kottke.org posts about science


South Korea currently has a probe called Danuri orbiting the Moon at an altitude of about 62 miles above the surface. It’s just begun its mission but has already sent back some black & white photos of the Moon and the Earth, including the two above. Over at EarthSky, Dave Adalian says these shots “rival the work of legendary nature photographer Ansel Adams” and it’s difficult to disagree.
Also worth a look: Danuri’s shot of the Earth and Moon from a distance, hanging in the blackness of space like a pair of pearls. (via petapixel)
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Magnets are cool. Full stop. The Magnetic Games channel has a ton of videos about all the neat stuff you can do with them.
I can’t be the only person who, after watching this, wants to spend a significant amount of money on neodymium magnets and magnetic putty? Some people do puzzles, others do Lego — maybe I could be a magnet guy?
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Clive Thompson, himself a person with a number of “weird, offbeat obsessions”, writes about the power of curiosity, including the story of how a trip to Yellowstone’s burbling hot springs led to the PCR method that enables accurate Covid testing.
Back in 1964, the microbiologist Thomas Brock visited Yellowstone National Park to do some sightseeing. He was on a long car ride, and wanted to break up the monotony.
While peering into the hot springs, he noticed a curious blue-green tinge. When he asked a park ranger about it, he was told it was algae. That surprised Brock: Those pools are so hot that some of them reach a boiling temperature. At the time, scientists didn’t know of many lifeforms that could readily thrive such scalding environments.
But Brock couldn’t stop wondering about what exactly was going on in those boiling pools. He was dying to know: What was alive down there? How was it surviving?
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Canada’s Bay of Fundy has the highest tides in the world, with a difference between low and high tides reaching more than 50 feet in some areas. That’s a lot of water in motion:
In a single tidal cycle of just over 12 hours, about 110 billion tons of water flows in and out of the Bay of Fundy. That sounds like a lot. To get a handle on just how much it is, it is equivalent to the combined total 24 hr flow of all the rivers of the world!
With that much flowing water, you should be able to generate a massive amount of hydroelectric power. But as Tom Scott explains in this succinct video, the problem is that there’s almost too much energy to harness — the tide is so strong that it just destroys turbines.
See also Bay of Fundy Extreme Tides Time Lapse.
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Creative coder Neal Agarwal has launched his newest project: Asteroid Launcher. You can choose the asteroid’s composition (iron, stone, comet, etc.), size, speed, angle of incidence, and place of impact. Then you click “launch” and see the havoc you’ve wrought upon the world, with all kinds of interesting statistics. I bombarded Los Angeles with an iron asteroid a half-mile across moving at 50,000 mph and the results were significant, as you can see from the fireball it created:

Some of the most interesting bits about the impact:
- The crater is 2,087 ft deep.
- Clothes would catch on fire within 86 miles of the impact.
- An estimated 4,343,300 people would die from the 249 decibel shock wave.
- Winds would reach 13,373 mph; within 105 miles it would feel like being inside an EF5 tornado.
Crikey! See also the description of the much more massive meteorite that slammed into the Yucatan peninsula 66 million years ago:
The meteorite itself was so massive that it didn’t notice any atmosphere whatsoever,” said Rebolledo. “It was traveling 20 to 40 kilometers per second, 10 kilometers - probably 14 kilometers — wide, pushing the atmosphere and building such incredible pressure that the ocean in front of it just went away.
And The World’s Loudest Sound:
The sound made by the Krakatoa volcanic eruption in 1883 was so loud it ruptured eardrums of people 40 miles away, travelled around the world four times, and was clearly heard 3,000 miles away.
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From Maastricht University in The Netherlands, this is a fantastic animation of the lifecycle of the SARS-CoV-2 virus as it invades and then multiplies in the human lung. A more scientific version is available as well. Great explanation but I love the visual style of this. They used textures similar to stop motion animations — e.g. the proteins look like clay and the cell membranes seem to be made of felt. (via carl zimmer)
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It is Friday and this is the perfect Friday sort of post. BeamNG is a video game of sorts that’s “a dynamic soft-body physics vehicle simulator capable of doing just about anything”. In the simulator, you can quickly devise all sorts of situations with a variety of cars and then press play to see what happens, with (mostly) realistic physics and collisions. For instance, here’s Cars vs Big Bulge:
Chained Cars vs Bollards:
Cars vs 100 Fallen Trees:
Trains vs Giant Pit:
And many many more. My god if this simulator had been around when I was 12 years old, I might not have done anything else. Hell, if I downloaded and installed this right now, I might not ever get anything done ever again. (via @tvaziri)
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In retrospect, maybe today wasn’t such a good day to watch a video about how incredibly scary brain-eating amoebas are. But, as you might guess from the title, we don’t actually need to worry too much about them.
While the Naegleria fowleri is clearly extremely deadly and the infection truly horrible, there have only been a few hundred cases in the last few decades. You are way more likely to drown in a pool than to get infected.
A reminder that in our current media environment, calibrating personal risk can be challenging.
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On the 26th flight of Ingenuity, NASA’s helicopter on Mars, it spotted and photographed the wreckage of the Perseverance rover’s landing gear, protective shell, and parachute. From a NY Times article on the photos:
“There’s definitely a sci-fi element to it,” Ian Clark, an engineer who worked on Perseverance’s parachute system, said of photographs released on Wednesday. “It exudes otherworldly, doesn’t it?”
Part of the reason NASA had Ingenuity go take a look is to see how all of that equipment held up during the landing process. Data from the photos will inform future missions.
“Perseverance had the best-documented Mars landing in history, with cameras showing everything from parachute inflation to touchdown,” said JPL’s Ian Clark, former Perseverance systems engineer and now Mars Sample Return ascent phase lead. “But Ingenuity’s images offer a different vantage point. If they either reinforce that our systems worked as we think they worked or provide even one dataset of engineering information we can use for Mars Sample Return planning, it will be amazing. And if not, the pictures are still phenomenal and inspiring.”
In the images of the upright backshell and the debris field that resulted from it impacting the surface at about 78 mph (126 kph), the backshell’s protective coating appears to have remained intact during Mars atmospheric entry. Many of the 80 high-strength suspension lines connecting the backshell to the parachute are visible and also appear intact. Spread out and covered in dust, only about a third of the orange-and-white parachute — at 70.5 feet (21.5 meters) wide, it was the biggest ever deployed on Mars — can be seen, but the canopy shows no signs of damage from the supersonic airflow during inflation. Several weeks of analysis will be needed for a more final verdict.
It is really remarkable, the images we’re seeing from Mars, taken by a robotic helicopter.
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In the last installment of a video series called The Universe in Verse, Maria Popova, Yo-Yo Ma, and Kelli Anderson have collaborated on a video that features words spoken by Nobel Prize-winning physicist Richard Feynman in a 1955 speech, a poem of sorts on the wonder of life.
Deep in the sea, all molecules repeat the patterns of one another till complex new ones are formed. They make others like themselves… and a new dance starts.
Growing in size and complexity… living things, masses of atoms, DNA, protein… dancing a pattern ever more intricate.
Out of the cradle onto the dry land… here it is standing… atoms with consciousness… matter with curiosity.
Lovely. And of course I love the visuals by Kelli Anderson.
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You may have noticed, while twisting apart Oreos (aka the world’s favorite “trilayer laminate composite”) to get at the creme inside, that the creme tends to mostly stick to one half of the cookie. MIT graudate student Crystal Owens decided to study this phenomenon and has co-authored a paper about the failure mechanics of the Oreo’s layer of creme in the journal Physics of Fluid. From Ars Technica:
“I had in my mind that if you twist the Oreos perfectly, you should split the creme perfectly in the middle,” said Owens. “But what actually happens is the creme almost always comes off of one side.” The experiments showed that this creme distribution is not affected by rotation rate, the amount of creme filling, or the flavor. Rather, the pre-existing level of adhesion between the creme and the chocolate wafers seemed to be the determining factor. Cookies from the package within any one box typically separated with the same preferred orientation most of the time. This suggests that it has something to do with how the cookies are manufactured and then oriented during packaging, as well as how they are stored.
They even built a 3D printed “oreometer” so that people can study this phenomenon without using an expensive rheometer.
As a very amateur kitchen scientist myself, the Oreo situation reminds me of what happens when you try to tear three connected pieces of paper towel apart in one move by pulling on the outside pieces in opposite directions: the middle piece of paper towel almost always ends up attached to one of the outside pieces. In fact, in extensive testing over the past 3-4 years, this maneuver has only separated all three pieces a few times.1 (thx, eric)
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Wow, NASA just released a video shot by the Mars Perseverance rover of a solar eclipse by the moon Phobos. The video description calls it “the most zoomed-in, highest frame-rate observation of a Phobos solar eclipse ever taken from the Martian surface”. According to this article from JPL, the video of the eclipse is played in realtime; it only lasted about 40 seconds.
Captured with Perseverance’s next-generation Mastcam-Z camera on April 2, the 397th Martian day, or sol, of the mission, the eclipse lasted a little over 40 seconds — much shorter than a typical solar eclipse involving Earth’s Moon. (Phobos is about 157 times smaller than Earth’s Moon. Mars’ other moon, Deimos, is even smaller.)
Just a hunk of space rock passing in front of a massive burning ball of gas recorded by a robot from the surface of an extraterrestrial planet, no big deal.
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I had always heard that the engineering of Roman aqueducts was impressive, but as this video demonstrates, I didn’t know the half of it. The stuff about how precise the descending slope of the aqueducts were over several hundred miles is just incredible. (via open culture)
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Is there a physical limit to how loud a noise can be? As you might imagine, the answer is somewhat complicated, even if you assume normal atmospheric conditions. In video, Benn Jordan discusses a few possible answers, as well as how we should think about the question in the first place. One possible answer is 194 decibels, although experiencing a sound that loud would probably kill you.
See also The World’s Loudest Sound, aka the sound generated by the Krakatoa volcanic eruption in 1883, which Jordan mentions in the video.
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A new video from Kurzgesagt is designed to provide a little hope that humans can figure a way out of the climate crisis, without being overly pollyannish.
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.
There’s been progress in the last decade, in terms of economics, technology, policy, and social mores. It’s not happening fast enough to limit warming to 1.5°C, but if progress continues, gains accumulate, people keep pushing, and politicians start to figure out where the momentum is heading, we can get things under control before there’s a global apocalypse.
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The European Space Agency’s Solar Orbiter recently took 25 images of the Sun from a distance of 46 million miles that, when stitched all together, form the highest resolution photo of the Sun (and its corona) ever created.
The high-resolution telescope of EUI takes pictures of such high spatial resolution that, at that close distance, a mosaic of 25 individual images is needed to cover the entire Sun. Taken one after the other, the full image was captured over a period of more than four hours because each tile takes about 10 minutes, including the time for the spacecraft to point from one segment to the next.
In total, the final image contains more than 83 million pixels in a 9148 x 9112 pixel grid. For comparison, this image has a resolution that is ten times better than what a 4K TV screen can display.
You can zoom in on the image here to see how remarkably detailed it is.
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Using Lego bricks, a Raspberry Pi mini-computer, an Arduino microcontroller, some off-the-shelf components like lenses, and 3D-printed components, IBM scientist Yuksel Temiz built a fully functional microscope to help him with his work. The materials cost around $300 and the microscope performs as well as scopes many times more expensive — the images above were taken with the Lego scope.
The microscope works so well that for the past two years Temiz and his colleagues in the microfluidics lab at IBM Research, just meters away from the picturesque Zurich lake, have been using the images they took with it in their papers, published in leading journals. They also use them for presentations at major conferences. Not all images relate to microfluidics — the area of science that involves manipulating fluids on miniscule chips in a very precise manner. The liquids can be blood or urine, used for cancer and infectious diseases research as well as understanding heart attack conditions, and more. Researchers also routinely take images of typical computer chips, and Temiz showed me, for instance, how to take a stunning close up of a fruit fly.
Here’s a quick video look at how to build your own:
The the full set of open-sourced instructions are available on GitHub.
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For his music video for Sébastien Guérive’s Bellatrix, Thomas Blanchard filmed ice crystals forming at close range and ultra-high resolution.
Bellatrix Sébastien Guérive music video is an experimental film on the crystallization of ice stars. It is a chemical saturation in hot water which is then cooled. The chemical saturation becomes very unstable when the liquid cools. The slightest disturbance in the liquid activates crystallization.
I spent hours and hours as a kid watching snowflakes accumulate on windowsills, raindrops rolling down windows, clouds rolling in from the west, and frost advance on surfaces, looking for patterns in the seeming randomness, so this is right up my alley. (via colossal)
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The Earth is some 4.5 billion years old and the first life on Earth appeared 3.7 billion years ago (if not earlier). That’s a lot of time…so maybe it’s possible that a civilization existed at some point during that time and then vanished without a trace. In this video, Kurzgesagt explores the Silurian hypothesis.
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?
See also Could an Industrial Prehuman Civilization Have Existed on Earth Before Ours? and Was There a Civilization on Earth Before Humans?.
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Sometimes the sky above powerful thunderstorms can light up in massive displays of color; they’re called transient luminous events. Whoa, I’ve never seen or heard of this phenomenon before!
On rare nights with clear visibility over powerful distant thunderstorms, you might be able to see and capture red sprites. Sprites are large scale electrical discharges occurring high above thunderstorms in the upper atmosphere. They are massive events, sometimes 50 kilometers tall by 50 kilometers wide. Sprites belong to a mysterious and colorful group of phenomenon called Transient Luminous Events, or TLEs. Other TLE’s include halos, Elves, trolls, secondary jets, Blue starters, Blue jets and the magnificent gigantic jets. But what exactly are these transient luminous Events, and how do they form?
This video is a great explainer about the phenomenon — how it arises, where the colors come from, etc. (via the kid should see this)
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Historically, contracting the measles has been linked to subsequent illness (and possibly death) from other causes. In the past few years, scientists have discovered why this is: measles causes “immune amnesia”.
Enter “immune amnesia”, a mysterious phenomenon that’s been with us for millennia, though it was only discovered in 2012. Essentially, when you’re infected with measles, your immune system abruptly forgets every pathogen it’s ever encountered before — every cold, every bout of flu, every exposure to bacteria or viruses in the environment, every vaccination. The loss is near-total and permanent. Once the measles infection is over, current evidence suggests that your body has to re-learn what’s good and what’s bad almost from scratch.
“In a way, infection of the measles virus basically sets the immune system to default mode,” says Mansour Haeryfar, a professor of immunology at Western University, Canada, “as if it has never encountered any microbes in the past”.
This re-learning process takes up to three years, which “around the time it takes infants to acquire immunity to everyday pathogens in the first place”. In the meantime…
It’s not surprising, then, that measles doesn’t just increase the risk of illness, but also death. In fact, childhood mortality from other viruses is strongly linked to the incidence of measles. The 2015 study showed that when childhood mortality in the UK, US, or Denmark goes up, this is usually because measles has become more prevalent.
The findings explain why vaccinating children against measles has the unexpected, beneficial side-effect of reducing deaths among children, way beyond the numbers who were ever at risk of dying from measles itself.
Of course, an extremely effective and safe vaccine offers protection against both measles and the immune amnesia it causes. But with the steep rise in anti-vaccination sentiment during the pandemic and the increasing willingness of conservative leaders to disregard public health protections in favor of “individual freedom”, widely vaccinating against this dangerous pathogen in the US & elsewhere will be more difficult than in the past.
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In 1974, the Journal of Applied Behavior Analysis published a paper by Dennis Upper called The Unsuccessful Self-Treatment of a Case of “Writer’s Block”. Here’s the paper, in its entirety:

“Portions of this paper were not presented at 81st Annual American Psychological Association Convention…” — LOL. You can read more about this paper at Wikipedia. (via @ecohugger)
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About 5.9 million years ago, due to a combination of tectonic movements and changes in climate, the Mediterranean Sea mostly dried up for over 600,000 years. The Messinian salinity crisis may have raised global sea levels by as much as 33 feet and decreased the salinity of the world’s oceans, raising the freezing point. And then, much more suddenly, it was refilled in less than two years in the Zanclean Flood.
Two years to refill the whole Mediterranean! Apparently the water level rose at 30 feet per day, fed by a river that carried 1000 times more water than the Amazon at velocities exceeding 88 mph. When the water reached a barrier near present-day Sicily, it flowed into the eastern basin via a mile-high waterfall in which the water was moving at 100 mph. The weight of so much water moving into the area so quickly would have triggered seismic activity, resulting in landslides that could have produced tsunamis with wave heights of 330 feet. So much wow!
Anyway, watch the PBS Eons video above for the whole story. And then check out this animation of what the drying up and the flood may have looked like.
P.S. For XKCD, Randall Munroe wrote a comic called Time that unfolded over a series of four months and was based on a future Zanclean-like flood. (via open culture)
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From Veritasium, a video about an experiment in evolution that’s been running continuously for more than 33 years.1The LTEE (the E. coli long-term evolution experiment) was started with 12 identical bacterial populations in 1988 and as of early 2020, they have reached 73,500 generations (the equivalent of 1.5 to 2 million years in human generational terms). When you can fast-forward evolution while also preserving past generations (the bacteria can be easily frozen and reanimated), you can discover some surprising things about it.
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No doubt motivated by this month’s release of Moonfall, the latest movie from disaster shlockmeister Roland Emmerich, Kurzgesagt has made a video that shows what would happen to civilization should the Moon somehow get knocked from its orbit and head straight for the Earth. Spoiler: the Moon doesn’t even need to reach us to kill almost all life on the planet.
See also A Scientific Simulation of Seveneves’ Moon Disaster.
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The James Webb Space Telescope is designed to be positioned near one of the five Lagrange Points in the Sun/Earth system, special areas of gravitational equilibrium that keep objects stationary relative to both the Earth and the Sun. Here’s how Lagrange Points work and why they are so useful for spacecraft like the Webb.
See also What Makes Lagrange Points Special Locations In Space.
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A recent study estimates that indigenous people in the US “have lost nearly 99% of the land they historically occupied”.
The data set — the first to quantify land dispossession and forced migration in the United States — also reveals that tribes with land today were systematically forced into less-valuable areas, which excluded them from key sectors of the U.S. economy, including the energy market. The negative effects continue to this day: Modern Indigenous lands are at increased risk from climate change hazards, especially extreme heat and decreased precipitation.
What’s different about this study, says Deondre Smiles, a geographer and citizen of the Leech Lake Band of Ojibwe, is the quantification of the land dispossession:
Indigenous people have always understood the devastating effects of these policies, Smiles says. But most of their stories existed only in qualitative historical records, including hundreds of treaties, or oral histories. “The pushback you get in academia is that qualitative narratives are not robust. [Scientists often ask,] ‘Where’s the data? Where’s the hard science?’” Smiles says. “It’s right here, in this article.”
See also A New Online Archive of 374 Treaties Between Indigenous Peoples and the United States and these Native Land maps. (thx, meg)
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The Wageningen University & Research houses a collection of almost 1200 drawings of the root systems of trees, grasses, crops, shrubs, weeds, flowers, and other plants. These drawings were done of plants in Europe, mostly in Austria, over a period of 40 years and are a wonderful combination of scientifically valuable and aesthetically pleasing.
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The James Webb Space Telescope is still winging its way to its permanent home at the L2 point1 about 930,000 miles from Earth — it’s due to arrive in about 4 days. It’s a massive and fascinating project and for his YouTube series Smarter Every Day, Destin Sandlin talked to Nobel laureate John Mather, the senior project scientist for the JWST, about how the telescope works.
Also worth a watch is Real Engineering’s The Insane Engineering of James Webb Telescope:
It really is a marvel of modern science & engineering — I can’t wait to see what the telescope sees once it’s fully operational.
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In this clever simulation, bouncing balls obeying the laws of physics somehow arrange themselves, mid-chaos, into neat patterns. This is immensely satisfying.
Spoiler: the trick here is a pair of simulations stitched together, like a physics Texas Switch: “Each sequence is obtained by joining two simulations, both starting from the time in which the balls are arranged regularly. One simulates forward in time, one backwards.”
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