This video focuses on one of my favorite astrophysics facts: 94% of the observable universe is permanently unreachable by humans. (Unless we discover faster-than-light travel, but that’s fantasy at this point.)
This expansion means that there is a cosmological horizon around us. Everything beyond it, is traveling faster, relative to us, than the speed of light. So everything that passes the horizon, is irretrievably out of reach forever and we will never be able to interact with it again. In a sense it’s like a black hole’s event horizon, but all around us. 94% of the galaxies we can see today have already passed it and are lost to us forever.
“Since you started watching this video, around 22 million stars have moved out of our reach forever.” And future generations, billions of years from now, won’t even be able to see any other galaxies or detect cosmic background radiation, making knowledge about the Big Bang impossible.
You’re probably aware that black holes are weird. You can learn more about just how extremely odd they are by watching this animated primer on black holes by Kurzgesagt. The explanation about how long black holes live starting at ~9:30 is legitimately mindblowing — that hourglass metaphor especially.
This new video from Kurzgesagt takes a look at the possible role of nuclear energy in helping to curb the effects of our climate emergency.
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.
In the course of years, Hoff grew increasingly comfortable at the plant. She switched roles, working in the control room and then as a procedure writer, and got to know the workforce — mostly older, avuncular men. She began to believe that nuclear power was a safe, potent source of clean energy with numerous advantages over other sources. For instance, nuclear reactors generate huge amounts of energy on a small footprint: Diablo Canyon, which accounts for roughly nine per cent of the electricity produced in California, occupies fewer than six hundred acres. It can generate energy at all hours and, unlike solar and wind power, does not depend on particular weather conditions to operate. Hoff was especially struck by the fact that nuclear-power generation does not emit carbon dioxide or the other air pollutants associated with fossil fuels. Eventually, she began to think that fears of nuclear energy were not just misguided but dangerous. Her job no longer seemed to be in tension with her environmentalist views. Instead, it felt like an expression of her deepest values.
For their latest video, Kurzgesagt ventures into What If? territory with a hypothetical exploration of what would happen if King Midas turned the entire Earth into gold. This video did not go where I thought it was going to. Ten minutes of freefall? Shrinking mountains?
The Milky Way galaxy may be home to billions or even trillions of rogue planets (planets that don’t orbit stars). In this video, Kurzgesagt considers how the Earth could go rogue (by following a nearby massive star away from the Sun) and what would happen to our oceans, atmosphere, and lives if it happened.
The first part of the video is pretty bleak — “as the days turn dark, the final winter of humanity would begin” — while the second part is hopeful: we’ll be able to predict our ejection thousands of years before it happens and may be able to prepare. In light of the world’s response to the pandemic and climate change, it would certainly be interesting to see if human civilization could get it together to save itself from a cold death in outer space. I have no doubt that scientist could accurately diagnose the problem and supply solutions, but the politics would be a total mess.
For Kurzgesagt’s latest video, they explore the challenges the world faces in attempting to get the rate of climate change under control before it’s too late and how to get there.
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?
According to the video, global population growth and economic growth will be working against us over the next few decades and that increasing our energy efficiency and lowering emissions from energy sources are the main ways in which we will be able to slow things down. It’s worth noting that on the wizard vs. prophet continuum, this video is firmly in the wizard camp. That’s not wrong or bad; it’s just that other people have different ideas about how to combat climate change.
The breadth of scale of measurable objects in the universe — our distance from the most distant objects we can observe (billions of light years away) to particles measured in something called a yoctometer (1×10-24 meters) — is staggering to think about. That’s where the Universe in a Nutshell app comes in. Developed by Kurzgesagt & Wait But Why (both kottke.org favorites), you can use the app to quickly and easily zoom in and out through objects at all the scales of the universe, like quarks, DNA, cells, earthworms, Europe, Jupiter, the black hole at the center of our galaxy, the Crab Nebula, galaxies, and galaxy superclusters.
You can tap on any object you encounter to learn more about it, like an interactive Powers of Ten. I spent 20 minutes just now playing around and it’s really fun. You can download the app for $2.99 from the App Store or on Google Play.
To mark the release, Kurzgesagt made a video comparing the sizes of stars:
And Wait But Why’s Tim Urban wrote a post about the scales of objects: The Big and the Small.
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.
The nests that weaver ants build out of leaves and silk from larve (that the ants use as “tiny cute glue guns”) are incredible. Since Kurzgesagt is animated, I went looking for some actual footage of weaver ants doing their thing. Here’s a clip from BBC Earth:
I found this video via The Kid Should See This, who explains that a mango orchard in Thailand uses the ants to keep pests away without using chemical pesticides:
In this mango orchard in Northern Thailand, weaver ants are nurtured so they can thrive and protect the harvest. The ants hunt the pests that would eat the mangoes, eliminating any need to use harmful chemical pesticides. The farmer creates strategic highways of red string to connect the weaver ants to new trees, expanding where they forage.
How is it that I am sitting here writing this right now and you are sitting there reading this at some later point which seems like now to you? These behaviors are the result of a series of interconnected processes that have evolved over billions of years that we collective call “intelligence”.
In this video, Kurzgesagt takes a crack at explaining the simple view of intelligence as “a mechanism to solve problems” that involves several aspects: information, memory, learning, knowledge, creativity, the use of physical tools, the ability to plan for the future, and culture. As usual, their extensive list of sources provides more details and opportunities for further exploration.
In their newest video, Kurzgesagt explores the question of responsibility around climate change: which countries are most responsible for carbon emissions and for fixing the damage they’ve caused. As always, their source material is worth a look.
This morning Kurzgesagt released their video about COVID-19 that they’ve been working on for a week, and it is excellent, particularly the first part where they explain exactly what the SARS-CoV-2 virus does to a human body and why it can be so dangerous. I hadn’t heard that described before, especially in such relatively simple terms.
The virus has not caused too much damage yet, but corona is now going to release a real beast on you: your own immune system. The immune system, while there to protect you, can actually be pretty dangerous to yourself and needs tight regulation. And as immune cells pour into the lungs to fight the virus, corona infects some of them and creates confusion. Cells have neither ears nor eyes — they communicate mostly via tiny information proteins called cytokines — nearly every important immune reaction is controlled by them. Corona causes infected immune cells to overreact and yell bloody murder. In a sense, it puts the immune system into a fighting frenzy and sends way more soldiers than it should, wasting its resources and causing damage.
Even though larger animals like elephants and blue whales have up to 100 billion more cells than humans in their bodies — and therefore many more chances for harmful mutations to develop — they are much more immune to cancer. This is called Peto’s paradox the subject of Kurzgesagt’s latest video. Scientists aren’t sure why this happens, but one hypothesis is that in order to have grown so large, the evolutionary process that resulted in these animals provided built-in defenses against cancer that other animals didn’t need. Further reading on the topic is available here.
When humans domesticated barnyard animals (goats, sheep, cows) starting around 10,000 years ago, they stumbled upon one of the most amazing schemes of all time. Instead of relying on the few human-edible plants scattered around for their energy needs, humans could raise animals that ate the plain old grass that was growing anywhere & everywhere and converted it into ultra-nutritious and energy-rich superfoods like meat and milk. Land back then was plentiful and the scheme allowed humans to produce many more calories with less effort using an energy source (the grass) that they didn’t otherwise have much use for.
But how does milk fit into the picture these days? It’s still a superfood that’s very beneficial to people in many parts of the world where adequate nutrition isn’t available from other sources. But as Kurzgesagt explains in this video, our land use has changed in the past 10,000 years, and cow’s milk production is a major source of carbon emissions (when compared to foods w/ similar nutritional value):
In this episode of Kurzgesagt, they’re talking about building engines powerful enough to move entire stars, dragging their solar systems along with them.
At some point we could encounter a star going supernova. Or a massive object passing by and showering earth with asteroids.
If something like this were to happen we would likely know thousands, if not millions of years in advance. But we still couldn’t do much about it.
Unless… we move our whole solar system out of the way.
Kurzgesagt did something interesting for this one. Instead of relying on already available sources, they commissioned physicist Matthew Caplan to write a paper about a novel stellar engine design, a massive contraption that could theoretically move the solar system a distance of 50 light years over 1 million years.
Stellar engines, megastructures used to control the motion of a star system, may be constructible by technologically advanced civilizations and used to avoid dangerous astrophysical events or transport a star system into proximity with another for colonization.
Is this the first scientific paper published in a peer-reviewed journal commissioned by a YouTube channel? The 2019 media landscape is wild.
I love rocket launches. They are loud, carry cool things into space, and last a surprisingly long time considering how fast the rocket is already traveling when it clears the tower. But I think we’re going to look back on this era of space travel and marvel that launches & rockets were our only means of getting things into and around space (planetary gravity assists notwithstanding). We’re already moving in that direction; the initial tests of a space sail inspired by Carl Sagan have been promising. Another space propulsion idea is to use spinning space tethers to whip smaller, slower space vehicles from relatively low altitudes to higher orbits or even to the Moon, Mars, or beyond. This video from Kurzgesagt explains how these tethers work and what we could do with them.
I believe Neal Stephenson wrote about space tethers (or something very similar) in Seveneves.
The latest video from Kurzgesagt is a short primer on neutron stars, the densest large objects in the universe.
The mind-boggling density of neutron stars is their most well-known attribute: the mass of all living humans would fit into a volume the size of a sugar cube at the same density. But I learned about a couple of new things that I’d like to highlight. The first is nuclear pasta, which might be the strongest material in the universe.
Astrophysicists have theorized that as a neutron star settles into its new configuration, densely packed neutrons are pushed and pulled in different ways, resulting in formation of various shapes below the surface. Many of the theorized shapes take on the names of pasta, because of the similarities. Some have been named gnocchi, for example, others spaghetti or lasagna.
Simulations have demonstrated that nuclear pasta might be some 10 billion times stronger than steel.
The second thing deals with neutron star mergers. When two neutron stars merge, they explode in a shower of matter that’s flung across space. Recent research suggests that many of the heavy elements present in the universe could be formed in these mergers.
But how elements heavier than iron, such as gold and uranium, were created has long been uncertain. Previous research suggested a key clue: For atoms to grow to massive sizes, they needed to quickly absorb neutrons. Such rapid neutron capture, known as the “r-process” for short, only happens in nature in extreme environments where atoms are bombarded by large numbers of neutrons.
If this pans out, it means that the Earth’s platinum, uranium, lead, and tin may have originated in exploding neutron stars. Neat!
Kurzgesagt has partnered with the Red Cross and their “no to nukes” initiative to depict what it would be like if a nuclear weapon detonated in a major city. I’m not going to lie to you here, this is a difficult video to watch. Super bleak. There is no bright side to nuclear weapons.
The reason no government wants you to think about all this is because there is no serious humanitarian response possible to a nuclear explosion. There’s no way to really help the immediate victims of a nuclear attack. This is not a hurricane, wildfire, earthquake, or nuclear accident — it is all of these things at once, but worse. No nation on earth is prepared to deal with it.
Between the climate crisis, the rise of authoritarianism around the world, the AI bogeyman, and other things, nuclear weapons have gotten lost in the shuffle recently, but they remain a massive existential threat to society. A small group of people, some careful planning, years of patience, and you could possibly see an event that would make 9/11 look quaint.
Ants are fascinating. They’re small and individually dumb, but together they can form very complex societies capable of activities like farming and altering entire ecosystems. In this video, Kurzgesagt shows how the Argentine ant became one of the most numerous and successful species of ant in the world, forming a single mega-colony across the entire Earth, from Argentina to the US to Japan.
“The enormous extent of this population is paralleled only by human society,” the researchers write in the journal Insect Sociaux, in which they report their findings.
However, the irony is that it is us who likely created the ant mega-colony by initially transporting the insects around the world, and by continually introducing ants from the three continents to each other, ensuring the mega-colony continues to mingle.
“Humans created this great non-aggressive ant population,” the researchers write.
For their latest video, Kurzgesagt takes a typically informative journey from the surface of the ocean all the way down to the deepest spot on Earth, Challenger Deep.
In the segment about marine snow — decaying matter and feces that falls from the resource-rich sliver of ocean near the surface to provide the thin sustenance for the entire rest of the ocean — I couldn’t help but think about trickle-down economics.
Kurzgesagt are known for their animated explainers about science and society. For their latest video, they’ve applied their signature style to a metaphysical short story by Andy Weir (author of The Martian). It’s called The Egg — you can read it here.
You were on your way home when you died.
It was a car accident. Nothing particularly remarkable, but fatal nonetheless. You left behind a wife and two children. It was a painless death. The EMTs tried their best to save you, but to no avail. Your body was so utterly shattered you were better off, trust me.
And that’s when you met me.
“What… what happened?” You asked. “Where am I?”
“You died,” I said, matter-of-factly. No point in mincing words.
“There was a… a truck and it was skidding…”
“Yup,” I said.
“I… I died?”
“Yup. But don’t feel bad about it. Everyone dies,” I said.
You looked around. There was nothingness. Just you and me. “What is this place?” You asked. “Is this the afterlife?”
According this video by Kurzgesagt (and their extensive list of sources), the answer to that question for now is: no, our electronic devices are not causing long- or short-term health problems in the brains or bodies of people who use them.
Electrosmog is one of those things that is a bit vague and hard to grasp. When personal health is involved, feelings clash extra hard with scientific facts and there is a lot of misinformation and exaggeration out there. On the other hand, some people are really worried and distressed by the electricity that surrounds them. And just to wave this off is not kind or helpful.
While there is still a lot of researching being done on the dangers of constant weak electromagnetic radiation, it is important to stress that so far, we have no reason to believe that our devices harm us. Other than… well… spending too much time with them.
The development of vaccines against infectious diseases is among the greatest of human accomplishments and has saved ten of millions of people from dying. And yet some are still hung up on their side effects (and also the widely disproved and debunked fraudulent claim that vaccines cause autism). In this video, Kurzgesagt looks at how vaccines work and compares the impact of their side effects (minuscule) to the potential effect of the diseases they protect against (children dying).
The extensive list of sources they used for the video can be found here.
The title of this video is “The Side Effects of Vaccines - How High is the Risk?”, which seems like it’s maximized for clicks and to spread amongst anti-vaxxers on social media. I wish it had a more accurate title — something like “The Absurdly Low Risk of Vaccine Side Effects” or maybe “Vaccines. And Now My Kids Don’t Die.” — but perhaps positioning it this way is a good strategy to get folks who may not be quite so radicalized to watch it.
Nuclear physicists hypothesize that when the cores of neutron stars are subject to enough pressure, the quarks that make up the core can turn from up and down quark varieties into strange quarks. As this Kurzgesagt video explains, this strange matter is particularly stable and if it were to escape from the core of the neutron star, it would convert any ordinary matter it came into contact with to more strange matter. If you hadn’t heard about this hypothesis before, you can read up on it in their list of sources for the video.
Religion and philosophy have their own answers as to where our consciousness comes from, but in this video, Kurzgesagt explores how scientists believe consciousness first evolved, from organisms moving more quickly when consuming food to animals being able to animals who can remember where they hid food to reading the minds of competitors and allies.
In it, they detail the process of making their videos, which has gotten more extensive as the channel matures. The second half is about a pair of videos that didn’t meet their current standard: one about addiction (which I posted about here) and another about the European migrant crisis of 2015. The addiction video represented only one side of a controversial issue within the scientific community while the migrant video was hastily produced and poorly researched. As a result, they deleted both videos, even though they were among the channel’s most popular and plan to publish a future video about addiction that will look more broadly at its causes.
With 20+ years of kottke.org archives, I’ve been thinking about this issue as well. There are many posts in the archive that I am not proud of. I’ve changed my mind in some cases and no longer hold the views attributed to me in my own words. I was too frequently a young and impatient asshole, full of himself and knowing it all. I was unaware of my privilege and too frequently assumed things of other people and groups that were incorrect and insensitive. I’ve amplified people and ideas in the past that I wouldn’t today.
My process today is more rigorous (but not as rigorous as Kurzgesagt b/c we have different aims) and I’ve gained some wisdom (I hope!) about when vigor or sensitivity are called for. I still place a lot of responsibility on the shoulders of the reader — you are a smart bunch and I expect you to read and view everything here with a critical eye — but I am also more aware of my (small but not insignificant) responsibility as an informational gatekeeper.
But so anyway, I don’t know what to do about those old problematic posts. Tim Berners-Lee’s idea that cool URIs don’t change is almost part of my DNA at this point, so deleting them seems wrong. Approximately no one ever reads any post on this site that’s more than a few years old, but is that an argument for or against deleting them? (If a tree falls in the woods, etc…) Should I delete but leave a note they were deleted? Should I leave the original posts but append updates citing my current displeasure? Or like Mister Rogers used to do, should I rewrite the posts to bring them more into line with my current thinking? Is the kottke.org archive trapped in amber, a record of what I’ve written when I wrote it, or is it a living, breathing thing that thrives on activity? Is it more like a book or a performance? In my mind it’s both, which is why the site is compelling (IMO) but also makes this issue so thorny for me. The web is weird that way…but how do I embrace the weirdness re: this issue?
In their latest video, Kurzgesagt takes a look at black holes, specifically how they deal with information. According to the currently accepted theories, one of the fundamental laws of the Universe is that information can never be lost, but black holes destroy information. This is the information paradox…so one or both of our theories must be wrong.
The paradox arose after Hawking showed, in 1974-1975, that black holes surrounded by quantum fields actually will radiate particles (“Hawking radiation”) and shrink in size (Figure 4), eventually evaporating completely. Compare with Figure 2, where the information about the two shells gets stuck inside the black hole. In Figure 4, the black hole is gone. Where did the information go? If it disappeared along with the black hole, that violates quantum theory.
Maybe the information came back out with the Hawking radiation? The problem is that the information in the black hole can’t get out. So the only way it can be in the Hawking radiation (naively) is if what is inside is copied. Having two copies of the information, one inside, one outside, also violates quantum theory.
So maybe black holes holographically encode their information on the surface?
In the first in a series of videos, Kurzgesagt tackles one of my favorite scientific subjects: how the sizes of animals governs their behaviors, appearance, and abilities. For instance, because the volume (and therefore mass) of an organism increases according to the cube of the increase in length (e.g. if you double the length/height of a dog, its mass roughly increases by 8 times), when you drop differently sized animals from high up, the outcomes are vastly different (a mouse lands safely, an elephant splatters everywhere).
When humans get smaller, the world and its resources get bigger. We’d live in smaller houses, drive smaller cars that use less gas, eat less food, etc. It wouldn’t even take much to realize gains from a Honey, I Shrunk Humanity scheme: because of scaling laws, a height/weight proportional human maxing out at 3 feet tall would not use half the resources of a 6-foot human but would use somewhere between 1/4 and 1/8 of the resources, depending on whether the resource varied with volume or surface area. Six-inch-tall humans would potentially use 1728 times fewer resources.
This new video by Kurzgesagt examines automation in the past (“big stupid machines doing repetitive work in factories”) and argues that automation in the information age is fundamentally different. In a nutshell,1 whereas past automation resulted in higher productivity and created new and better jobs for a growing population, automation in the future will happen at a much quicker pace, outpacing the creation of new types of jobs for humans.
A group called Kurzgesagt, in collaboration with author Johann Hari, made this video about taking a new approach to understanding addiction. You’ve probably heard of the experiments where rats in cages were given access to drugs. The rats quickly became addicted to them and used them heavily until overdosing. But perhaps the problem is not the drugs but the cage. Later experiments showed that if rats were given plenty of alternate activities, freedom, and room to roam, they were not likely to become heavy drugs users or overdose.
Human studies are more difficult to come by, but it still appears that when available, living life, family, and friends are more addictive than heroin. And so, according to Hari, who wrote a book about all this, what we should be doing is not isolating those who become addicted to drugs, alcohol, and other things. Instead, we should build a society that reconnects people to each other so that the drugs become unnecessary.
I started to research my book, Lost Connections: Uncovering The Real Causes of Depression — and the Unexpected Solutions, because I was puzzled by two mysteries. Why was I still depressed when I was doing everything I had been told to do? I had identified the low serotonin in my brain, and I was boosting my serotonin levels — yet I still felt awful. But there was a deeper mystery still. Why were so many other people across the western world feeling like me? Around one in five US adults are taking at least one drug for a psychiatric problem. In Britain, antidepressant prescriptions have doubled in a decade, to the point where now one in 11 of us drug ourselves to deal with these feelings. What has been causing depression and its twin, anxiety, to spiral in this way? I began to ask myself: could it really be that in our separate heads, all of us had brain chemistries that were spontaneously malfunctioning at the same time?
Update: Kurzgesagt deleted this video from their channel. You can view the deleted video (they gave people permission to repost it) and hear why they deleted it. As for Hari’s view on addiction, neuroscientist Dean Burnett addresses the controversy in a pairof posts for The Guardian and there are others within the east reach of a quick Googling.
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