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kottke.org posts about science

The Reason Why Cancer Is So Hard to Beat

Using the metaphor of a cancerous tumor as an unruly village, Kurzgesagt explains how cancer develops in the human body, how the body fights against it, and how, sometimes, the cancer develops into something unmanageable.

In a sense this tiny tumor is like a rogue town. Imagine a group of rebels in Brooklyn decided that they were no longer part of New York but started a new settlement called Tumor Town, which happens to occupy the same space. The new city wants to grow, so it orders tons of steel beams, cement and drywall. New buildings follow no logic, are badly planned, ugly and dangerously crooked. They are built right in the middle of streets, on top of playgrounds and on existing infrastructure. The old neighborhood is torn down or overbuilt to make room for new stuff. Many of the former residents are trapped in the middle of it and begin to starve. This goes on for a while until the smell of death finally attracts attention. Building inspectors and police show up.


A Massive 5.7 Terapixel Mosaic of the Surface of Mars

part of a crater on the surface of Mars

Using imagery from the Mars Reconnaissance Orbiter, the Bruce Murray Laboratory for Planetary Visualization at Caltech has created a 5.7 terapixel mosaic image that covers 99.5% of the surface of Mars. The whole image is available to navigate with a 3D viewer in your browser.


The Black Hole That Kills Galaxies

Astronomers believe that there’s a black hole at the center of almost every large galaxy in the universe. Some of those black holes are particularly energetic, chewing up the galaxies in which they reside and releasing massive amounts of energy out into the cosmos. Those black holes and the energy emitted from matter and gas falling towards their centers are what astronomers call quasars.

But if we look closely, we see who is actually in charge. Small as a grain of sand compared to the filaments, the centers of some of these galaxies shine with the power of a trillion stars, blasting out huge jets of matter, completely reshaping the cosmos around them. Quasars, the single most powerful objects in existence, so powerful that they can kill a galaxy.


The Sun, as Seen by the World’s Largest Solar Telescope

closeup shot of a sunspot taken with the Inouye Solar Telescope

closeup shot of a sunspot taken with the Inouye Solar Telescope

closeup shot of a sunspot taken with the Inouye Solar Telescope

closeup shot of the surface of the Sun taken with the Inouye Solar Telescope

The Inouye Solar Telescope is the largest and most powerful solar telescope in the world. The telescope is still in a “learning and transitioning period” and not up to full operational speed, but scientists at the National Solar Observatory recently released a batch of images that hint at what it’s capable of. Several of the photos feature sunspots, cooler regions of the Sun with strong magnetic fields.

The sunspots pictured are dark and cool regions on the Sun’s “surface”, known as the photosphere, where strong magnetic fields persist. Sunspots vary in size, but many are often the size of Earth, if not larger. Complex sunspots or groups of sunspots can be the source of explosive events like flares and coronal mass ejections that generate solar storms. These energetic and eruptive phenomena influence the outermost atmospheric layer of the Sun, the heliosphere, with the potential to impact Earth and our critical infrastructure.

In the quiet regions of the Sun, the images show convection cells in the photosphere displaying a bright pattern of hot, upward-flowing plasma (granules) surrounded by darker lanes of cooler, down-flowing solar plasma. In the atmospheric layer above the photosphere, called the chromosphere, we see dark, elongated fibrils originating from locations of small-scale magnetic field accumulations.

(via petapixel)


The Fastest Maze-Solving Competition On Earth

Oh this is so nerdy and great: Veritasium introduces us to Micromouse, a maze-solving competition in which robotic mice compete to see which one is the fastest through a maze. The competitions have been held since the late 70s and today’s mice are marvels of engineering and software, the result of decades of small improvements alongside bigger jumps in performance.

I love stuff like this because the narrow scope (single vehicle, standard maze), easily understood constraints, and timed runs, combined with Veritasium’s excellent presentation, makes it really easy to understand how innovation works. The cars got faster, smaller, and learned to corner better, but those improvements created new challenges which needed other solutions to overcome to bring the times down even more. So cool.


Building a Scale Model of Time

The length of a human life is around 80 years. You might get 100 if you’re lucky. The universe is about 13.7 billion years old. The vast difference between a human lifespan and the age of the universe can be difficult to grasp โ€” even the words we use in attempting to describe it (like “vast”) are comically insufficient.

To help us visualize what a difference of eight orders of magnitude might look like, Wylie Overstreet and Alex Gorosh have created a scale model of time in the Mojave Desert, from the Big Bang to the present day. This is really worth watching and likely to make you think some big think thoughts about your place in the universe and in your life.

This is a followup of the scale model of the solar system they built and a video they made about people seeing the Moon through a telescope for the first time.

See also a behind-the-scenes: How We Built a Scale Model of Time. (via colossal)


Ze Frank on Slime Molds

As part of his True Facts series about the natural world, Ze Frank explains all about slime molds, which are super interesting! Slime molds can efficiently solve mazes, plan efficient train routes, adapt to changing conditions, and learn from each other.

See also many beautiful photos of slime molds.


Is Ozempic an Anti-Addiction Drug?

Writing for The Atlantic, Sarah Zhang details how some people taking Ozempic for weight loss are reporting that the drug has also curbed their addictive impulses (to drink, to shop, to smoke).

Earlier this year, she began taking semaglutide, also known as Wegovy, after being prescribed the drug for weight loss. (Colloquially, it is often referred to as Ozempic, though that is technically just the brand name for semaglutide that is marketed for diabetes treatment.) Her food thoughts quieted down. She lost weight. But most surprisingly, she walked out of Target one day and realized her cart contained only the four things she came to buy. “I’ve never done that before,” she said. The desire to shop had slipped away. The desire to drink, extinguished once, did not rush in as a replacement either. For the first time โ€” perhaps the first time in her whole life โ€” all of her cravings and impulses were gone. It was like a switch had flipped in her brain.

Not everyone experiences these effects, but there’s enough anecdotal evidence at this point that scientists are interested and investigating.


Curve-Fitting Methods and the Messages They Send

Curve-Fitting Methods and the Messages They Send

From XKCD, Curve-Fitting Methods and the Messages They Send. Ahhhh, this takes me back to my research days in college, tinkering with best fits and R-squared values…


The Future Pandemic Playbook: What the US Got Right

From The Atlantic, 23 Pandemic Decisions That Actually Went Right, the result of interviews with more than a dozen pandemic experts.

17. Basic research spending matters. The COVID vaccines wouldn’t have been ready for the public nearly as quickly without a number of existing advances in immunology, Anthony Fauci, the former head of the National Institute of Allergy and Infectious Diseases, told us. Scientists had known for years that mRNA had immense potential as a delivery platform for vaccines, but before SARS-CoV-2 appeared, they hadn’t had quite the means or urgency to move the shots to market. And research into vaccines against other viruses, such as RSV and MERS, had already offered hints about the sorts of genetic modifications that might be needed to stabilize the coronavirus’s spike protein into a form that would marshal a strong, lasting immune response.


How Big Are the Biggest Black Holes?

This short animation from NASA shows the sizes of some of the supermassive black holes that feature at the center of galaxies. Some are relatively small:

First up is 1601+3113, a dwarf galaxy hosting a black hole packed with the mass of 100,000 Suns. The matter is so compressed that even the black hole’s shadow is smaller than our Sun.

While others are much larger than the solar system…and this isn’t even the biggest one:

At the animation’s larger scale lies M87’s black hole, now with a updated mass of 5.4 billion Suns. Its shadow is so big that even a beam of light โ€” traveling at 670 million mph (1 billion kph) โ€” would take about two and a half days to cross it.


Your Body Is Never Not Killing Cancer

From Kurzgesagt, this video is a good overview of the arms race going on in all human bodies between cancer cells and the defenses developed by our immune systems over the years.

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?


Should We Reflect Sunlight to Cool the Planet?

In this video in their ongoing series on the climate crisis and how to fix it, Vox looks at the pros and cons of solar geoengineering (aka using artificial means to reflect sunlight in order to cool the Earth).

The climate change crisis has become so dire that we’re being forced not only to think of ways to curb emissions and mitigate greenhouse gases, but of ways to adapt to our current situation to buy ourselves more time.

One of those technologies is called solar geoengineering. It happens in nature when huge volcanic eruptions cover the stratosphere with ash: That ash forms a layer that reflects sunlight and cools the planet underneath. Solar geoengineering takes advantage of that principle, using different scientific methods to make the planet more reflective overall. The problem is, deploying it would require messing with our very complicated climate on a massive scale, and many scientists don’t think the risks are worth it.


Can Water Solve a Maze?

I saw this video on the front page a YouTube a couple of weeks ago and ignored it. Like, of course water can solve a maze, next! But then it got the Kid Should See This seal of approval so I gave it a shot. It turns out: water can solve a maze…but specifics are super interesting in several respects. Steve Mould, who you may remember from the assassin’s teapot video not too long ago, built four mazes of different sizes and shapes, each of them useful for demonstrating a different wrinkle in how the water moves through a maze. Recommended viewing for all ages.


What Happens When You Get Sick?

From Kurzgesagt, an accessible explanation of what happens to the human body when you get sick.

Your brain activates sickness behavior and reorganizes your body’s priorities to defense. The first thing you notice is that your energy level drops and you get sleepy. You feel apathetic, often anxious or down and you lose your appetite. Your sensitivity to pain is heightened and you seek out rest. All of this serves to save your energy and reroute it into your immune response.

They also reveal the best way to boost your immune system to protect yourself against disease. I don’t want to spoil it but it’s vaccines. Vaccines are one of the best things humans have ever invented.


Tapping the Vast Renewable Energy of the Yellowstone Supervolcano

geological map of the Yellowstone Caldera

The first few sentences of the abstract for this paper from the scientific journal Renewable Energy contain a twist in the middle that’s worthy of M. Night Shyamalan:

The USA is confronted with three epic-size problems: (1) the need for production of energy on a scale that meets the current and future needs of the nation, (2) the need to confront the climate crisis head-on by only producing renewable, green energy, that is 100% emission-free, and (3) the need to forever forestall the eruption of the Yellowstone Supervolcano. This paper offers both a provable practical, novel solution, and a thought experiment, to simultaneously solve all of the above stated problems.

If you don’t know about the supervolcano lurking under Yellowstone National Park, now’s your chance to learn more. Here’s Bill Bryson from his book A Short History of Nearly Everything:

Yellowstone, it turns out, is a supervolcano. It sits on top of an enormous hot spot, a reservoir of molten rock that rises from at least 125 miles down in the Earth. The heat from the hot spot is what powers all of Yellowstone’s vents, geysers, hot springs, and popping mud pots. Beneath the surface is a magma chamber that is about forty-five miles across โ€” roughly the same dimensions as the park โ€” and about eight miles thick at its thickest point. Imagine a pile of TNT about the size of Rhode Island and reaching eight miles into the sky, to about the height of the highest cirrus clouds, and you have some idea of what visitors to Yellowstone are shuffling around on top of. The pressure that such a pool of magma exerts on the crust above has lifted Yellowstone and about three hundred miles of surrounding territory about 1,700 feet higher than they would otherwise be. If it blew, the cataclysm is pretty well beyond imagining. According to Professor Bill McGuire of University College London, “you wouldn’t be able to get within a thousand kilometers of it” while it was erupting. The consequences that followed would be even worse.

Back to the paper. The authors are proposing to generate massive amounts of energy from the supervolcano โ€” “well over 11 Quadrillion Watt hours of electrical energy” per year:

Through a new copper-based engineering approach on an unprecedented scale, this paper proposes a safe means to draw up the mighty energy reserve of the Yellowstone Supervolcano from within the Earth, to superheat steam for spinning turbines at sufficient speed and on a sufficient scale, in order to power the entire USA. The proposed, single, multi-redundant facility utilizes the star topology in a grid array pattern to accomplish this. Over time, bleed-off of sufficient energy could potentially forestall this Supervolcano from ever erupting again.

I mean, this actually sounds like a great idea if it could be done safely, without ruining the park and, you know, accidentally blowing shit up. As of 2016, Iceland generated 65% of its energy from geothermal sources โ€” the US could certainly stand to lean more on geothermal.


The Assassin’s Teapot

The assassin’s teapot is certainly an eye-catching name for pottery, but there’s also an interesting bit of physics going on here. The teapot in question has two separate chambers for holding liquid, and the flow out of the pot from each chamber can be controlled by covering or uncovering small holes located on the handle. So, as the legend goes, a would-be assassin could pour themselves a perfectly fine drink from one chamber and then pour a poisoned drink to their prey from the other chamber, just by discreetly covering and uncovering the proper holes with their fingers. As the video explains, the mechanism here has to do with surface tension and air pressure.

You can get your own assassin’s teapot right here.


What’s the Deal with Ozempic, the “Breakthrough” Diabetes and Weight-Loss Drug?

In the last several months, semaglutide, a drug originally developed to help manage type 2 diabetes, has been in the news for its “breakthrough” weight loss abilities. This video from Vox is a good overview of what the drug does and the interest & controversy around it.

Both Ozempic and Wegovy, Ozempic’s counterpart approved specifically for weight loss by the FDA, are brand names of a drug called semaglutide. Semaglutide is one of several drugs that mimics a crucial digestive hormone called glucagon-like peptide 1, or GLP-1. It amplifies a process our bodies perform naturally.

GLP-1 is released in our intestines when we eat, and there are receptors for the hormone in cells all over the body. In the pancreas, GLP-1 promotes the production of insulin and suppresses the production of glucagon. This helps insulin-resistant bodies, like those with type 2 diabetes or obesity, manage blood sugar levels. In the stomach, GLP-1 slows gastric emptying, extending the feeling of being full. In the brain, GLP-1 suppresses appetite, which also promotes satiety and curbs hunger, so we eat less.

Jia Tolentino wrote a long piece about semaglutide for the New Yorker this week: Will Ozempic Change How We Think About Being Fat and Being Thin?

But, as I kept reminding Ozempic-curious friends, these medications were designed for chronic conditions, obesity and diabetes. For people who are dealing with those conditions, Ozempic appears to create a path toward a healthy relationship to food. For those who aren’t, it might function more like an injectable eating disorder. As the side effects make clear, it’s not a casual thing to drastically alter your body’s metabolic process, and there is no large-scale data about the safety of these drugs when taken by people who are mainly interested in treating another chronic condition, the desire to be thin.

Julia Belluz wrote a piece for Vox on Obesity in the age of Ozempic and Eric Topol wrote about The New Obesity Breakthrough Drugs.

Update: In the shuffle of the last few months, I’d missed reading Paul Ford’s piece about “the post-hunger age”, A New Drug Switched Off My Appetite. What’s Left?

I can see my anxiety mirrored in the wave of reactions starting to appear โ€” op-eds, TV segments, people explaining why it’s good, actually, that the vast majority of those using this drug lose a quarter of their body weight. On social media, fat activists are pointing out that our lives were worthy even without this drug. The wave of opinion will not crest for years.

And that’s fair because this is new โ€” not just the drug, but the idea of the drug. There’s no API or software to download, but this is nonetheless a technology that will reorder society. I have been the living embodiment of the deadly sin of gluttony, judged as greedy and weak since I was 10 years old-and now the sin is washed away. Baptism by injection. But I have no more virtue than I did a few months ago. I just prefer broccoli to gloopy chicken. Is this who I am?

Even outside the context of drugs, I find the tension between accepting who you are versus trying to change some behavior you find unappealing is challenging to navigate โ€” it’s something that comes up in therapy a lot. (thx, anil)


A Prelude to a Supernova

The luminous, hot star Wolf-Rayet 124 (WR 124) is prominent at the center of the James Webb Space Telescope's composite image combining near-infrared and mid-infrared wavelengths of light from Webb's Near-Infrared Camera and Mid-Infrared Instrument

Folks, I told you that this was going to become a JWST fan blog and if you didn’t hear me the first time, consider yourself notified. NASA’s newest space telescope is still stretching its legs, but even back in its early days last summer, it captured this breathtaking near-infrared and mid-infrared image of a star preparing to go supernova.

The 10 light-years-wide nebula is made of material cast off from the aging star in random ejections, and from dust produced in the ensuing turbulence. This brilliant stage of mass loss precedes the star’s eventual supernova, when nuclear fusion in its core stops and the pressure of gravity causes it to collapse in on itself and then explode.

Images like these are useful for studying dust, which sounds a little boring but actually is fascinating (italics mine):

The origin of cosmic dust that can survive a supernova blast and contribute to the universe’s overall “dust budget” is of great interest to astronomers for multiple reasons. Dust is integral to the workings of the universe: It shelters forming stars, gathers together to help form planets, and serves as a platform for molecules to form and clump together โ€” including the building blocks of life on Earth. Despite the many essential roles that dust plays, there is still more dust in the universe than astronomers’ current dust-formation theories can explain. The universe is operating with a dust budget surplus.

Currently imagining a sci-fi office dramedy about the dust budget surplus โ€” someone over at HBO Max or Apple+ get on this.


Finally, the Answers to Cold Weather Mysteries

If you live in any sort of winter climate, you have, at one time or another, wrestled with the two great mysteries of cold weather life:

1. Why does 50ยฐF in the fall make you want to bundle up while 50ยฐF in the spring makes you want to go for a walk in short sleeves?

2. Why the hell do kids wear shorts during the winter or go without coats when it’s literally freezing out? Like seriously, what the hell?

This short video answers both questions with one magical substance: brown fat.

55 degrees in the summer feels colder than 55 degrees in the winter. And 55 degrees as an adult likely feels colder than 55 degrees as a kid. But it’s not just a feeling. It all has to do with how our bodies use fat - specifically brown fat, a lesser-known type of fat that can produce roughly 300 times more heat than any other tissue in the body.

Brown fat isn’t the type of fat that adds to our weight (that’s white fat). Brown fat has the sole purpose of being burnt for heating the body, and it’s extremely effective at that. It only appears in specific parts of the body: around the neck, spine, heart, and kidneys. (It clumps around major blood vessels, in order to warm the blood as it passes through the body.)

In brief: 1. We have more brown fat in the spring, and 2. Kids have more brown fat in their bodies than adults. Cool! (har har)


Zeynep Tufekci: Here’s Why the Science Is Clear That Masks Work

You may have seen the online kerfuffle a few weeks ago about a study that was released recently that indicated that there was no evidence that masks work against respiratory illnesses (see Bret Stephen’s awful ideologically driven piece in the NY Times for instance). As many experts said at the time, that’s not what the review of the studies actually meant and the organization responsible recently apologized and clarified the review’s assertions.

In a typically well-argued and well-researched piece for the NY Times, Zeynep Tufekci explains what the review actually shows and why the science is clear that masks do work.

Scientists routinely use other kinds of data besides randomized reviews, including lab studies, natural experiments, real-life data and observational studies. All these should be taken into account to evaluate masks.

Lab studies, many of which were done during the pandemic, show that masks, particularly N95 respirators, can block viral particles. Linsey Marr, an aerosol scientist who has long studied airborne viral transmission, told me even cloth masks that fit well and use appropriate materials can help.

Real-life data can be complicated by variables that aren’t controlled for, but it’s worth examining even if studying it isn’t conclusive.

Japan, which emphasized wearing masks and mitigating airborne transmission, had a remarkably low death rate in 2020 even though it did not have any shutdowns and rarely tested and traced widely outside of clusters.

David Lazer, a political scientist at Northeastern University, calculated that before vaccines were available, U.S. states without mask mandates had 30 percent higher Covid death rates than those with mandates.

Randomized trials are difficult to do with masks and are not the only way to scientifically prove something. I’m hoping for an update that the entire premise of that Stephens piece is incorrect and will be removed from the Times’ website, but I don’t think it’s going to happen.


Travelling to The Most Extreme Place in The Universe

In a 1959 talk entitled There’s Plenty of Room at the Bottom, physicist Richard Feynman casually invented nanotechnology, inviting the audience and then the world to imagine exploring and making use of the “inner space” of the micro and nano realms. In this video from Kurzgesagt, thye imagine how things would seem if you could somehow shrink yourself down to the size of a grain of sand or a molecule or even smaller, sort of a more educational (but still fun) Ant-Man and the Wasp: Quantumania.

You are the size of a grain of sand just 2 mm high, standing on a blade of grass that seems as tall as an eight storey building to you. A square meter of lawn is now a dense metropolitan area, with 100,000 blades, or two Manhattans worth of grass towers. From your new tiny perspective, the park that you could quickly stroll through before, is now the size of France. Crossing it would take at least a week. Human-sized humans loom over you, 4 times taller than the Empire state building, their steps falling from horizon to horizon.

A bee the size of a helicopter lands near you, making the ground shake, as its hairy carapace vibrates with each wingbeat. You try to escape but are barely able to move because the air is so… gooey. Before you clicked the button air resistance was barely noticeable โ€” but as you’re now a thousand times smaller, it is as if the air has become a thousand times denser. It feels like you are moving through honey.

Flying insects like bees use this to their advantage. Their wings are not made for gliding but like paddles that row through the air. Scaled up to human size, the bee would outrun a Concorde Jet โ€” except it couldn’t even take off because it would be too heavy for its wings.

See also Meet the Nano Sapiens, Scaling Laws and the Speed of Animals, The Biology of B-Movie Monsters, and Powers of Ten.


Unprecedented Infrared Photos of Nearby Galaxies

a top-down view of a galaxy

a top-down view of a galaxy

I don’t know how kottke.org isn’t going to turn into a JWST-only blog โ€” it seems like there’s some never-before-seen imagery released every other week that just absolutely knocks my socks off. Like these unprecedented images of nearby galaxies that were taken to help study how individual stars affect galactic structure.

The saying goes, ‘From a tiny acorn grows the mighty oak.’ This is accurate not just here on Earth, but in our solar system and beyond. Even on a galactic scale, where individual stars and star clusters can sculpt a galaxy’s overall structure. Scientists say NASA’s James Webb Space Telescope is perfectly primed to study these phenomena, and the first data is astounding astronomers.

New imagery from Webb’s Mid-Infrared Instrument is revealing never-before-seen details into how young, newly forming stars influence the structure of the gas and dust of nearby galaxies, and therefore how they evolve over time. Areas of galaxies that once appeared dim and dark in visible light, now under Webb’s infrared eye, are glowing cavities and huge cavernous bubbles of gas and dust.


New Synthetic Antibiotic “Cures Superbugs Without Bacterial Resistance”

Well, this is potentially a huge deal:

In a potential game changer for the treatment of superbugs, a new class of antibiotics was developed that cured mice infected with bacteria deemed nearly “untreatable” in humans โ€” and resistance to the drug was virtually undetectable.

Developed by a research team of UC Santa Barbara scientists, the study was published in the journal eBioMedicine. The drug works by disrupting many bacterial functions simultaneously โ€” which may explain how it killed every pathogen tested and why low-level of bacterial resistance was observed after prolonged drug exposure.

Huge if true, etc. What really caught my attention is how they discovered this in the first place…they were working on a way to charge cell phones:

The discovery was serendipitous. The U.S. Army had a pressing need to charge cell phones while in the field โ€” essential for soldier survival. Because bacteria are miniature power plants, compounds were designed by Bazan’s group to harness bacterial energy as a “‘microbial”’ battery. Later the idea arose to re-purpose these compounds as potential antibiotics.

“When asked to determine if the chemical compounds could serve as antibiotics, we thought they would be highly toxic to human cells similar to bleach,” said Mahan, the project lead investigator. “Most were toxic โ€” but one was not โ€” and it could kill every bacterial pathogen we tested.”

Here’s the original paper if you’d like to take a look.


Leonardo da Vinci’s Surprisingly Accurate Experiments with Gravity

notes and graphs from Leonardo da Vinci regarding his gravity experiments

This is super-interesting: in papers written by Leonardo da Vinci collected in the Codex Arundel, he documents experiments that show that gravity is a form of acceleration and also calculated the gravitational constant to within 97% accuracy, hundreds of years before Newton formalized gravity in theory.

In an article published in the journal Leonardo, the researchers draw upon a fresh look at one of da Vinci’s notebooks to show that the famed polymath had devised experiments to demonstrate that gravity is a form of acceleration โ€” and that he further modeled the gravitational constant to around 97 percent accuracy.

Da Vinci, who lived from 1452 to 1519, was well ahead of the curve in exploring these concepts. It wasn’t until 1604 that Galileo Galilei would theorize that the distance covered by a falling object was proportional to the square of time elapsed and not until the late 17th century that Sir Isaac Newton would expand on that to develop a law of universal gravitation, describing how objects are attracted to one another. Da Vinci’s primary hurdle was being limited by the tools at his disposal. For example, he lacked a means of precisely measuring time as objects fell.

As the piece notes, Leonardo didn’t get things exactly right:

Da Vinci sought to mathematically describe that acceleration. It is here, according to the study’s authors, that he didn’t quite hit the mark. To explore da Vinci’s process, the team used computer modeling to run his water vase experiment. Doing so yielded da Vinci’s error.

“What we saw is that Leonardo wrestled with this, but he modeled it as the falling object’s distance was proportional to 2 to the t power [with t representing time] instead proportional to t squared,” Roh says. “It’s wrong, but we later found out that he used this sort of wrong equation in the correct way.” In his notes, da Vinci illustrated an object falling for up to four intervals of time-a period through which graphs of both types of equations line up closely.

But it’s still pretty impressive how far he did get. The piece also notes that this work was discovered because the codex was made available online to the general public, demonstrating the value of easy access of materials like this.


Supermassive Black Holes: A Possible Source of Dark Energy

A group of astronomers say they have evidence that links supermassive black holes at galactic centers with dark energy, the mysterious force that accounts for roughly 68% of the energy in the universe. Here’s the news release and the paper. From the Guardian:

Instead of dark energy being smeared out across spacetime, as many physicists have assumed, the scientists suggest that it is created and remains inside black holes, which form in the crushing forces of collapsing stars.

“We propose that black holes are the source for dark energy,” said Duncan Farrah, an astronomer at the University of Hawaii. “This dark energy is produced when normal matter is compressed during the death and collapse of large stars.”

The claim was met with raised eyebrows from some independent experts, with one noting that while the idea deserved scrutiny, it was far too early to link black holes and dark energy. “There’s a number of counter-arguments and facts that need to be understood if this claim is going to live more than a few months,” said Vitor Cardoso, a professor of physics at the Niels Bohr Institute in Copenhagen.

And here’s a short video explainer:

It’s a radical claim to be sure โ€” it’ll be interesting to see how it shakes out in the weeks and months to come as other scientists interpret the results.


Proteins and Life: How Do Dead Things Become Alive?

DNA and RNA get all of the headlines, but it’s not difficult to argue that much of the glorious complexity and possibility of life is due to proteins. In the latest episode of Kurzgesagt, they explain the role of cellular proteins in creating life.

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?

As always, you can see a list of their sources and further reading for the video.


New Massive Image of the Milky Way with 3.32 Billion Individual Objects

image of part of the Milky Way with 3.32 billion individually identifiable objects

small portion of an image of part of the Milky Way with 3.32 billion individually identifiable objects

Thanks to a planet-wide collaboration, scientists have released an image of the Milky Way that contains 3.32 billion individually identifiable objects, most of which are stars.

Gathering the data required to cover this much of the night sky was a Herculean task; the DECaPS2 survey identified 3.32 billion objects from over 21,400 individual exposures. Its two-year run, which involved about 260 hours of observations, produced more than 10 terabytes of data.

Most of the stars and dust in the Milky Way are located in its spiral disk โ€” the bright band stretching across this image. While this profusion of stars and dust makes for beautiful images, it also makes the galactic plane challenging to observe. The dark tendrils of dust seen threading through this image absorb starlight and blot out fainter stars entirely, and the light from diffuse nebulae interferes with any attempts to measure the brightness of individual objects. Another challenge arises from the sheer number of stars, which can overlap in the image and make it difficult to disentangle individual stars from their neighbors.

It’s worth checking out the largest size of the image published on the web (which is actually much smaller than the image’s actual size) as well as a tiny portion of the full image (second image above) that shows just how much detail is there. A zoomable interface for the entire image is available here.


Where the Elements Came From

a color-coded periodic table of the elements that shows how each element was created

From Wikipedia contributor Cmglee and Astronomy Picture of the Day, a color-coded periodic table that displays which cosmic events โ€” the Big Bang, exploding stars, merging neutron stars, etc. โ€” was responsible for creating each element, according to our present understanding of the universe.

The hydrogen in your body, present in every molecule of water, came from the Big Bang. There are no other appreciable sources of hydrogen in the universe. The carbon in your body was made by nuclear fusion in the interior of stars, as was the oxygen. Much of the iron in your body was made during supernovas of stars that occurred long ago and far away. The gold in your jewelry was likely made from neutron stars during collisions that may have been visible as short-duration gamma-ray bursts or gravitational wave events.

The data for the table came from OSU’s Jennifer Johnson, who quotes Carl Sagan:

The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. We are made of starstuff.

(thx, caroline)


H5N1 Bird Flu: “An Even Deadlier Pandemic Could Soon Be Here”

Zeynep Tufekci on the H5N1 strain of the avian influenza, which is showing some recent signs of spreading in mammals.

Bird flu — known more formally as avian influenza — has long hovered on the horizons of scientists’ fears. This pathogen, especially the H5N1 strain, hasn’t often infected humans, but when it has, 56 percent of those known to have contracted it have died. Its inability to spread easily, if at all, from one person to another has kept it from causing a pandemic.

But things are changing. The virus, which has long caused outbreaks among poultry, is infecting more and more migratory birds, allowing it to spread more widely, even to various mammals, raising the risk that a new variant could spread to and among people.

Alarmingly, it was recently reported that a mutant H5N1 strain was not only infecting minks at a fur farm in Spain but also most likely spreading among them, unprecedented among mammals. Even worse, the mink’s upper respiratory tract is exceptionally well suited to act as a conduit to humans, Thomas Peacock, a virologist who has studied avian influenza, told me.

The three relevant facts here are: 56% of humans who’ve contracted H5N1 have died, there are signs of spreading among mammals, and that particular mammal is “exceptionally well suited” to pass viral infections along to humans. Tufekci, who attempted to sound the alarm relatively early-on about Covid-19, goes on to urge the world to action about H5N1, before it’s too late. Will we act? (No. The answer is no.)

*sigh*

You know, it’s a little shocking to read about a potential solution to the Fermi paradox on a random February Monday, but here we are.