The ghoul's head and the three-body problem

Ever heard of Algol?

Known to astronomers as Beta Persei, it's the second-brightest star in the constellation of Perseus.  It was singled out as strange a long time ago.  Even in a small telescope it looks like a single star, but in 1881 it became the first identified eclipsing binary, a pair of stars orbiting around a common center of gravity with the orbital plane lined up so that from our perspective, one passes in front of the other.  Because one of the stars is dimmer than the other, when the dimmer one crosses in front of the brighter one, the brightness of the pair appears to diminish -- the transit takes ten hours and happens every 2.86 days, so it's regular as clockwork.

The first certain mention of Algol's variability was by Italian astronomer Geminiano Montanari in 1667, but way before that the star had a reputation for being uncanny.  The name Algol comes from the Arabic رأس الغول (raʾs al-ghūl) -- "the head of the ghoul."  The Greeks, who named the constellation in which it resides Perseus, thought that Algol was the Gorgon's head that the hero was carrying.  The ancient Hebrews called it Rōsh ha Sāṭān (Satan's head).  These are similar enough that they probably come from a common source, but the Chinese as well thought there was something evil about it; they called Algol and the stars surrounding it Dà Líng -- the Mausoleum.

So even if there's no certain evidence that the ancients knew about Algol's odd variability, it seems pretty likely.

What no one realized until recently is that Algol is weirder even than that.  To see just how strange it is, first a brief physics lesson.

Some of the great names of physics and astronomy in the sixteenth and seventeenth centuries -- Galileo Galilei, Tycho Brahe, Johannes Kepler, and Isaac Newton, especially -- used highly accurate data on planetary positions to conclude that the planets in the Solar System go around the Sun in elliptical orbits, all powered by the Universal Law of Gravitation.  The mathematical model they came up with worked to a high degree of accuracy, allowing earthbound astronomers to predict where the planets were in the sky, and also such phenomena as eclipses.

Lucky for them, though, that the Sun is so massive.  Because the Sun is huge -- it has a thousand times more mass than the largest planet, Jupiter -- its gravitational pull is big enough that it swamps the pull the planets exert on each other.  For most purposes, you can treat each orbit as independent two-body problems; you can (for example) look at the masses, velocities, and distances between the Sun and Saturn and ignore everything else for the time being.  (Interestingly, it's the slight deviation of the orbit of Uranus from the predictions of its position using the two-body solution that led astronomers to deduce that there must be another massive planet out there pulling on it -- and in 1846 Neptune was observed for the first time, right where the deviations suggested it would be.)

I said it was "lucky" that the mass imbalance is so large, but I haven't told you how lucky.  It turns out that all you have to do is add one more object of close to the same size, and you now have the three-body problem -- a big problem, because physicists have been unable to find a general solution to the equations it generates.  You can pick the parameters (mass, separation distance, initial velocity, and so on) and have a computer model what the orbits would look like, but there's no overarching set of mathematical equations that physicists can use on any other system with different parameters.  The unifying model just doesn't exist, or at least hasn't been discovered yet.

Worse still, most individual three-body systems generate chaotic orbits.  Here's a rather mesmerizing gif showing one of them:

[Image is licensed under the Creative Commons Dnttllthmmnm, Three-body Problem Animation with COM, CC BY-SA 4.0]

The reason this comes up  is a paper in The Astrophysical Journal showing that Algol isn't a simple double star system, with two stars orbiting their common center of gravity like Newton said.  In the 1950s astronomers figured out that the known binary system (Algol A and Algol B) is in an orbit with a third star (Algol C), with the whole trio orbiting their center of gravity once every 1.86 years, and presumably tracing out some kind of bizarre Spirograph pattern like the one in the gif.

But the recent paper showed that it's not even that simple.  Algol isn't a weird, chaotic three-star system.

The "star" we call Algol is apparently made up of at least seven stars all moving in a complex dance around their collective center of gravity.

Algol is in our stellar neighborhood -- only ninety light years away -- so why haven't they been observed until now?

"The paradox is that Algol A is 'too bright,' " said astrophysicist Lauri Jetsu, author of the paper, in an interview with Science Daily.  "It can hide these new companion candidate stars even from our most powerful modern space telescopes, just like our Sun can hide all other stars during daytime...  Even the cutting-edge equipment onboard the Gaia satellite could not detect these new companion candidates.  Future interferometric observations may be used to directly confirm the existence of at least some of Algol's companions."

I find it fascinating that even in a part of physics that is usually considered pretty well sussed-out -- classical mechanics, the study of objects in motion -- there are unsolved problems that the experts consider very close to intractable.  Further reinforcing the notion that the universe doesn't seem to feel obliged to choose how it acts based upon whether humans find it comprehensible.  It does what it does, leaving us to try to explain how on earth (or off it) that kind of thing could happen -- in this case, seven massive objects all whirling around each other in apparently stable orbits.

It's a little like the famous (if apocryphal) story about bumblebees -- that physicists have analyzed their mass, wing size, wing beat frequency, and so on, and have come to the conclusion that bumblebees can't fly.  The bumblebees, not knowing this, go ahead and fly anyway.  Here, the seven members of the Algol system are apparently unaware that the steps of their cosmic dance is beyond what our current physics can explain, but it doesn't stop them from dancing.

Think of that the next time you look at the night sky, and see the bright blue pinpoint of the ghoul's head twinkling against the blackness.

**********************************

My master's degree is in historical linguistics, with a focus on Scandinavia and Great Britain (and the interactions between them) -- so it was with great interest that I read Cat Jarman's book River Kings: A New History of Vikings from Scandinavia to the Silk Road.

Jarman, who is an archaeologist working for the University of Bristol and the Scandinavian Museum of Cultural History of the University of Oslo, is one of the world's experts on the Viking Age.  She does a great job of de-mythologizing these wide-traveling raiders, explorers, and merchants, taking them out of the caricature depictions of guys with blond braids and horned helmets into the reality of a complex, dynamic culture that impacted lands and people from Labrador to China.

River Kings is a brilliantly-written analysis of an often-misunderstood group -- beginning with the fact that "Viking" isn't an ethnic designation, but an occupation -- and tracing artifacts they left behind traveling between their homeland in Sweden, Norway, and Denmark to Iceland, the Hebrides, Normandy, the Silk Road, and Russia.  (In fact, the Rus -- the people who founded, and gave their name to, Russia -- were Scandinavian explorers who settled in what is now the Ukraine and western Russia, intermarrying with the Slavic population there and eventually forming a unique melded culture.)

If you are interested in the Vikings or in European history in general, you should put Jarman's book in your to-read list.  It goes a long way toward replacing the legendary status of these fierce, sea-going people with a historically-accurate reality that is just as fascinating.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

Gems of dialogue

It's hard to describe why some particular lines of dialogue are memorable, any more than you could say "wow, those three notes in that symphony are brilliant!"  The dialogue itself only shows its excellence in the context that the author has set.  Nevertheless, there are passages of dialogue in books and stories that to me still stand out as absolute genius.

It's probably futile to try to explain why these particular passages leaped off the page for me, but I thought it might be a fun topic for this week's Fiction Friday to present here a few lines of dialogue that for me exemplify sheer, unadulterated brilliance in writing.  Each one of these sent a little shiver up my spine, and I thought: this is perfect.  See how many you recognize, and if you recognize them, whether you agree.  Feel free to add some of your favorites.  If nothing else, we'll all have a list of books to put on our winter reading list.

"Mother was always shoving me out into the world," Meg said.  "She'd want me to do this.  You know she would.  Tell her..." she started, choked, then held up her head and said, "No.  Never mind.  I'll tell her myself." -- Madeleine l'Engle, A Wrinkle in Time


"I am tired," he said.  "I did a lot today.  That is, I did something.  The only thing I have ever done.  I pressed a button.  It took the entire will power, the accumulated strength of my entire existence, to press one damned 'Off' button." -- Ursula LeGuin, The Lathe of Heaven


"Most people are not looking for provable truths.  As you said, truth is often accompanied by intense pain, and almost no one is looking for painful truths.  What people need is beautiful, comforting stories that make them feel as if their lives have some meaning." -- Haruki Murakami, 1Q84

"This belonged to my great-granddad," the sergeant said.  "He was in the battle we had against Pseudopolis and my great-gran gave him this book of prayer for soldiers, ‘cos you need all the prayers you can get, believe you me, and he stuck it in the top pocket of his jerkin, ‘cos he couldn’t afford armour, and next day in battle - whoosh, this arrow came out of nowhere, wham, straight into this book and it went all the way through to the last page before stopping, look, you can see the hole."

"Pretty miraculous," Captain Carrot agreed.

"Yeah, it was, I s’pose," said the sergeant.  He looked ruefully at the battered volume.  "Shame about the other seventeen arrows, really." -- Terry Pratchett, Jingo

"We will have peace, " said Théoden at last thickly and with an effort.  Several of the Riders cried out gladly.  Théoden held up his hand.  "Yes, we will have peace," he said, now in a clear voice, "we will have peace, when you and all of your works have perished -- and the works of your dark master to whom you would deliver us.  You are a liar, Saruman, and a corrupter of men's hearts.  You hold out your hand to me, and I perceive only a finger of the claw of Mordor.  Cruel and cold!  Even if your war on me was just -- as it was not, for were you ten times as wise you would have no right to rule me and mine for your own profit as you desired -- even so, what will you say of your torches in Westfold and the children that lie dead there?  And they hewed Háma's body before the gates of the Hornburg, after he was dead.  When you hang from a gibbet at your window for the sport of your own crows, I will have peace with you and Orthanc.  So much for the House of Eorl.  A lesser son of great sires am I, but I do not need to lick your fingers.  Turn elsewhither.  But I fear your voice has lost its charm." -- J. R. R. Tolkien, The Two Towers

"You suggested that Hazel should tell them of our adventures, Blackberry, but it didn't go down well, did it?  Who wants to hear about brave deeds when he's ashamed of his own, and who likes an open, honest tale from someone he's deceiving?  Do you want me to go on?  I tell you, every single thing that's happened fits like a bee in a foxglove.  And kill them, you say, and help ourselves to the great burrow?  We shall help ourselves to a roof of bones, hung with shining wires.  Help ourselves to misery and death." -- Richard Adams, Watership Down


"In that face, deformed by hatred of philosophy, I saw for the first time the portrait of the Antichrist, who does not come from the tribe of Judas, as his heralds have it, or from a far country.  The Antichrist can be born from piety itself, from excessive love of God or of the truth, as the heretic is born from the saint and the possessed from the seer.  Fear prophets, Adso, and those prepared to die for the truth, for as a rule they make many others die with them, often before them, at times instead of them.  Jorge did a diabolical thing because he loved his truth so lewdly that he dared anything in order to destroy falsehood." -- Umberto Eco, The Name of the Rose

"I believe that I am mad," said Vertue presently.  "The world cannot be as it seems to me.  If there is something to go to, it is a bribe, and I cannot go to it; if I can go, then there is nothing to go to."

"Vertue," said John, "give in.  For once, yield to desire.  Have done with your choosing.  Want something."

"I cannot," said Vertue.  "I must choose because I choose because I choose; and it goes on forever, and in the whole world I cannot find a single reason for rising from this stone." -- C. S. Lewis, The Pilgrim's Regress


"As for my gravestone?  I would like to borrow that great barber-pole from out front of the town shoppe, and have it run at midnight if you happened to drop by my mound to say hello.  And there the old barber-pole would be, lit, its bright ribbons twining up out of mystery, turning, and twining away up into further mysteries, forever.  And if you come to visit, leave an apple for the ghosts." -- Ray Bradbury, Something Wicked This Way Comes


"Yes," she said coldly.  "Better that they die here and now, if that's what has to happen, than that they go with you and live.  They -- we -- did some lousy things.  But the price is much too high." -- Stephen King, Needful Things

So there are a few of my favorites.  I'd love to hear yours!

**********************************

My master's degree is in historical linguistics, with a focus on Scandinavia and Great Britain (and the interactions between them) -- so it was with great interest that I read Cat Jarman's book River Kings: A New History of Vikings from Scandinavia to the Silk Road.

Jarman, who is an archaeologist working for the University of Bristol and the Scandinavian Museum of Cultural History of the University of Oslo, is one of the world's experts on the Viking Age.  She does a great job of de-mythologizing these wide-traveling raiders, explorers, and merchants, taking them out of the caricature depictions of guys with blond braids and horned helmets into the reality of a complex, dynamic culture that impacted lands and people from Labrador to China.

River Kings is a brilliantly-written analysis of an often-misunderstood group -- beginning with the fact that "Viking" isn't an ethnic designation, but an occupation -- and tracing artifacts they left behind traveling between their homeland in Sweden, Norway, and Denmark to Iceland, the Hebrides, Normandy, the Silk Road, and Russia.  (In fact, the Rus -- the people who founded, and gave their name to, Russia -- were Scandinavian explorers who settled in what is now the Ukraine and western Russia, intermarrying with the Slavic population there and eventually forming a unique melded culture.)

If you are interested in the Vikings or in European history in general, you should put Jarman's book in your to-read list.  It goes a long way toward replacing the legendary status of these fierce, sea-going people with a historically-accurate reality that is just as fascinating.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

Analysis of a triple-whammy

I always find it wryly amusing when I hear someone talk about the Strong Anthropic Principle -- the idea that the universe was fine-tuned by a creator to be hospitable to life, particularly human life -- because it doesn't take much of a close look to become aware of exactly how inhospitable the universe actually is.

Even here on Earth, the situation is kind of dicey.  Our planet's history is really one cataclysm after another; that our own particular lineage survived is probably more a matter of luck than anything else.  In fact, only 74,000 years ago, climate havoc caused by the eruption of the Indonesian volcano Toba is thought by some scientists to have nearly wiped out our species -- they estimate the "Toba bottleneck event" to have reduced the entire population of Homo sapiens to under ten thousand individuals.  (For reference, that means that the human population of the whole planet was about as many people as currently live in Sitka, Alaska.)  Besides major volcanic eruptions, add in earthquakes and tsunamis, global marine anoxia events, and meteor strikes, and you can see that where we live isn't nearly as hospitable as it might look at first.

So the truth lies closer to the Weak Anthropic Principle -- of course the universe, and the Earth in particular, have the conditions necessary for life to exist, because if they didn't, we wouldn't be here to consider the question.

The reason all this catastrophic stuff comes up is a paper that came out a couple of weeks ago in Nature Communications Biology.  Entitled, "Widespread Loss of Mammalian Lineage and Dietary Diversity in the Early Oligocene of Afro-Arabia," by Dorien de Vries (of the University of Salford), Steven Heritage (of Stony Brook University), and Matthew Borths, Hesham Sallam, and Erik Seiffert (of the Duke University Museum of Natural History), it looks at a little-known extinction event that was apparently the result of a one-two-three punch that nearly halted the mammalian species in Africa in their tracks.

Which, of course, also includes our own ancestors.

Some of the Eocene animal groups affected by the extinction -- the left two are primates, the upper right a hyaenodont, and the lower right a prehistoric rodent.  [Photo by Matthew Borths]

The researchers had their first clues about the magnitude of the event, which occurred on the order of thirty-three million years ago, from looking at fossilized mammal teeth from East Africa, and found that right on the boundary of the Eocene and Oligocene, the number of mammal species dropped drastically.

"In our anthropoid ancestors, diversity bottoms out to almost nothing around thirty million years ago, leaving them with a single tooth type,” said Erik Seiffert, senior co-author of the paper, in an interview with EurekAlert.  "That ancestral tooth shape determined what was possible in terms of later dietary diversification...  There's an interesting story about the role of that bottleneck in our own early evolutionary history.  We came pretty close to never existing, if our monkey-like ancestors had gone extinct thirty million years ago.  Luckily they didn’t."

What seems to have driven the extinction was a triple-whammy -- rapid cooling of the climate after the equally catastrophic Paleocene-Eocene Thermal Maximum (during which the global average temperature was eight degrees warmer than it is now), followed by the huge Chesapeake Bay meteorite collision and a near-simultaneous massive eruption of flood basalts in Ethiopia.

Diversity plummeted.  More interestingly, the extinction preferentially spared generalists -- mammals which, from their tooth morphology, apparently could eat a variety of different kinds of food.  Specialists got hit the hardest, once again reinforcing the general evolutionary concept that if the ecosystem is stable, specialization is a good thing, but during periods of rapid change, it's the generalists who come out on top.

This -- as Seiffert says, luckily for us -- left our own distant ancestors to continue loping about on the African savanna, and also knocked out a lot of the competition.  The shape and structure of our own teeth reflect that event.  "We lost a lot of diversity at the Eocene-Oligocene boundary," said study co-author Matthew Borths.  "But the species that survived apparently had enough of a toolkit to persist through this fluctuating climate."

This should be yet another cautionary note about the fragility of the Earth's suitability for humanity, not to mention our current heedless messing-about with the planetary climate and ecosystems.  It's unlikely to, of course.  We don't have a very good record of listening to scientists, even when our own survival is at stake.  Part of this is that in recent memory we haven't had to deal with planet-wide natural disasters -- it's made us cocky.

"We've always been fine before," is the general attitude.

All it takes is reading the de Vries et al. paper to realize that "always" is singularly inapt.

**********************************

My master's degree is in historical linguistics, with a focus on Scandinavia and Great Britain (and the interactions between them) -- so it was with great interest that I read Cat Jarman's book River Kings: A New History of Vikings from Scandinavia to the Silk Road.

Jarman, who is an archaeologist working for the University of Bristol and the Scandinavian Museum of Cultural History of the University of Oslo, is one of the world's experts on the Viking Age.  She does a great job of de-mythologizing these wide-traveling raiders, explorers, and merchants, taking them out of the caricature depictions of guys with blond braids and horned helmets into the reality of a complex, dynamic culture that impacted lands and people from Labrador to China.

River Kings is a brilliantly-written analysis of an often-misunderstood group -- beginning with the fact that "Viking" isn't an ethnic designation, but an occupation -- and tracing artifacts they left behind traveling between their homeland in Sweden, Norway, and Denmark to Iceland, the Hebrides, Normandy, the Silk Road, and Russia.  (In fact, the Rus -- the people who founded, and gave their name to, Russia -- were Scandinavian explorers who settled in what is now the Ukraine and western Russia, intermarrying with the Slavic population there and eventually forming a unique melded culture.)

If you are interested in the Vikings or in European history in general, you should put Jarman's book in your to-read list.  It goes a long way toward replacing the legendary status of these fierce, sea-going people with a historically-accurate reality that is just as fascinating.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

Feats of clay

As I write this, I'm waiting for a kiln full of pottery to cool enough that I can open it.

Opening a kiln, especially after the final (glaze) firing, is a bit like Forrest Gump's box of chocolates; you never know what you're gonna get.  Even though I have about ten years of experience making pottery, it's still a crapshoot every single time, mostly because so many things can go wrong along the way.  My first pottery teacher said never to get attached to a pot until it's cool, in your hands, after the final firing, and there's a lot of truth in that.  Besides the built-in uncertainty of a complex, multi-step process that never quite works the same way twice, there's the added complication that I love to mess around with new techniques, especially new glaze combinations.

So I must admit that just about all of my failures have been my own damn fault.

Sometimes, though, things work out a great deal better than you expect.

I got into pottery on a whim.  I've never been much good at artistic pursuits -- my former students will attest to the fact that my ability to draw kind of topped out in third grade -- but my wife is a brilliant artist, and had been taking lessons in pottery for a while.  She convinced me to give it a try, and after one lesson I was hooked.  I'm still at it ten years later, even though mostly I still just think of it as playing in the mud for adults.

Then there are the (many) times it doesn't go so well.  We have turned our failures into a game called "Confusing Future Archaeologists."

I've done a lot of wheel-throwing and hand-building, and we now have a studio that is completely taken over by pottery equipment.  I must say, in all seriousness, that pottery kind of saved my sanity during the pandemic lockdown.  Having something creative to focus on was a godsend.

Working on the wheel

I have no desire to learn to be a professional potter; an amateur I am, and an amateur I shall remain.  If every once in a while I produce something I judge as worthy of keeping, that's cool, but mostly I'm just in it to have fun.

Then, there's the potential for combining pottery with my other obsessions.  Yes, I know I'm a total fanboy.  No, I don't care.

The reason this comes up is a paper I ran into a couple of days ago in The Journal of Anthropological Archaeology about the techniques for pottery-making used by the mysterious Indus Valley Civilization of northwestern India four thousand years ago.  A team led by Alessandro Ceccarelli of the University of Cambridge did a detailed analysis of fragments of pottery from the Indus Civilization, and found that they were already using a great many of the techniques potters still use today -- pinching, slab-building, coiling, and wheel-throwing.  You might wonder how the researchers could discern the latter; a well-made coiled pot and a wheel-thrown pot can look a great deal alike.  But microscopic analysis of the shards showed that even after smoothing and firing, hand-built pottery still shows traces of the scraping potters do to join the pieces together and avoid cracking, while wheel-thrown pottery retains evidence of rotational stress in the clay particles that comes from the torque on the clay from the spinning wheel and the drag exerted by the potter's hands.

When I read that last bit, I thought, "Oh, of course."  One of the things wheel-throwers learn very early on is that throwing creates a twist in the clay, even if the homogeneity of the material makes it hard to see.  Multi-part pieces like teapots are where this is the most critical; when you put the spout on a teapot, you have to account for the fact that during firing the clay will "relax" or untwist a little, so what was joined to the body of the teapot as a perfectly-aligned spout can come out of the kiln tilted to the side.  Once you figure out how much the clay you're using untwists, you compensate by putting the spout on tilted a little in the other direction -- so during the firing, the spout will right itself and come out properly aligned.

It's kind of amazing to me how far back these techniques go.  Think about the insight our distant ancestors must have had to take this common substance -- clay -- and fashion it into something not only useful, but beautiful.  Now, I sit down at an electric wheel with homogeneous store-bought clay and perfectly-formulated stains and glazes, and fire my work in an electric kiln.  (And I still have pieces that flop sometimes.)  Consider the trial-and-error that must have gone into digging and refining natural clay, developing techniques for shaping (including figuring out how to build a kick-wheel), figuring out which available minerals would work as colorants and glazes, and using pit firing to harden the clay to make the piece usable for containing food or drink.  Modern potters are the inheritors of what clay artisans have learned over millennia of attempts, innovations, successes and failures.

"This study doesn’t just look at how pottery was made – it gives us a fascinating insight into some of the earliest ‘social networks’ and how people passed on knowledge and skills over centuries without the use of books or the technology we now take for granted," Ceccarelli said, in an interview with Heritage Daily.  "The objects we examined suggested that while communities of ceramic makers lived in the same regions – and often in the same settlements – different traditions emerged and were sustained over centuries.  There was a clear effort to keep alive their unique ways of making pottery to set them apart from other communities, like a statement of their identity."

All of which makes me wonder what those future archaeologists will think about my pile of smashed pottery.

But now, I need to wrap this up, and go check the kiln.  I swear, waiting for it to cool is like a kid waiting for Christmas.  And hoping that the brightly-colored boxes under the tree contain something better than socks, underwear, or an ugly sweater.

**********************************

My master's degree is in historical linguistics, with a focus on Scandinavia and Great Britain (and the interactions between them) -- so it was with great interest that I read Cat Jarman's book River Kings: A New History of Vikings from Scandinavia to the Silk Road.

Jarman, who is an archaeologist working for the University of Bristol and the Scandinavian Museum of Cultural History of the University of Oslo, is one of the world's experts on the Viking Age.  She does a great job of de-mythologizing these wide-traveling raiders, explorers, and merchants, taking them out of the caricature depictions of guys with blond braids and horned helmets into the reality of a complex, dynamic culture that impacted lands and people from Labrador to China.

River Kings is a brilliantly-written analysis of an often-misunderstood group -- beginning with the fact that "Viking" isn't an ethnic designation, but an occupation -- and tracing artifacts they left behind traveling between their homeland in Sweden, Norway, and Denmark to Iceland, the Hebrides, Normandy, the Silk Road, and Russia.  (In fact, the Rus -- the people who founded, and gave their name to, Russia -- were Scandinavian explorers who settled in what is now the Ukraine and western Russia, intermarrying with the Slavic population there and eventually forming a unique melded culture.)

If you are interested in the Vikings or in European history in general, you should put Jarman's book in your to-read list.  It goes a long way toward replacing the legendary status of these fierce, sea-going people with a historically-accurate reality that is just as fascinating.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

Canine gap analysis

One of the reasons that it's (generally) much easier to learn to read a second language than it is to understand it in speech has to do not with the words, but with the spaces in between them.

Students learning to understand spoken conversation in another language have the common complaint that "they talk so fast."  They don't, really, or at least no faster than the speakers of your native language.  But unfamiliarity with the lexicon of the new language makes it hard to figure out where the gaps are between adjacent words.  Unless you concentrate (and sometimes even if you do), it sounds like one continuous stream of random phonemes.

As an aside, sometimes I have the same problem with English spoken with a different accent than the one I grew up with.  The character of Yaz in the last three seasons of Doctor Who is from Yorkshire, and her accent -- especially when she's agitated and speaking quickly -- sometimes leaves me thinking, "Okay, what did she just say?"  (That's why I usually watch with the subtitles on.)  This isn't unique to accents from the UK, of course; it's why a lot of non-southerners find southern accents difficult to parse.  Say to someone from Louisiana, "Jeetyet? and they'll clearly hear "Did you eat yet?"; and one of the most common greetings is "howzyamommandem?"

I'd never really considered how important the spaces between the words are until I ran into some research last week in Current Biology in a paper entitled, "Dogs Learn About Word Boundaries as Human Infants Do," that showed dogs -- perhaps unique amongst non-human animals -- are able to use some pretty complex mental calculations to figure out where the gaps are in "Do you want to play ball?"  Say that phrase out loud, especially in an excited tone, and you'll notice that in the actual sounds there are minuscule gaps, or none at all, so what they're listening for can't be little bits of silence.

By looking at brain wave activity in pre-verbal infants presented with actual speech, speech using unfamiliar/rare words, and gibberish, scientists found that the neural activity spiked when syllables are spoken that almost always (in the infant's experience) occur together.  An example is the phrase, "Do you want breakfast now?"  The syllables /brek/ and /fǝst/ aren't used much outside of the word "breakfast," so apparently the brain is doing some complex statistical calculations to identify that as a discrete word and not adjoined to the words coming before or afterward.

What the current research finds is that dogs are doing precisely the same thing when they listen to human language.

The authors write:

To learn words, humans extract statistical regularities from speech.  Multiple species use statistical learning also to process speech, but the neural underpinnings of speech segmentation in non-humans remain largely unknown. Here, we investigated computational and neural markers of speech segmentation in dogs, a phylogenetically distant mammal that efficiently navigates humans’ social and linguistic environment.  Using electroencephalography (EEG), we compared event-related responses (ERPs) for artificial words previously presented in a continuous speech stream with different distributional statistics...  Using fMRI, we searched for brain regions sensitive to statistical regularities in speech.  Structured speech elicited lower activity in the basal ganglia, a region involved in sequence learning, and repetition enhancement in the auditory cortex.  Speech segmentation in dogs, similar to that of humans, involves complex computations, engaging both domain-general and modality-specific brain areas.

I know that when I talk to Guinness -- not using the short, clipped words or phrases recommended by dog trainers, but full complex sentences -- he has this incredibly intent, alert expression, and I get the sense that he's really trying to understand what I'm saying.  I've heard people say that outside of a few simple commands like "sit" or "stay," dogs respond only to tone of voice, not the actual words spoken.

Apparently that isn't true.

So I suppose when I say "whoozagoodboy?", he actually knows it's him.

"Keeping track of patterns is not unique to humans: many animals learn from such regularities in the surrounding world, which is called statistical learning," said Marianna Boros of Eötvös Loránd University, who co-authored the study, in an interview with Vinkmag.  "What makes speech special is its efficient processing requires complex computations.  To learn new words from continuous speech, it is not enough to count how often certain syllables occur together.  It is much more efficient to calculate the probability of those syllables occurring together.  This is exactly how humans, even eight-month-old infants, solve the seemingly difficult task of word segmentation: they calculate complex statistics about the probability of one syllable following the other.  Until now we did not know if any other mammal can also use such complex computations to extract words from speech.  We decided to test family dogs’ brain capacities for statistical learning from speech.  Dogs are the earliest domesticated animal species and probably the one we speak most often to.  Still, we know very little about the neural processes underlying their word learning capacities."

So remember this next time you talk to your dog.  He might well be understanding more than you realize.  He might not get much if you read to him from A Brief History of Time, but my guess is that common speech is less of a mystery to him than it might have seemed.

**********************************

My master's degree is in historical linguistics, with a focus on Scandinavia and Great Britain (and the interactions between them) -- so it was with great interest that I read Cat Jarman's book River Kings: A New History of Vikings from Scandinavia to the Silk Road.

Jarman, who is an archaeologist working for the University of Bristol and the Scandinavian Museum of Cultural History of the University of Oslo, is one of the world's experts on the Viking Age.  She does a great job of de-mythologizing these wide-traveling raiders, explorers, and merchants, taking them out of the caricature depictions of guys with blond braids and horned helmets into the reality of a complex, dynamic culture that impacted lands and people from Labrador to China.

River Kings is a brilliantly-written analysis of an often-misunderstood group -- beginning with the fact that "Viking" isn't an ethnic designation, but an occupation -- and tracing artifacts they left behind traveling between their homeland in Sweden, Norway, and Denmark to Iceland, the Hebrides, Normandy, the Silk Road, and Russia.  (In fact, the Rus -- the people who founded, and gave their name to, Russia -- were Scandinavian explorers who settled in what is now the Ukraine and western Russia, intermarrying with the Slavic population there and eventually forming a unique melded culture.)

If you are interested in the Vikings or in European history in general, you should put Jarman's book in your to-read list.  It goes a long way toward replacing the legendary status of these fierce, sea-going people with a historically-accurate reality that is just as fascinating.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

The galactic spiderweb

Saturday's post was about the bizarre behavior of matter on very small scales; today's is about the equally bizarre behavior of matter on very large scales.

I was alerted to this latest discovery by two different loyal readers of Skeptophilia, who sent me a link to an article in LiveScience describing research on cosmic radio wave sources by a team led by astrophysicist Jennifer West of the University of Toronto.  The radio region of the spectrum is made up of the longest-wavelength light, and is invisible to human eyes.  In fact, the majority of the electromagnetic spectrum is invisible to us; visible light makes up only a tiny fraction of it. 

As a brief aside, I remember being kind of blown away when I first ran into this concept, back in high school.  I subsequently found out that because the refraction of light -- key to how our lenses focus the light reflected from what we're looking at onto our retinas -- is a function of wavelength, to see light in the radio region of the spectrum we'd need eyes about ten meters across.  That's assuming they functioned in an analogous fashion to our own eyes, and that the massive retinas had a light-sensitive pigment that responded to radio waves.

Which would be cumbersome, to say the least.

Anyhow, because our eyes can't see in the radio region of the spectrum, scientists have developed radio telescopes to see what's up there emitting radio waves.  And ever since we've started analyzing those invisible-to-us wavelengths, we've found surprise after surprise, starting with the 1964 discovery of the three-centimeter cosmic background radiation by Arno Penzias and Robert Wilson -- which turned out to be the relic radiation of the Big Bang.

The research by Jennifer West et al., however, has yet to be explained.  It turns out that our region of the Milky Way is surrounded by a looped array of radio-wave-emitting magnetic filaments, some of them thousands of light years long, and which connect the North Polar Spur to the Fan Region -- two segments of the night sky on opposite sides of the Earth.

At first, it wasn't even clear how far away these radio sources are.  The authors write:

Since the time of their discoveries and right up to the present day, astronomers have questioned the origin of these two regions, with some arguing that they are local features, while others argue that they are distant, Galactic-scale features...  If these features are indeed local, understanding their structure and morphology is critical since we are embedded among the stars, dust, and gas that comprise them, and all features beyond must be observed through this local veil of material.  Features that are extremely nearby can have a very large angular size on the sky, and only with good models can we account for this “contamination” when developing large-scale models of the Galactic magnetic field and foreground models for cosmology experiments.

Further study, however, clarified a couple of points; first, they're huge; second, they're kind of everywhere you look.  These cosmic filaments are strung across the Milky Way like a giant spiderweb, and some researchers believe that they're all connected -- that together they represent pieces of a single, much larger structure.

What the night sky would look like if we had enormous eyes and could see in the radio region of the spectrum

What could create something on that scale?  The simple answer is: we don't know.  These huge magnetic tubes might have been created by the explosions of massive supernovae early in the galaxy's history; one of the theories calls the structures "galactic chimneys," with matter from the explosions being funneled along the magnetic field lines of the galaxy, much as the walls of a chimney flue constrain and direct the smoke from a fireplace. "Magnetic fields don't exist in isolation," West said.  "They all must connect to each other.  So a next step is to better understand how this local magnetic field connects both to the larger-scale galactic magnetic field and also to the smaller-scale magnetic fields of our sun and Earth...  I think it's just awesome to imagine that these structures are everywhere, whenever we look up into the night sky."

Whatever they are, and however they were formed, we're currently sitting in the middle of a huge network of them -- long, hollow filaments that crisscross the sky, invisible to human eyes but clearly visible to a radio telescope tuned to the right wavelength.  

Just as in Saturday's post about the "quantum Cheshire cat," this paper raises as many questions as it settles -- certainly one of the hallmarks of cutting-edge science  And both of these discoveries further reinforce that we live in a very bizarre universe, where the familiar objects that drive our "common sense" about how things work are caught square in the middle of a world of the submicroscopic and a world of the very macroscopic, where everything we look at seems to defy our intuition.  Which you could find exciting, or disorienting and a little frightening.

Me, I think it's both.  I love that nature keeps us a little off balance, that every time we come to the smug conclusion that we've got it all figured out, we get pitched a serious curveball.  It'd be a mighty boring place if everywhere we looked, we thought, "Meh, works pretty much like I expected."

**********************************

My master's degree is in historical linguistics, with a focus on Scandinavia and Great Britain (and the interactions between them) -- so it was with great interest that I read Cat Jarman's book River Kings: A New History of Vikings from Scandinavia to the Silk Road.

Jarman, who is an archaeologist working for the University of Bristol and the Scandinavian Museum of Cultural History of the University of Oslo, is one of the world's experts on the Viking Age.  She does a great job of de-mythologizing these wide-traveling raiders, explorers, and merchants, taking them out of the caricature depictions of guys with blond braids and horned helmets into the reality of a complex, dynamic culture that impacted lands and people from Labrador to China.

River Kings is a brilliantly-written analysis of an often-misunderstood group -- beginning with the fact that "Viking" isn't an ethnic designation, but an occupation -- and tracing artifacts they left behind traveling between their homeland in Sweden, Norway, and Denmark to Iceland, the Hebrides, Normandy, the Silk Road, and Russia.  (In fact, the Rus -- the people who founded, and gave their name to, Russia -- were Scandinavian explorers who settled in what is now the Ukraine and western Russia, intermarrying with the Slavic population there and eventually forming a unique melded culture.)

If you are interested in the Vikings or in European history in general, you should put Jarman's book in your to-read list.  It goes a long way toward replacing the legendary status of these fierce, sea-going people with a historically-accurate reality that is just as fascinating.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

A smile without a cat

Every time I hear some new discovery in quantum physics, I think, "Okay, it can't get any weirder than this."

Each time, I turn out to be wrong.

A few of the concepts I thought had blown my mind as much as possible:

• Quantum superposition -- a particle being in two states at once until you observe it, at which point it apparently decides on one of them (the "collapse of the wave function")
• The double-slit experiment -- if you pass light through a closely-spaced pair of slits, it creates a distinct interference pattern -- an alternating series of parallel bright and dark bands.  The same interference pattern occurs if you shoot the photons through one of the slits, one photon at a time.  If you close the other slit, the pattern disappears.  It's as if the photons passing through the left-hand slit "know" if the right-hand slit is open or closed.
• Quantum entanglement -- two particles that somehow are "in communication," in the sense that altering one of them instantaneously alters the other, even if it would require superluminal information transfer to do so (what Einstein called "spooky action-at-a-distance")
• The pigeonhole paradox -- you'd think that if you passed three photons through polarizing filters that align their vibration plane either horizontally or vertically, there'd be two of them polarized the same way, right?  It's a fundamental idea from set theory; if you have three gloves, it has to be the case that either two are right-handed or two are left-handed.  Not so with photons.  Experiments showed that you can polarize three photons in such a way that no two of them match.

Bizarre, counterintuitive stuff, right there.  But wait till you hear the latest:  three physicists, Yakim Aharonov of Tel Aviv University, Sandu Popescu of the University of Bristol, and Eliahu Cohen of Bar Ilan University, have demonstrated something they're calling a quantum Cheshire Cat.  Apparently under the right conditions, a particle's properties can somehow come unhooked from the particle itself and move independently of it -- a bit like Lewis Carroll's cat disappearing but leaving behind its disembodied grin.

The Cheshire Cat from John Tenniel's illustrations for Alice in Wonderland (1865) [Image is in the Public Domain]

I'll try to explain how it works, but be aware that I'm dancing right along the edge of what I'm able to understand, so if you ask for clarification I'll probably say, "Damned if I know."  But here goes.

Imagine a box containing a particle with a spin of 1/2.  (Put more simply, this means that if you measure the particle's spin along any of the three axes (x, y, and z), you'll find it in an either-or situation -- right or left, up or down, forward or backward.)  The box has a partition down the middle that is fashioned to have a small, but non-zero, probability of the particle passing through.  At the other end of the box is a second partition -- if the particle is spin-up, it passes through; if not, it doesn't and is reflected back into the box.

With me so far?  'Cuz this is where it gets weird.

In quantum terms, the fact that there's a small but non-zero chance of the particle leaking through means that part of it does leak through; this is a feature of quantum superposition, which boils down to particles being in two places at once (or, more accurately, their positions being fields of probabilities rather than one specific location).  If the part that leaks through is spin-up, it passes through the right-hand partition and out of the box; otherwise it reflects back and interacts with the original particle, causing its spin to flip.

The researchers found that this flip occurs even if measurements show that the particle never left the left-hand side of the box.

So it's like the spin of the particle becomes unhooked from the particle itself, and is free to wander about -- then can come back and alter the original particle.  See why they call it a quantum Cheshire Cat?  Like Carroll's cat's smile, the properties of the particle can somehow come loose.

Whatever a "loose property" actually means.

The researchers have suggested that this bizarre phenomenon might allow counterfactual communication -- communication between two observers without any particle or energy being transferred between them.  In the setup I described, the observer left of the box would know if the observer on the right had turned the spin-dependent barrier on or off by watching to see if the particle in the left half of the box had altered its spin.  More spooky action-at-a-distance, that.

What I have to keep reminding myself is that none of this is some kind of abstract idea or speculation of what could be; these findings have been experimentally verified over and over.  Partly because it's so odd and counterintuitive, the theories of quantum physics have been put through rigorous tests, and each time they've passed with flying colors.  As crazy as it sounds, this is what reality is, despite how hard it is to wrap our minds around it.

"What is the most important for us is not a potential application – though that is definitely something to look for – but what it teaches us about nature," said study co-author Sandu Popescu.  "Quantum mechanics is very strange, and almost a hundred years after its discovery it continues to puzzle us.  We believe that unveiling even more puzzling phenomena and looking deeper into them is the way to finally understand it."

Indeed.  I keep coming back to the fact that everything you look at -- all the ordinary stuff we interact with on a daily basis -- is made of particles and energy that defy our common sense at every turn.  As the eminent biologist J. B. S. Haldane famously put it, "The universe is not only queerer than we imagine -- it is queerer than we can imagine."

**********************************

Some of the most enduring mysteries of linguistics (and archaeology) are written languages for which we have no dictionary -- no knowledge of the symbol-to-phoneme (or symbol-to-syllable, or symbol-to-concept) correspondences.

One of the most famous cases where that seemingly intractable problem was solved was the near-miraculous decipherment of the Linear B script of Crete by Alice Kober and Michael Ventris, but it bears keeping in mind that this wasn't the first time this kind of thing was accomplished.  In the early years of the nineteenth century, this was the situation with the Egyptian hieroglyphics -- until the code was cracked using the famous Rosetta Stone, by the dual efforts of Thomas Young of England and Jean-François Champollion of France.

This herculean, but ultimately successful, task is the subject of the fascinating book The Writing of the Gods: The Race to Decode the Rosetta Stone, by Edward Dolnick.  Dolnick doesn't just focus on the linguistic details, but tells the engrossing story of the rivalry between Young and Champollion, ending with Champollion beating Young to the solution -- and then dying of a stroke at the age of 41.  It's a story not only of a puzzle, but of two powerful and passionate personalities.  If you're an aficionado of languages, history, or Egypt, you definitely need to put this one on your to-read list.

[Note: if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]