Skeptophilia (skep-to-fil-i-a) (n.) - the love of logical thought, skepticism, and thinking critically. Being an exploration of the applications of skeptical thinking to the world at large, with periodic excursions into linguistics, music, politics, cryptozoology, and why people keep seeing the face of Jesus on grilled cheese sandwiches.

Thursday, September 30, 2021

I feel pretty

The drive to adorn our bodies is pretty close to universal.

Clothing, for example, serves the triple purpose of protecting our skin, keeping us warm, and making us look good.  Well, some of us.  I'll admit up front that I have a fashion sense that, if you were to rank it on a scale of one to ten, would have to be expressed in imaginary numbers.  But for a lot of people, clothing choice is a means of self-expression, a confident assertion that they care to look their best.  

Then there are tattoos, about which I've written here before because I'm a serious fan (if you want to see photos of my ink, take a look at the link).  Tattooing goes back a long way -- Ötzi the "Ice Man," a five-thousand-year-old body discovered preserved in glacial ice in the Alps, had no fewer than 61 tattoos.  No one knows what Ötzi's ink signifies; my guess is that just like today, the meanings of tattoos back then were probably specific to the culture, perhaps even to the individual.  

Then there's jewelry.  We know from archaeological research that jewelry fashioned from gems and precious metals also has a long history; a 24-karat gold pendant found in Bulgaria is thought to have been made in around 4,300 B.C.E., which means that our distant ancestors used metal casting for more than just weapon-making.  So between decorative clothing, tattoos, and jewelry, we've been spending inordinate amounts of time and effort (and pain, in the case of tattooing, piercing, and scarification) altering our appearances.  

Why?  No way to be sure, but my guess is that there are a variety of reasons.  Enhancing sexual attractiveness certainly played, and plays, a role.  Some adornments were clearly signs of rank, power, or social role.  Others were personal means of self-expression.  Evolutionists talk about "highly conserved features" -- adaptations that are between common and universal within a species or a clade -- and the usual explanation is that anything that is so persistent must be highly selected, and therefore important for survival and reproduction.  It's thin ice to throw learned behaviors in this same category, but I think the same argument at least has some applicability here; given that adornment is common to just about all human groups studied, the likelihood is that it serves a pretty important purpose.  What's undeniable is that we spend a lot of time and resources on it that could be used for more directly beneficial activities.

What's most interesting is that we're the only species we know of that does this.  There are a few weak instances of this sort of behavior -- for example, the bowerbirds of Australia and New Guinea, in which the males collect brightly-colored objects like flower petals, shells, and bits of glass or stone to create a little garden to attract mates.  But we seem to be the only animals that regularly adorn their own bodies.

How far back does this impulse go?  We got at least a tentative answer to this in a paper this week in Science Advances, which was about an archaeological discovery in Morocco of shell beads that were used for jewelry...

... 150,000 years ago.

"They were probably part of the way people expressed their identity with their clothing," said study co-author Steven Kuhn, of the University of Arizona.  "They’re the tip of the iceberg for that kind of human trait.  They show that it was present even hundreds of thousands of years ago, and that humans were interested in communicating to bigger groups of people than their immediate friends and family."

A sampling of the Stone Age shell beads found in Morocco

Like with Ötzi's tattoos, we don't know what exactly the beads were intending to communicate.  Consider how culture-dependent those sorts of signals are; imagine, for example, taking someone from three thousand years ago, and trying to explain what the subtle and often complex significance of appearances and behaviors that we here in the present understand immediately.  "You think about how society works – somebody’s tailgating you in traffic, honking their horn and flashing their lights, and you think, ‘What’s your problem?'" Kuhn said.  "But if you see they’re wearing a blue uniform and a peaked cap, you realize it’s a police officer pulling you over."

Unfortunately, there's probably no way to know whether the shell beads were used purely for personal adornment, or if they had another religious or cultural significance.  "It’s one thing to know that people were capable of making them," Kuhn said, "but then the question becomes, 'OK, what stimulated them to do it?'...  We don’t know what they meant, but they’re clearly symbolic objects that were deployed in a way that other people could see them."

So think about that next time you put on a necklace or bracelet or earrings.  You are participating in a tradition that goes back at least 150,000 years.  Maybe our jewelry-making ability has improved beyond shell beads with a hole drilled through, but the impulse remains the same -- whatever its origins.

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

Mathematics tends to sort people into two categories -- those who revel in it and those who detest it.  I lucked out in college to have a phenomenal calculus teacher who instilled in me a love for math that I still have today, and even though I'm far from an expert mathematician, I truly enjoy considering some of the abstruse corners of the theory of numbers.

One of the weirdest of all of the mathematical discoveries is Euler's Equation, which links five of the most important and well-known numbers -- π (the ratio between a circle's circumference and its diameter), e (the root of the natural logarithms), i (the square root of -1, and the foundation of the theory of imaginary and complex numbers), 1, and 0.  

They're related as follows:

Figuring this out took a genius like Leonhard Euler to figure out, and its implications are profound.  Nobel-Prize-winning physicist Richard Feynman called it "the most remarkable formula in mathematics;" nineteenth-century Harvard University professor of mathematics Benjamin Peirce said about Euler's Equation, "it is absolutely paradoxical; we cannot understand it, and we don't know what it means, but we have proved it, and therefore we know it must be the truth."

Since Peirce's time mathematicians have gone a long way into probing the depths of this bizarre equation, and that voyage is the subject of David Stipp's wonderful book A Most Elegant Equation: Euler's Formula and the Beauty of Mathematics.  It's fascinating reading for anyone who, like me, is intrigued by the odd properties of numbers, and Stipp has made the intricacies of Euler's Equation accessible to the layperson.  When I first learned about this strange relationship between five well-known numbers when I was in calculus class, my first reaction was, "How the hell can that be true?"  If you'd like the answer to that question -- and a lot of others along the way -- you'll love Stipp's book.

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


Wednesday, September 29, 2021

Illuminating Hessdalen

In his wonderful poem/performance piece Storm, Tim Minchin said: "Throughout history, every mystery ever solved has turned out to be 'not magic'."

As I've pointed out many times here before, it's not that I'm saying any of the thus-far-classified-as "out there beliefs" are impossible; it's that if they actually do exist, they should be accessible to scientific inquiry.  Auras, qi, chakras?  Demonstrate they're detectable by something other than a subjective viewer.  Hauntings?  Ditto.  Cryptids of various shapes and descriptions?  Give me something analyzable other than blurry photos and anecdotal eyewitness accounts.  Psychic abilities?  Show they work under controlled conditions.  

Interestingly, there was just an article in The Skeptic asserting that parapsychology has grown to the point that it deserves the title of science rather than pseudoscience.  I'm sure that the author, Chris French, professor of psychology at the University of London, will receive some blowback from this essay, as will The Skeptic in general for publishing it; but I agree with his central thesis, which is that parapsychological claims stand and fall on exactly the same basis as scientific claims do -- evidence.

And, as Minchin says, if a supernatural explanation turns out to be scientifically demonstrable, then it's no longer supernatural, is it?  It's just natural.  After that, it can be studied by the methods of science, just like every other feature of our weird, wonderful, amazingly complex universe.

What brings this up is a recent paper in Meteorology and Atmospheric Physics that considered the odd phenomenon of the "Hessdalen Lights" which occurs in a valley in central Norway, wherein people report seeing free-floating balls of light.  I'd written about the Hessdalen Lights (and various other accounts of lights in the sky) back in 2017, and described it as follows:

The Hessdalen Lights have been seen since the 1940s in the valley of Hessdalen in Norway.  They're stationary, bright white or yellow lights, floating above the ground, sometimes remaining visible for over an hour.  With such a cooperative phenomenon, you would think it would be easily explained; but despite the efforts of scientists, who have been studying the Hessdalen Lights for decades, there is yet to be a convincing explanation.  Hypotheses abound: that it is the combustion of dust from the valley floor; that it is a stable plasma, ionized by the decay of radon from minerals in the valley; or even that it is an electrical discharge from piezoelectric compression of quartz crystals in the underlying rock.  None of these is completely convincing, and the Hessdalen Lights remain one of the most puzzling natural phenomena I know of.

The lack of a convincing explanation opens the door to all sorts of wild speculation, and those abound -- ghosts, aliens, portals in time and space, you name it.  

Photograph of the Hessdalen Lights

As usual, my fallback position was, "I may not know what the scientific explanation is, but I'm certain that one exists."  Given how many times this phenomenon has been reported and photographed, it seemed pretty likely that it wasn't a hoax, or even misattributing it to something purely prosaic (like Neil deGrasse Tyson's story of a cop who was driving down a winding country road, chasing a "weird light in the sky" -- which turned out to be the planet Venus).  So accepting that the Hessdalen Lights actually occur as advertised, what the hell are they?

Much was my delight when I ran across the recent paper, by atmospheric chemist Gerson Paiva of Federal University Pernambuco (Brazil), which seems to have solved the mystery, using...

... wait for it...

... science.

Here's what Paiva writes:

Hessdalen lights are unusual, free-floating light balls presenting different shapes and light colors, observed in the Hessdalen valley in rural central Norway.  In this work, it is shown that these ghostly light balls are produced by an electrically active inversion layer above Hessdalen valley during geomagnetic storms.  Puzzling geometric shapes and energy content observed in the HL phenomenon may be explained through a little-known solution of Maxwell’s equations to electric (and magnetic) field lines: they can form loops in a finite space...  “Natural battery”, aerosols and global atmospheric electric circuits may play a crucial role for the electrification of the temperature inversion layers.
Now, I hasten to add that I don't know if Paiva's explanation is right.  But that's the other great thing about science; it's falsifiable.  When a researcher publishes something like this, it's immediately analyzed and taken to pieces by other experts in the field.  Unlike us fiction writers, who basically want everyone to read our writing and tell us how awesome it is, scientists are looking for rigorous criticism; they want their colleagues to try to tear it down, to see if their analysis is robust enough to withstand attempts to refute it.  So time will tell if Paiva has found the answer to this enduring mystery of atmospheric science.

But even if he hasn't, I'd bet cold hard cash that like Tim Minchin said, the answer will still turn out to be "not magic."

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

Mathematics tends to sort people into two categories -- those who revel in it and those who detest it.  I lucked out in college to have a phenomenal calculus teacher who instilled in me a love for math that I still have today, and even though I'm far from an expert mathematician, I truly enjoy considering some of the abstruse corners of the theory of numbers.

One of the weirdest of all of the mathematical discoveries is Euler's Equation, which links five of the most important and well-known numbers -- π (the ratio between a circle's circumference and its diameter), e (the root of the natural logarithms), i (the square root of -1, and the foundation of the theory of imaginary and complex numbers), 1, and 0.  

They're related as follows:

Figuring this out took a genius like Leonhard Euler to figure out, and its implications are profound.  Nobel-Prize-winning physicist Richard Feynman called it "the most remarkable formula in mathematics;" nineteenth-century Harvard University professor of mathematics Benjamin Peirce said about Euler's Equation, "it is absolutely paradoxical; we cannot understand it, and we don't know what it means, but we have proved it, and therefore we know it must be the truth."

Since Peirce's time mathematicians have gone a long way into probing the depths of this bizarre equation, and that voyage is the subject of David Stipp's wonderful book A Most Elegant Equation: Euler's Formula and the Beauty of Mathematics.  It's fascinating reading for anyone who, like me, is intrigued by the odd properties of numbers, and Stipp has made the intricacies of Euler's Equation accessible to the layperson.  When I first learned about this strange relationship between five well-known numbers when I was in calculus class, my first reaction was, "How the hell can that be true?"  If you'd like the answer to that question -- and a lot of others along the way -- you'll love Stipp's book.

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


Tuesday, September 28, 2021

The disappearance of Tartessos

I'm not a historian, but I certainly have been fascinated with history for years.  I just finished re-reading Robert Graves's wonderful books I, Claudius and Claudius the God -- fictionalized, but largely historically accurate, accounts of the tumultuous life of Tiberius Caesar Augustus Germanicus, better known as the Roman emperor Claudius, fifth and penultimate emperor of the Julio-Claudian dynasty.  Since then I've gone back into reading some of the mytho-historical works I first looked at while doing my master's degree, the Icelandic saga literature (I'm currently in the middle of the Laxdæla Saga, the tale of the people of the Lax River Valley.  The highly entertaining chapter I just finished is about a guy named Killer-Hrapp who was so awful he didn't want to stop doing awful things after he died, so he had his wife bury his body under the floor of their house, and he proceeded to haunt the place as a reanimated corpse.  Apparently zombies are not a recent invention.)  After that, I'm back to the southern Mediterranean (and pure non-fiction) for How Rome Fell: Death of a Superpower by Adrian Goldsworthy.

So I'm what I'd consider a reasonably well-informed amateur.  Which is why a link I was sent by my friend and frequent contributor to Skeptophilia, Gil Miller, came as such a surprise.  Because the article describes a civilization on the Iberian Peninsula, contemporaneous to the ancient Greeks, that I'd never heard of before.

The civilization was called Tartessos.  They dominated the southern parts of what are now Spain and Portugal in the first part of the first millennium B.C.E., and inexplicably vanished sometime around the middle of it.  They spoke an unknown non-Indo-European language which has survived in written form in 95 different inscriptions; the alphabet has been deciphered -- "Southwestern Paleohispanic Script," a "semi-syllabic" script in which some characters represent single sounds and others represent syllables -- but the language itself is still largely a mystery, and doesn't appear to be closely related to any known language.

The Tartessian Fonte Velha inscription, found near Bensafrim, Portugal, which dates to the seventh century B.C.E.  [Image is in the Public Domain]

The Tartessians were known to the Greeks, who valued their trading partnerships with them because it gave them access to tin, necessary for the fabrication of bronze.  In the fourth century B.C.E. they were going strong -- the historian Ephorus describes "a very prosperous market called Tartessos, with much tin carried by river, as well as gold and copper from Celtic lands" -- but then, right around that time, they vanished completely, for reasons that are still uncertain.

They went out with a bang, too.  The link Gil sent, which was to an article at the wonderful site Atlas Obscura, describes an archaeological site called Casas del Turuñuelo, located in the Spanish province of Extremadura, near the border of Portugal.  What the researchers found seems to indicate that immediately before their mysterious disappearance, the Tartessians had a massive sacrifice of horses, donkeys, cattle, dogs, pigs... and possibly humans.  After arraying the sacrificed animals -- for example, deliberately arranging two horses facing each other symmetrically, with their forelegs crossed -- the Tartessians set fire to the entire place, burning to the ground what had been a thriving city.  They then apparently buried the ash, bones, and rubble...

... and took off for parts unknown.

Why a thriving and apparently wealthy civilization would do this is an open question.  There's been some speculation that they had been hit repeatedly by earthquakes, and thought that an enormous hecatomb would appease the gods.  But without any hard evidence, this is nothing more than a guess.  And the great likelihood, of course, is that they didn't vanish, nor even die out, but migrated elsewhere and merged with a pre-existing population.  But if that's true, then where did they go?  After about 400 B.C.E. there seems to be no sign of clearly Tartessian artifacts anywhere in western Europe.

They were still remembered long afterward, though.  In the second century C.E. the Greek historian Pausanias was in Olympia, Greece, and saw two bronze chambers in a sanctuary that the locals said were of Tartessian manufacture.  He elaborated thusly:

They say that Tartessos is a river in the land of the Iberians, running down into the sea by two mouths, and that between these two mouths lies a city of the same name.  The river, which is the largest in Iberia, and tidal, those of a later day called Baetis, and there are some who think that Tartessos was the ancient name of Carpia, a city of the Iberians.

Which squares with what we know about the Tartessians from archaeological sites, centering on the area near the mouth of the Guadalquivir River, which flows into a marshland that is now the Doñana National Park, a beautiful place I was lucky enough to visit a few years ago.

But of course, there's no historical mystery without some kind of wild speculation appended to it, and the Tartessians are no exception.  There are people who claim that Tartessos is actually the civilization of Atlantis, described by the ancient Greeks as being "beyond the Pillars of Hercules" (i.e. the Straits of Gibraltar).  Which Tartessos is.  But any other connection to Atlantis seems way beyond tentative to me, starting with the fact that supposedly Atlantis "sank beneath the sea," while all of the sites known to be inhabited by the Tartessians are on dry land.

Inconvenient, that.

Of course, I have to admit it's hard to do underwater archaeology, so if there are Tartessian sites sunk in the Atlantic, we might not know about them.  Still, it seems a little sketchy to decide that "rich civilization near Gibraltar that vanished suddenly" leads to "Tartessos = Atlantis."

So that leaves us with a conundrum -- an apparently wealthy and powerful civilization upping stakes and taking off.  Of course, the Tartessians aren't the only instance of this happening; pretty much the same disappearing act had occurred eight hundred years earlier to the Myceneans, who had dominated the eastern Mediterranean for a good half a millennium before suddenly abandoning their strongholds (many of them were burned to the ground) in around 1,200 B.C.E.  (Some historians have attributed the collapse of Mycenae to a prolonged drought, but that's also speculation.)

In any case, that's today's historical mystery that I'd never heard of.  Hope you enjoyed it.  For me, it brings to mind the words of Socrates, when someone told him he'd been judged the wisest man in the world, and what did he think of that?  Socrates responded: "If I am accounted wise, it is only because I realize how little I know."

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

Mathematics tends to sort people into two categories -- those who revel in it and those who detest it.  I lucked out in college to have a phenomenal calculus teacher who instilled in me a love for math that I still have today, and even though I'm far from an expert mathematician, I truly enjoy considering some of the abstruse corners of the theory of numbers.

One of the weirdest of all of the mathematical discoveries is Euler's Equation, which links five of the most important and well-known numbers -- π (the ratio between a circle's circumference and its diameter), e (the root of the natural logarithms), i (the square root of -1, and the foundation of the theory of imaginary and complex numbers), 1, and 0.  

They're related as follows:

Figuring this out took a genius like Leonhard Euler to figure out, and its implications are profound.  Nobel-Prize-winning physicist Richard Feynman called it "the most remarkable formula in mathematics;" nineteenth-century Harvard University professor of mathematics Benjamin Peirce said about Euler's Equation, "it is absolutely paradoxical; we cannot understand it, and we don't know what it means, but we have proved it, and therefore we know it must be the truth."

Since Peirce's time mathematicians have gone a long way into probing the depths of this bizarre equation, and that voyage is the subject of David Stipp's wonderful book A Most Elegant Equation: Euler's Formula and the Beauty of Mathematics.  It's fascinating reading for anyone who, like me, is intrigued by the odd properties of numbers, and Stipp has made the intricacies of Euler's Equation accessible to the layperson.  When I first learned about this strange relationship between five well-known numbers when I was in calculus class, my first reaction was, "How the hell can that be true?"  If you'd like the answer to that question -- and a lot of others along the way -- you'll love Stipp's book.

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


Monday, September 27, 2021

Flipping out

There's been a lot of buzz lately about the Earth's impending magnetic field reversal.

Well, the alleged impending magnetic field reversal.  We don't know for sure that one is imminent; it's the same sort of thing as when you hear that the Yellowstone Supervolcano is "overdue for an eruption."  Neither of these is on some kind of timetable.  You rarely hear volcanoes say, "Well, I'd love to visit, but I'm supposed to erupt at 3:34 PM today, and I can't afford to be late."

The magnetic field flip is even more irregular than supervolcano eruptions, at least to judge by the geological record.  We know reversals have happened by looking at (relatively) new igneous rock formations near the Mid-Atlantic Ridge; as the lava cools, magnetic particles in the molten rock freeze into place, locking in a magnetic signature that tells you what the Earth's magnetic field was doing at the time.  And if you do a scan across the Mid-Atlantic Ridge you find mirror-image parallel stripes along the ridge, progressively older as you move away, documenting 183 reversals over the past 83 million years.  The timing of those reversals, however -- and therefore the width of the stripes -- varies tremendously, from about 25,000 years to about ten million years (the longest stable interval discovered so far).

[Image is in the Public Domain courtesy of NOAA]

As a quick aside, you may know that these magnetic stripes were one of the most persuasive arguments for the developing theory of plate tectonics, back in the late 1950s and early 1960s.  The mid-ocean ridges were identified as divergent zones -- places where the plates were moving apart, and new rock upwelling to fill the space in between.

In any case, we don't know for sure if the Earth's field is ready to flip, but it certainly seems to be wandering around a bit.  The last full reversal was about 780,000 years ago, but there was what seems to have been an abortive flip -- the Laschamps Event -- about 41,400 years ago, which only lasted about five hundred years before flipping back to its original polarity.  (Because of the speed of the switch, geologists don't consider this to be a full geomagnetic reversal, but a "geomagnetic excursion," where the poles didn't make a long-term move but just kind of went on walkabout.)

In fact, the Laschamps Event is why the whole topic comes up.  Recently a paper was published in Science describing what scientists have learned from an unexpected source -- the sixty-ton trunk of a kauri tree (Agathis australis) that was accidentally unearthed in New Zealand by some workers breaking ground for a new power plant.  The tree trunk had been submerged in a bog and preserved, and as luck would have it, the tree's 1,700 year life span was right across the Laschamps Event.

Specifically, they looked at the content of carbon-14 in the wood; C-14 is a radioactive form of carbon that is best-known for its role in the dating of preserved organic matter, but also is a good indicator of the level of cosmic ray bombardment (because it's formed when stratospheric carbon dioxide is hit by ionizing radiation).  

What they found is a little alarming.  During the Laschamps Event the magnetic field of the Earth collapsed for something like five centuries, and the tree rings during that time show a significant spike in carbon-14 formation.  The level of bombardment, the researchers say, would have caused auroras in the subtropics -- and would have been sufficient to knock out the power grid.

Right around the same time, there were some significant biological shifts going on.  Large mammals in Australia died out, including the terrifying giant clawed wombat, Palorchestes.

In case you thought I was making this up. This thing got up to three meters from nose to tail and weighed an estimated 1,000 kilograms. [Image licensed under the Creative Commons Nobu Tamura, Palorchestes BW, CC BY 3.0]

At around the same time, Neanderthals disappeared from Europe, and things got a good bit colder -- our ancestors started taking up residence in caves, to judge by the appearance of sophisticated cave art.  Whether any or all of this is connected to the Laschamps Event, however, is unknown.

What seems certain is that if it were to occur today, it would be bad news for technology.  Not only would the flip wreak havoc on our power grid, it would foul up a lot of navigational systems.  (I wonder how birds would be affected, since many of them rely on magnetic field lines to guide their migration twice a year.)

As with all of these sorts of things, there are some people who are Chicken-Littling about the pole reversal spelling the death of humanity, and others who are shrugging and saying we'll be fine because this has happened many times in Earth's history, and here we are.  Well, yeah, giant meteor strikes and flood basalt events and ice ages have also happened many times in Earth's history, but that doesn't mean they're a good thing.

My own response is that we shouldn't panic, but we should try to prepare for it if and when it happens, i.e., listen to the damn scientists.  Which I've said about a million times before, mostly in connection to climate change and the COVID-19 vaccine, but it seems like good advice in general.

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

Mathematics tends to sort people into two categories -- those who revel in it and those who detest it.  I lucked out in college to have a phenomenal calculus teacher who instilled in me a love for math that I still have today, and even though I'm far from an expert mathematician, I truly enjoy considering some of the abstruse corners of the theory of numbers.

One of the weirdest of all of the mathematical discoveries is Euler's Equation, which links five of the most important and well-known numbers -- π (the ratio between a circle's circumference and its diameter), e (the root of the natural logarithms), i (the square root of -1, and the foundation of the theory of imaginary and complex numbers), 1, and 0.  

They're related as follows:

Figuring this out took a genius like Leonhard Euler to figure out, and its implications are profound.  Nobel-Prize-winning physicist Richard Feynman called it "the most remarkable formula in mathematics;" nineteenth-century Harvard University professor of mathematics Benjamin Peirce said about Euler's Equation, "it is absolutely paradoxical; we cannot understand it, and we don't know what it means, but we have proved it, and therefore we know it must be the truth."

Since Peirce's time mathematicians have gone a long way into probing the depths of this bizarre equation, and that voyage is the subject of David Stipp's wonderful book A Most Elegant Equation: Euler's Formula and the Beauty of Mathematics.  It's fascinating reading for anyone who, like me, is intrigued by the odd properties of numbers, and Stipp has made the intricacies of Euler's Equation accessible to the layperson.  When I first learned about this strange relationship between five well-known numbers when I was in calculus class, my first reaction was, "How the hell can that be true?"  If you'd like the answer to that question -- and a lot of others along the way -- you'll love Stipp's book.

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


Saturday, September 25, 2021

Buried treasure

Maybe I need to get myself a metal detector.

The reason I say this is that it's apparently an auspicious time for treasure hunters, at least judging by two discoveries I found out about (once again!) from my friend and fellow writer Gil Miller, without whom in the last couple of weeks I wouldn't have had much to write about here.

The first one was a discovery in Norway made by an amateur treasure hunting enthusiast, using his newly-purchased metal detector for the first time (maybe there's something to beginner's luck after all...).  The fortunate fellow is named Ole Ginnerup Schytz, and I have to point out that (1) no, I am not making this name up, and (2), yes, this is from a reputable source, specifically the National Museum of Denmark.

In any case, the discovery, made a couple of months ago near the town of Jelling but only announced recently, is absolutely stupendous.  It's a collection of gold artifacts dating from the Danish Iron Age, about seventh century C.E.  It consists primarily of bracteates -- rune-decorated medallions thought to have not only a decorative but a magical purpose.  This new collection has bracteate designs the archaeologists say they've never seen before.

"It is the symbolism represented on these objects that makes them unique, more than the quantity found," explained Mads Ravn, director of research at the Vejle Museum.

As far as Schytz, he was as stunned as everyone else by his discovery.  "When the device activated, I knelt down and found a small, bent piece of metal," he said.  "It was scratched and covered in mud.  I had no idea, so all I could think of was that it looked like the lid of a can of herring."

One of the bracteates from the Jelling cache

"It was the epitome of pure luck," Schytz said.  "Denmark is 43,000 square kilometers, and then I happen to choose to put the detector exactly where this find was."

One thing I find fascinating about the discovery is that it contained gold coins from the Roman Empire that had been converted into jewelry, and a medallion depicting Constantine the Great (ruler of the Eastern Roman Empire from 306 to 337 C.E.).  So even though the cache seems to have been buried in the seventh century, some of the artifacts are a good three hundred years older than that.  Jelling, apparently, was the center of trade back then -- including trade from over two thousand kilometers away.

The second discovery was made on the other side of the world, in Colombia.  Recently archaeologists discovered a trove of gold and emeralds, filling eight ceramic jars of a type made by the Muisca people, an indigenous group known for their find goldsmithing (and who may have inspired the legend of the city of El Dorado).  The jars are thought to have been buried about six centuries ago, but this is much less certain than the Jelling cache's date, because there were no obvious historical benchmarks here as there were in Denmark.

One of the jars from the Muisca site

A lot of the pieces from this discovery are figurines in the shape of snakes and other animals, as well as people wearing headdresses and carrying staffs and weapons.  This has prompted the leader of the team which made the discovery, Francisco Correa, to conclude that the site may have been associated with the worship of ancestor spirits and animal totems.

In any case, both the Danish and the Colombian find are staggeringly precious, not just because of the monetary value of the gold and jewels, but because of what it tells us about the cultures that created these beautiful pieces.  So like I said, if you believe in auspices, maybe it's time to go out and get yourself a metal detector.

I probably won't bother.  Not only do I not believe in strings of good fortune, I don't think there's any gold buried around here.  About the only use I've seen people make of metal detectors in this area is sweeping the village fairgrounds after the annual fair wraps up, looking for lost pocket change.

And frankly, I don't think the return on that investment would be enough to justify the time and expense.

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

Like graphic novels?  Like bizarre and mind-blowing ideas from subatomic physics?

Have I got a book for you.

Described as "Tintin meets Brian Cox," Mysteries of the Quantum Universe is a graphic novel about the explorations of a researcher, Bob, and his dog Rick, as they investigate some of the weirdest corners of quantum physics -- and present it at a level that is accessible (and extremely entertaining) to the layperson.  The author Thibault Damour is a theoretical physicist, so his expertise in the cutting edge of physics, coupled with delightful illustrations by artist Mathieu Burniat, make for delightful reading.  This one should be in every science aficionado's to-read stack!

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


Friday, September 24, 2021

Stories in music

I was driving to work a couple of days ago, listening to classical music on satellite radio, and I heard Ferde Grofé's Grand Canyon Suite.

[Image licensed under the Creative Commons Lennart Sikkema, Canyon River Tree (165872763), CC BY 3.0]

Pretty cool piece of music, but to me the fifth and final movement is something really special.  It's called "Cloudburst" and is a musical depiction of a thunderstorm in the desert.

And the thought occurred to me that you don't need words to tell a story, which I thought would be an interesting topic for this week's Fiction Friday.  Grofé gives us a picture in sounds -- the approach of the storm, lightning, thunder, wind -- then its subsidence (and just like in a real storm, afterward you can still hear the thunder in the distance as it recedes).


This is a pretty well-known piece of music, and is far from the only one that tells a story using music.  Another famous one is Saint-Saëns's Danse Macabre, depicting the devil playing the fiddle and summoning the dead to dance in the cemetery (xylophones for the bones knocking together!).  Listen at the end for the church bells ringing in the distance to signal the sunrise, and the little musical shiver the devil gives when he knows the day is coming -- followed by a sad, mournful violin solo.  But then, the last few notes seem to promise that he'll be back once night falls again.


Beethoven drew his inspiration from stories as well, and I'm not only thinking of pieces like the Pastoral Symphony.  Check out this amazing performance of his piano solo Rondo a Capriccio: Rage Over a Lost Penny.  (All I can say is that if losing a penny made me come up with tunes like this, I'd be flinging coins all over the place.)


One of my favorite musical depictions is from the incredibly prolific American composer Alan Hovhaness.  His Symphony #50 (he wrote 67 of them, and about 450 other sorts of pieces) is subtitled Mount Saint Helens.  Listen to it -- if that's not a musical version of a volcanic eruption, I don't know what is.


Jean Sibelius wrote a lot of music based upon Finnish folk tales, myths, and legends, but to me none gives as vivid a picture as "Lemminkainen's Return" from the Kalevala Suite.  Lemminkainen is a folk hero, and the piece depicts his triumphant return to his home after a long adventure.  It gallops along, and you can almost see the hero with his long hair flying in the wind, riding his horse through a snowstorm.


One of the funniest pieces in classical music -- once you know the story it's telling -- is Sergei Prokofiev's brilliant Lieutenant Kije Suite.  The story behind it is that during an inspection of a military regiment by the Tsar, he was reviewing the roster and saw that someone had scribbled in the word "Kije" (Russian for "thingamajig"), and mistakenly thought it was the name of a soldier.  No one wanted to correct the Tsar, so they invented a Lieutenant Kije, and waxed rhapsodic about his exploits and bravery, along with romantic vignettes of his courtship of, and eventual marriage to, a beautiful young lady.  But they overdid it -- so much that the Tsar decided that he needed to meet this exemplary military man and paragon of virtue.  Cornered, the leaders of the regiment had to invent a heroic death in battle for Kije so the Tsar wouldn't uncover the deception.


I'll end with one of my favorite pieces, the stunning suite Firebird by Igor Stravinsky.  It tells of the magical Firebird, half bird and half human, who is captured by the heroic Prince Ivan.  She gives him one of her feathers, and tells him he can use it to defeat the evil sorcerer King Katschei.  Katschei keeps his soul hidden in an egg in a casket and thinks he's immortal because of it (shades of J. K. Rowling's horcruxes).  But using the magic of the feather, Ivan forces Katschei and his minions to dance themselves to exhaustion.  He then finds the egg and destroys it, killing Katschei and freeing all of the people he'd magically enslaved -- including the young woman Ivan is in love with.  The end is one of the most joyful, stirring, triumphant pieces of music ever written.


So that's a few of my favorite stories in music.  I hope you enjoyed listening.  What are your favorites?

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

Like graphic novels?  Like bizarre and mind-blowing ideas from subatomic physics?

Have I got a book for you.

Described as "Tintin meets Brian Cox," Mysteries of the Quantum Universe is a graphic novel about the explorations of a researcher, Bob, and his dog Rick, as they investigate some of the weirdest corners of quantum physics -- and present it at a level that is accessible (and extremely entertaining) to the layperson.  The author Thibault Damour is a theoretical physicist, so his expertise in the cutting edge of physics, coupled with delightful illustrations by artist Mathieu Burniat, make for delightful reading.  This one should be in every science aficionado's to-read stack!

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


Thursday, September 23, 2021

The natural pharmacy

A couple of weeks ago, we looked at the discovery and decipherment of a codex written in Nahuatl, one of the languages spoken by the Aztecs (and still spoken in central Mexico).  The study highlighted the fact that language is one of the most critical pieces of culture, embodying a unique way of describing the world.  When languages disappear, that perspective is forever lost.

It's even worse than that, according to another study, that appeared in Proceedings of the National Academy of Sciences a couple of months ago.  In "Language Extinction Triggers the Loss of Unique Medicinal Knowledge," authors Rodrigo Cámara-Leret and Jordi Bascompte of the University of Zürich look at the role of language in preserving information about medicinal plants -- information that might well be encoded in only a single one of the estimated 6,500 languages currently spoken on Earth.

Cámara-Leret and Bascompte considered indigenous languages in three places -- New Guinea, Amazonia, and North America -- lining up those languages with databases of medicinal native plants.  Specifically, they were looking at whether the knowledge of the medicinal value of native flora crossed linguistic boundaries, and were known (and used) in the cultures of the speakers of different languages.

Some, of course, were.  The use of willow bark as an analgesic was widely known to Native Americans throughout the eastern half of North America.  The sedative nature of poppy sap was also widespread, and has a long (and checkered) history.  (It's no coincidence that these two plants produce compounds -- aspirin and morphine, respectively -- that are part of the modern pharmacopeia.)

Illustration and uses of mandrake (Mandragora officinarum) from Dioscurides's De Materia Medica (7th century C.E.) [Image is in the Public Domain]

But what about the rest of the myriad species of medicinal plants that have been catalogued?  What Cámara-Leret and Bascompte found is simultaneously fascinating and alarming.  They looked at 12,495 species of medicinal flora native to the regions they studied, and found that over 75% of them were only named and known as pharmacologically valuable in a single language.

Worse, the researchers found that there was a correlation between the languages with the rarest medicinal knowledge, and how endangered the language is.  "We found that those languages with unique knowledge are the ones at a higher risk of extinction," Bascompte said, in an interview with Mongabay.  "There is a sort of a double problem in terms of how knowledge will disappear."

That knowledge isn't purely of interest to anthropologists, as a sort of cultural curiosity.  Consider how many lives have been saved by quinine (from the Peruvian plant Cinchona officinalis, used in treating malaria), vincristine (from the Madagascar periwinkle, Catharanthus rosea, used in treating leukemia and Hodgkin's disease), digoxin (from the foxglove plant, Digitalis purpurea, used for treating heart ailments), taxol (from the Pacific yew, Taxus brevifolia, used in treating a variety of cancers), and reserpine (from the south Asian plant Rauvolfia serpentina, used in treating hypertension).  And that's just some of the better-known ones.  The whole point of the Cámara-Leret and Bascompte study is that the majority of pharmacologically-useful plants aren't known outside of a single indigenous ethnic group -- and when those languages and cultures are lost or homogenized into the dominant/majority culture, that information is lost, perhaps forever.

"There is life outside English," Bascompte said.  "These are languages that we tend to forget—the languages of poor or unknown people who do not play national roles because they are not sitting on panels, or sitting at the United Nations or places like that.  I think we have to make an effort to use that declaration by the United Nations [the UNESCO decision that 2022 to 2032 will be the "Decade of Action for Indigenous Languages"] to raise awareness about cultural diversity and about how lucky we are as a species to be part of this amazing diversity."

I can only hope that it works, at least to slow down the cultural loss.  It's probably hopeless to stop it entirely; currently, the top ten most common first languages (in order: Mandarin, Spanish, English, Hindi, Arabic, Portuguese, Bengali, Russian, Japanese, and Punjabi) account for almost fifty percent of the world's population.

The remaining 6,490 languages account for the other half.  

I understand the drive to learn one of the more-spoken languages, from the standpoint of participation in the business world (if that's your goal).  You probably wouldn't get very far international commerce if you only spoke only Ainu.  But the potential for losing unique knowledge from language extinction and cultural homogenization can't be overestimated.  Nor can the purely practical aspects of this knowledge -- including the possibility of life-saving medicinal plants that might only be recognized as such by a single small group of people in a remote area of New Guinea. 

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

Like graphic novels?  Like bizarre and mind-blowing ideas from subatomic physics?

Have I got a book for you.

Described as "Tintin meets Brian Cox," Mysteries of the Quantum Universe is a graphic novel about the explorations of a researcher, Bob, and his dog Rick, as they investigate some of the weirdest corners of quantum physics -- and present it at a level that is accessible (and extremely entertaining) to the layperson.  The author Thibault Damour is a theoretical physicist, so his expertise in the cutting edge of physics, coupled with delightful illustrations by artist Mathieu Burniat, make for delightful reading.  This one should be in every science aficionado's to-read stack!

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


Wednesday, September 22, 2021

The cities on the plain

Scary place, this universe of ours.

I've dealt here before with some cosmic-level catastrophes -- supernovas and Wolf-Rayet stars and black holes and gamma-ray bursters and false vacuums -- but the situation's not much better down here on the seemingly peaceful surface of the Earth.  There are weather-related disasters like hurricanes and tornadoes, as well as spectacular but less-known phenomena such as convective microbursts, which are not only scary and violent but strike seemingly out of nowhere, producing wind that goes from dead calm to 120 kilometers per hour in under two minutes (and are over equally quickly).  Volcanoes and earthquakes are seldom a surprise with regards to location, but are unpredictable in terms of timing -- although now with better remote sensing techniques, we're getting more accurate at forecasting quakes and eruptions, such as the one currently devastating the island of La Palma in the Canary Islands.  (The Ministry of Tourism announced that the island is "still open to tourism," adding, "You must have a valid passport, as well as proof that you are a complete idiot.")

So we're better off than the people in Pompeii in 79 C.E., or the poor folks in 1902 who were the victims of a pyroclastic eruption from Mont Pelée in Martinique, which killed thirty thousand people in less than five minutes.  There were only three known survivors, the most famous of which was in an underground jail cell at the time.  All three escaped with burns and other injuries, but at least didn't get flash-fried like the rest of the city.

I'm pretty lucky here in upstate New York.  We're not in an earthquake zone, even farther from the nearest volcano, very rarely have tornadoes, and although we sometimes get sideswiped by the remnants of an Atlantic hurricane, we seldom get anything serious.  The worst we have to contend with is snow, but even our worst storms (like the "Hundred-Year Storm" of  March 1993, eight months after I moved here from Seattle, Washington, which dropped almost two meters of snow on us in a space of 48 hours) are nowhere near as violent as the killer blizzards they get in the Rocky Mountain states and the upper Midwest.

So I can't complain.  Even though I do sometimes anyhow.

But I guess even in a relatively clement place, you never know what's going to hit you.  Sometimes literally, to judge by a paper this week in Nature by a team led by geologist Ted Bunch of Northern Arizona University, which describes the fate of the city of Tall el-Hammam in the southern Jordan Valley. 

Never heard of it?  Neither had I, which is surprising considering both its prominence and its ultimate fate.  Up till about 1650 B.C.E., Tall el-Hammam was the bustling center of commerce for a region inhabited by an estimated fifty thousand people.  

The authors describe it as follows:

The three largest settlements in this area were Tall el-Hammam [TeH], Tall Nimrin, and Jericho (aka, Tell Es-Sultan), urban anchors of three city-state clusters, each surrounded by numerous smaller satellite towns and villages.  At 36 hectares of fortifications (0.36 km2) and an additional 30 hectares of “suburban sprawl,” TeH at its zenith was > 4× larger than Tall Nimrin and > 5× larger than Jericho, and thus, was likely to have been the area’s politically dominant MBA [Middle Bronze Age] urban center for many centuries.  TeH was initially occupied during the early Chalcolithic Period (~ 6600 cal BP) and was a well-established fortified urban center by the Early Bronze Age (~ 5300 cal BP).  The city reached its peak of hegemony during the MBA and dominated the eastern half of the Middle Ghor and most likely, the western half as well.

Then -- suddenly -- the entire city was wiped off the map.  The entire region was abandoned for over six hundred years, and in fact wasn't substantially recolonized for almost a millennium.

So what happened? 

Bunch et al. believe they've figured it out.  In 1650 B.C.E., Tall el-Hammam was flattened -- by a stratospheric meteorite explosion.

Artist's conception of what the original palace at Tall el-Hammam looked like -- and what's left of it

You may recall the 2013 Chelyabinsk meteor, an object an estimated twenty meters across that exploded about thirty kilometers above the surface of the Earth, creating a shock wave that damaged houses and injured an estimated 1,491 people.  The 1908 Tunguska Event was even larger, caused by an object an estimated fifty meters across, and blew down trees radially outward from ground zero, destroying over two thousand square kilometers of forest that were (fortunately) far away from any densely-occupied areas.

The one that destroyed Tall el-Hammam is estimated to be larger still -- the researchers suggest a diameter of around seventy meters.  Tall el-Hammam was, quite literally, blown away, the thick walls of the palace sheared off at the foundation.  Mud bricks and roofing clay actually melted.  Mineralogical analysis of the rocks and debris show something kind of terrifying; inclusions of high-melting-point materials like platinum, iridium, and zircon melted as well, indicating temperatures above 2,000 C (and thus ruling out such causes as city-wide conflagrations, which don't get anywhere near that hot).  Quartz granules in the rocks of the area have radial fracture patterns similar to the circular cracks in your windshield when it's hit by a flying piece of gravel, indicating that something big punched the site.

Really hard.

The researchers suggest that the meteor strike at Tall el-Hammam might have been the origin of the biblical story of the destruction of "the Cities on the Plain," most famously Sodom and Gomorrah, although the jury's still out on that.  It would certainly explain the suddenness and totality of the destruction described in the biblical account, although it'd still leave up in the air why Lot's wife turned into a pillar of salt.

As an aside, the meteor strike in 1650 B.C.E. is not considered a possible basis of the biblical account of the destruction of Jericho, in Joshua chapter 6; by what we know of the chronology of the history of Judea, the Book of Joshua was written nearly a thousand years later.  And it's worth mentioning that there seems to be no evidence whatsoever of Jericho experiencing a catastrophic collapse (the Bible talks about the walls of the city "falling flat") during that entire time period, leading archaeologist and biblical scholar William Dever to state that the story of the fall of Jericho was "invented from whole cloth" as nationalist propaganda by the leaders of the state of Judah to bolster their reputation as not only the Chosen Ones of God, but as all-around tough motherfuckers.  (I paraphrase Dever's actual analysis slightly.)

Anyhow, the Bunch et al. paper is a tour de force of thorough scientific investigation, and from my (admitted layperson's) perspective, it seems like they've locked down their case pretty tightly.  So now you have something else to worry about, even if (like me) you're far away from raging volcanoes, earthquake zones, and Tornado Alley, not to mention any local gamma-ray bursters and black holes.  Exploding rocks from space.  At least it'd be a quick way to go; considering the level of destruction they describe at Tall el-Hammam, we're talking "loud noise and bright light, look upward for a second, then get blasted to smithereens."

Have a nice day.

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

Like graphic novels?  Like bizarre and mind-blowing ideas from subatomic physics?

Have I got a book for you.

Described as "Tintin meets Brian Cox," Mysteries of the Quantum Universe is a graphic novel about the explorations of a researcher, Bob, and his dog Rick, as they investigate some of the weirdest corners of quantum physics -- and present it at a level that is accessible (and extremely entertaining) to the layperson.  The author Thibault Damour is a theoretical physicist, so his expertise in the cutting edge of physics, coupled with delightful illustrations by artist Mathieu Burniat, make for delightful reading.  This one should be in every science aficionado's to-read stack!

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


Tuesday, September 21, 2021

Shake your tail feathers

My wife and I reset some pavers in our front sidewalk a couple of days ago.  In our area, most of the stone used for paving and wall-building is native slate and limestone, which make up the majority of the bedrock in this part of upstate New York; and given slate's tendency to fracture naturally along parallel planes, it makes an obvious good choice for paving stones.

We used a pry-bar to pull up one big stone -- maybe a meter across and two meters long -- and a piece of it sheared off.  Unfortunate but unavoidable.  When I stopped and picked up the chunk, a flat, triangular piece a little larger than the palm of my hand, I noticed something interesting about it.  It had ripple marks, the clear signature of the muddy environment where it formed.

Seeing this sort of thing always makes me imagine what things were like back then.  The rocks in this area are Devonian in age, on the order of four hundred million years old, at which time this whole area was at the bottom of a shallow sea.  So those ripple marks in my sidewalk paving stone were created by water movements that occurred so long ago it's hard to imagine.  At that point, there was virtually no terrestrial life -- a few plants and insect species had colonized the land, but everything else was still aquatic.  The first dinosaurs were still a good 150 million years in the future.

It's kind of cool the way these sorts of moments thrill me from two different perspectives.  Being a biology teacher (retired now), I find it absolutely fascinating to ponder the grand panorama that is the history of life on Earth, and to consider evolution's role in creating what Darwin famously called "endless forms most beautiful and most wonderful."  As a novelist, it never fails to fire my imagination -- to picture what it would be like to stand there on the beach with the bare, treeless Devonian landscape stretching out behind me, looking out over oceans where swam trilobites and bizarre armored fish (ostracoderms) and ammonites, all of which went extinct long, long ago.

The reason this comes up -- besides finding signs of four-hundred-million-year-old ocean waves in my slate sidewalk paver -- is a link sent to me (once again) by the indefatigable Gil Miller, about a fossil discovery found in northeastern China recently.  It's the fantastically well-preserved remains of a little feathered dinosaur from 120 million years ago called Yuanchuavis kompsosoura, which was about the size of a blue jay -- but had a thirty-centimeter-long tail, which is longer than its entire body.

Yuanchuavis kompsosoura

Extravagant tails like this are an interesting case of an evolutionary trade-off.  Modern birds like peacocks have tails so long they're actually a hindrance to flying, but apparently the disadvantages of having such a clumsy appendage are outweighed by the advantage in terms of attractiveness to potential mates (sexual selection).  It's theorized that having elaborate plumage is a way of advertising your overall genetic health.  "Look at me," they say.  "I am so genetically superior I can throw away all sorts of energy and resources on something completely frivolous.  I am totally who you want to have sex with."

Kind of the bird version of driving a Jaguar.

That sort of teleological reasoning, however, is always thin ice when you're talking about evolutionary drivers.  None of that selection is being done because of any kind of conscious weighing of options.  But whatever its basis, we see similar kinds of wild tails in a great many bird species today -- swallowtailed kites, African widowbirds, paradise flycatchers, quetzals, drongos, and a lot of hummingbirds, as just a few examples.  The fact that so many relatively unrelated species have gone down the same path supports the conjecture that whatever is propelling this selection, it's pretty powerful.

Reading the article about this fascinating little dinosaur immediately switched on the other mode, which led me to imagining what it actually looked like when alive, and wondering about its behavior and environment.  Of course, even most well-preserved fossils give you only a hint about what the living creature looked like; all the spots and patterns and colors in movies like Jurassic Park are guesses, as are the behaviors (like the dinosaur with the toxic spit that killed Dennis Nedry).  But here, the preservation is on such a fine scale that the paleontologists do have an idea of what color it was -- traces of pigment-producing cells suggest that the fan part of its tail was gray, and the two long banner feathers in the middle were jet black.

Here, we actually can visualize what it looked like when he was shaking his tail feathers in the early Cretaceous forests.

So that's our imagined trip into deep time for today.  I know I've quoted it here before, but the lines from Tennyson's "In Memoriam" are so poignant and so apposite that I will end with them anyhow:

There rolls the deep where grew the tree.
O Earth, what changes hast thou seen?
There where the long road roars hath been
The stillness of the central sea.

The hills are shadows, and they flow
From form to form, and nothing stands;
They melt like mist, the solid lands,
Like clouds, they shape themselves and go.

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

Like graphic novels?  Like bizarre and mind-blowing ideas from subatomic physics?

Have I got a book for you.

Described as "Tintin meets Brian Cox," Mysteries of the Quantum Universe is a graphic novel about the explorations of a researcher, Bob, and his dog Rick, as they investigate some of the weirdest corners of quantum physics -- and present it at a level that is accessible (and extremely entertaining) to the layperson.  The author Thibault Damour is a theoretical physicist, so his expertise in the cutting edge of physics, coupled with delightful illustrations by artist Mathieu Burniat, make for delightful reading.  This one should be in every science aficionado's to-read stack!

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


Monday, September 20, 2021

Hot times

In today's contribution from the Completely Useless Advice department: if you own property in southern Africa, you might want to consider selling it some time in the next ten million years or so.

The reason I say this is because of a paper published a couple of months ago in Nature Geoscience that was once again thrown my way by my pal Gil Miller, who seems to have an inordinate talent at ferreting out truly fascinating stuff I hadn't heard about.  The paper is entitled "A Tree of Indo-African Mantle Plumes Imaged by Seismic Tomography," by Maria Tsekhmistrenko, Karin Sigloch, and Kasra Hosseini (of Oxford University), and Guilhem Barruol (of the Université de Paris), and describes the structure of the mysterious "hotspots" -- upwelling of extremely hot magma from deep in the mantle -- that are responsible for such volcanically-active regions as Hawaii, Yellowstone, and Réunion Island.

These hotspots have long puzzled geologists, because they are quite distant from tectonic plate boundaries, where most of the world's seismic and volcanic activity occurs.  Hawaii is the best-studied hotspot; it was one of the most powerful pieces of evidence of plate movement, back in the 1960s when the theory of plate tectonics was first being studied.  The Big Island of Hawaii is just the easternmost point in a chain that extends way beyond what we usually think of as the Hawaiian Islands; even the westernmost island that pokes up above sea level, Kure Atoll, isn't the end of it.  It continues into the Emperor Seamount Chain, which extends underwater all the way to the Kamchatka Peninsula of Siberia. 

My long-ago geology professor described it as being like pulling a piece of fabric (the Pacific Plate) through an upside-down sewing machine (the Hawaiian Hotspot); the needle of the sewing machine punches regular holes upward through the fabric as it moves through, but the sewing machine itself stays in the same place.  The plates are moving; the hotspot isn't.  (And the angle in the chain of seamounts indicates that at some point in the past, the Pacific Plate changed direction, probably because of jostling against other plates.)

The Pacific Ocean floor, showing the Hawaiian-Emperor Seamount Chain [Image is in the Public Domain courtesy of NOAA]

What is still mysterious about hotspots is why they happen at all.  We have a pretty decent idea of why the activity along plate margins occurs -- strike-slip faults like the famous San Andreas, where two plates are moving along each other in opposite directions; trenches/subduction zones like Indonesia, where you get both powerful quakes and huge volcanoes; and mid-ocean ridges/divergent zones like the Mid-Atlantic Ridge, where plates are moving apart and new magma upwells to fill the gaps.  But why would there be a persistent chain of volcanoes out in the middle of a stable plate?

The current paper describes blobs of extremely hot magma originating from the lower parts of the mantle, which rise and then diverge into branches.  The authors write:
Mantle plumes were conceived as thin, vertical conduits in which buoyant, hot rock from the lowermost mantle rises to Earth’s surface, manifesting as hotspot-type volcanism far from plate boundaries.  Spatially correlated with hotspots are two vast provinces of slow seismic wave propagation in the lowermost mantle, probably representing the heat reservoirs that feed plumes...  Using seismic waves that sample the deepest mantle extensively, we show that mantle upwellings are arranged in a tree-like structure.  From a central, compact trunk below ~1,500 km depth, three branches tilt outwards and up towards various Indo-Austral hotspots.  We propose that each tilting branch represents an alignment of vertically rising blobs or proto-plumes, which detached in a linear staggered sequence from their underlying low-velocity corridor at the core–mantle boundary.  Once a blob reaches the viscosity discontinuity between lower and upper mantle, it spawns a ‘classical’ plume-head/plume-tail sequence.
So the Réunion Hotspot is apparently connected to the East African Rift Zone, three-thousand-odd kilometers away.  The EARZ is a developing rift that is ultimately going to shear off the "Horn of Africa," opening a new ocean and creating a new "microcontinent" made up Somalia and bits of Ethiopia, Kenya, and Tanzania.  (As an aside, it's also the site of Olduvai Gorge, where some of the earliest hominin fossils were found.)

[Image is in the Public Domain courtesy of the USGS]

"From looking at the core-mantle boundary, you can maybe predict where the oceans will open,” said study co-author Karin Sigloch.  "If the new models are accurate, a few tens of millions of years from now, you may not want to be in South Africa — or, perhaps, on planet Earth at all."

The reason Sigloch says this is that the team's analysis of the "tree" of magma that underlies both Réunion and the EARZ suggests that it's in the process of forming another branch -- another mantle plume -- that will ultimately end up underneath what is now South Africa.  "In tens of millions of years, a blob of nightmarishly gargantuan proportions will pinch off from the central cusp," Sigloch said, in an interview with Quanta magazine.  "This would produce cataclysmic eruptions.  The Deccan Traps [one of the largest volcanic eruptions ever, and which probably contributed to the extinction of the non-avian dinosaurs 66 million years ago] were caused by what we would think of as a solitary mantle plume.  This future mega-blob, though, would be capable of producing volcanism so prolific and extensive that the Deccan Traps would be a firecracker in comparison."

Pretty scary.  But like I said, if you want to visit South Africa, or if you live there, you still have a ten-million-year window to take care of business.  What's interesting from a geological perspective is that up till now, South Africa has been very stable tectonically.  The majority of the country is made of extremely old rock, what geologists call a "craton" -- a chunk of some of the oldest continents on Earth.  A massive flood basalt eruption, like the Deccan Traps, the Columbia River Flood Basalts, and the largest of them all -- the Siberian Traps, implicated in the cataclysmic Permian-Triassic Extinction -- would (literally) overturn three billion years of stable geology, with catastrophic results for the entire planet.

So yeah.  That's cheerful.  But since we have ten million years before we have anything serious to worry about, it'd be better if to turn your attention to more pressing concerns, even if you live in Johannesburg.  Like what we're doing to destroy the global ecosystem our own selves by our seeming commitment to burn every last gallon of fossil fuels out there, damn the climate, full speed ahead, and which could make the Earth pretty close to uninhabitable a great deal sooner. 

Which now that I think of it, isn't all that reassuring.

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

Like graphic novels?  Like bizarre and mind-blowing ideas from subatomic physics?

Have I got a book for you.

Described as "Tintin meets Brian Cox," Mysteries of the Quantum Universe is a graphic novel about the explorations of a researcher, Bob, and his dog Rick, as they investigate some of the weirdest corners of quantum physics -- and present it at a level that is accessible (and extremely entertaining) to the layperson.  The author Thibault Damour is a theoretical physicist, so his expertise in the cutting edge of physics, coupled with delightful illustrations by artist Mathieu Burniat, make for delightful reading.  This one should be in every science aficionado's to-read stack!

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