In her book The Sixth Extinction, Elizabeth Kolbert warns that we are in the midst of the Earth’s sixth mass extinction of life, this time caused by humans.
Over the last half a billion years, there have been five mass extinctions, when the diversity of life on earth suddenly and dramatically contracted. Scientists around the world are currently monitoring the sixth extinction, predicted to be the most devastating extinction event since the asteroid impact that wiped out the dinosaurs. This time around, the cataclysm is us.
This is a mainstream view of humanity’s effect on the Earth flora and fauna…for evidence, you don’t need to look any further than all of the large mammal species that have gone extinct or are endangered because of human activity.
A more controversial take is offered by Chris Thomas in his recent book, Inheritors of the Earth: How Nature Is Thriving in an Age of Extinction. Thomas allows that there’s a “mini mass extinction” happening, but he also argues that the extreme evolutionary pressure brought by our increasing dominance of our planet’s ecosystems will result in a “sixth mass genesis”, a dramatic increase in the Earth’s biodiversity.
Human cities and mass agriculture have created new places for enterprising animals and plants to live, and our activities have stimulated evolutionary change in virtually every population of living species. Most remarkably, Thomas shows, humans may well have raised the rate at which new species are formed to the highest level in the history of our planet.
Drawing on the success stories of diverse species, from the ochre-colored comma butterfly to the New Zealand pukeko, Thomas overturns the accepted story of declining biodiversity on Earth. In so doing, he questions why we resist new forms of life, and why we see ourselves as unnatural. Ultimately, he suggests that if life on Earth can recover from the asteroid that killed off the dinosaurs, it can survive the onslaughts of the technological age.
The history of life on Earth is a history of extinctions and ecological failures, but it is also a story of formation of new forms and spread of those new forms around the world. The net result has been a gain in diversity. In the human era we are seeing great losses, but we are also seeing all these biological gains of new animals and plants spreading around the world, new hybrids coming into existence. I am not saying there is yet a balance between the two. I accept the losses, but it is also scientifically, and in terms of our human attitudes to nature, extremely interesting to contemplate the gains simultaneously.
If the processes that are going on at the moment continue for a very long time, it is my expectation that the number of species on Earth will grow enormously. We are moving species of existing animals and plants back and forth across the world, so that they are all arriving in new geographic regions. We know when species have done this in the ancient past, they have turned into new species in those different regions. If you fast-forward a million years or a few million years, all of these introduced species that leave surviving descendants will have turned into new species. And that is going to generate many more species. We have effectively created a massive species generator.
That certainly does put an interesting spin on extinction and invasive species.
LRO WAC images have a resolution of about 100 meters per pixel over a swath of about 60 km of lunar surface (using what’s called the pushbroom technique, similar to how a flatbed scanner works). They are usually taken straight down, toward the spacecraft nadir (the opposite of the zenith). To get the correct perspective for the Moon as a globe, Doran took the images, along with altimeter data, and mapped them onto a sphere. That way features near the edge look foreshortened, as they really do when you look at the entire Moon. He also used Apollo images to make sure things lined up. So the image isn’t exactly scientifically rigorous, but it is certainly spectacular.
In a Twitter thread, author Oliver Morton compares the physical scale of the Universe with its age (from the perspective of humans).
If a human life is 70 years long, there has been room for 200 million lives since the big bang, but 200 million humans, end to end, would reach just a bit further than the moon. If you had started walking towards the centre of the galaxy on the day of the big bang (had there been days, you, paths & galaxies), you would have got about 20 parsecs by now: just 0.25% of the way.
Maybe walking pace is the wrong metric. A nerve impulse travels around 70 times faster than a person walks. But even at the speed of thought, the age of the universe is too small for something to have reached the centre of the galaxy.
The situation is even worse when you choose another reference object, like UY Scuti, the largest known star. The red hypergiant is nearly 1.5 billion miles across and, because of its size and position near the center of the galaxy, is probably around 13 billion years old, just a few hundred million years younger than the age of the Universe itself.
Even if you use light as a marker, the size of Universe remains unfathomably immense. Over the course of the Universe’s lifetime, a photon could have travelled 13.8 billion light-years, just 15% of the current estimate of the Universe’s diameter of 93 billion light-years. See also what are the physical limits of humanity?
In the first line of Seveneves, Neal Stephenson lays out the event that the entire book’s action revolves around:
The moon blew up without warning and for no apparent reason.
Mild spoilers, but fairly quickly, scientists in the book figure out that this is a very bad thing that will cause humanity to become extinct unless drastic action is taken.
In the novel, one day the moon breaks up into 7 roughly equal-sized pieces. These pieces continue peacefully orbiting the Earth for a while, and eventually two pieces collide. This collision causes a piece to fragment, making future collisions more likely. The process repeats, at what Stephenson says is an exponential rate, until the Earth is under near-constant bombardment from meteorites, wiping out (nearly) all life on Earth.
Jason Cole wondered how plausible that scenario is and created a simulation to model it. Turns out Stephenson had his figures right.
Put on by the Royal Observatory Greenwich, The Astronomy Photographer of the Year is the largest competition of its kind in the world. For the 2017 awards, more than 3800 photos were entered from 91 countries. It’s astounding to me that many of these were taken with telescopes you can easily buy online (granted, for thousands of dollars) rather than with the Hubble or some building-sized scope on the top of a mountain in Chile.
The photos above were taken by Andriy Borovkov, Alexandra Hart, and Kamil Nureev.
Currently, the only way to diagnose chronic traumatic encephalopathy (CTE), a disease caused by repeated head trauma, is by posthumously examining brain tissue for signs of tau protein buildup. But a group from Boston University may have found a way to test for CTE in living patients.
McKee and her team discovered a specific biomarker in the brains of former football players. A biomarker is a measurable substance which is, in this case, found in the brain and identifies an abnormality.
This particular biomarker is called CCL11, and it’s a secreted protein the human body uses to help regulate the immune system and inflammation in the body.
As The Ringer’s Claire McNear writes, if a CTE test is easily available to players, what will that do to football? (Or indeed, what will it do to sports like soccer, boxing, skateboarding, or even skiing?)
“After learning all of this,” the retiring Ferguson wrote of the clarity he gained when he began researching CTE, “I feel a bit betrayed by the people or committees put in place by the league who did not have my best interests at heart.” He should feel betrayed, as should many of his fellow players. As will, certainly, so very many, once they have the ability to see what has happened to them. They may wonder, rightfully, about the people who trained them and paid them, sometimes even as they attempted to shut down research into CTE. They may look at the league’s structure, at the lopsided contracts that rob many players of their leverage, forcing them to choose between getting back on the field or losing a paycheck (and possibly getting cut), and at how the league cycles through players like they’re nothing more than easily broken pieces on a board.
If you take a bin full of sand and blow air up through the bottom of it, the sand behaves like a liquid. The bubbles were freaky enough when I watched this for the first time, but when the guy reached in to submerge the ball and it buoyantly popped right to the surface, my brain broke a little bit. This video from The Royal Institution explains what’s going on:
Note that this is a different effect than non-Newtonian liquids (which are also very cool).
Update: Mark Rober made a hot tub-sized fluidized air bed:
Assuming the artificial intelligences now have truly overwhelming processing power, they should be able to reconstruct human society in every detail by tracing atomic events backward in time. “It will cost them very little to preserve us this way,” he points out. “They will, in fact, be able to re-create a model of our entire civilization, with everything and everyone in it, down to the atomic level, simulating our atoms with machinery that’s vastly subatomic. Also,” he says with amusement, “they’ll be able to use data compression to remove the redundant stuff that isn’t important.”
But by this logic, our current “reality” could be nothing more than a simulation produced by information entities.
“Of course.” Moravec shrugs and waves his hand as if the idea is too obvious. “In fact, the robots will re-create us any number of times, whereas the original version of our world exists, at most, only once. Therefore, statistically speaking, it’s much more likely we’re living in a vast simulation than in the original version. To me, the whole concept of reality is rather absurd. But while you’re inside the scenario, you can’t help but play by the rules. So we might as well pretend this is real - even though the chance things are as they seem is essentially negligible.”
And so, according to Hans Moravec, the human race is almost certainly extinct, while the world around us is just an advanced version of SimCity.
This paper argues that at least one of the following propositions is true: (1) the human species is very likely to go extinct before reaching a “posthuman” stage; (2) any posthuman civilization is extremely unlikely to run a significant number of simulations of their evolutionary history (or variations thereof); (3) we are almost certainly living in a computer simulation. It follows that the belief that there is a significant chance that we will one day become posthumans who run ancestor-simulations is false, unless we are currently living in a simulation.
In the above (as well as in this follow-up video by Vsauce 3), Kurzgesagt explores these ideas and their implications. Here’s the one that always gets me: If simulations are possible, there are probably a lot of them, which means the chances that we’re inside one of them is high. Like, if there’s one real Universe and 17 quadrillion simulated universes, you’re almost certainly in one of the simulations. Whoa.
Master sushi chefs in Japan spend years honing their skills in making rice, selecting and slicing fish, and other techniques. Expert chefs even form the sushi pieces in a different way than a novice does, resulting in a cohesive bite that doesn’t feel all mushed together. In this short video clip from a longer Japanology episode on sushi, they put pieces of sushi prepared by a novice and a master through a series of tests — a wind tunnel, a pressure test, and an MRI scan — to see just how different their techniques are. It sounds ridiculous and goofy (and it is!) but the results are actually interesting.
Spacetime Coordinates sells prints, metal mementos, and t-shirts that feature the planets of the solar system in the exact locations they were in on the date of your birth (or other significant date). For their new Kickstarter campaign, they’re offering color prints.
When I was a kid, I spent far too many hours mucking around in Lotus 1-2-3 trying to make a spreadsheet to calculate how often all the planets in the solar system would line up with each other (disregarding their differing planes, particularly Pluto’s).1 I could never get it working. Turns out that a precise alignment has probably never occurred, nor will it ever. But all the planets are “somewhat aligned” every 500 years or so. Neat! (via colossal)
I spent many more hours making a spreadsheet of every single baseball card I owned and how much it was worth, updated by hand from Beckett’s price guide. Time well spent?↩
Kurzgesagt asks and answers the question: what happens if we bring the Sun to the Earth? Since the density and makeup of the Sun varies, they go over scenarios of sampling a house-size chunk from four different spots of the Sun: the chromosphere, the photosphere, the radiative zone, and the core. The answers range from “not much” to “well, that was a terrifically bad idea”.
On one of its final passes of Saturn, the Cassini probe captured this image of a wave structure in Saturn’s rings known as the Janus 2:1 spiral density wave. The waves are generated by the motion of Janus, one of Saturn’s smaller moons.
This wave is remarkable because Janus, the moon that generates it, is in a strange orbital configuration. Janus and Epimetheus (see “Cruising Past Janus”) share practically the same orbit and trade places every four years. Every time one of those orbit swaps takes place, the ring at this location responds, spawning a new crest in the wave. The distance between any pair of crests corresponds to four years’ worth of the wave propagating downstream from the resonance, which means the wave seen here encodes many decades’ worth of the orbital history of Janus and Epimetheus. According to this interpretation, the part of the wave at the very upper-left of this image corresponds to the positions of Janus and Epimetheus around the time of the Voyager flybys in 1980 and 1981, which is the time at which Janus and Epimetheus were first proven to be two distinct objects (they were first observed in 1966).
The photograph is also an optical illusion of sorts. The rings appear to be getting farther away in the upper lefthand corner but the plane of the photograph is actually parallel to the plane of the rings…it’s just that the wavelength of the density wave gets shorter from right to left.
Update: Here are those density waves converted into sound waves. The first set sounds like an accelerating F1 car.
Seán Doran shared some recently processed photos of Jupiter that he worked on with Gerald Eichstädt. The photos were taken by NASA’s Juno probe on a recent pass by the planet. These are like Impressionist paintings…you could spend hours staring at the whirls & whorls and never find your way out. There are more images of Jupiter in Doran’s Flickr album, including this high-resolution shot that you can download for printing.
In their latest video, Kurzgesagt takes a look at black holes, specifically how they deal with information. According to the currently accepted theories, one of the fundamental laws of the Universe is that information can never be lost, but black holes destroy information. This is the information paradox…so one or both of our theories must be wrong.
The paradox arose after Hawking showed, in 1974-1975, that black holes surrounded by quantum fields actually will radiate particles (“Hawking radiation”) and shrink in size (Figure 4), eventually evaporating completely. Compare with Figure 2, where the information about the two shells gets stuck inside the black hole. In Figure 4, the black hole is gone. Where did the information go? If it disappeared along with the black hole, that violates quantum theory.
Maybe the information came back out with the Hawking radiation? The problem is that the information in the black hole can’t get out. So the only way it can be in the Hawking radiation (naively) is if what is inside is copied. Having two copies of the information, one inside, one outside, also violates quantum theory.
So maybe black holes holographically encode their information on the surface?
I had seen a partial eclipse in 1970. A partial eclipse is very interesting. It bears almost no relation to a total eclipse. Seeing a partial eclipse bears the same relation to seeing a total eclipse as kissing a man does to marrying him, or as flying in an airplane does to falling out of an airplane. Although the one experience precedes the other, it in no way prepares you for it.
I heard lots of disappointment with the eclipse among friends and on social media. It was neat — look, there’s a chunk out of the Sun — but they thought it would be darker or that the air would get colder. But none of that stuff really happens unless you’re really close to totality…and then it goes completely dark and your brain turns inside out. Twitter user @hwoodscotty said:
Probably the coolest thing I’ve ever seen. Totality is so much different than even 99%. 10/10 Would recommend.
Standing on a mountaintop for totality was crossing into another dimension, suddenly finding ourselves on another world. Amazing. Sparkling ring, sun fire ghostly streaming, darkest circle. I understand now why people chase the eclipse. Totality is unlike anything. Entire landscape shifted, valleys, hills, mountains painted in nightcolour and cold. Sparkling planets came out in a midnight sky.
But back to Dillard’s piece…this part, about the shadow rushing towards them, sounds amazing:
I have said that I heard screams. (I have since read that screaming, with hysteria, is a common reaction even to expected total eclipses.) People on all the hillsides, including, I think, myself, screamed when the black body of the moon detached from the sky and rolled over the sun. But something else was happening at that same instant, and it was this, I believe, which made us scream.
The second before the sun went out we saw a wall of dark shadow come speeding at us. We no sooner saw it than it was upon us, like thunder. It roared up the valley. It slammed our hill and knocked us out. It was the monstrous swift shadow cone of the moon. I have since read that this wave of shadow moves 1,800 miles an hour. Language can give no sense of this sort of speed — 1,800 miles an hour. It was 195 miles wide. No end was in sight — you saw only the edge. It rolled at you across the land at 1,800 miles an hour, hauling darkness like plague behind it. Seeing it, and knowing it was coming straight for you, was like feeling a slug of anesthetic shoot up your arm. If you think very fast, you may have time to think, “Soon it will hit my brain.” You can feel the deadness race up your arm; you can feel the appalling, inhuman speed of your own blood. We saw the wall of shadow coming, and screamed before it hit.
Next time, and there will definitely be a next time, I’m hoping to get up high somewhere so I can see the shadow and more of the 360-degree sunset. BRB, pricing plane tickets to Argentina…
Update: Before the 2017 eclipse, Vox talked to some eclipse chasers about what it’s like to witness a total solar eclipse.
now that i’ve recovered from the drive, i can say that a lot of what these eclipse chasers told me makes sense now. agree completely that it’s something you have to see for yourself. what was different for me though is …. i got pretty sad. there’s a fine line between awe and grief. maybe in a different year it would have gone the other way, but tbh every exceptionally beautiful sunset makes me a tiny bit sad too. but this was sunset sadness times a thousand. absolutely punched by the impermanence. i hope i see it again and i hope you can see it too.
I was not prepared for how incredible the total eclipse was. It was, literally, awesome. Almost a spiritual experience. I also did not anticipate the crazy-ass, reverse storm-chasing car ride we’d need to undertake in order to see it.
I’m not a bucket list sort of person, but ever since seeing a partial eclipse back in college in the 90s (probably this one), I have wanted to witness a total solar eclipse with my own eyes. I started planning for the 2017 event three years ago…the original idea was to go to Oregon, but then some college friends suggested meeting up in Nebraska, which seemed ideal: perhaps less traffic than Oregon, better weather, and more ways to drive in case of poor weather.
Well, two of those things were true. Waking up on Monday, the cloud cover report for Lincoln didn’t look so promising. Rejecting the promise of slightly better skies to the west along I-80, we opted instead to head southeast towards St. Joseph, Missouri where the cloud cover report looked much better. Along the way, thunderstorms started popping up right where we were headed. Committed to our route and trusting this rando internet weather report with religious conviction, we pressed on. We drove through three rainstorms, our car hydroplaning because it was raining so hard, flood warnings popping up on our phones for tiny towns we were about to drive through. Morale was low and the car was pretty quiet for awhile; I Stoically resigned myself to missing the eclipse.
But on the radar, hope. The storms were headed off to the northeast and it appeared as though we might make it past them in time. The Sun appeared briefly through the clouds and from the passenger seat, I stabbed at it shining through the windshield, “There it is! There’s the Sun!” We angled back to the west slightly and, after 3.5 hours in the car, we pulled off the road near the aptly named town of Rayville with 40 minutes until totality, mostly clear skies above us. After our effort, all that was missing was a majestic choral “ahhhhhh” sound as the storm clouds parted to reveal the Sun.
My friend Mouser got his camera set up — he’d brought along the 500mm telephoto lens he uses for birding — and we spent some time looking at the partial eclipse through our glasses, binoculars (outfitted with my homemade solar filter), and phone cameras. I hadn’t seen a partial eclipse since that one back in the 90s, and it was cool seeing the Sun appear as a crescent in the sky. I took this photo through the clouds:
Some more substantial clouds were approaching but not quickly enough to ruin the eclipse. I pumped my fist, incredulous and thrilled that our effort was going to pay off. As totality approached, the sky got darker, our shadows sharpened, insects started making noise, and disoriented birds quieted. The air cooled and it even started to get a little foggy because of the rapid temperature change.
We saw the Baily’s beads and the diamond ring effect. And then…sorry, words are insufficient here. When the Moon finally slipped completely in front of the Sun and the sky went dark, I don’t even know how to describe it. The world stopped and time with it. During totality, Mouser took the photo at the top of the page. I’d seen photos like that before but had assumed that the beautifully wispy corona had been enhanced with filters in Photoshop. But no…that is actually what it looks like in the sky when viewing it with the naked eye (albeit smaller). Hands down, it was the most incredible natural event I’ve ever seen.
After two minutes — or was it several hours? — it was over and we struggled to talk to each other about what we had just seen. We stumbled around, dazed. I felt high, euphoric. Raza Syed put it perfectly:
It was beautiful and dramatic and overwhelming — the most thrillingly disorienting passage of time I’ve experienced since that one time I skydived. It was a complete circadian mindfuck.
After waiting for more than 20 years, I’m so glad I finally got to witness a total solar eclipse in person. What a thing. What a wondrous thing.
There were a tumult, and disorder. All were disquieted, unnerved, frightened. Then there was weeping. The commonfolk raised a cup, lifting their voices, making a great din, calling out shrieking. People of light complexion were slain as sacrifices; captives were killed. All offered their blood.
But even in modern times, a lack of scientific understanding of what happens during a solar eclipse can cause apprehension and panic. Until hearing the same story from two different people in the past week, I had no idea that during solar eclipses, it is routine for schoolchildren to be kept inside until the “danger” has passed. Charles Fulco, a NASA and AAS 2017 U.S. Eclipse Educator, is trying to allay these fears by addressing common eclipse misconceptions.
“The Sun is more dangerous during an eclipse.” This is utter nonsense and for some reason, has persisted into the 21st Century. An eclipsed Sun is no more dangerous than the “everyday” Sun, but for some reason, some districts still keep teachers and students in their rooms with pulled shades, watching the eclipse on a screen, rather than outdoors, safely and under the care of a professional educator. I believe their fear of nature is transferred to the students as well: If the adult says an eclipse is scary and dangerous, than it must be!
As I make my final preparations for my eclipse travels (rural western Wyoming, if you’re curious) I’m hearing stories that are making me very unhappy: Some school districts across the country are telling children to stay inside during the eclipse, out of fear they’ll damage their eyes.
Let me be clear: Schools, administrators, teachers, parents: Don’t do this. YOU CAN LET THE KIDS SEE THE ECLIPSE. You just have to be safe about it.
I can appreciate the difficulty of telling 25 first graders there’s something cool happening with the Sun and then trying to get them not to look directly at it, but keeping kids inside is not the answer. For one thing, they’re missing out on a genuine celestial spectacle & learning opportunity and for another, you’re teaching people bad science. A friend, who is one of the smartest people I know, was genuinely concerned for her kids’ safety during the eclipse because when she was a kid, she was kept inside a classroom with the shades drawn because, she was told, it was dangerous for them to be outside. Dangerous to be outside in the sunshine! A clear case of educators doing the exact opposite of what they should be doing.
This video from the Weather Channel is pretty neat and useful: a play-by-play of what to expect during the eclipse, from being able to see Venus in broad daylight to animals possibly acting weird to the 360-degree “sunset” that happens about 2 minutes before totality.
The Exploratorium in San Francisco has produced a great explainer video about the science of predicting total solar eclipses. Each eclipse belongs to a repeating series of eclipses called a Saros cycle that repeats every 18 years 11 days and 8 hours.
There are now 40 active Saros cycles and the August 2017 eclipse belongs to Saros 145, which produced its first total eclipse in June 1909 and will produce its last total eclipse in September 2648.
Timeline of the far future is one of my favorite pages on Wikipedia. It details what might happen to humanity, human artifacts, the Earth, the solar system, and the Universe from 10,000 years from now until long past the heat death of the Universe. Information is Beautiful has made a lovely infographic of the timeline.
Reading through the timeline is a glorious way to spend time…here are a few favorites I noticed this time around as well as some from my first post.
August 20, 10,663: “A simultaneous total solar eclipse and transit of Mercury.”
20,000 years: “The Chernobyl Exclusion Zone, the 1,000 sq mi area of Ukraine and Belarus left deserted by the 1986 Chernobyl disaster, becomes safe for human life.”
296,000 years: “Voyager 2 passes within 4.3 light-years of Sirius, the brightest star in the night sky.”
1 million years: “Highest estimated time until the red supergiant star Betelgeuse explodes in a supernova. The explosion is expected to be easily visible in daylight.”
1 million years: “On the Moon, Neil Armstrong’s ‘one small step’ footprint at Tranquility Base will erode by this time, along with those left by all twelve Apollo moonwalkers, due to the accumulated effects of space weathering.”
15.7 million: “Half-life of iodine-129, the most durable long-lived fission product in uranium-derived nuclear waste.”
100 million years: “Future archaeologists should be able to identify an ‘Urban Stratum’ of fossilized great coastal cities, mostly through the remains of underground infrastructure such as building foundations and utility tunnels.”
1 billion years: “Estimated lifespan of the two Voyager Golden Records, before the information stored on them is rendered unrecoverable.”
4 billion years: “Median point by which the Andromeda Galaxy will have collided with the Milky Way, which will thereafter merge to form a galaxy dubbed ‘Milkomeda’.”
7.59 billion years: The Earth and Moon are very likely destroyed by falling into the Sun, just before the Sun reaches the tip of its red giant phase and its maximum radius of 256 times the present-day value. Before the final collision, the Moon possibly spirals below Earth’s Roche limit, breaking into a ring of debris, most of which falls to the Earth’s surface.
100 billion years: “The Universe’s expansion causes all galaxies beyond the Milky Way’s Local Group to disappear beyond the cosmic light horizon, removing them from the observable universe.”
In a meditative video for the NY Times, Dennis Overbye takes us on a tour of eclipses that happen in our solar system and beyond.
On the 21st day of August, 2017, the moon will slide between the Earth and the sun, painting a swath of darkness across North America. The Great American Solar Eclipse. An exercise in cosmic geometry. A reminder that we live on one sphere among many, all moving to the laws of Kepler, Newton and Einstein.
Humans have many more vantage points from which to observe solar eclipses than when the last solar eclipse occurred in the US in 1979. I had no idea that the Mars rovers had caught partial solar eclipses on Mars…so cool. (via @jossfong)
The prevailing theory of how the Americas were settled has been than human hunters followed big game across the ice-free land bridge between North America and Asia around 13,000 years ago. These are the Clovis people you may have learned about in school. But evidence is mounting that the first humans to settle the Americas came down the Pacific Coast somewhat earlier than that.
The Cedros Island sites add to a small but growing list that supports a once-heretical view of the peopling of the Americas. Whereas archaeologists once thought that the earliest arrivals wandered into the continent through a gap in the ice age glaciers covering Canada, most researchers today think the first inhabitants came by sea. In this view, maritime explorers voyaged by boat out of Beringia — the ancient land now partially submerged under the waters of the Bering Strait — about 16,000 years ago and quickly moved down the Pacific coast, reaching Chile by at least 14,500 years ago.
Part of the problem in confirming this hypothesis is that the rise in sea level that accompanied the melting of the glaciers (a 120-meter rise globally) submerged likely settlement sites, trapping archeological evidence under hundreds of feet of ocean. (via @CharlesCMann)
In the first in a series of videos, Kurzgesagt tackles one of my favorite scientific subjects: how the sizes of animals governs their behaviors, appearance, and abilities. For instance, because the volume (and therefore mass) of an organism increases according to the cube of the increase in length (e.g. if you double the length/height of a dog, its mass roughly increases by 8 times), when you drop differently sized animals from high up, the outcomes are vastly different (a mouse lands safely, an elephant splatters everywhere).
When humans get smaller, the world and its resources get bigger. We’d live in smaller houses, drive smaller cars that use less gas, eat less food, etc. It wouldn’t even take much to realize gains from a Honey, I Shrunk Humanity scheme: because of scaling laws, a height/weight proportional human maxing out at 3 feet tall would not use half the resources of a 6-foot human but would use somewhere between 1/4 and 1/8 of the resources, depending on whether the resource varied with volume or surface area. Six-inch-tall humans would potentially use 1728 times fewer resources.
Starting with an overhead shot of people sitting out in the sun in NYC’s Bryant Park, Rod Bogart laid what’s called a Voronoi diagram on top of it. A Voronoi diagram is a way of mapping out areas where any point in a given area is closer to a seed point than it is to any other seed point. You can think of it as a sphere of influence…and in this case, you can see how the park-goers have organized themselves into having their own personal space. As Bogart says:
It’s fascinating to see the real world optimization problem of wanting to get a nice large patch of grass.
I stand alone in the elevator, right in the middle, equidistant from the four walls. Before the doors close, a woman enters. Unconsciously, I move over to make room for her. We stand side by side with equal amounts of space between the two of us and between each of us and the walls of the elevator. On the 12th floor, a man gets on and the woman and I slide slightly to the side and to the back, maximizing the space that each of us occupies in the elevator. At the 14th floor, another man gets on. The man in front steps to the back center and the woman and I move slightly toward the front, forming a diamond shape that again maximizes each person’s distance from the elevator walls and the people next to them.
Leonardo da Vinci was an avid taker of notes. Over the course of his working life, he filled thousands of pages with drawings, sketches, equations, and his distinctive mirrored handwriting. The British Library has one of Leonardo’s notebooks and has digitized and put all 570 pages of it online. It’s interesting to see all of the spare geometric line drawings and then every once in awhile there’s this wonderfully rendered 3D-shaded tiny masterpiece in the margin when more detail was required. (via open culture)
From the ViaScience YouTube channel comes this 31-part video explainer of quantum mechanics. As the introduction video notes, there is a fair bit of math in these videos presented at a quick pace, but if you took calculus in high school or college and remember the notation, that (and the pause button) should get you through this pretty well. (via @jsonpaul, who calls the series “fantastic”)
Well, the short answer is that they don’t happen all that often and when they do, they’ve visible from only a small bit of Earth. Joss Fong elaborates in a video for Vox.
The next total solar eclipse to visit the US will be in 2024. If an eclipse happens to come to your town, you’re lucky. Any given location will see a total solar eclipse only once in more than 300 years, on average. The vast majority of us will have to travel to an eclipse path if we want to see a total eclipse in our lifetimes.
I’m off to Nebraska in August to meet up with some friends and see the eclipse. (And that 2024 eclipse Fong mentions? The path of totality goes right over my damn house. Woooo!) But no matter where you are in North America, you can enjoy the eclipse…just make sure you buy some safety glasses (and other supplies) if you want to look directly at the Sun. (via @veganstraightedge)
In the wake of his diagnosis, many of those expressing support for McCain reference his considerable personal strength in his fight against cancer. President Obama said:
John McCain is an American hero & one of the bravest fighters I’ve ever known. Cancer doesn’t know what it’s up against. Give it hell, John.
John and I have been friends for 40 years. He’s gotten through so much difficulty with so much grace. He is strong — and he will beat this.
This is the right thing to say to those going through something like this, and hearing this encouragement and having the will & energy to meet this challenge will undoubtably increase McCain’s chances of survival. But what Biden said next is perhaps more relevant:
Incredible progress in cancer research and treatment in just the last year offers new promise and new hope. You can win this fight, John.
As with polio, smallpox, measles, and countless other diseases before it, beating cancer is not something an individual can do. Being afflicted with cancer is the individual’s burden to bear but society’s responsibility to cure. In his excellent biography of cancer from 2011, The Emperor of All Maladies, Siddhartha Mukherjee talks about the progress we’ve made on cancer:
Incremental advances can add up to transformative changes. In 2005, an avalanche of papers cascading through the scientific literature converged on a remarkably consistent message — the national physiognomy of cancer had subtly but fundamentally changed. The mortality for nearly every major form of cancer — lung, breast, colon, and prostate — had continuously dropped for fifteen straight years. There had been no single, drastic turn but rather a steady and powerful attrition: mortality had declined by about 1 percent every year. The rate might sound modest, but its cumulative effect was remarkable: between 1990 and 2005, the cancer-specific death rate had dropped nearly 15 percent, a decline unprecedented in the history of the disease. The empire of cancer was still indubitably vast — more than half a million American men and women died of cancer in 2005 — but it was losing power, fraying at its borders.
What precipitated this steady decline? There was no single answer but rather a multitude. For lung cancer, the driver of decline was primarily prevention — a slow attrition in smoking sparked off by the Doll-Hill and Wynder-Graham studies, fueled by the surgeon general’s report, and brought to its full boil by a combination of political activism (the FTC action on warning labels), inventive litigation (the Banzhaf and Cipollone cases), medical advocacy, and countermarketing (the antitobacco advertisements). For colon and cervical cancer, the declines were almost certainly due to the successes of secondary prevention — cancer screening. Colon cancers were detected at earlier and earlier stages in their evolution, often in the premalignant state, and treated with relatively minor surgeries. Cervical cancer screening using Papanicolaou’s smearing technique was being offered at primary-care centers throughout the nation, and as with colon cancer, premalignant lesions were excised using relatively minor surgeries. For leukemia, lymphoma, and testicular cancer, in contrast, the declining numbers reflected the successes of chemotherapeutic treatment. In childhood ALL, cure rates of 80 percent were routinely being achieved. Hodgkin’s disease was similarly curable, and so, too, were some large-cell aggressive lymphomas. Indeed, for Hodgkin’s disease, testicular cancer, and childhood leukemias, the burning question was not how much chemotherapy was curative, but how little: trials were addressing whether milder and less toxic doses of drugs, scaled back from the original protocols, could achieve equivalent cure rates.
Perhaps most symbolically, the decline in breast cancer mortality epitomized the cumulative and collaborative nature of these victories — and the importance of attacking cancer using multiple independent prongs. Between 1990 and 2005, breast cancer mortality had dwindled an unprecedented 24 percent. Three interventions had potentially driven down the breast cancer death rate-mammography (screening to catch early breast cancer and thereby prevent invasive breast cancer), surgery, and adjuvant chemotherapy (chemotherapy after surgery to remove remnant cancer cells).
Understanding how to defeat cancer is an instance where America’s fierce insistence on individualism does us a disservice. Individuals with freedom to pursue their own goals are capable of a great deal, but some problems require massive collective coordination and effort. Beating cancer is a team sport; it can only be defeated by a diverse collection of people and institutions working hard toward the same goal. It will take government-funded research, privately funded research, a strong educational system, philanthropy, and government agencies from around the world working together. This effort also requires a system of healthcare that’s available to everybody, not just to those who can afford it. Although cancer is not a contagious disease like measles or smallpox, the diagnosis and treatment of each and every case brings us closer to understanding how to defeat it. We make this effort together, we spend this time, energy, and money, so that 10, 20, or 30 years from now, our children and grandchildren won’t have to suffer like our friends and family do now.
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