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kottke.org posts about science

Tetanus Has Nothing To Do With Rust

posted by Tim Carmody   Mar 15, 2019

Tetanus, popularly called “lockjaw,” is a serious illness, fatal in 10 percent of cases in North America and a larger percentage elsewhere. But despite the popular perception of its association with cutting oneself on a rusty nail, the disease has nothing to do with iron oxide, or rust:

Rather, tetanus is a product of the bacteria Clostridium tetani, which is in dirt, dust, and feces—in other words, everywhere. It can enter your body through puncture wounds, yes, but also through superficial cuts, bug bites, surgical procedures, and any other rupture to your skin. It can come from stepping on a rusty nail, or tending the soil in your garden. That’s why it’s so essential to track your booster shots: You need one every decade, not just when you rip your palm open on a rusty chain link fence. Waiting for a classic tetanus injury won’t work when anything could, in theory, be a tetanus injury.

If the bacteria enter your body and you aren’t up-to-date on your vaccinations, the tiny invaders begin to multiply rapidly. This incubation period, which lasts between three and 21 days, according to the CDC, is symptom free. But as the bacteria begin to die inside you, they form a neurotoxin that attacks the nervous system. Specifically, it inhibits the chemical GABA, which regulates muscle contractions. The result is a body-wide state of tension, from lockjaw in your face to uncontrollable arching spasms in your back to permanently-curled toes.

Luckily, here as elsewhere, tetanus vaccines (a series of three shots and a booster every ten years) work. Get those shots up to date and mind those cuts, no matter where they came from.

What Counts As Evidence in Mathematics?

posted by Tim Carmody   Mar 15, 2019

Einstein-Blackboard-01.jpg

The ultimate form of argument, and for some, the most absolute form of truth, is mathematical proof. But short of a conclusive proof of a theorem, mathematicians also consider evidence that might 1) disprove a thesis or 2) suggest its possible truth or even avenues for proving that it’s true. But in a not-quite-empirical field, what the heck counts as evidence?

The twin primes conjecture is one example where evidence, as much as proof, guides our mathematical thinking. Twin primes are pairs of prime numbers that differ by 2 — for example, 3 and 5, 11 and 13, and 101 and 103 are all twin prime pairs. The twin primes conjecture hypothesizes that there is no largest pair of twin primes, that the pairs keep appearing as we make our way toward infinity on the number line.

The twin primes conjecture is not the Twin Primes Theorem, because, despite being one of the most famous problems in number theory, no one has been able to prove it. Yet almost everyone believes it is true, because there is lots of evidence that supports it.

For example, as we search for large primes, we continue to find extremely large twin prime pairs. The largest currently known pair of twin primes have nearly 400,000 digits each. And results similar to the twin primes conjecture have been proved. In 2013, Yitang Zhang shocked the mathematical world by proving that there are infinitely many prime number pairs that differ by 70 million or less. Thanks to a subsequent public “Polymath” project, we now know that there are infinitely many pairs of primes that differ by no more than 246. We still haven’t proved that there are infinitely many pairs of primes that differ by 2 — the twin primes conjecture — but 2 is a lot closer to 246 than it is to infinity.

This starts to get really complicated once you leave the relatively straightforward arithmetical world of prime numbers behind, with its clearly empirical pairs and approximating conjectures, and start working with computer models that generate arbitrarily large numbers of mathematical statements, all of which can be counted as evidence.

Patrick Hanner, the author of this article, gives what seems like a simple example: are all lines parallel or intersecting? Then he shows how the models one can use to answer this question vary wildly based on their initial assumptions, in this case, whether one is considering lines in a single geometric plane or lines in an n-dimensional geometric space. As always in mathematics, it comes back to one’s initial set of assumptions; you can “prove” (i.e., provide large quantities of evidence for) a statement with one set of rules, but that set of rules is not the universe.

Video of a Japanese Space Probe Touching Down on an Asteroid

posted by Jason Kottke   Mar 05, 2019

In this video released by JAXA, the Japanese space agency, you can see an on-board view of the Hayabusa2 probe touching down on an asteroid called Ryugu.

The blast you see is the probe firing a bullet made of tantalum at the surface in order to collect a sample. Here’s a photo of the landing site. From Wikipedia:

When the sampler horn attached to Hayabusa2’s underside touched the surface, a projectile (5-gram tantalum bullet) was fired at 300 m/s into the surface. The resulting ejecta particles were collected by a catcher at the top of the horn, which the ejecta reaches under their own momentum under microgravity conditions.

This is the first of three samples that are scheduled to be collected by Hayabusa2. The third sampling will try to collect material located under the surface of the asteroid. To achieve this, a separate gun will detach from the probe and fire a copper bullet at the surface, blasting a hole in the surface and exposing “pristine material”. Meanwhile, the probe itself will deploy a separate camera to watch the bullet’s impact, scoot out of the way to avoid debris, and then come back in a couple of weeks to collect a sample from the resulting crater, which will then be returned to Earth along with the other two samples. Ingenious! I love it when a plan comes together!

Flat-Earther Proves in Simple Experiment that the Earth Is Round

posted by Jason Kottke   Feb 26, 2019

Behind the Curve, now available on Netflix, is a 2018 documentary about the global community of people who believe that the Earth is flat. In this scene at the end of the film (um, spoilers?), a Flat-Earther named Jeran Campanella devises a simple experiment that he claims will prove that the Earth is flat…but very quickly proves the opposite:

Campanella’s reaction: “Interesting. Interesting. That’s interesting.” This is one of two straightforward experiments shown in the film that are devised by Flat-Earthers to prove the planet’s flatness that end up affirming that the Earth is indeed round (or, more accurately, an oblate spheroid).

One of the more jaw-dropping segments of the documentary comes when Bob Knodel, one of the hosts on a popular Flat Earth YouTube channel, walks viewers through an experiment involving a laser gyroscope. As the Earth rotates, the gyroscope appears to lean off-axis, staying in its original position as the Earth’s curvature changes in relation. “What we found is, is when we turned on that gyroscope we found that we were picking up a drift. A 15 degree per hour drift,” Knodel says, acknowledging that the gyroscope’s behavior confirmed to exactly what you’d expect from a gyroscope on a rotating globe.

“Now, obviously we were taken aback by that. ‘Wow, that’s kind of a problem,’” Knodel says. “We obviously were not willing to accept that, and so we started looking for ways to disprove it was actually registering the motion of the Earth.”

Knodel & Campanella are the co-hosts of a YouTube channel called Globebusters (I’m not going to link to it…YouTube’s conspiracy-minded algorithms don’t need any help) where they claim to debunk the Earth’s curvature and heliocentrism as well as discussing how NASA fakes space activities. Their failed experiments don’t seem to have diminished their Flat Earth zeal. One of their recent videos, nearly 4 hours long, is an attempt to “[debunk] the bogus claim that Globebusters proved a 15 degree per hour rotation of the Earth” and another, also almost 4 hours long, is a rebuttal to the “misrepresentation” of their views and experiments in Behind the Curve.

Goodbye Opportunity, the Little Mars Rover that Could

posted by Jason Kottke   Feb 14, 2019

Yesterday, NASA declared the official end to the Opportunity rover mission on Mars.

One of the most successful and enduring feats of interplanetary exploration, NASA’s Opportunity rover mission is at an end after almost 15 years exploring the surface of Mars and helping lay the groundwork for NASA’s return to the Red Planet.

The Opportunity rover stopped communicating with Earth when a severe Mars-wide dust storm blanketed its location in June 2018. After more than a thousand commands to restore contact, engineers in the Space Flight Operations Facility at NASA’s Jet Propulsion Laboratory (JPL) made their last attempt to revive Opportunity Tuesday, to no avail. The solar-powered rover’s final communication was received June 10.

Opportunity was the longest-lived robot ever sent to another planet; it lasted longer than anyone could have imagined.

Designed to last just 90 Martian days and travel 1,100 yards (1,000 meters), Opportunity vastly surpassed all expectations in its endurance, scientific value and longevity. In addition to exceeding its life expectancy by 60 times, the rover traveled more than 28 miles (45 kilometers) by the time it reached its most appropriate final resting spot on Mars — Perseverance Valley.

Here’s a quick video overview of the milestones of Opportunity’s mission:

The NY Times has a great interactive feature about the rover’s activities and achievements and XKCD has a tribute.

Xkcd Oppy

The Hoover Dam’s “Hidden” 26,000-Year Astronomical Monument

posted by Jason Kottke   Feb 13, 2019

There’s a little-known monument located at the site of the Hoover Dam that shows the progression of “North Stars” as the Earth moves through its 25,772-year change of rotational axis. Alexander Rose of the Long Now Foundation couldn’t find much public documentation related to this celestial map, so he did some research.

I now had some historical text and photos, but I was still missing a complete diagram of the plaza that would allow me to really understand it. I contacted the historian again, and she obtained permission from her superiors to release the actual building plans. I suspect that they generally don’t like to release technical plans of the dam for security reasons, but it seems they deemed my request a low security risk as the monument is not part of the structure of the dam. The historian sent me a tube full of large blueprints and a CD of the same prints already scanned. With this in hand I was finally able to re-construct the technical intent of the plaza and how it works.

In order to understand how the plaza marks the date of the dam’s construction in the nearly 26,000-year cycle of the earth’s precession, it is worth explaining what exactly axial precession is. In the simplest terms, it is the earth “wobbling” on its tilted axis like a gyroscope — but very, very slowly. This wobbling effectively moves what we see as the center point that stars appear to revolve around each evening.

Presently, this center point lies very close to the conveniently bright star Polaris. The reason we have historically paid so much attention to this celestial center, or North Star, is because it is the star that stays put all through the course of the night. Having this one fixed point in the sky is the foundation of all celestial navigation.

Here are some explanatory notes that Rose wrote over the blueprints of the monument showing how to read the map:

Hoover Celestial Map

A Flyover of Europa

posted by Jason Kottke   Feb 11, 2019

Using recently processed data from the Galileo probe, NASA-JPL software engineer Kevin Gill created this low-altitude flyover of Europa, one of Jupiter’s moons.

The surface was imaged between 1996 & 1998 and is made up of a water-ice crust. Despite the cracks and streaks that you can see in the video, Europa actually has the smoothest surface of any object in the solar system.

These images are not super high-res because they were taken with equipment designed and built in the 80s. But we’re going to get a better look at Europa soon…both ESA’s JUICE probe and NASA’s Europa Clipper are planning on imaging the moon in the next decade.

Watch a Single Cell Become a Complex Organism in Just Six Minutes

posted by Jason Kottke   Feb 07, 2019

In this time lapse filmed by Jan van IJken, the embryo of a salamander is shown transforming into a hatched tadpole, from a single cell to a complex organism in a three-week process that’s condensed into just six minutes of video.

The first stages of embryonic development are roughly the same for all animals, including humans. In the film, we can observe a universal process which normally is invisible: the very beginning of an animal’s life. A single cell is transformed into a complete, complex living organism with a beating heart and running bloodstream.

The Colonization of the Americas Cooled the Earth

posted by Jason Kottke   Feb 06, 2019

A new paper from researchers at University College London argues that the genocide of indigenous peoples in the Americans after Columbus’s landing in 1492 had a significant effect on the Earth’s global climate and was a major cause of the Little Ice Age, the dip in global temperatures from the 16th to the 19th centuries. They estimate that 55 million indigenous people died during Europe’s conquest of the Americas (~90% of the population), and the 56 million hectares of land that they had cleared of vegetation (roughly the area of Kenya) was then reclaimed by forests, which then took in more carbon dioxide, reduced the greenhouse effect, and caused the Earth to cool. From the paper’s conclusion:

We calculate that this led to an additional 7.4 Pg C being removed from the atmosphere and stored on the land surface in the 1500s. This was a change from the 1400s of 9.9 Pg C (5 ppm CO2). Including feedback processes this contributed between 47% and 67% of the 15-22 Pg C (7-10 ppm CO2) decline in atmospheric CO2 between 1520 CE and 1610 CE seen in Antarctic ice core records. These changes show that the Great Dying of the Indigenous Peoples of the Americas is necessary for a parsimonious explanation of the anomalous decrease in atmospheric CO2 at that time and the resulting decline in global surface air temperatures.

Little Ice Age Graph

The authors also assert that this effect of human action on global climate marks the beginning of the Anthropocene epoch.

I first heard about this theory from Charles Mann’s excellent 1493, which led me to William Ruddiman’s 2003 paper. I heard about this most recent study from Mann too… he called it “most careful study of the impacts of Euro conquest of Americas I’ve yet seen”.

If you’re not up for reading the paper itself, you can check out the coverage from the BBC, the Guardian, Nature, or the NY Times.

What Time Is the Super Bowl? (According to a Theoretical Physicist)

posted by Jason Kottke   Jan 31, 2019

Ever since the Huffington Post struck SEO gold in 2011 with their post about what time the Super Bowl started, pretty much every online publication now runs a similar article in an attempt to squeeze some of Google’s juice into their revenue stream. My “attempt” from last year: What Time Isn’t the Super Bowl?

For this year’s contest, Sports Illustrated decided to ask theoretical physicist Carlo Rovelli, author of The Order of Time, his thoughts on time and Super Bowls.

6:30 p.m. is the time the Super Bowl will start in Atlanta. Most of us are not in Atlanta. So for us, the game will start later than that. You need the time for the images to be captured by the cameras, be broadcasted to air or cable, be captured by my TV screen, leave my TV screen, get to my eyes (not to mention the time my brain needs to process and decode the images). You may say this is fast — of course this is fast. But it takes some time nevertheless, and I am a physicist, I need precision. For most of us, the game will actually start some time later than the kickoff in Atlanta.

Not only that, but time moves at different speeds for each of us:

We have discovered that clocks run at different speed depending on how fast they are moved, and depending on how high they are positioned. That’s right, it is a fact: Two equal clocks go out of time with respect each other if one is moved and the other is kept fixed. The same will happen if one is kept, say, above your head, and the other lower, say, at your feet. All this was discovered by Einstein a century ago; for a while it was just brainy stuff for nerds, but today we are sure it is true. A good lab clock can check this, and it is truly true. Your head lives a bit longer than your feet (unless you spend a lot of time upside down).

So, the clock of the guy up in the high sections of the stadium runs faster than the clock of the referee on the field. And Tom Brady’s clock (if he were to wear one) runs slower, because Tom moves fast (okay, maybe not “fast,” but faster than the people sitting and watching him).

P.S. The Super Bowl starts at approximately 6:30pm EST on Feb 3, 2019. (via laura olin)

It’s So Cold Out! Where’s the Global Warming?!

posted by Jason Kottke   Jan 30, 2019

In what is now an annual tradition, when the temperatures in some part of the US plunge below zero degrees on the Fahrenheit scale, some nitwit Republican climate change-denier live-tweets from the back pocket of industry something like “It’s so cold out where’s the global warming when we need it???? #OwnTheLibs”. This time around, it was our very own Shitwhistle-in-Chief who tweeted merrily about the current polar vortex bearing down on the Midwest:

In the beautiful Midwest, windchill temperatures are reaching minus 60 degrees, the coldest ever recorded. In coming days, expected to get even colder. People can’t last outside even for minutes. What the hell is going on with Global Waming? Please come back fast, we need you!

Some time ago, Randall Munroe addressed what severe cold in the US has to do with climate change on XKCD: it used to be colder a lot more often but we don’t really remember it.

XKCD Cold Weather Global Warming

When I was a kid growing up in Wisconsin, I recall experiencing overnight low temperatures in the -30°F to -40°F range several times and vividly remember being stranded in my house for a week in 1996 when the all-time record low for the state (-55°F) was established in nearby Couderay.

Munroe’s observation isn’t even the whole story. Jennifer Francis, senior scientist at the Woods Hole Research Center, writes that the polar vortex bringing cold air into the Midwest is connected to the rapidly warming Arctic.

Because of rapid Arctic warming, the north/south temperature difference has diminished. This reduces pressure differences between the Arctic and mid-latitudes, weakening jet stream winds. And just as slow-moving rivers typically take a winding route, a slower-flowing jet stream tends to meander.

Large north/south undulations in the jet stream generate wave energy in the atmosphere. If they are wavy and persistent enough, the energy can travel upward and disrupt the stratospheric polar vortex. Sometimes this upper vortex becomes so distorted that it splits into two or more swirling eddies.

These “daughter” vortices tend to wander southward, bringing their very cold air with them and leaving behind a warmer-than-normal Arctic.

(via @mkonnikova)

In a Race to the Edge of the Solar System, Which Star Trek Ship Would Win?

posted by Jason Kottke   Jan 29, 2019

These visualizations of the speed of light I posted last week somehow demonstrate both how fast light speed is and how slow it is compared the vastness of the galaxy & universe. Science fiction often bends the rules of physics as we currently understand them, with fictional spacecraft pushing beyond the speed of light. In Star Trek, the measure of a ship’s velocity is warp speed. Warp 1 is the speed of light, Warp 6 is 392 times the speed of light, etc. In this Warp Speed Comparison video, EC Henry compares the top speeds of various Star Trek vessels (the original Enterprise, Voyager, the Defiant), racing them from Earth to the edge of the solar system.

Once again, you get a real sense of how fast these ships would be if they actually existed but also of the vastness of space. It would take 10 seconds for the fastest ship to reach the edge of the solar system at maximum warp and just over 6 hours to get to the nearest star, Proxima Centauri. Wikipedia lists a few dozen stars that are within a day’s journey at full warp…a trip that takes light more than 16 years. The mighty speed of light is no match for the human imagination. (thx, jim)

Visualizing the Speed of Light

posted by Jason Kottke   Jan 24, 2019

Light is fast! In a recent series of animations, planetary scientist James O’Donoghue demonstrates just how fast light is…and also how far away even our closest celestial neighbors are. Light, moving at 186,000 mi/sec, can circle the Earth 7.5 times per second and here’s what that looks like:

It can also travel from the surface of the Earth to the surface of the Moon in ~1.3 seconds, like so:

That seems both really fast and not that fast somehow. Now check out light traveling the 34 million miles to Mars in a pokey 3 minutes:

And Mars is close! If O’Donoghue made a real-time animation of light traveling to Pluto, the video would last over 5 hours. The animation for the closest undisputed galaxy, Seque 1, would last 75,000 years and 2.5 million years for the Andromeda galaxy animation. The farthest-known objects from Earth are more than 13 billion light years away. Light is slow!

See also The Leisurely Pace of Light Speed.

Universe, a Short Documentary from 1960 that Inspired Kubrick’s 2001

posted by Jason Kottke   Jan 23, 2019

In 1960, the National Film Board of Canada released a short documentary called Universe. The film follows the work of astronomer Donald MacRae at an observatory in Ontario, which is accompanied a special effects-heavy tour of the solar system, galaxy, and universe: “a vast, awe-inspiring picture of the universe as it would appear to a voyager through space”. Universe was nominated for an Oscar in 1961 and also caught the eye of Stanley Kubrick, who used it as inspiration for 2001: A Space Odyssey.

“Stanley had seen the National Film Board movie Universe.” Most of the crew on 2001 were familiar with the Canadian production, made by filmmakers Colin Low and Roman Kroitor, all having seen it at the early stages of 2001’s production, it being “required watching” at the insistence of Kubrick himself, who had seen the documentary “almost 100 times”, “until the sprockets wore out,” 2001 special effects supervisor Con Pedersen remembers.

Kubrick was so taken by the depiction of the celestial objects in the film that he hired the co-director and a special effects technician from Universe to work on 2001. The narrator of Universe, Douglas Rain, also became a integral part of Kubrick’s masterpiece. After ditching the idea that 2001 would be narrated by Rain — “as more film cut together, it became apparent narration was not needed” — Kubrick chose Rain as the now-iconic voice of HAL 9000.

After finally excising the narrator altogether, he simply made Rain the voice of HAL, liking his “bland mid-Atlantic accent”. The decision was entirely Kubrick’s, who had become concerned with the character of the computer. “Kubrick was having,” Rain says, “a problem with the computer. ‘I think I made him too emotional and too human,’ he said. ‘I’m having trouble with what I’ve got in the can. Would you consider doing his voice?’ So we decided on the voice of the computer.”

But back to Universe, which is a marvelous little film (even though it asserts at one point that “it is reasonably certain” that Mars contains vegetation). I love the early sequence of the astronomer setting up his telescope — the way he walks along inside of it and then casually lifts it up into place. It’s really just a bigger version of the small reflector that I have, not any more complicated than a couple of mirrors pointed in the right direction. It’s incredible what we humans have learned about the universe simply by collecting ancient starshine with polished lenses and mirrors. (via clayton cubitt)

Why Is the Night Sky Dark?

posted by Jason Kottke   Jan 17, 2019

I love how simple questions can reveal deep truths about how the universe works. Take “why is the night sky dark?” It’s a question a small child might ask but stumped the likes of Newton, Halley, and Kepler and wasn’t really resolved until Einstein’s theory of general relativity and the Big Bang theory rolled around. Here’s the paradox: if we live in a static infinite universe, shouldn’t the sky be unbearably bright?

Distant stars look weak, and very distant stars shine too dimly for you to see with your eyes. But when space telescopes like Hubble peer deep into the darkest spots of sky, they uncover bunches of incredibly faint galaxies. And the deeper they look, the more they find. If the universe went on forever with stars sprinkled evenly throughout — as many early stargazers assumed — the night sky would be full of so many points of light that it would never look dark.

“The fact that the stars are everywhere makes up for the fact that some of the stars are far away,” says Katie Mack, an astrophysicist at North Carolina State University. No matter which way you look, in an endless universe your line of sight would always end smack on the surface of a star, and the entire sky would always blaze with the brightness of the sun.

The answer to this paradox is that the universe is both finite & unbounded (per Einstein) and the darkness we see is the Big Bang.

The mystery of the dark sky is solved by the fact that this history has a beginning — a time before stars and galaxies. Many cosmologists think the universe started out as a very small point, and then started inflating like a balloon in an event called the Big Bang. If you look deep enough, you can see so far back in time that you get close to the Big Bang. “You just run out of stars,” Kinney says. “And you run out of stars, in the grand scheme of things, relatively quickly.”

If you’re anything like me, you just had a Little Bang go off in your brain. (via laura olin)

The Incurable Disease vs the Relentless Couple

posted by Jason Kottke   Jan 16, 2019

When Sonia Vallabh lost her mother to a rare disease called fatal familial insomnia, she soon found out that she had inherited the disease, that there was no cure, and that she’d be dead in “a decade or two”. Despite almost no scientific training, Vallabh and her husband both quit their jobs to work on a cure. Talk about going all-in.

Within a few weeks of the diagnosis, Sonia had quit her job to study science full time, continuing classes at MIT during the day and enrolling in a night class in biology at Harvard’s extension school. The pair lived off savings and Eric’s salary. Sonia had expected to take a temporary sabbatical from her real life, but soon textbooks and academic articles weren’t enough. “The practice of science and the classroom version of science are such different animals,” Sonia says. She wanted to try her hand in the lab. She found a position as a technician with a research group focusing on Huntington’s disease. Eric, not wanting to be left behind, quit his job too and offered his data-crunching expertise to a genetics lab. The deeper they dove into science, the more they began to fixate on finding a cure.

They’re now on the brink of getting their Harvard PhDs and are pushing ahead with a promising medical therapy.

As soon as the couple began their presentation, Lander says, there was a sense of “pushing on an open door” — quite a surprise, given the agency’s stodgy reputation. “People still flat-out don’t believe the FDA was cool with it,” Minikel says. Afterward, one of the 25 scientists in the audience pulled Lander aside and said, “That was one of the best presentations I’ve ever seen.” Schreiber agreed. He alluded to a pharmaceutical company he’d helped set up early in his career. “Twenty-four years into that company, there was nothing to show for it. Not one thing,” he says. “For two graduate students who are not trained in science to come in and do what they did? Absolute forces of nature, savants. They keep seeing things that other people don’t see.”

Update: D.T. Max wrote a book on prions and prion-based diseases called The Family That Couldn’t Sleep. I looked in the kottke.org archives and found a 2010 post on a National Geographic article Max wrote about sleep that specifically referenced fatal familial insomnia:

The main symptom of FFI, as the disease is often called, is the inability to sleep. First the ability to nap disappears, then the ability to get a full night’s sleep, until the patient cannot sleep at all. The syndrome usually strikes when the sufferer is in his or her 50s, ordinarily lasts about a year, and, as the name indicates, always ends in death.

(via @mattbucher)

The Self-Domestication of Humans

posted by Jason Kottke   Jan 11, 2019

In an essay adapted from his forthcoming book, The Goodness Paradox: The Strange Relationship Between Virtue and Violence in Human Evolution, anthropologist Richard Wrangham says that before humans domesticated dogs, cows, and pigs, we domesticated ourselves.

No other mammal has the brainpower to organize capital punishment. When language became sufficiently sophisticated, our ancestors’ ability to conspire led not only to a more peaceful species but also to a new kind of hierarchy. No longer would human groups be ruled by the physical force of an individual. The emergence of capital punishment meant that henceforth, anyone aspiring to be an alpha couldn’t get away with just being a fighter. He had to be a politician, too.

The result of generations of such selective pressure is that human beings are best understood as an animal species that has been domesticated — like dogs, horses or chickens. Recent archaeological evidence suggests that humans became increasingly docile and less reactively aggressive around the time of becoming Homo sapiens, a process that started about 300,000 years ago.

Markers of domestication show up in the fossil records of domesticated animals and they are present in human fossils too:

Dr. Leach listed four characteristics of the bones of domesticated animals: They mainly have smaller bodies than their wild ancestors; their faces tend to be shorter and don’t project as far forward; the differences between males and females are less highly developed; and they tend to have smaller brain cavities (and thus brains). As it turns out, all of these changes appear in human fossils. Even our brain size fits the pattern: While the human brain grew steadily over the last two million years, that trajectory took a sudden turn about 30,000 years ago, when brains started to become smaller.

The essay is from the WSJ and might be paywalled…here’s an article from Big Think early last year that goes over some of the same material. I couldn’t find a definitive paper that Wrangham has written on the topic…feel free to browse through his published papers on Google Scholar.

Slipping the Surly Bonds of Earth

posted by Jason Kottke   Jan 10, 2019

Shuttle Endeavour rising through the clouds

I love this photo of the Space Shuttle Endeavour rising through the clouds on a plume of smoke during its last launch in 2011. We are but infinitesimal specks on a tiny rock orbiting a small star in an ordinary galaxy among trillions in an endless universe. And yet we’ve pushed our way into that vastness, just a little bit. I wonder where we’ll end up?

Richard Feynman and the Myth of Separating Science from the Scientist

posted by Jason Kottke   Jan 09, 2019

In Surely You’re a Creep, Mr. Feynman, science historian Leila McNeill writes about the difficulty in separating science from the behavior of the scientist.

In addition to cataloguing the trespasses of individual scientists who abuse the cultural power of their position, we have to dismantle the structures that have allowed their abuses to continue with little to no disruption. Just for starters, this means abandoning the myth that the science can be separated from the scientist.

The conversation about separating the person from the practice has been slower to surface in science than it has in the literary, film, journalism, and art worlds. It might seem that there is less distance between an artist and the thing they create than for their counterparts in the sciences because art is often positioned as subjective and abstract. It’s easier to draw a clear line from a writer like Junot Diaz who has displayed abusive behaviors to women in real life and his male characters who do the same. Scientists, however, have been framed as objective observers of phenomena while scientific practice itself has been seen as empirical, measureable, stable, and separate. This typical framing disconnects science from the rest of the world, allowing it to be perceived as a disembodied conduit for unadulterated knowledge. But science isn’t just a body of knowledge; it’s an institution and a culture with material connections to a lived-in world. Its practitioners are makers of and participants in that institution and culture.

Our Unbounded Finite Universe

posted by Jason Kottke   Jan 08, 2019

I’ve always had a hard time wrapping my head around the idea that the universe could be both finite and infinite at the same time (or something like that *takes bong rip*), but this passage from Coming of Age in the Milky Way by Timothy Ferris succinctly explains what’s going on:

General relativity resolved the matter by establishing that the universe could be both finite — i.e., could contain a finite number of stars in a finite volume of space — and unbounded. The key to this realization lay in Einstein’s demonstration that, since matter warps space, the sum total of the mass in all the galaxies might be sufficient to wrap space around themselves. The result would be a closed, four-dimensionally spherical cosmos, in which any observer, anywhere in the universe, would see galaxies stretching deep into space in every direction, and would conclude, correctly, that there is no end to space. Yet the amount of space in a closed universe would nonetheless be finite: An adventurer with time to spare could eventually visit every galaxy, yet would never reach an edge of space. Just as the surface of the earth is finite but unbounded in two dimensions (we can wander wherever we like, and will not fall off the edge of the earth) so a closed four-dimensional universe is finite but unbounded to us who observe it in three dimensions.

In the terms of Edwin Abbott Abbott’s Flatland: A Romance of Many Dimensions, we are Flatlanders living in a Lineland world who, with the aid of mathematics, have been able to peer into Spaceland.

Can You Start a Fire with Moonlight and a Magnifying Glass?

posted by Jason Kottke   Dec 31, 2018

Equipped with only a magnifying glass and the light of the Sun, it’s pretty easy to start a fire.1 So, with a much bigger glass, could you start a fire with moonlight?

First, here’s a general rule of thumb: You can’t use lenses and mirrors to make something hotter than the surface of the light source itself. In other words, you can’t use sunlight to make something hotter than the surface of the Sun.

There are lots of ways to show why this is true using optics, but a simpler — if perhaps less satisfying — argument comes from thermodynamics:

Lenses and mirrors work for free; they don’t take any energy to operate.[2] If you could use lenses and mirrors to make heat flow from the Sun to a spot on the ground that’s hotter than the Sun, you’d be making heat flow from a colder place to a hotter place without expending energy. The second law of thermodynamics says you can’t do that. If you could, you could make a perpetual motion machine.

In a better world, Randall Munroe would be writing middle school science textbooks.

  1. A few summers ago when I was showing my kids how to do this, I started futzing with the small pile of tissue paper and pine needles we’d assembled and forgot about the magnifying glass I was holding…until I felt a searing pain in my leg and looked down to see a bit of smoke curling up from my slightly toasted thigh. Kids, do as dad says, not as he does.

How to Build a Dyson Sphere

posted by Jason Kottke   Dec 20, 2018

Perhaps the most fundamental way to think about the Universe is in terms of energy. Even when you get away from physics and chemistry (where energy is obviously central) and into a topic like human history or economics, following how and where energy flows can be enlightening. In 1964, Soviet astronomer Nikolai Kardashev proposed thinking about the progress of human civilization in terms of how much energy we were capable of harnessing. On the Kardashev scale, a Type I civilization would be capable of using all of the energy available on their planet, a Type II civilization could use all the energy from their local star, and a Type III civilization could harness all the energy in a galaxy.

According to an equation suggested by Carl Sagan, humans are currently sitting at ~73% of a Type I civilization. But once we reach that milestone in perhaps a few hundred years (assuming we don’t blow ourselves up in the process), the construction of a Dyson sphere or, more likely, a Dyson swarm around the Sun is probably the key to eventually hitting Type II. In the video above, Kurzgesagt explores what would go into building some type of Dyson structure capable of harvesting most of the Sun’s energy. For starters, we’d probably have to completely dismantle the planet Mercury in order to have enough raw materials to build the swarm.

Life-Size Stone Mosaics Based on 16th-Century Anatomical Drawings

posted by Jason Kottke   Dec 18, 2018

John Unger Anatomy

Sculptor John T. Unger is making a series of life-size stone mosaics based on anatomical drawings by the 16th-century Italian scientist Bartolomeo Eustachi.

Bartolomeo Eustachi, one of the first modern anatomists, is also considered the first comparative anatomist, as he was the first to use examples from the animal realm for comparison and clarity. Eustachi was a contemporary of Vesalius, and they share the credit of having created the science of human anatomy. In 1552 (nine years after Vesalius published his Fabrica) Eustachi completed a series of anatomical illustrations so accurate that had they been published in his lifetime, a modern understanding of anatomy might have come to pass two centuries before it was attained.

Unger has completed about half of the mosaics and is doing a Kickstarter campaign to help finish the rest of them. The first public showing of the finished artworks will be at the Carrie Haddad Gallery in Hudson, NY starting in June 2019.

Ultra-Precise Ice Core Sampling and the Explosive Cause of the Dark Ages

posted by Jason Kottke   Dec 17, 2018

536 AD was an exceedingly bad year for humanity, perhaps even “the worst year to be alive”.

A mysterious fog plunged Europe, the Middle East, and parts of Asia into darkness, day and night — for 18 months. “For the sun gave forth its light without brightness, like the moon, during the whole year,” wrote Byzantine historian Procopius. Temperatures in the summer of 536 fell 1.5°C to 2.5°C, initiating the coldest decade in the past 2300 years. Snow fell that summer in China; crops failed; people starved. The Irish chronicles record “a failure of bread from the years 536-539.” Then, in 541, bubonic plague struck the Roman port of Pelusium, in Egypt. What came to be called the Plague of Justinian spread rapidly, wiping out one-third to one-half of the population of the eastern Roman Empire and hastening its collapse, McCormick says.

For Science magazine, Ann Gibbons writes about a new ice core sampling technique that is providing new insight into the causes of the fall of the Roman Empire and the Dark Ages in Europe.

Mayewski and his interdisciplinary team decided to look for the same eruptions in an ice core drilled in 2013 in the Colle Gnifetti Glacier in the Swiss Alps. The 72-meter-long core entombs more than 2000 years of fallout from volcanoes, Saharan dust storms, and human activities smack in the center of Europe. The team deciphered this record using a new ultra-high-resolution method, in which a laser carves 120-micron slivers of ice, representing just a few days or weeks of snowfall, along the length of the core. Each of the samples — some 50,000 from each meter of the core — is analyzed for about a dozen elements. The approach enabled the team to pinpoint storms, volcanic eruptions, and lead pollution down to the month or even less, going back 2000 years, says UM volcanologist Andrei Kurbatov.

Wow, this is like time travel! You should read the whole piece…it’s not long or technical. I loved the bit about how lead pollution provides evidence for the rise of the merchant class in medieval Europe. (via @tylercowen)

Hear the First Sounds Ever Recorded on Mars

posted by Jason Kottke   Dec 09, 2018

NASA’s InSight mission recently landed on Mars and like other missions before it, the lander is a equipped with a camera and has sent back some pictures of the red planet. But InSight is also carrying a couple of instruments that made it possible to record something no human has ever experienced: what Mars sounds like:

InSight’s air pressure sensor recording the sound of the wind directly and the seismometer recorded the sounds of the lander’s solar panels vibrating as Martian winds blew across them.

Two very sensitive sensors on the spacecraft detected these wind vibrations: an air pressure sensor inside the lander and a seismometer sitting on the lander’s deck, awaiting deployment by InSight’s robotic arm. The two instruments recorded the wind noise in different ways. The air pressure sensor, part of the Auxiliary Payload Sensor Subsystem (APSS), which will collect meteorological data, recorded these air vibrations directly. The seismometer recorded lander vibrations caused by the wind moving over the spacecraft’s solar panels, which are each 7 feet (2.2 meters) in diameter and stick out from the sides of the lander like a giant pair of ears.

The sounds are best heard with a good pair of headphones.

Computer Simulations of Black Hole Mergers Observed by LIGO

posted by Jason Kottke   Dec 06, 2018

As of December 1, 2018, the LIGO experiment has detected gravitational waves from 10 black hole merger events. In the computer simulations shown in this video, you can see what each of the mergers looked like along with the corresponding gravitational waves generated and subsequently observed by the LIGO detectors.

The End of Space Travel?

posted by Jason Kottke   Nov 28, 2018

Remember Alfonso Cuarón’s Gravity? A missile strike on a satellite causes a chain reaction, which ends up destroying almost everything in low Earth orbit. As this Kurzgesagt video explains, this scenario is actually something we need to worry about. In the past 60 years, we’ve launched so much stuff into space that there are millions of pieces of debris up there, hurtling around the Earth at 1000s of miles per hour. The stuff ranges in size from marbles to full-sized satellites. If two larger objects in low Earth orbit (LEO) collided with each other, the resulting debris field could trigger a chain reaction of collisions that would destroy everything currently in that orbit and possibly prevent any new launches. Goodbye ISS, goodbye weather satellites, goodbye GPS, etc. etc. etc. The Moon, Mars, and other destinations beyond LEO would be a lot harder to reach because you’d have to travel through the deadly debris field, particularly with crewed missions.

The Effects of Pollution on Human Cognition & Performance

posted by Jason Kottke   Nov 28, 2018

While I am not a big fan of shifting to an economic argument for things that are already plenty bad for other better reasons (see diversity in the workplace, immigration policy, healthcare, etc.), this article by Austin Frakt on the economic cost of pollution reports on the results of a number of studies linking pollution to low performance in work and school. This study of baseball umpires was particularly troubling:

Pollution may also affect the quality of work, which is much harder to measure. An intriguing study in the Journal of the Association of Environmental and Resource Economists got at this issue by examining how accurately baseball umpires called balls and strikes under different pollution conditions.

Since 2008, pitch calls have been checked by Major League Baseball with an electronic system. In a typical game, an umpire makes 140 ball/strike calls. When there was a 150 percent increase over average carbon monoxide levels or the same increase in small particulate matter, the study found an average of 1.4 additional incorrect calls. Levels of pollution that high occur in about one in 10 games.

Imagine what the rest of us, especially kids, are getting wrong when we’re in polluted areas (i.e. many American cities). (via @tylercowen)

Watch It Live: NASA’s InSight Probe Lands on Mars Today

posted by Jason Kottke   Nov 26, 2018

After a seven-month journey covering over 300 million miles, NASA’s InSight probe will land on the surface of Mars today around 3pm. The video embedded above is a live stream of mission control at NASA’s Jet Propulsion Laboratory that starts at 2pm and will be the best thing to watch as the probe lands. (See also this live stream of NASA TV.) The landing will occur around 2:47pm ET but the landing signal from Mars won’t arrive on Earth until 2:54pm ET at the earliest. And no video from the landing itself of course…”live” is a bit of a misnomer here but it still should be exciting.

NASA produced this short video that shows what’s involved in the landing process, aka how the probe goes from doing 13,000 mph to resting on the surface in just six-and-a-half minutes.

The NY Times has a good explainer on the InSight mission and landing.

NASA’s study of Mars has focused on the planet’s surface and the possibility of life early in its history. By contrast, the InSight mission — the name is a compression of Interior Exploration Using Seismic Investigations, Geodesy and Heat Transport — will study the mysteries of the planet’s deep interior, aiming to answer geophysical questions about its structure, composition and how it formed.

I love this stuff…the kids and I will be watching for sure!

Update: The Oatmeal has a great comic about the InSight landing.

Chinese Scientists Are Creating CRISPR Babies

posted by Jason Kottke   Nov 26, 2018

In an article for MIT Technology Review, Antonio Regalado reports that researchers in Shenzhen, led by He Jiankui, are recruiting couples for a study to produce the first genetically edited human babies. They are hoping to use the CRISPR gene editing technique to “eliminate a gene called CCR5 in hopes of rendering the offspring resistant to HIV, smallpox, and cholera”.

The birth of the first genetically tailored humans would be a stunning medical achievement, for both He and China. But it will prove controversial, too. Where some see a new form of medicine that eliminates genetic disease, others see a slippery slope to enhancements, designer babies, and a new form of eugenics.

“In this ever more competitive global pursuit of applications for gene editing, we hope to be a stand-out,” He and his team wrote in an ethics statement they submitted last year. They predicted their innovation “will surpass” the invention of in vitro fertilization, whose developer was awarded a Nobel Prize in 2010.

A follow-up by the Associated Press indicates that He’s program is already underway and has resulted in a successful birth of twins earlier this month.

The researcher, He Jiankui of Shenzhen, said he altered embryos for seven couples during fertility treatments, with one pregnancy resulting thus far. He said his goal was not to cure or prevent an inherited disease, but to try to bestow a trait that few people naturally have - an ability to resist possible future infection with HIV, the AIDS virus.

He said the parents involved declined to be identified or interviewed, and he would not say where they live or where the work was done.

Update: He is now under investigation for legal and ethical misconduct.

On Sunday, the Shenzhen City Medical Ethics Expert Board said it would begin an investigation of He’s research and released a statement saying that HarMoniCare “according to our findings … never conducted the appropriate reporting according to requirements.” The former medical director of the private hospital, Jiang Su-Qi, told Southern Capital News he had no recollection of approving He’s research while he was on its ethics committee.

“These two children are the guinea pigs. They will go through their whole maturing process having not understood the risks ahead of time,” said Liu Ying of Peking University’s Institute of Molecular Medicine.