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kottke.org posts about science

Why Do Birds Fly in a V-Formation?

posted by Jason Kottke   May 16, 2019

Many species of migratory birds, like the Canada goose in North America, fly in a v-formation. Scientists have long suspected that there was some energy-saving advantage to flying in formation and a 2014 study provides evidence to that effect.

By comparing the birds’ flight data to computer simulations, Portugal found that the ibises are apparently drafting — catching an uprush of air from the wingtip of the bird ahead. “Furthermore, when they’re in that position, they time wing beats perfectly,” he says. “So they don’t just sit there passively hoping to get some of the good air from the bird in front.”

They actually flap along the perfect sweet spot. Portugal thinks there’s a very good reason why the ibises do this. Previous studies have shown that flying is hard work.

“When we get exercising, our heart rate gets up to around 180 beats per minute on a good day,” Portugal says. “When birds are flying, it goes up to 400 beats per minute.”

You can read the paper published by the researchers in Nature. (via the kid should see this)

Meet Aerospace Engineer Judith Love Cohen

posted by Jason Kottke   May 14, 2019

Judith Love Cohen was, at various times in her fascinating life, an engineer who worked on the Pioneer, Apollo, and Hubble missions, an author & publisher of books about women in STEM and environmentalism in the 90s, a ballet dancer with the New York Metropolitan Opera Ballet Company, an advocate for better treatment of women in the workplace, and actor Jack Black’s mother. From an obituary written by her son Neil Siegel after her death in 2016:

My mother usually considered her work on the Apollo program to be the highlight of her career. When disaster struck the Apollo 13 mission, it was the Abort-Guidance System that brought the astronauts home safely. Judy was there when the Apollo 13 astronauts paid a “thank you” [visit] to the TRW facility in Redondo Beach.

She finished her engineering career running the systems engineering for the science ground facility of the Hubble Space Telescope.

During her engineering career, she was a vigorous and tireless advocate of better treatment for women in the workplace. Many things that today we consider routine — the posting of job openings inside of a company so that anyone could apply, formal job descriptions for every position, and so forth - were her creations. She had a profound impact on equality in the workforce.

Here’s Cohen pictured with an early Pioneer spacecraft in 1959:

June Love Cohen

Frustrated with the lack of female role models for girls interested in science, math, and technology, she retired from engineering to write and publish a series of books. From a 1999 LA Times profile:

The 11-book series features female professionals such as a paleontologist, Egyptologist and marine biologist. Cohen’s first book in 1991, “You Can Be a Woman Engineer,” traces her arc from a girl who had never heard of female engineers to a woman who led a team of engineers on the design for NASA’s Hubble Space Telescope.

“You only think about things when you see people doing it. Most girls know now they can be lawyers” from TV shows like “Ally McBeal” and female lawyers in the news, Cohen said. “They know that they can work in an emergency room — they’ve seen ‘ER.’ But I don’t recall that anyone has seen scientists on a large scale, except for a few paleontologists in ‘Jurassic Park.’”

At NASA’s Jet Propulsion Laboratory in Pasadena, physicist Barbara Wilson, 50, said she never knew of any female scientists while growing up in the Midwest. At age 10, she started reading science fiction books for inspiration, but none of them featured women. In school, counselors dismissed the idea of her becoming a scientist, saying she should consider jobs that “women are more likely to be good at.” Books like Cohen’s would have provided the validation she sought, said Wilson, JPL’s chief technologist.

“It was really difficult psychologically and emotionally to be better than all the boys in math and science,” she said. “[The books] really would have helped encourage my feeling good about myself, that this was the direction I wanted to go. I didn’t see role models. I didn’t get encouragement other than at home.”

It’s difficult to imagine a better role model than Cohen…she obviously loved engineering and her work. When her son Jack Black was born, she barely hit the pause button:

Her fourth child, Jack, was born a few years later. She actually went to her office on the day that Jack was born. When it was time to go to the hospital, she took with her a computer printout of the problem she was working on. Later that day, she called her boss and told him that she had solved the problem. And… oh, yes, the baby was born, too.

If anyone from the NY Times is reading, I think Cohen would make a good subject for the Overlooked series. (via history cool kids)

On the Safety of Vaccines and the Low Risk of Side Effects

posted by Jason Kottke   May 13, 2019

The development of vaccines against infectious diseases is among the greatest of human accomplishments and has saved ten of millions of people from dying. And yet some are still hung up on their side effects (and also the widely disproved and debunked fraudulent claim that vaccines cause autism). In this video, Kurzgesagt looks at how vaccines work and compares the impact of their side effects (minuscule) to the potential effect of the diseases they protect against (children dying).

The extensive list of sources they used for the video can be found here.

The title of this video is “The Side Effects of Vaccines - How High is the Risk?”, which seems like it’s maximized for clicks and to spread amongst anti-vaxxers on social media. I wish it had a more accurate title — something like “The Absurdly Low Risk of Vaccine Side Effects” or maybe “Vaccines. And Now My Kids Don’t Die.” — but perhaps positioning it this way is a good strategy to get folks who may not be quite so radicalized to watch it.

Eight Ways to Teach Climate Change in School

posted by Jason Kottke   May 02, 2019

According to a poll conducted by NPR/Ipsos, over 80% of American parents want climate change to be taught in our schools, but only 42% of the teachers polled say that they teach it in their classrooms.

If they don’t hear about it at home, will kids learn about climate change in school? To answer this question, NPR/Ipsos also completed a nationally representative survey of around 500 teachers. These educators were even more likely than the general public to believe in climate change and to support teaching climate change.

In fact, 86% of teachers believe climate change should be taught in schools. In theory.

But in practice, it’s more complicated. More than half — 55% — of teachers we surveyed said they do not cover climate change in their own classrooms or even talk to their students about it.

The most common reason given? Nearly two-thirds (65%) said it’s outside their subject area.

NPR education correspondent Anya Kamenetz shared 8 Ways To Teach Climate Change In Almost Any Classroom, regardless of what subject you teach.

5. Assign a research project, multimedia presentation or speech.

Gay Collins teaches public speaking at Waterford High School in Waterford, Conn. She is interested in “civil discourse” as a tool for problem-solving, so she encourages her students “to shape their speeches around critical topics, like the use of plastics, minimalism, and other environmental issues.

I am, however, still hung up on the 12% of teachers polled who said that the world’s climate is not changing.

Climate Poll Teachers

Grace Hopper Explains a Nanosecond

posted by Jason Kottke   May 01, 2019

In this short clip from 1983, legendary computer scientist Grace Hopper uses a short length of wire to explain what a nanosecond is.

Now what I wanted when I asked for a nanosecond was: I wanted a piece of wire which would represent the maximum

distance that electricity could travel in a billionth of a second. Now of course it wouldn’t really be through wire — it’d be out in space, the velocity of light. So if we start with a velocity of light and use your friendly computer, you’ll discover that a nanosecond is 11.8 inches long, the maximum limiting distance that electricity can travel in a billionth of a second.

You can watch the entirety of a similar lecture Hopper gave at MIT in 1985, in which she “practically invents computer science at the chalkboard”. (via tmn)

Fighting Climate Change with CO2-Eating “Ideal Plants”

posted by Jason Kottke   May 01, 2019

At the Salk Institute for Biological Studies, Dr. Joanne Chory is working on a project to create plants capable of storing more carbon for a longer period of time than normal plants in order to help mitigate the effects of climate change.

Suberin — also known as cork — is a naturally occurring carbon-rich substance found in plant roots. It absorbs carbon yet resists decomposition (which releases carbon back into the atmosphere), enriches soil and helps plants resist stress.

By understanding and improving just a few genetic pathways in plants, Salk’s plant biologists believe they can help plants grow bigger, more robust root systems that absorb larger amounts of carbon, burying it in the ground in the form of suberin.

The Salk team will use cutting-edge genetic and genomic techniques to develop these Salk Ideal Plants.

Salk Ideal Plants

According to this piece in the Guardian on the project, one of the techniques they’re using is CRISPR, basically a genetic copy/paste system. Once the team demonstrates they can grow these larger root systems in model plants, they’ll genetically transfer that capability to the world’s largest food crops like rice, wheat, and corn.

As a bonus, the team believes that Ideal Plants will have other positive effects:

In addition to mitigating climate change, the enhanced root systems will help protect plants from stresses caused by climate changes and the additional carbon in the soil will make the soil richer, promoting better crop yields and more food for a growing global population.

This project is firmly on the wizard end of the wizards vs prophets spectrum.

Strange Stars and Strange Matter

posted by Jason Kottke   Apr 17, 2019

Nuclear physicists hypothesize that when the cores of neutron stars are subject to enough pressure, the quarks that make up the core can turn from up and down quark varieties into strange quarks. As this Kurzgesagt video explains, this strange matter is particularly stable and if it were to escape from the core of the neutron star, it would convert any ordinary matter it came into contact with to more strange matter. If you hadn’t heard about this hypothesis before, you can read up on it in their list of sources for the video.

The first photo of a black hole

posted by Chrysanthe Tenentes   Apr 10, 2019

The first photo of a black hole

Ok, this is pretty cool. We have the first photo of a supermassive black hole, from imagery taken two years ago of the elliptical galaxy M87 (in the constellation Virgo) by the Event Horizon Telescope project. The EHT team is a group of 200 scientist that has been working on this project for two decades. The image was created using data captured from radio telescopes from Hawaii to the South Pole and beyond using very long baseline interferometry.

The image, of a lopsided ring of light surrounding a dark circle deep in the heart of the galaxy known as Messier 87, some 55 million light-years away from here, resembled the Eye of Sauron, a reminder yet again of the power and malevolence of nature. It is a smoke ring framing a one-way portal to eternity.

Now is a good time to (re)read Jonathan Lethem’s early novel, the absurdist physics love story As She Climbed Across the Table.

Update: Vox’s Joss Fong has a good 6-minute video that explains how the photo was taken:

And this video by Veritasium is even more meaty (and this one too):

One woman’s story of self-discovery through psychotropic withdrawl

posted by Chrysanthe Tenentes   Apr 08, 2019

In this week’s New Yorker, Rachel Aviv looks at why it’s so hard to go off psychiatric drugs, and why they may often be overprescribed. She tells the story of Laura Delano, a descendant of Franklin Delano Roosevelt from Greenwich, CT.

Laura received a bipolar diagnosis as a teen and was medicated for several conditions and a cascade of associated symptoms. She assumed her depression was due to a chemical imbalance being corrected by the cocktail of psychotropic drugs used longterm. Her decades-long cycle through different drugs, diagnoses, and symptoms show an under-discussed side of psychopharmacology.

Dorian Deshauer, a psychiatrist and historian at the University of Toronto, has written that the chemical-imbalance theory, popularized in the eighties and nineties, “created the perception that the long term, even life-long use of psychiatric drugs made sense as a logical step.” But psychiatric drugs are brought to market in clinical trials that typically last less than twelve weeks. Few studies follow patients who take the medications for more than a year. Allen Frances, an emeritus professor of psychiatry at Duke, who chaired the task force for the fourth edition of the DSM, in 1994, told me that the field has neglected questions about how to take patients off drugs—a practice known as “de-prescribing.” He said that “de-prescribing requires a great deal more skill, time, commitment, and knowledge of the patient than prescribing does.” He emphasizes what he called a “cruel paradox: there’s a large population on the severe end of the spectrum who really need the medicine” and either don’t have access to treatment or avoid it because it is stigmatized in their community. At the same time, many others are “being overprescribed and then stay on the medications for years.” There are almost no studies on how or when to go off psychiatric medications, a situation that has created what he calls a “national public-health experiment.”

Aviv makes an apt observation about our culture and willingness to confront mental health:

Overprescribing isn’t always due to negligence; it may also be that pills are the only form of help that some people are willing to accept.

But back to Laura. In 2010, after years of cycling through diagnoses (most recently borderline personality disorder), psychiatrists, pharmacologists, and prescriptions, she came across what would turn out to be a life-altering discovery in a bookstore.

On the table of new releases was “Anatomy of an Epidemic,” by Robert Whitaker, whose cover had a drawing of a person’s head labelled with the names of several medications that she’d taken. The book tries to make sense of the fact that, as psychopharmacology has become more sophisticated and accessible, the number of Americans disabled by mental illness has risen. Whitaker argues that psychiatric medications, taken in heavy doses over the course of a lifetime, may be turning some episodic disorders into chronic disabilities. (The book has been praised for presenting a hypothesis of potential importance, and criticized for overstating evidence and adopting a crusading tone.)

Not only did this alter the course of Laura’s treatment, but her life’s work as well. Last year, she helped launched the online resource the Withdrawal Project after years of both informal and formal counseling of others.

But what’s next for our brain health? Some health experts say probiotics and our microbiome should not be ignored.

The Day the Dinosaurs Died

posted by Jason Kottke   Apr 01, 2019

It’s only Monday, but I’m confident this will be my favorite read of the week. Since 2012, paleontologist Robert DePalma has been excavating a site in North Dakota that he thinks is “an incredible and unprecedented discovery”. What’s potentially so special about this site? Fossils from dinosaurs and other animals from thousands of years before the asteroid impact are very hard to come by, leading some to believe that dinosaurs died out before the impact, not because of it. DePalma believes the site preserves, as if in amber, the day, the precise and exact day (and perhaps even the exact hour), that the massive asteroid believed to have caused the extinction of the dinosaurs hit the Earth 65 million years ago.

As DePalma carefully excavated the upper layers, he began uncovering an extraordinary array of fossils, exceedingly delicate but marvellously well preserved. “There’s amazing plant material in there, all interlaced and interlocked,” he recalled. “There are logjams of wood, fish pressed against cypress — tree root bundles, tree trunks smeared with amber.” Most fossils end up being squashed flat by the pressure of the overlying stone, but here everything was three-dimensional, including the fish, having been encased in sediment all at once, which acted as a support. “You see skin, you see dorsal fins literally sticking straight up in the sediments, species new to science,” he said. As he dug, the momentousness of what he had come across slowly dawned on him. If the site was what he hoped, he had made the most important paleontological discovery of the new century.

The type of evidence present at the site is almost too good to believe:

He noted that every fish he’d found in the site had died with its mouth open, which may indicate that the fish had been gasping as they suffocated in the sediment-laden water.

“Most died in a vertical position in the sediment, didn’t even tip over on their sides,” he said. “And they weren’t scavenged, because whatever would have dug them up afterward was probably gone.”

Depalma Fossil Fish

Clues from the growth stages of animals and pollen found at the site might even point to what season it was when the asteroid struck…DePalma’s current guess is in autumn. And then there’s this, about a burrow that DePalma discovered:

“Any Cretaceous mammal burrow is incredibly rare,” he said. “But this one is impossible — it’s dug right through the KT boundary.” Perhaps, he said, the mammal survived the impact and the flood, burrowed into the mud to escape the freezing darkness, then died. “It may have been born in the Cretaceous and died in the Paleocene,” he said.

A scientific paper is forthcoming this week. I couldn’t find it online, but this piece in Science says that it’s generating some discussion and controversy already.

“Outcrops like [this] are the reasons many of us are drawn to geology,” says David Kring, a geologist at the Lunar and Planetary Institute in Houston, Texas, who wasn’t a member of the research team. “Those few meters of rock record the wrath of the Chicxulub impact and the devastation it caused.” But not everyone has fully embraced the find, perhaps in part because it was first announced to the world last week in an article in The New Yorker. The paper, in the Proceedings of the National Academy of Sciences (PNAS), does not include all the scientific claims mentioned in The New Yorker story, including that numerous dinosaurs as well as fish were buried at the site.

“I hope this is all legit-I’m just not 100% convinced yet,” says Thomas Tobin, a geologist at the University of Alabama in Tuscaloosa. Tobin says the PNAS paper is densely packed with detail from paleontology, sedimentology, geochemistry, and more. “No one is an expert on all of those subjects,” he says, so it’s going to take a few months for the research community to digest the findings and evaluate whether they support such extraordinary conclusions.

I’m eager to follow the progress of this story as more of the results are released and analyzed by the scientific community.

A Timelapse of the Entire Universe

posted by Jason Kottke   Apr 01, 2019

John Boswell has made a 10-minute time lapse video showing the history of the universe, from its formation 13.8 billion years ago up to the present. Each second of the video represents the passing of 22 million years. But don’t blink right near the end…you might miss the tiny fraction of a second that represents the entire history of humanity.

See also: Boswell’s Timelapse of the Future, a dramatized time lapse of possible events from now until the heat death of the universe many trillion trillion trillions of years from now.

What Is Our Least Useful Body Part?

posted by Jason Kottke   Mar 29, 2019

Gizmodo’s Daniel Kolitz recently asked a panel of anatomists and evolutionary biologists about what the most useless part of the human body might be. Biology professor Dr. Nathan Lents reminds us that our bodies contain ample evidence of our design by evolution:

It’s hard to pick just one! The human wrist is a clunky hodgepodge of unnecessary bones. If we could design that joint from scratch, there is no way we would stick eight small, fixed, and mostly useless bones in there. We also have the stump of a tail that we could totally do without. It does nothing for us except occasionally gets injured or develops cancer.

I think my favorite useless body part is the pyramidalis muscle, which is located in our pelvic floor and attaches to the pelvis and some other connective tissue in our nether regions. What does it do? Well, when you flex this muscle, you can sort of squish the tissue in that area around pointlessly, but in monkeys and other mammals, it helps to manipulate the tail. So useless is this muscle that at least 20% of us don’t even have one and we don’t even miss it. I always enjoy telling people that, although humans and other apes don’t have tails, we still have the muscles to flex them!

Timelapse of the Future

posted by Jason Kottke   Mar 27, 2019

One of my favorite Wikipedia articles is the timeline of the far future, which details the predictions science makes about the possible futures of the Earth, solar system, galaxy, and universe, from Antares exploding in a supernova visible from Earth in broad daylight in 10,000 years to the end of star formation in galaxies 1 trillion years from now…and beyond.

In his new video, Timelapse of the Future, John Boswell takes us on a trip through that timeline, a journey to the end of time.

We start in 2019 and travel exponentially through time, witnessing the future of Earth, the death of the sun, the end of all stars, proton decay, zombie galaxies, possible future civilizations, exploding black holes, the effects of dark energy, alternate universes, the final fate of the cosmos — to name a few.

A regular time lapse of that voyage would take forever, so Boswell cleverly doubles the pace every 5 seconds, so that just after 4 minutes into the video, a trillion years passes in just a second or two.1 You’d think that after the Earth is devoured by the Sun about 3 minutes in, things would get a bit boring and you could stop watching, but then you’d miss zombie white dwarfs roaming the universe in the degenerate era, the black hole mergers era 1000 trillion trillion trillion trillion years from now, the possible creation of baby “life boat” universes, and the point at which “nothing happens and it keeps not happening forever”.

  1. This is similar to Charles and Ray Eames’ Powers of Ten increasing its speed and field of view every 10 seconds.

The Collective Effervescence of Dancing

posted by Jason Kottke   Mar 27, 2019

Why do we dance? It’s a silly question because the answer seems obvious — “because we want to, duh” — but this video from Aeon looks a bit closer at why humans like to collectively move to the beat. It has to do with our social nature and this great phrase, “collective effervescence”.

The answer, it seems, is in our need for social cohesion - that vital glue that keeps societies from breaking apart despite interpersonal differences. The French sociologist Émile Durkheim (1858-1917) theorised that ‘collective effervescence’ — moments in which people come together in some form of unifying, excitement-inducing activity — is at the root of what holds groups together. More recently, Bronwyn Tarr, an evolutionary biologist and psychologist at the University of Oxford who is also a dancer, has researched the evolutionary and neurological underpinnings of our innate tendency to bust a move. Drawing on the work of both Durkheim and Tarr, this Aeon Original video explores that unifying feeling of group ‘electricity’ that lifts us up when we’re enthralled by our favourite sports teams, participating in religious rituals, entranced by music - and, yes, dancing the night away.

You can read more about Durkheim and his work here and about Tarr’s work here.

One hypothesis is that it provides an opportunity for people to come together, making them move — dance — and in doing so we experience internal hormonal cascades which are made up of ‘feel good’ chemicals. These bursts of chemicals are part of our brain’s pain and pleasure and reward circuitry, and when they are triggered they provide an experience of elation and positive reward. When we get this kick in the presence of others, the result is that of collective joy — positive, shared experiences through which we establish and maintain important social connections with others. Now we feel like we belong to a unified, cohesive whole.

Being part of a cohesive social group would have been really important for our ancestors — collaborating with others to find shelter, hunt, rear young would have increased our chances of survival. Music and dance are by no means the only ways we can stimulate these positive social ‘highs’. But they’re really good ways of doing it because it’s an experience that we can share with lots of people at once. In order to understand why that would have given us such a great advantage we need to look at our species in the context of primates.

(via open culture)

What’s Eating Dan?

posted by Jason Kottke   Mar 21, 2019

From America’s Test Kitchen and Dan Souza, the editor-in-chief of Cook’s Illustrated, a YouTube series called What’s Eating Dan? In each episode, Souza picks a different food — pizza, rice, salmon — shares some of the science involved, and then shows us the best way to cook it. For starters, I’d suggest the first episode on burgers and a more recent one on mushrooms:

Actually, Mercury Is Our Closest Planetary Neighbor

posted by Jason Kottke   Mar 21, 2019

If you look at the orbits of the planets adjacent to the Earth’s orbit (Venus & Mars), you’ll see that Venus’s orbit is closest to our own. That is, at its closest approach, Venus gets closer to Earth than any other planet. But what about the average distance?

According to this article in Physics Today by Tom Stockman, Gabriel Monroe, and Samuel Cordner, if you run a simulation and do a proper calculation, you’ll find that Mercury, and not Venus or Mars, is Earth’s closest neighbor on average (and spends more time as Earth’s closest neighbor than any other planet):

Although it feels intuitive that the average distance between every point on two concentric ellipses would be the difference in their radii, in reality that difference determines only the average distance of the ellipses’ closest points. Indeed, when Earth and Venus are at their closest approach, their separation is roughly 0.28 AU — no other planet gets nearer to Earth. But just as often, the two planets are at their most distant, when Venus is on the side of the Sun opposite Earth, 1.72 AU away. We can improve the flawed calculation by averaging the distances of closest and farthest approach (resulting in an average distance of 1 AU between Earth and Venus), but finding the true solution requires a bit more effort.

What the calculation also shows is that Mercury is the closest planetary neighbor to every planet, on average. Also, the authors of the paper don’t explicitly mention this, but the Sun (at 1 AU) is closer on average to the Earth than even Mercury (1.04 AU).

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)