? Will we lose our industrial technology, and with that our greatest achievements, from one dollar pizza to smartphones or laser eye surgery? Will all this go away too?

In the 1970s thousands of Chickenheads rained from the sky in Europe, making foxes and other wildlife confused and very happy. Why? They were filled with a vaccine to fight the deadliest virus known to humanity – since the 1930s a rabies epidemic had been sweeping across wildlife populations in Europe and humans wanted to finally get rid of the virus once and for all. Rabies is named after Lyssa, the ancient Greek spirit of mad rage, and has been haunting us for at least 4000 years. It can turn animals into angry beasts and humans into zombies that fear water. But what makes Lyssa fascinating is not just how bizarre and deadly its infection is, but also how incredibly good it is at avoiding our defenses.

The future of humanity seems insecure. Rapid climate change, political division, our greed and failings make it hard to look at our species with a lot of optimism and so many people think our end is in sight. But humans always thought they lived in the end times. Every generation assumes they’re important enough to witness the apocalypse and then life just goes on. This is a problem because it leads to short term thinking and prevents us from creating the best world for ourselves and our descendants. What makes this worse is that we actually may live at an extremely critical moment in human history. To understand why, let us look at the temporal window of humanity and ask: When will the last human be born and how many people will there ever be?

If you are like most people, there is a gap between the person you are and the person you wish to be. There are little things you think you should do and big things you ought to achieve.

Look around you. Where are you? Where is this place you are occupying? Somewhere in a room, maybe in a city on a continent on a planet orbiting a star in a galaxy among billions. But… where is all of that? While this may feel like a daft question, it turns out that the concept of an absolute position is something humans made up. In a nutshell, the universe is a big bag of space that has things in it. If someone removed all these things, the stars and planets and black holes and dust, there would just be empty space left. In empty space, the concept of having a position loses all meaning. Empty space is uniform, the same everywhere.

A war has been going on for billions of years that breeds well armed monsters who struggle with other monsters for survival. Having no particular interest in us, most of them are relatively harmless, as our immune systems deal with their weapons handily. But there are exceptions. Naegleria fowleri is an amoeba that not only has developed a deadly taste for human brains but is also a match for our defenses and a guest in dramatic headlines. What happens when this monster enters your body?

Our home is burning. Rapid climate change is destabilizing our world. It seems our emissions will not fall quickly enough to avoid runaway warming and we may soon hit tipping points that will lead to the collapse of ecosystems and our civilization. While scientists, activists and much of the younger generation urge action, it appears most politicians are not committed to do anything meaningful while the fossil fuel industry still works actively against change. It seems humanity can’t overcome its greed and obsession with short term profit and personal gain to save itself. And so for many the future looks grim and hopeless. Young people feel particularly anxious and depressed. Instead of looking ahead to a lifetime of opportunity they wonder if they will even have a future or if they should bring kids into this world. It’s an age of doom and hopelessness and giving up seems the only sensible thing to do. But that’s not true. You are not doomed. Humanity is not doomed.

When we think about alien civilizations we tend to look into the vastness of space, to far away planets. But there is another incredibly vast dimension that we might be giving too little thought to: time. Could it be that over the last hundreds of millions of years, other civilizations existed on earth? Indigenous technological species that rose and died out? And that they or their artifacts are buried beneath our feet? What does science have to say about this and what are the implications for us?

Today we are answering an age-old very scientific and important question: What if the moon crashes into earth? It’s more interesting and weird than you probably think. Let's start with the basics: Why isn't the Moon on its way to crash into us already?

The past is a vast and mysterious land that begins at the big bang and ends in the present, expanding with each passing moment. It is the home of everything that came before, the key to understanding our present. Here we find the most amazing creatures to ever roam our planet, hundreds of millions of species so diverse that our imagination cannot do them justice. Unfortunately the past carefully guards its secrets.

Never before in human history have we been richer, more advanced or powerful. And yet we feel overwhelmed in the face of rapid climate change. It seems simple on the surface. Greenhouse gases trap energy from the Sun and transfer it to our atmosphere. This leads to warmer winters, harsher summers. Dry places become drier and wet places wetter. Countless ecosystems will die while the rising oceans swallow coasts and the cities we build on them. So why don’t we just like… prevent all of that? Well, it’s complicated.

Hidden in the microverse all around you, there is a merciless war being fought by the true rulers of this planet, microorganisms. Amoebae, protists, bacteria, archaea and fungi compete for resources and space. And then there are the strange horrors that are viruses, hunting everyone else. Not even being alive, they are the tiniest, most abundant and deadliest beings on earth, killing trillions every day. Not interested in resources, only in living things to take over. Or so we thought. It turns out that there are giant viruses that blur the line between life and death – and other viruses hunting them.

The human immune system is the most complex biological system we know, after the human brain, and yet, most of us never learn how it works. Or what it is. Your immune System consists of hundreds of tiny and two large organs, it has its own transport network spread throughout your body. Every day it makes hundreds of billions of fresh cells. It is not some sort of abstract entity. Your immune system is YOU. Your biology protecting you from the billions of microorganisms that want to consume you and from your own perverted cells that turn into cancer. It's so manifold that it is impossible to cover in one video, so we’ll make a series looking at different aspects of it. Today, what happens when your body is invaded and your first lines of defenses are engaged in a fight for life and death?

The largest things in the universe are black holes. In contrast to things like planets or stars they have no physical size limit, and can literally grow endlessly. Although in reality specific things need to happen to create different kinds of black holes, from really tiny ones to the largest single things in the universe. So how do black holes grow and how large is the largest of them all?

Leaving earth to find new homes in space is an old dream of humanity and will sooner or later be necessary for our survival. The planet that gets the most attention is Mars, a small, toxic and energy poor planet that just about seems good enough for a colony of depressed humans huddled in underground cities. But what if we think bigger? What if we take Venus, one of the most hostile and deadly places in the solar system and turn it into a colony? Not by building lofty cloud cities, but by creating a proper second earth? It might be easier than you think.

66 million years ago, maybe on a Tuesday afternoon, life was the same as it had been the day before or a thousand years before or pretty much a million years before. Things were good for our feathered dinosaur buddies. Until a tiny, tiny detail in the sky changed.

Wrapping your mind around your life is pretty hard, because you are up to your neck in it. It's like trying to understand the ocean while learning how to swim. On most days you are busy just keeping your head above water. So it is not easy to figure out what to do with your life and how to spend your time. There are a million distractions. Your family, friends and romantic partners, boring work, and exciting projects. Video games to play and books to read. And then there is your couch that somebody needs to lie on. It’s easy to get lost. So let us take a step back and take a look at your life from the outside.

Is there a border we will never cross? Are there places we will never reach, no matter how hard we try? It turns out, there are. Even with sci-fi technology, we are trapped in a limited pocket of the Universe and the finite stuff within it. How much universe is there for us and how far can we go?

What would happen if we were to detonate a very very powerful nuclear weapon on the moon? Would the explosion knock its orbit towards earth, causing tidal waves and misery? Could the moon be destroyed, showering the earth in a rain of meteoric death?

Do we need nuclear energy to stop climate change? More and more voices from science, environmental activists and the press have been saying so in recent years – but this comes as a shock to those who are fighting against nuclear energy and the problems that come with it. So who is right? Well - it is complicated.

Let us explore the scientific mystery of what would happen to you, if Earth suddenly turned into gold! The “Midaspocalypse”, based on the ancient tale of King Midas who was cursed so everything he touched turned into gold.

Nuclear energy creates an uneasy feeling of danger for many people: ancient and dangerous minerals are concentrated to awaken seemingly unnatural powers, creating toxic elements that, if they escape, can and have killed people in horrible ways. How many people has nuclear energy killed and how?

By the end of the 21st century, humanity is becoming desperate. Decades of heatwaves and droughts have led to unusually poor harvests, while the warming oceans yield fewer fish each year. In the tropical zones, millions suffer from famine and resource wars have made millions more flee to the north. As things quickly get worse, in an act of desperation, the world's governments decide to enact an emergency plan... It is far from certain that a grim scenario like this will play out. But the failure of world leaders to effectively address climate change, makes it far from impossible. So in the near future it might become necessary to try something radical to slow down rapid climate change: Geoengineering. Interventions so massive in scale that they might undo centuries of human behavior. Or make everything much worse. What is geoengineering, is it really an option and what if it goes wrong?

For the fifth time, we present to you the Human Era Calendar for the year 12,021 – this time it is all about the journey of humanity, beginning tens of thousands of years ago, leading into the revolution of agriculture, to ancient high civilizations and the beginning of modern times, culminating in a vision for our future. You can get the limited Edition now until we sell out and then never again. As always the calendar features 12 illustrated pages printed on high quality paper in Europe and the US. And this year the cover is especially shiny. The calendar will look great on your wall and let you dream about a glorious future. We truly have come far as a species!

Climate Change is just too much. There is never any good news. Only graphs that get more and more red and angry. Almost every year breaks some horrible record, from the harshest heat waves to the most rapid Glacier melt. It’s endless and relentless. We have known for decades that rapid Climate Change is being caused by the release of Greenhouse Gases. But instead of reducing them, in 2019 the world was emitting 50% more CO2 than in the year 2000. And emissions are still rising. Why is that? Why is it so hard to just stop emitting these gases?

What is the largest star in the Universe? And why is it that large? And what ARE stars anyway?

Deep in tropical jungles lie floating kingdoms ruled by beautiful and deadly masters: They are sort of the high elves of the ant kingdoms: Talented architects that create castles and city states. But they are also fierce and expansionist warriors and their kingdoms are ensnared in a never ending war for survival. Oecophylla weaver ants.

Getting rare materials from the ground into your phone is ugly. The mining industry is responsible for air and water pollution and the destruction of entire landscapes. But what if we could replace the mining industry on Earth with a clean process that can’t harm anyone? Well, we can. All we need to do is look up.

The observable universe is a big place that has been around for more than 13 billion years. Up to two trillion galaxies made up of something like 20,000 billion billion stars surround our home galaxy. In the milky way alone scientists assume there are some 40 billion earth like planets in the habitable zone of their stars. When we look at these numbers it is hard to imagine that there is nobody else out there.

Humans are proud of a lot of things, from particle accelerators, to poetry to pokemon. All of them made possible because of something humans value extremely highly: intelligence.

Since the Industrial Revolution, humans have released over 1.5 trillion tonnes of carbon dioxide or CO2 into the earth's atmosphere. In the year 2019 we were still pumping out around 37 billion more. That’s 50% more than the year 2000 and almost three times as much as 50 years ago. And it’s not just CO2. We’re also pumping out growing volumes of other greenhouse gases such as methane and nitrous oxide. Combining all of our greenhouse gases, we’re emitting 51 billion tonnes of carbon dioxide equivalents each year. And emissions keep rising – but they need to get down to 0!

The sun. Smooth and round and peaceful. Except when it suddenly vomits radiation and plasma in random directions. These solar flares and coronal mass ejections, or CMEs can hit earth and have serious consequences for humanity. How exactly do they work, how bad could they be and can we prepare for them?

In September of 1940, an 18-year-old mechanic named Marcel Ravidat was walking his dog, Robot, in the countryside of Southwestern France when the dog disappeared down a hole. Robot eventually returned but the next day, Ravidat went to the spot with three friends to explore the hole. And after quite a bit of digging, they discovered a cave with walls covered with paintings, including over 900 paintings of animals, horses, stags, bison and also species that are now extinct, including a wooly rhinoceros. The paintings were astonishingly detailed and vivid with red, yellow and black paint made from pulverized mineral pigments that were usually blown through a narrow tube, possibly a hollowed bone, onto the walls of the cave. It would eventually be established that these artworks were at least 17,000 years old.

At this very second, you are on a narrow ledge between life and death. You probably don’t feel it, but there is an incredible amount of activity going on inside you. And this activity can never stop. Picture yourself as a slinky falling down an escalator moving upwards – the falling part represents the self replicating processes of your cells, the escalator represents the laws of physics, driving you forwards. To be alive is to be in motion but never arriving anywhere. If you reach the top of the escalator there is no more falling possible and you are dead forever. Somewhat unsettlingly, the universe wants you to reach the top. How do you avoid that and why are you alive?

A huge thanks to the experts who helped us on short notice with the video. Especially “Our World in Data”, the online publication for research and data on the world’s largest problems – and how to make progress solving them. Check out their site. It also includes a constantly updated page on the Corona Pandemic. In December 2019 the Chinese authorities notified the world that a virus was spreading through their communities. In the following months it spread to other countries, with cases doubling within days. This virus is the “Severe acute respiratory syndrome-related coronavirus 2”, that causes the disease called COVID19, and that everyone simply calls Coronavirus. What actually happens when it infects a human and what should we all do?

Cancer is a creepy and mysterious thing. While we tried to understand it, to get better at killing it, we discovered a biological paradox that remains unsolved to this day: large animals seem to be immune to cancer. Which doesn’t make any sense – the bigger a being, the more cancer it should have. To understand why, we first need to take a look at the nature of cancer itself.

For years, you have been asking us how we make our videos. So let’s finally talk about it! From research, writing the script, illustrating, to animating, narrating and composing music, a Kurzgesagt video takes roughly 1.200 hours to produce!

Over the last decade milk has become a bit controversial. Some people say it’s a necessary and nutritious food, vital for healthy bones, but others say it can cause cancer and lead to an early death. So who is right? And why are we drinking it anyway?

Neutron stars are one of the most extreme and violent things in the universe. Giant atomic nuclei, only a few kilometers in diameter but as massive as stars. And they owe their existence to the death of something majestic.

As you may have noticed, we like to blow stuff up on this channel. So when the International Red Cross approached us to collaborate on a video about nuclear weapons, we were more than excited. Until we did the research. It turned out we were a bit oblivious off the real impact of nuclear weapons in the real world, on a real city. And especially, how helpless even the most developed nations on earth would be if an attack occurred today. So hopefully this video demonstrates how extremely non fun a real world nuclear attack would be, without being to gruesome. This collaboration was a blast (no pun intended) and we want to say a huge thank you to the International Red Cross!

In nearly every corner of the Earth, ants wage war against each other. Their weapons are what nature gave them. Some have strong armour, deadly stingers or sharp mandibles. And then there is this tiny, and not very impressive ant. But it rules the biggest empire any ant has ever built. A colony spanning continents and fighting wars that leave millions of casualties. Let’s take a look at this unlikely warrioress: Linepithema humile, the Argentine ant.

Sometimes the world feels boring. All the remote islands are visited, the arctic conquered, the dense jungles discovered. Except, there is still a place to explore: A wet deadly desert where mysterious creatures live in total darkness: The deep sea. Let us dive down.

The Egg, a story by Andy Weir, animated by Kurzgesagt. This video was more than 2 years in the making and is a little bit different than the others on this channel. We hope you like it.

Every day billions of soldiers fight a merciless war on thousands of fronts, that has been going on for over one hundred million years: the world war of the ants.

One of the key players of our immune system is the complement system. An army of millions and trillions of tiny bombs, which work together in a complex and elegant dance to stop intruders in your body.

Electricity is all around us, all the time. It makes our lives easier, safer, more fun and most of us never think about it. But is there such a thing as too much electricity? Electronic devices emit an electromagnetic field, which is suspected to cause cancer. We read countless sources on this topic to summarize the results of the latest research for you.

Over the last few years eating meat has increasingly been associated with health risks, like heart disease, cancer and an early death. How unhealthy is meat really?

Being a citizen of the European Union means that many aspects of our lives are regulated by a weird entity. It feels like a huge bureaucracy is making decisions over our heads. How democratic is the EU really and does your vote actually affect anything?

Vaccines are one of our best tools to prevent dangerous diseases, but they come with side effects. So would it be safer not to vaccinate?

Inside neutron stars we can find the weirdest and most dangerous substance in the universe: Strange matter. What is strange matter, how dangerous is it and what can it tell us about the origin of the universe?

What happens if make a huge pile from all 15,000 nuclear bombs and pull the trigger? And what happens if we make an even bigger pile?

Consciousness is perhaps the biggest riddle in nature. In the first part of this three part video series, we explore the origins of consciousness and take a closer look on how unaware things became aware.

Everybody feels lonely sometimes. But only few of us are aware how important this feeling was for our ancestors - and that our modern world can turn it into something that really hurts us. Why do we feel this way and what can we do about it?

Humans love to explore. Strangely enough even horrible places – like Mars. Let’s see how building a Mars base could work and how insanely nerve-wracking exactly it would be.

Organic food is a huge trend: it promises a healthier and better life. But can Organic food really live up to the expectations or is it just baloney?

It’s hard to define what makes something beautiful, but we seem to know beauty when we see it. Why is that and how does beauty affect our subconscious?

Meat is a complicated issue. But also a delicious one. Let's talk about it.

Did you know that we could start building a Lunar Base today?

Are wormholes real or are they just magic disguised as physics and maths? And if they are real how do they work and where can we find them?

Did you ever wonder what happened if you detonated a nuclear bomb in the Marianas Trench? No? We neither! Let us find out together!

Modern life would be impossible without plastic – but we have long since lost control over our invention. Why has plastic turned into a problem and what do we know about its dangers?

We take a fair look at some of the best counter arguments for legalization and see how they hold up in review.

A war has been raging for billions of years, killing trillions every single day, while we don’t even notice. This war involves the single deadliest being on our planet: the bacteriophage.

Why should you care about the well-being of people half a globe away?

Is String Theory the final solution for all of physic’s questions or an over-hyped dead end?

What are the principles behind Homeopathy and does it work?

Finding alien life on a distant planet would be amazing news - or would it? If we are not the only intelligent life in the universe, this probably means our days are numbered and doom is certain.

If you could decide today... how long do you want to live?

What happens when microbes talk to your brain?

What happens if we bring the sun to earth? No, seriously.

Black holes are scary things. But they also might reveal the true nature of the universe to us.

Size is the most under appreciated regulator of living things. Let us demonstrate that by throwing animals from buildings.

Automation in the Information Age is different.

Everything will end. Even the universe. But in a future so far away that it defies description, there will still be light and therefore a chance for life. It will be around white dwarfs, the corpses of stars. But even they will fade one day...

Should we double down or give up and go our separate ways?

Are GMOs bad for your health? Or is this fear unfounded?

What shall we do once machines become conscious? Do we need to grant them rights?

We are trapped on Earth. Controlled by an ancient debt to the universe...

What if there is a way to destroy the universe so fundamentally that life as we know it will be impossible forever?

We have the choice to attack one of our oldest enemies with genetic engineering. But should we do it?

Designer babies, the end of diseases, genetically modified humans that never age. Outrageous things that used to be science fiction are suddenly becoming reality. The only thing we know for sure is that things will change irreversibly.

There are cosmic snipers firing at random into the unvierse. What are they and what happens if they hit us?

Humans. We have been around for a while now. When we think about our past we think about ancient civilizations, the pyramids, stuff like that. But this is only a tiny, tiny part of our history.

So. Are you your body? And if so, how exactly does this work? Lets explore lots of confusing questions.

Is there a border we will never cross? Are there places we will never be able to reach, no matter what? It turns out there are. Far, far more than you might have thought…

So. Space elevators. Are they are thing that we should talk about?

What is the Antibiotic Apocalypse? What is it all about? And how dangerous is it?

The war against drugs has been a terrible disaster for everybody involved. Why? And can we do something differently?

The last star in the universe will be a red dwarf. Red dwarfs in general might be great places to look for aliens – or planets for humans to find a new home after our solar system has died.

We are so used to some things that we stopped wondering about them. Like light. What is light? Some kind of wavy thing, right? Kind of.

What causes addiction? Easy, right? Drugs cause addiction. But maybe it is not that simple.

What is dark energy? What is dark matter? Well, if we knew exactly we would have a nobel prize – we know that they exist though. So what do we know about those strange things?

What would happen to you if a black hole the size of a coin suddenly appeared in your pocket? Lets find out!

In 2015 the bees are still dying in masses. Which at first seems not very important until you realize that one third of all food humans consume would disappear with them. Millions could starve. The foes bees face are truly horrifying – some are a direct consequence of human greed. We need to help our small buzzing friends or we will face extremely unpleasant consequences.

Where are all the aliens? The universe is too big and too old, why have we not met aliens yet? Do they live in computers? Were they wiped out by an ancient super intelligence? Or are we just to primitive to understand their motives? Whatever the answer is, it is incredibly important for our own future.

The universe is unbelievably big – trillions of stars and even more planets. So… there just has to be life out there, right? But where is it? Why don’t we see any aliens? Where are they? And more importantly, what does this tell us about our own fate in this gigantic and scary universe?

Nuclear energy might have a lot of unused potential. Not only is it one of the best mid term solutions for global warming bit despite what gut feeling tells us, it has saved millions of lives. By investing more into better technologies we might be able to make nuclear energy finally save and clean forever.

Nuclear energy might be a failed experiment. In over sixty years the technology has not only failed to keep its promise of cheap, clean and safe energy, it also caused major catastrophes and enabled more nuclear weapons while the nuclear waste problem is still not solved.

Nuclear Energy is a controversial subject. The pro- and anti-nuclear lobbies fight furiously, and it's difficult to decide who is right. So we're trying to clear up the issue - in this video we discuss how we got to where we are today, as the basis for discussion.

Banks are a riddle wrapped up in an enigma. We all kind of know that they do stuff with money we don’t understand, while the last crisis left a feeling of deep mistrust and confusion. We try to shed a bit of light onto the banking system. Why were banks invented, why did they cause the last crisis and are there alternatives?

Everybody is talking about Measles – but what does the virus actually do in the body? Is it really so harmful that you need a vaccination? We go deep into the body of an infected person and see what Measles does and how the immune system reacts to it!

Atoms are very weird. Wrapping your head around exactly how weird, is close to impossible – how can you describe something that is SO removed from humans experience? But then again, they kind of make up everything, so let us try anyways.

Neutron stars are some of the strangest things in the Universe. Not quite massive enough to become black holes they are basically atoms as big as mountains, with properties so extreme it's mind-blowing. And if you get too close to a neutron star, you are in big trouble…

Planet Earth is this solid thing you are standing on right now. In your everyday life you don't really waste a thought about how amazing this is. A giant, ancient, hot rock. How did it come into existence and how big is it really? You will be surprised. The ground you are standing on is just a very, very small part of the big picture.

Every second of your life you are under attack. Bacteria, viruses, spores and more living stuff wants to enter your body and use its resources for itself. The immune system is a powerful army of cells that fights like a T-Rex on speed and sacrifices itself for your survival. Without it you would die in no time. This sounds simple but the reality is complex, beautiful and just awesome. An animation of the immune system.

The current crisis in Iraq explained in under 5 minutes.

Are you alone? To answer this question we have to take a look what "you" are first. What are you made of and where you stand in this universe. Are you your body? Your atoms? And how are your parts connected to the big picture?

If Neptune didn't catch Triton we might have another Dwarf Planet in our Solar system -- maybe even another Planet or double system. We show how this could have happened.

What do you know about the Moons of Mars? Nothing? They are super cool (and strange), promise.

The Moon might be much bigger than you think it is.

Nuclear war, cat gifs and reddit? Wait, what?

How did everything get started?

How will the Universe die?

An info-graphic trip through the wonders of the Solar system.