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.

Tuesday, September 15, 2020

In the dark

 "Okay, that's cool, but what the hell am I looking at?"

That was my reaction to a press release last week from the Harvard-Smithsonian Center for Astrophysics about a new study of the distribution of dark matter in the universe.  Turns out it's not uniform, which is what I'd have expected given that it apparently doesn't interact with anything except via gravitation (although I hardly need to point out that my opinion on the matter counts for next to nothing because I'm not a physicist).  It exists in filaments and haloes, where the majority of galaxies are concentrated.  Here's one of the images they generated:


I know you can't read much into appearances, but I was immediately struck by how much this image, especially the right-hand part, looks like a neural net.  (I'm just waiting for the woo-woos to latch onto this and claim that this proves the universe is a giant brain.)

"Amongst the things we’ve learned from our simulations is that gravity leads to dark matter particles 'clumping' in overly dense regions of the universe, settling into what’s known as dark matter haloes," said study lead author Sownak Bose.  "These can essentially be thought of as big wells of gravity filled with dark matter particles.  We think that every galaxy in the cosmos is surrounded by an extended distribution of dark matter, which outweighs the luminous material of the galaxy by between a factor of 10-100, depending on the type of galaxy.  Because this dark matter surrounds every galaxy in all directions, we refer to it as a 'halo.'"

So this could be a partial explanation for structures like the Boötes Void, a region of space so empty that (in the words of astronomer Greg Aldering) if the Milky Way was at the center of it, we wouldn't have known about the existence of other galaxies until the 1960s.  It's about 236,000 cubic megaparsecs -- equivalent to a cube 61 trillion parsecs on each side -- and, as of this writing, seems to contain only sixty galaxies.

That, my friends, is a whole lot of nothing.

The distribution of matter in space is clumpy and irregular.  Whether this drives the distribution of dark matter, or it's the other way around (the distribution of dark matter drives the arrangement of ordinary matter in the cosmos) is unknown.

Because that's the trouble, here, to go back to my initial question.  We've got some wonderful pictures of dark matter haloes and filaments, but what the hell is it?  I know the physicists have been working on this question ever since astronomer Vera Rubin demonstrated its existence back in the 1990s, but for cryin' in the sink, it makes up 83% of the mass of the universe, and we still don't have a good idea of what it's made of or how it interacts (again, other than its gravitational signature, which is how it was detected in the first place).

But what dark matter actually is still lies in the realm of speculation.  "Ground-based telescopes like the Very Energetic Radiation Imaging Telescope Array System (VERITAS) can be used for this purpose [detecting dark matter], too." said Jie Wang, who co-authored the study.  "And, pointing telescopes at galaxies other than our own could also help, as this radiation should be produced in all dark matter haloes.  With the knowledge from our simulation, we can evaluate many different tools to detect haloes—gamma-ray, gravitational lensing, dynamics.  These methods are all promising in the work to shed light on the nature of dark matter particles."

So the upshot is there's a network of invisible stuff spreading through the entire universe, perhaps organizing the distribution of ordinary matter, but for sure surrounding and penetrating everything there is.  Without interacting with it in any way other than gravity (as far as we can tell).

Which is a hell of a mystery, isn't it?

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

This week's Skeptophilia book-of-the-week is about one of the most terrifying viruses known to man: rabies.

In Rabid: A Cultural History of the World's Most Diabolical Virus, by Bill Wasik and Monica Murphy, we learn about the history and biology of this tiny bit of protein and DNA that has, once you develop symptoms, a nearly 100% mortality rate.  Not only that, but it is unusual amongst pathogens at having extremely low host specificity.  It's transmissible to most mammal species, and there have been cases of humans contracting rabies not from one of the "big five" -- raccoons, foxes, skunks, bats, and dogs -- but from animals like deer.

Rabid goes through not only what medical science has to say about the virus and the disease it causes, but its history, including the possibility that it gave rise to the legends of lycanthropy and werewolves.  It's a fascinating read.

Even though it'll make you a little more wary of wildlife.

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



Monday, September 14, 2020

Solution to the Census Taker Puzzle

A few days ago, I posted a puzzle, and challenged my readers to try to solve it.  (If you haven't seen it yet, it's in my post "Pieces of the Puzzle.")  I promised I'd post a solution, so here it is.  (If you're still working on it, read no further!  It's always more fun to work something out yourself than to have someone simply tell you the answer.)

Here's the puzzle:
A census taker goes to a man's house, and asks for the ages of the man's three daughters.  
The man says, "The product of their ages is 36."  
The census taker says, "That's not enough information to figure it out." 
The man says, "Okay. The sum of their ages is equal to the house number across the street."  
The census taker looks out of the window at the house across the street, and says, "That's still not enough information to figure it out."  
The man says, "Okay.  My oldest daughter has red hair."  
The census taker says thank you and writes down the ages of the three daughters.  
How old are they?
Clue #1 -- that the product of the three girls' ages is equal to 36 -- gives us eight possible combinations of ages:
1, 1, 36
1, 2, 18
1, 3, 12
1, 4, 9
1, 6, 6
2, 3, 6
2, 2, 9
3, 3, 4
So the census taker is quite right that this is insufficient information.

The second clue is that the sum of their ages is equal to the house number across the street. So let's see what the house number could be:
1 + 1 + 36 = 38
1 + 2 + 18 = 21
1 + 3 + 12 = 16
1 + 4 + 9 = 14
1 + 6 + 6 = 13
2 + 3 + 6 = 11
2 + 2 + 9 = 13
3 + 3 + 4 = 10
The census taker looks at the house number through the window, and still can't figure it out.  This is the key to the puzzle. 

Suppose the house number had been 21.  Then looking at the house number would have been sufficient information for solving it; the children would be 1, 2, and 18.  The only way that looking at the house number would be insufficient is if there were two sets of ages that added to the same thing -- which is only true for 1, 6, and 6, and 2, 2, and 9, both which add to 13.

The third clue is that the oldest daughter has red hair.  In the first of our remaining possibilities, 1, 6, and 6, there is no oldest daughter -- the eldest children are twins.  Therefore the daughters are 2, 2, and 9.

I hope you enjoyed this puzzle -- I think it's one of the cleverest ones I've ever seen!

Voices from the past

Sometimes I'll bump into a story that is so down my alley that I'm surprised I didn't find out about it earlier.  That was my reaction to the link sent to me by a friend and long-time loyal reader of Skeptophilia, about a discovery back in 2017 of some samples of two languages that were up till then almost completely unknown.

The discovery was made because of palimpsests, which are documents that have been erased and written over.  This happened because the writing surfaces available -- mostly parchment made from lambskin -- were often considered more valuable than the text written on them, so when it was in short supply people would erase what was there (often it was sanded off with a stone) and rewrite over the new surface.  Some parchments were reused multiple times this way.

The erasing process, though -- just like using an eraser on a piece of paper today -- was never perfect, and traces of the original document(s) were left behind.  Which is why some researchers studying parchments at one of the oldest continuously-run libraries in the world, Saint Catherine's Monastery in Sinai, Egypt, were able to detect passages from two languages for which there were almost no samples left, Caucasian Albanian and Christian Palestinian Aramaic.

Saint Catherine's Monastery [Image licensed under the Creative Commons Berthold Werner / Wikimedia Commons / CC BY-SA.]

The palimpsests were read by photographing them repeatedly in different frequencies of light (including ultraviolet and infrared) and turning a computer loose on the composite images to see what was there that might not be visible to the naked eye.  The results were stunning -- new text from one hundred and thirty different palimpsests that has drastically increased our knowledge of the two extinct languages.

Caucasian Albanian (the language, and place, are unrelated to the present country of Albania), in the Lezgic family of languages -- its closest currently-spoken relative is Udi, spoken by about four thousand people in Azerbaijan and the Caucasian region of Russia.  Caucasian Albanian seems to have vanished from the region some time around 1000 C.E., and until now was only known from a handful of inscriptions on stone tablets.  Linguist Josh Gippert, who is an expert in this language family, is unequivocal about the find.  "This one discovery has brought about a twenty-five percent increase in the readability of Caucasian Albanian," Gippert said.

Christian Palestinian Aramaic is a dialect of Aramaic spoken between the fifth and thirteenth centuries C.E. by the Melkites, a Christian group in Syria.  Over the years, the speaking of Christian Palestinian Aramaic dwindled, replaced by Arabic, and seems to have vanished completely some time in the Middle Ages.  "This was an entire community of people who had a literature, art, and spirituality," said Michael Phelps, director of the Early Manuscripts Electronic Library, who oversaw the project. "Almost all of that has been lost, yet their cultural DNA exists in our culture today.  These palimpsest texts are giving them a voice again and letting us learn about how they contributed to who we are today."

The whole thing is pretty stupendous, not only for the ingenuity of the discovery but because it gives us at least a little bit more information about languages that haven't been spoken for eight hundred years or more.  We're seeing language extinctions today at an increasing rate, as the world's dominant languages (primarily Mandarin, English, Russian, Spanish, and Arabic) replace small/isolated languages.  There are hundreds of languages for which there are only a handful of remaining native speakers -- primarily older people -- which will be extinct without intervention (and possibly even with intervention) in the next twenty years.  Indigenous languages in Australia and South America are especially at risk.  There are places where indigenous people in two villages ten miles apart speak mutually unintelligible languages, and the natives there have mostly adopted the lingua franca (English and Spanish, respectively) in order to be able to travel and communicate.

You can understand why they do it, but it's still kind of sad, considering the cultural knowledge that is vanishing before our eyes.

In any case, the discovery in Egypt is a happy note, giving us a window into the speech of people from over a thousand years ago.  It's nice to know that we can still hear the voices of people who were thought to be silenced forever.

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

This week's Skeptophilia book-of-the-week is about one of the most terrifying viruses known to man: rabies.

In Rabid: A Cultural History of the World's Most Diabolical Virus, by Bill Wasik and Monica Murphy, we learn about the history and biology of this tiny bit of protein and DNA that has, once you develop symptoms, a nearly 100% mortality rate.  Not only that, but it is unusual amongst pathogens at having extremely low host specificity.  It's transmissible to most mammal species, and there have been cases of humans contracting rabies not from one of the "big five" -- raccoons, foxes, skunks, bats, and dogs -- but from animals like deer.

Rabid goes through not only what medical science has to say about the virus and the disease it causes, but its history, including the possibility that it gave rise to the legends of lycanthropy and werewolves.  It's a fascinating read.

Even though it'll make you a little more wary of wildlife.

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



Saturday, September 12, 2020

Color my world

 I'm not absolutely certain about this, but I strongly suspect that every time I taught my biology students about the physiology of color vision, someone asked, "Is it possible that we see colors differently?  Like, what you call red is the color I see as green, but we've both learned to call it red?"

My usual response was, "It's possible, given that I can't see the world through your eyes and interpreted by your brain.  I only have access to my own perceptive apparatus.  However, it's pretty unlikely, given that your eyes and brain are structured pretty much identically to mine, so there's no reason to surmise they see the world in a radically different way.  The most parsimonious explanation is that we all perceive colors alike."

That parsimonious explanation got a boost this week by a paper in Psychological Science called, "Universal Patterns in Color-Emotion Associations Are Further Shaped by Linguistic and Geographic Proximity," by a huge team led by Domicele Jonauskaite of the University of Lausanne.  The researchers asked 4,598 volunteers from different cultures to answer questions about the connections they saw between colors and emotions.  In English, for example, we talk about seeing red, being green with envy, or feeling blue.  Presumably other cultures also associate colors with emotions -- but are the correspondences the same across cultures?

[Image is in the Public Domain]

Interestingly, the answer appears to be yes.  There were a few unusual ones that popped out, such as the association in China of the color white with sadness.  White is traditionally worn at Chinese funerals, thus the link.  The same was found with the color purple in Greece; in Greek Orthodox culture, purple is considered the color of mourning.

But there were far more similarities than differences, including some that when you think about it, are rather odd.  Red is one of the only colors that has connection to two essentially opposite emotions; it is the color both of love and of anger.  This same link turns out to be relatively uniform across cultures.  (The anger part might be because of the association with violence and blood; the connection to love is the stranger one.)  Likewise, brown is the color that has the least emotional impact, regardless what culture you are from.

Unsurprisingly, the closer two cultures were geographically and linguistically, the more similar the correspondences were.  That much you'd expect, because of an overlapping or shared heritage.  But even accounting for that, there were more similarities than differences even between very distantly-related cultures.  "There is a range of possible influencing factors: language, culture, religion, climate, the history of human development, the human perceptual system," said study co-author Daniel Oberfeld of Johannes Gutenberg-Universität Mainz.  "Many fundamental questions about the mechanisms of color-emotion associations have yet to be clarified."

It does, though, settle one thing; we are very likely to all see colors the same way.  Your blue and my blue, for example, are perceived alike, and if we were somehow to switch bodies, we wouldn't suddenly see the world painted in a completely different palette.  If that weren't true, why would yellow be the color of cowardice in both the United States and west Africa?

This doesn't, of course, answer the question of why yellow is for cowards in the first place.  Other than the obvious ones like red=blood, the color-to-emotion correspondences are pretty weird.  But it does seem to support the conjecture that regardless of why we link emotions to colors, my color perception works the same as yours does.

Just as well.  Trying to picture a world where the grass is orange and the sky is yellow is making my head hurt.

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

Humans have always looked up to the skies.  Art from millennia ago record the positions of the stars and planets -- and one-off astronomical events like comets, eclipses, and supernovas.

And our livelihoods were once tied to those observations.  Calendars based on star positions gave the ancient Egyptians the knowledge of when to expect the Nile River to flood, allowing them to prepare to utilize every drop of that precious water in a climate where rain was rare indeed.  When to plant, when to harvest, when to start storing food -- all were directed from above.

As Carl Sagan so evocatively put it, "It is no wonder that our ancestors worshiped the stars.  For we are their children."

In her new book The Human Cosmos: Civilization and the Stars, scientist and author Jo Marchant looks at this connection through history, from the time of the Lascaux Cave Paintings to the building of Stonehenge to the medieval attempts to impose a "perfect" mathematics on the movement of heavenly objects to today's cutting edge astronomy and astrophysics.  In a journey through history and prehistory, she tells the very human story of our attempts to comprehend what is happening in the skies over our heads -- and how our mechanized lives today have disconnected us from this deep and fundamental understanding.

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



Friday, September 11, 2020

Forecasting on a fault line

Living in an earthquake zone is risky business.

I lived for ten years in Seattle, which is immediately adjacent to the Cascadia Subduction Zone, widely considered to be one of the most potentially dangerous faults in the world.  The little Juan de Fuca plate -- all that's left of a much larger piece of oceanic crust that once lay underneath Panthalassa, the ocean that surrounded the supercontinent Pangaea back around the time of the Permian-Triassic Extinction of 251 million years ago -- is slowly disappearing as it gets pulled underneath the North American Plate by convection currents in the mantle.  Subduction zone earthquakes occur along trenches that form the boundaries between plates that are moving toward each other, generating a "thrust fault" as one plate dives beneath the other.  Not only do these produce some of the most massive earthquakes known, they also generate volcanoes like Mount Saint Helens and Mount Rainier.

So lovely as the Seattle area is, it's kind of a disaster waiting to happen.  If you have a high tolerance for being freaked out by the power of the natural world, or you don't live in the Pacific Northwest (or both), you should read journalist Kathryn Schulz's wonderful analysis "The Really Big One" that appeared in The New Yorker in 2015.  Her predictions for what will happen to the area when Cascadia ruptures are truly terrifying -- and would be enough to keep me from ever moving back there, much as I loved western Washington for its culture, climate, and natural beauty.


[Image is in the Public Domain]

If you read the article hoping that Schulz (or the geologists she interviewed) can tell you when the "Really Big One" is going to occur, you're not going to find what you're looking for.  We have a pretty good idea of where earthquakes occur and the types of faults that cause them, but predicting when they'll happen is far more problematic.  And sometimes, even the "where" isn't predictable.  In November of 2019 a 5.0 magnitude quake hit the Rhône Valley in France, along the La Rouvière Fault -- a fault zone that we thought was last active twenty million years ago.

Just last week, though, three papers came out looking at the warning signs that a fault is about to rupture, and methods we may be able to use to predict when they'll happen and how big they'll be.  Getting better at this is imperative for the millions of people who live in quake-prone areas, and could potentially save countless lives.

The first, in the journal Nature, was by a team led by Jonathan Bedford of Helmholtz Centre Potsdam.  In "Months-Long Thousand-Kilometre-Scale Wobbling Before Great Subduction Earthquakes," we learn that there are warning signs -- a slow backward drag on the plate margin that ends with a massive slip in the opposite direction, a little like pulling backward on a bowstring and then letting go suddenly.  The authors write:
[We used] a recently developed trajectory modelling approach that is designed to isolate secular tectonic motions from the daily GNSS time series to show that the 2010 Maule, Chile (moment magnitude 8.8) and 2011 Tohoku-oki, Japan (moment magnitude 9.0) earthquakes were preceded by reversals of 4–8 millimetres in surface displacement that lasted several months and spanned thousands of kilometres.  Modelling of the surface displacement reversal that occurred before the Tohoku-oki earthquake suggests an initial slow slip followed by a sudden pulldown of the Philippine Sea slab so rapid that it caused a viscoelastic rebound across the whole of Japan.

The second paper, in Science, looked at what's happening deep underground beneath one of the most famous fault zones, the strike-slip San Andreas Fault.  In "Excitation of San Andreas Tremors by Thermal Instabilities Below the Seismogenic Zone," geologists Lifeng Wang of the China Earthquake Administration and Sylvain Barbot of the University of Southern California found that temperature patterns can predict the likelihood of a fault suddenly giving way.  For a while, the pieces of the plate margin can slowly, steadily grind past each other, but that motion generates frictional heating.  This can lead to rapid fault failure as the warming rock becomes more plastic.  "Just like rubbing our hands together in cold weather to heat them up, faults heat up when they slide. The fault movements can be caused by large changes in temperature," said study co-author Sylvain Barbot, in an interview with Science Daily.  "This can create a positive feedback that makes them slide even faster, eventually generating an earthquake."

Last, in Nature Communications, geologists Claudia Hulbert and Romain Jolivet (of the École Normale Superieure) and Bertrand Rouet-LeDuc and Paul Johnson (of the Geophysics Group at Los Alamos National Laboratory) turned the power of machine learning on past patterns of seismic instability, and found that large "megathrust" earthquakes were preceded by as much as a year-long slow slip.  Where this slip is occurring, and how fast, might give us advance warning of a major fault rupture:

Slow slip events result from the spontaneous weakening of the subduction megathrust and bear strong resemblance to earthquakes, only slower.  This resemblance allows us to study fundamental aspects of nucleation that remain elusive for classic, fast earthquakes.  We rely on machine learning algorithms to infer slow slip timing from statistics of seismic waveforms.  We find that patterns in seismic power follow the 14-month slow slip cycle in Cascadia, arguing in favor of the predictability of slow slip rupture.  Here, we show that seismic power exponentially increases as the slowly slipping portion of the subduction zone approaches failure, a behavior that shares a striking similarity with the increase in acoustic power observed prior to laboratory slow slip events.  Our results suggest that the nucleation phase of Cascadia slow slip events may last from several weeks up to several months.

Even though such a pattern of slow slips might tell us that a major earthquake is imminent, it's unlikely we'll ever be able to say "... and it's going to happen next Friday at ten A.M."  And given our penchant for ignoring science unless it can give us pinpoint accuracy, we're probably not going to see much change in our behavior.  After all, that tendency is at the heart of the United States's failure to address the COVID-19 pandemic -- the scientists were saying back in December and January, "this has the capacity to be deadly and fast-spreading," and government officials said, "How fast and how deadly?"  The scientists had to say, "We're not sure yet," and that was insufficient for leaders to take swift and decisive action.  (And that's not even taking into consideration that Donald Trump knew about the danger, admitted up front the potential devastation COVID-19 could cause, and deliberately decided to lie about it because he was afraid it would hurt his chances of being re-elected.)

So we're not so good at reacting to clear and present dangers if the remedy is inconvenient or costly.  As James Burke said, in his frighteningly prescient 1991 documentary After the Warming, "The scientists said that devastating climate change was going to happen at some point, but for most people that wasn't good enough.  We wouldn't pay for what amounts to climate insurance, even though we happily insure our lives and our property against far less likely occurrences."

Be that as it may, I'm glad we're seeing this progress being made.  Earthquakes are notorious amongst natural disasters at giving no warning whatsoever, so anything we could do to figure out how to predict them more accurately could potentially save lives.

But even so, I don't think I'd want to live in the Pacific Northwest again.

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

Humans have always looked up to the skies.  Art from millennia ago record the positions of the stars and planets -- and one-off astronomical events like comets, eclipses, and supernovas.

And our livelihoods were once tied to those observations.  Calendars based on star positions gave the ancient Egyptians the knowledge of when to expect the Nile River to flood, allowing them to prepare to utilize every drop of that precious water in a climate where rain was rare indeed.  When to plant, when to harvest, when to start storing food -- all were directed from above.

As Carl Sagan so evocatively put it, "It is no wonder that our ancestors worshiped the stars.  For we are their children."

In her new book The Human Cosmos: Civilization and the Stars, scientist and author Jo Marchant looks at this connection through history, from the time of the Lascaux Cave Paintings to the building of Stonehenge to the medieval attempts to impose a "perfect" mathematics on the movement of heavenly objects to today's cutting edge astronomy and astrophysics.  In a journey through history and prehistory, she tells the very human story of our attempts to comprehend what is happening in the skies over our heads -- and how our mechanized lives today have disconnected us from this deep and fundamental understanding.

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



Thursday, September 10, 2020

Pieces of the puzzle

I'm curious about where the human drive to solve puzzles comes from.

It's a cool thing, don't get me wrong.  But you have to wonder why it's something so many of us share.  We are driven to know things, even things that don't seem to serve any particular purpose in our lives.   The process is what's compelling; many times, the answer itself is trivial, once you find it.  But still we're pushed onward by an almost physical craving to figure stuff out.

When I taught Critical Thinking, every few weeks I devoted a day to solving divergent thinking puzzles.  My rationale is that puzzle-solving is like mental calisthenics; if you want to grow your muscles, you exercise, and if you want to sharpen your intellect, you make it work.  I told the students at the outset that they were not graded and that I didn't care if they didn't get to all of them by the end of the period.  You'd think that this would be license for high school students to blow it off, to spend the period chatting, but I found that this activity was one of the ones for which I almost never had to work hard to keep them engaged, despite more than once hearing kids saying things like, "This is making my brain hurt."

Here's a sample -- one of the most elegant puzzles I've ever seen:
A census taker goes to a man's house, and asks for the ages of the man's three daughters. 
The man says, "The product of their ages is 36." 
The census taker says, "That's not enough information to figure it out." 
The man says, "Okay. The sum of their ages is equal to the house number across the street." 
The census taker looks out of the window at the house across the street, and says, "That's still not enough information to figure it out." 
The man says, "Okay. My oldest daughter has red hair." 
The census taker says thank you and writes down the ages of the three daughters. 
How old are they?
And yes, I just re-read this, and I didn't leave anything out.  It's solvable from what I've given you.  Give it a try!  (I'll post a solution in a few days.)

This drive to figure things out, even things with no immediate application, reaches its apogee in two fields that are near and dear to me: science and linguistics.  In science, it takes the form of pure research, which, as a scientist friend of mine put it, is "trying to make sense of one cubic centimeter of the universe."  To be sure, a lot of pure research results in applications afterwards, but that's not usually why scientists pursue such knowledge.  The thrill of pursuit, and the satisfaction of knowing, are motivations in and of themselves.

In linguistics, it has to do with deepening our understanding of how humans communicate, with figuring out the connections between different modes of communication, and with deciphering the languages of our ancestors.  It's this last one that spurred me to write this post; just yesterday, I finished re-reading the phenomenal book The Riddle of the Labyrinth by Margalit Fox, which is the story of how three people set out, one after the other, to crack the code of Linear B.

Linear B was a writing system used in Crete 4,500 years ago, and for which neither the sound values of the characters, nor the language they encoded, was known.  This is the most difficult possible problem for a linguist; in fact, most of the time, such scripts (of which there are a handful of other examples) remain closed doors permanently.  If you neither know what sounds the letters represent, nor what language was spoken by the people who wrote them, how could you ever decipher it?

One of the Linear B tablets found at Knossos by Arthur Evans [Image licensed under the Creative Commons vintagedept, Clay Tablet inscribed with Linear B script, CC BY 2.0]

I'd known about this amazing triumph of human perseverance and intelligence ever since I read John Chadwick's The Decipherment of Linear B when I was in college.  I was blown away by the difficulty of the task these people undertook, and their doggedness in pursuing the quest to its end.  Chadwick's book is fascinating, but Fox's is a triumph; and you're left with the dual sense of admiration at minds that could pierce such a puzzle, and wonderment at why they felt so driven.

Because once the Linear B scripts were decoded, the tablets and inscriptions turned out to be...

... inventories.  Lists of how many jugs of olive oil and bottles of wine they had, how many arrows and spears, how many horses and cattle and sheep.  No wisdom of the ancients; no gripping sagas of heroes doing heroic things; no new insights into history.

But none of that mattered.  Because of the form that the inscriptions took, Arthur Evans, Alice Kober, and Michael Ventris realized pretty quickly that this was the sort of thing that the Linear B tablets were about.  The scholars who deciphered this mysterious script weren't after a solution because they thought the inscriptions said something profound or worth knowing; they devoted their lives to the puzzle because it was one cubic centimeter of the universe that no one had yet made sense of.

That they succeeded is a testimony to this peculiar drive we have to understand the world around us, even when it seems to fall under the heading of "who cares?"   We need to know, we humans.  Wherever that urge comes from, it becomes an almost physical craving.  All three of the people whose work cracked the code were united by one trait; a desperate desire to figure things out.  Only one, in fact, had a particularly good formal background in linguistics.  The other two were an architect and a wealthy amateur historian and archaeologist.  Training wasn't the issue.  What allowed them to succeed was persistence, and methodical minds that refused to admit that a solution was out of reach.

The story is fascinating, and by turns tragic and inspirational, but by the time I was done reading it I was left with my original question; why are we driven to know stuff that seems to have no practical application whatsoever?  I completely understood how Evans, Kober, and Ventris felt, and in their place I no doubt would have felt the same way, but I'm still at a loss to explain why.  It's one of those mysterious filigrees of the human mind, which perhaps is selected for because curiosity and inquisitiveness have high survival value in the big picture, even if they sometimes push us to spend our lives bringing light to some little dark cul-de-sac of human knowledge that no one outside of the field cares, or will even hear, about.

But as the brilliant geneticist Barbara McClintock, about whom I wrote last week and whose decades-long persistence in solving the mystery of transposable elements ("jumping genes") eventually resulted in a Nobel Prize, put it: "It is a tremendous joy, the whole process of finding the answer.  Just pure joy."

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

Humans have always looked up to the skies.  Art from millennia ago record the positions of the stars and planets -- and one-off astronomical events like comets, eclipses, and supernovas.

And our livelihoods were once tied to those observations.  Calendars based on star positions gave the ancient Egyptians the knowledge of when to expect the Nile River to flood, allowing them to prepare to utilize every drop of that precious water in a climate where rain was rare indeed.  When to plant, when to harvest, when to start storing food -- all were directed from above.

As Carl Sagan so evocatively put it, "It is no wonder that our ancestors worshiped the stars.  For we are their children."

In her new book The Human Cosmos: Civilization and the Stars, scientist and author Jo Marchant looks at this connection through history, from the time of the Lascaux Cave Paintings to the building of Stonehenge to the medieval attempts to impose a "perfect" mathematics on the movement of heavenly objects to today's cutting edge astronomy and astrophysics.  In a journey through history and prehistory, she tells the very human story of our attempts to comprehend what is happening in the skies over our heads -- and how our mechanized lives today have disconnected us from this deep and fundamental understanding.

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



Wednesday, September 9, 2020

A planetary Tilt-o-Whirl

A long-standing unsolved puzzle in physics is the three-body problem, which despite its name is not about a ménage-à-trois.  It has to do with calculating the trajectory of orbits of three objects around a common center of mass, and despite many years of study, the equations it generates seem to have no general solution.

There are specific solutions for objects of a particular mass starting out with a particular set of coordinates and velocities, and lots of them result in highly unstable orbits.  Take, for example, this one, which involves three objects of equal masses, starting out with zero velocity and sitting at the vertices of a scalene triangle:

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

It's a problem that has application to our understanding of double and triple star systems, which seem to be quite common out there in the cosmos.  For people like me, who are fascinated with the possibility of extraterrestrial life, it's especially important -- because if the majority of planets in orbit around a double star (or worse, a triple star) follow unstable trajectories, that would represent a considerable impediment to the evolution of life.  Such planets would have wildly fluctuating climates, a possibility that resulted in a plot twist on the generally abysmal 1960s science fiction show Lost in Space, even though when it came up (1) the writers evidently didn't know the difference between a planet's rotation and its revolution, with the result that the blazing heat wave and freezing cold only lasted a few hours each, and (2) in subsequent episodes they conveniently forgot all about it, and it was never mentioned again.


Be that as it may, now that we have a vastly-improved ability to detect extrasolar planets and determine their orbits around their host star(s), it's given us more information about what kinds of trajectories these complex systems can take.  For example, consider the system GW Orionis, which was the subject of a paper last week in Science.

GW Orionis is a trio of young stars, two of which are quite close together, and the third further away.  The two closer ones are whirling around pretty quickly, and the third making long swoopy dives in toward (and then away from) the others.

Complicated enough, but add to that a set of proto-planetary rings.  Three of them, in fact.  And unlike our own rather sedate star system, where all the planets except for Pluto are orbiting within under seven degrees' tilt with respect to a flat plane -- even Pluto's orbit is only tilted by fifteen degrees -- this system is kind of all over the place.

Here's an artist's conception of what GW Orionis looks like, based on the measurements and observations we have:

[Image courtesy of L. Calçada/ESO, S. Kraus et al., University of Exeter]

Pretty cool-looking.  Given our lack of knowledge of (in this case) six-body problems -- the three stars and the three planetary rings -- no one knows for sure if this is going to be a long-lasting, stable system, or if it will eventually collapse or fly apart.  It seems likely that the system would be a planetary Tilt-o-Whirl, and any orbits formed would be as chaotic as the animation I included above, but honestly, that's just a guess.

However, it's entertaining to think of what life would be like on a planet with three suns in the sky.  One more even than Tatooine:


The more we scan the skies, the more awe-inspiring things we find.  I'm glad to live in a time when our ability to study the stars has improved to the point that we're able to consider not just systems like our own, but the vast array of possibilities that are out there.  One thing's for certain: if you are into astronomy, you'll never be bored.

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Humans have always looked up to the skies.  Art from millennia ago record the positions of the stars and planets -- and one-off astronomical events like comets, eclipses, and supernovas.

And our livelihoods were once tied to those observations.  Calendars based on star positions gave the ancient Egyptians the knowledge of when to expect the Nile River to flood, allowing them to prepare to utilize every drop of that precious water in a climate where rain was rare indeed.  When to plant, when to harvest, when to start storing food -- all were directed from above.

As Carl Sagan so evocatively put it, "It is no wonder that our ancestors worshiped the stars.  For we are their children."

In her new book The Human Cosmos: Civilization and the Stars, scientist and author Jo Marchant looks at this connection through history, from the time of the Lascaux Cave Paintings to the building of Stonehenge to the medieval attempts to impose a "perfect" mathematics on the movement of heavenly objects to today's cutting edge astronomy and astrophysics.  In a journey through history and prehistory, she tells the very human story of our attempts to comprehend what is happening in the skies over our heads -- and how our mechanized lives today have disconnected us from this deep and fundamental understanding.

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