The lost forests of the Fens

It will come as no surprise to regular readers of Skeptophilia that I have a fascination for considering how the terrain of the Earth has changed over its history.  It's a topic I've come back to again and again as scientists piece together the shifting topography of the continents, molded by plate tectonics and glaciations and even the occasional meteorite impact.

It's tempting to think that you have to go back hundreds of millions of years to see a significant difference from what we have now, as we did in yesterday's post about the peculiar geology of Scotland.  In some cases, though, things have changed on a far shorter time scale, so recently that the remnants of the past lie right beneath the surface of the modern landscape.

The Fens are a region in eastern England, lying in Lincolnshire, Cambridgeshire, and Norfolk.  It's virtually all dead-flat and only a meter or two above sea level, so the whole area is prone to flooding -- water is controlled by a network of levees and drainage channels that crisscross the entire nearly four thousand square kilometer region.  You'd think this would discourage people from living there, but the opposite is true; it's been settled since Mesolithic times, mostly because of the excellent quality of the soil for agriculture.  The largest communities in the Fens are understandably concentrated on the highest ground, which are nicknamed "islands" (and in rainy periods, they sometimes are islands in actual fact).  The largest of these is Ely, a beautiful cathedral city that is now home to twenty thousand people.

Ely Cathedral [Image licensed under the Creative Commons Tilman2007, Ely-071, CC BY-SA 4.0]

It's a strange and surreal landscape, prone to long periods of fog and swirling mist, largely devoid of trees, dominated by wide grassy marshes that are home to a great variety of birds and other wildlife.  The region so impressed composer Ralph Vaughan Williams that he wrote his melancholy and evocative piece In the Fen Country to try to capture the otherworldly beauty of the place.

Wicken Fen, Cambridgeshire [Image is in the Public Domain]

What brings up this topic today is a study by researchers at the University of Cambridge that appeared in the journal Quaternary Science Reviews last week, which showed that only five thousand years ago, the Fens looked very different -- and traces of that vanished landscape still lurk right below the surface.

Farmers plowing the rich soil to plant crops such as grains, vegetables, potatoes, canola, and mustard frequently find their plows getting snagged on heavy logs that then have to be dug up and dragged out.  "A common annoyance for Fenland farmers is getting their equipment caught on big pieces of wood buried in the soil, which can often happen when planting potatoes, since they are planted a little deeper than other crops," said study lead author Tatiana Bebchuk.  "This wood is often pulled up and piled at the edge of fields: it's a pretty common sight to see these huge piles of logs when driving through the area."

Upon analysis, Bebchuk and her team found that nearly all of the wood came from yew trees -- many of them absolutely enormous, on the order of twenty meters tall.  Only five millennia ago, what is now the marshland of the Fens was a huge forest of yew trees.

Then, about 4,200 years ago, all of them suddenly died.

The reason, Bebchuk found, was a sudden influx of salt water as the world warmed following a cold period, and sea levels rose.  Within a generation the yew forests were nothing more than a vast expanse of bleached trunks, which ultimately fell and were buried in the marshy soil.  Replacing them was an ecosystem of salt-tolerant marshland grasses that still dominate the region today.

What's curious is that this coincided with significant events in other parts of the world -- a serious drought in China, and the collapse of the Egyptian Old Kingdom and the Mesopotamian Akkadian Empire.  Whether these are all directly related is, of course, impossible to say; it's rare that complex historical events have only a single cause.  Climate change may, however, been a significant contributor -- otherwise this is quite the coincidence.

"We want to know if there is any link between these climatic events," said Bebchuk.  "Are the megadroughts in Asia and the Middle East possibly related to the rapid sea level rise in northern Europe?  Was this a global climate event, or was it a series of unrelated regional changes?  We don't yet know what could have caused these climate events, but these trees could be an important part of solving this detective story."

It's fascinating, and a little scary, to see how rapidly things can change -- and if this doesn't put you in mind of what we're currently doing to the climate, it should.  Consider what landscapes we have today, places that seem like they'll never change, that might be drastically different fifty years from now.

I wonder what the scientists five thousand years in the future will piece together about our current world?

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

Straight as an arrow

My novel The Fifth Day begins with an unnamed beast waking up and finding itself in the world of humans -- and realizing it can recognize artificial from natural structures by their shapes.  Here's its first sight of a house with an open garage door:

The thing in front of it was too regular, too square to be a cave, but the opening in the front showed a shadowed interior and the promise of coolness.  The cave was a man-structure, probably.  Men liked such things, with straight edges and right angles, to show that they could master nature, bend it to their desires, eliminate the rough and the irregular and the uneven.

The suggestion that straight lines don't occur in nature is false, of course.  Crystals, for example, have abundant straight lines and perfect angles.  The difference (although it probably didn't occur to a mind like the beast's) is a subtle one; humans cut, fold, or shape objects into flat surfaces with straight edges and definite angles for reasons of functionality.  We superimpose regularity onto irregular materials from the top down, for our own purposes.  In nature, however, the patterns emerge from the bottom up; they're reflections of some underlying regularity of structure.  (In crystals, the internal angles of the chemical bonds holding the lattice together.)

So it's not that nature is irregular; it's more that regularity, especially somewhere you wouldn't expect it, demands an explanation.

Which brings us to the two nearly perfectly straight lines that bisect Scotland from southwest to northeast.

[Image licensed under the Creative Commons Woudloper, Scotland metamorphic zones EN, CC BY-SA 3.0]

The southern one is called the Highland Boundary Fault, and wavers a bit (as you can see from the map); but the northern one, the Great Glen Fault, is just about ruler-straight.  As you might guess from the name, the Highland Boundary Fault separates the Highlands (to the north and west) from the Lowlands (to the south and east), and represents a dramatic shift in topography and geology.  The Great Glen Fault is even more puzzling, not only because of its oddly perfect geometry, but because it cuts straight across a region of Scotland that is relatively uniform geologically.

Reconstructing what happened here took geologists delving into the deep past.  Between the late Ordovician and early Devonian Periods, on the order of from 490 to 390 million years ago, a pair of continents that had joined some thirty million years earlier, nicknamed Baltica and Avalonia, collided with the continent of Laurentia (which makes up the majority of what is now North America, and -- most germane to our discussion -- the northwestern part of Scotland).  This gave rise to a series of orogenies (mountain-building episodes), first the Caledonian Orogeny (that raised the Grampian Mountains in Scotland and the Scandinavian Mountains in Norway and Sweden), then the Acadian Orogeny (which raised the Appalachians).

This is a vast oversimplification of what was a complex event, but the gist is that the process that created all three mountain ranges is the same one that is currently creating the Alps and Himalayas -- continental blocks colliding, and raising mountain ranges along the suture.  (This is why you can find marine fossils at the tops of the Himalayas; the rock at the peak of Mount Everest was once at the bottom of the a piece of the Indian Ocean that vanished when India slammed into Asia.)  After the Caledonian and Acadian Orogenies raised that entire massive mountain range, rifting tore it into three pieces, leaving the longest chunks in eastern North America and Scandinavia, and a smaller piece cutting through Scotland, once again from southwest to northeast.

The fact that the trend of the mountain range is the same as the trend of the two strangely straight faults is no coincidence.  The answer seems to be that when Baltica/Avalonia collided with Laurentia, the direction of motion wasn't perpendicular to the coastline.  The two approached at an angle, so when the collision occurred, the force wasn't exerted directly into the margin.  A component of the force was exerted along the suture, so this created what's called a strike-slip fault -- where the movement is parallel to the fault rather than perpendicular to it.  (A famous example is the San Andreas Fault in California.)

And this is what created the two huge faults in Scotland.  The southern one, the Highland Boundary Fault, represents the suture line between Baltica/Avalonia (to the southeast) and Laurentia (to the northwest); the Great Glen Fault is just a stress-relieving crack that formed because the sideways pressure from the collision became too high for the rock to bear, and it split along a straight line, creating a deep valley straight across the country that now includes the famous Loch Ness.

So (very) long-ago continental collisions explain the odd geology of Scotland.  The drastic difference in the rocks between the Highlands and Lowlands comes from the fact that they started out on different continents -- the Highlands on Laurentia, the Lowlands on Avalonia.  The two long faults were created by the stress of the collision, which involved forces large enough to raise mountain ranges that at the time were as high as the Himalayas.

The straight-line cracks in the ground that characterize the topology of Scotland give us a hint about some fascinating underlying causes -- just as the symmetry of a snowflake represents the intricate hexagonal shape of the crystal lattice that forms it, the fact that the Fibonacci series shows up in the arrangement of plant leaves and stems is driven by maximizing the light-catching surface, and the bilateral symmetry of most animals comes from patterns set deep in their evolutionary history.  Regularities in nature aren't accidents; noticing things like this, and (more importantly) asking why, is the very basis of science.

As science educator Roger Olstad put it, "Science is, at its core, the search for explanations to account for patterns in our observations."

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

Pushing the envelope

Two nights ago, I watched "The Star Beast," the first of three sixtieth anniversary specials of my favorite show, Doctor Who.  As I might have expected, it was campy good fun, and featured the return of my favorite of the Doctor's companions, Donna Noble (played brilliantly by the inimitable Catherine Tate).

As I also might have expected, the howling from the right-wingers started almost immediately.

The problem this time is Donna's daughter, Rose (played by the wonderful Yasmin Finney), who is a trans woman.  The script looks at her identity head on; our first introduction to Rose shows her being taunted by some transphobic classmates, and there was a scene where Donna's irascible mother Sylvia struggles with her own guilt about sometimes slipping up and misgendering her granddaughter.  It was handled with sensitivity, and not with any sort of hit-you-over-the-head virtue signaling, but there's no doubt that Rose's being trans is an important part of the storyline.

Then later, one of the aliens in the episode, Beep the Meep (I shit you not, that's this alien's name), is talking with the Doctor, and the Doctor asks what pronouns the Meep uses, and gets the response, "My chosen pronoun is the definite article.  The.  Same as you, Doctor."

Which is a funny and poignant line -- especially considering that the Doctor's previous incarnation was female.

Well, you'd swear Doctor Who had declared war on everything good and holy in the world.

"Doctor Who has gone woke!" one ex-fan shrieked.  "I'm done with it for good!"  Another declared that Doctor Who "hates men."  Yet another made a whole YouTube video dedicated to the statement that the show had "set its legacy on fire."

To which I respond: my dudes, have you ever even watched this show?

Doctor Who has been on the leading edge of social acceptance and representation ever since the reboot in 2005.  Captain Jack Harkness gave new meaning to "pansexual" by flirting with damn near everyone he came into contact with, ultimately falling hard (and tragically) for a Welshman named Ianto Jones.  Freema Agyeman and Pearl Mackie were the first two Black women to play companions; Mackie's character, Bill Potts, was lesbian as well, as was the Thirteenth Doctor's companion Yasmin Khan (played by Mandip Gill).  Then there's the wonderfully badass Madame Vastra (Neve McIntosh) and her wife Jenny Flint (Catrin Stewart), who are in a same-sex relationship that is also an interspecies one.

Not only has this show steadfastly championed representation, its themes frequently press us to question societal issues.  It's addressed racial prejudice (several episodes, most notably Rosa and Cold Blood), slavery (The Planet of the Ood), climate change (Orphan 55), whether it's ever possible to forgive your sworn enemies (Dalek), the terrifying evils of tribalism (Midnight), how power eventually corrupts anyone who wields too much of it (The Waters of Mars), how easy it is to dehumanize those whom we don't understand (The Rebel Flesh/The Almost People), if vengeance ever goes too far (Human Nature/The Family of Blood), and the devastating horrors of war (The Zygon Inversion).

So it's not like the people running this show shy away from looking hard at difficult issues.  It's pushed the envelope pretty much from day one.

More to the point, though -- the most troubling part of all the backlash is the subtext of the whining about how "woke" Doctor Who is.  What they're saying is they want to be able to pretend that those who are different -- in this case, trans people, but more generally, LGBTQ+ individuals -- don't exist.  They don't want to be reminded that everyone isn't straight and White; even having queer folks or people of color appear on a show like this is "ramming wokeness down everyone's throats."

Well, let me say this loud and clear -- as a queer guy who was in the closet for four decades because of this kind of mindless, heartless bigotry: never again.  We will never again be silent, never again be shamed into hiding, never again pretend we're invisible, never again quietly accept that we don't deserve exactly the same respect -- and representation -- as anyone else.  I can only imagine how different the trajectory of my life would have been if there'd been these kinds of positive depictions of queer people on the shows I watched as a teenager; how dare you wish that fate upon yet another generation of young adults.

So if that makes you stop watching Doctor Who -- I think I can speak for the majority of fans by saying, "Oh well."  *shoulder shrug*  We don't need you.  However, it does make me wonder how you don't see the irony of calling us snowflakes, when you are the ones who get your knickers in a twist because of someone asking what pronouns a furry alien prefers.  

In other words, don't let the door hit you on the ass on your way out.  Because we LGBTQ+ people are here to stay, as are people of other races, ethnicities, cultures, and religions.  If you don't like that, you might want to sit and think about why you believe the world has the obligation to reshape itself in order to conform to your narrow-mindedness and prejudice.

As for me, I'm going to continue to watch Doctor Who and continue to enjoy it, and -- to judge by the great ratings "The Star Beast" got -- so are millions of other "woke" fans.

Deal with it.

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

Brighter than the Sun

A frequent (and maddening) thing in science journalism is when they lead news stories with clickbait-y headlines like "This Will Rewrite All Of The Science Textbooks!"  When, in fact, the story turns out to be no more than mildly interesting, and will at best generate a footnote in chapter 23 of the science textbooks.

Likewise for stories headed by "Researchers Dumbfounded" or "Scientists Are Back To The Drawing Board."

Sometimes, though, there really are discoveries that leave scientists baffled, and one of these was the subject of a paper last week in Science (although the event it analyzes happened in May of 2021).  And despite intensive research during the intervening two and a half years, physicists are still unsure of how to explain what happened -- especially since it isn't the first time.

The discovery was made by the Telescope Array in Utah, which doesn't follow the usual pattern of astronomers giving new telescopes clever names (like MeerKAT in South Africa and IceCube in Antarctica).  Did they just give up during the naming process?  You have to wonder if the conversation went like this:

Astronomer 1: I'm completely out of ideas.  All the cool names for observatories are already taken.

Astronomer 2: Plus, don't you think it's time we do some actual research rather than spending all our time trying to name this damn telescope array?

Astronomer 1 and Astronomer 2: *look at each other*

Astronomer 1 and Astronomer 2 (simultaneously):  I have an idea.

In any case, the Telescope Array was studying cosmic rays, high-energy particles that constantly bombard the Earth's upper atmosphere.  Most of them come from the Sun, but some originate outside the Solar System (or even outside the Milky Way).  They're a pretty well understood phenomenon -- but every once in a while, there's one that makes astrophysicists sit up and take notice, like the one recorded on 27 May 2021.

This one had an energy of 244 exa-electron-volts.  If you're not familiar with the prefix exa-, you're not alone; I used to teach science and I had to look it up.  It means 10^18 -- 10 followed by 18 zeroes.  So this cosmic ray had an energy of 244,000,000,000,000,000,000 electron volts, or -- as the brilliant science writer Jennifer Ouellette described it, the energy of a bowling ball dropped from shoulder height compressed into a volume smaller than a hydrogen atom.

Researchers nicknamed the event Amaterasu, after the Shinto goddess of the Sun.

[Image is in the Public Domain]

It's an evocative choice for a name but inaccurate in one respect -- the particle didn't come from the Sun.  In fact, where exactly it came from is a significant mystery.  There is an astrophysical principle called the GZK cutoff (named for the three scientists who proposed it, Kenneth Greisen, Georgiy Zatsepin, and Vadim Kuzmin), which showed that there is a theoretical limit for the energy of a cosmic ray -- it can carry no more than 50 EeV, and come from no farther away than three hundred million light years.  Amaterasu is one of two events that exceeded that -- the other is the aptly-named "Oh-My-God particle," which carried an estimated 320 EeV (equivalent to the kinetic energy of a hundred-mile-an-hour baseball).

Most baffling of all, when astrophysicists traced the trajectory of both Amaterasu and the OMG particle backwards, they led into different parts of an area called the Local Void -- a vast region of empty space.

So not only is there nothing there that looks capable of being able to produce such a high-energy particle, there's... nothing there.

But whatever's doing this, there are at least two of them.

"These events seem like they're coming from completely different places in the sky,” said study co-author John Belz, of the University of Utah. "It’s not like there's one mysterious source.  It could be defects in the structure of spacetime, colliding cosmic strings.  I mean, I’m just spit-balling crazy ideas that people are coming up with because there's not a conventional explanation.  Maybe magnetic fields are stronger than we thought, but that disagrees with other observations that show they’re not strong enough to produce significant curvature at these ten-to-the-twentieth electron volt energies.  It’s a real mystery."

So thanks to my eagle-eyed writer friend Gil Miller, who alerted me to this story.  I guess this is a discovery that may "rewrite the textbooks," or at least add an interesting new chapter.

Once they figure out what the hell it actually is.

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

Paradoxes within paradoxes

Sometimes the simplest, most innocuous-seeming questions can lead toward mind-blowingly profound answers.

I remember distinctly running into one of these when I was in -- I think -- eighth grade science class.  It was certainly pre-high-school; whether it was from Mrs. Guerin at Paul Breaux Junior High School, or another of my teachers, is a memory that has been lost in the sands of time and middle-aged forgetfulness.

What I have never forgotten is the sudden, pulled-up-short response I had to what has been nicknamed Olbers's Paradox, named after 18th century German astronomer Heinrich Wilhelm Matthias Olbers, who first thought to ask the question -- if the universe is infinite, as it certainly seems to be, why isn't the night sky uniformly and dazzlingly bright?

I mean, think about it.  If the universe really is infinite, then no matter what direction you look, your line of sight is bound to intersect with a star eventually.  So there should be light coming from every direction at once, and the night sky shouldn't be dark.  Why isn't it?

The first thought was that there was something absorptive in the way -- cosmic dust, microscopic or submicroscopic debris left behind by stars and blown outward by stellar wind.  The problem is, there doesn't seem to be enough of it.  The average density of cosmic dust in interstellar space is less than a millionth of a gram per cubic meter.

When the answer was discovered, it was nothing short of mind-boggling.  It turns out Olbers's paradox isn't a paradox at all, because there is light coming at us from all directions, and the night sky is uniformly bright -- it's just that it's shining in a region of the spectrum our eyes can't detect.  It's called the three-degree cosmic microwave background radiation, and it appears to be pretty well isotropic (at equal intensities no matter where you look). It's one of the most persuasive arguments for the Big Bang model, and in fact what scientists have theorized about the conditions in the early universe added to what we know about the phenomenon of red-shifting (the stretching of wavelengths of light if the space in between the source and the detector is expanding) gives a number that is precisely what we see -- light peaking at a wavelength of around one millimeter (putting it in the microwave region of the spectrum) coming from all directions.

[Image licensed under the Creative Commons Original: Drbogdan Vector: Yinweichen, History of the Universe, CC BY-SA 3.0]

So, okay.  Olbers's paradox isn't a paradox, and its explanation led to powerful support for the Big Bang model.  But in science, one thing leads to another, and the resolution of Olbers's paradox led to another paradox -- the horizon problem.

The horizon problem hinges on Einstein's discovery that nothing, including information, can travel faster than the speed of light.  So if two objects are separated by a distance so great that there hasn't been time for light to travel from one to the other, then they are causally disconnected -- they can't have had any contact with each other, ever.

The problem is, we know lots of such pairs of objects.  There are quasars that are ten billion light years away -- and other quasars ten billion light years away in the opposite direction.  Therefore, those quasars are twenty billion light years from each other, so light hasn't had time to travel from one to the other in the 13.8 billion years since they were created.

Okay, so what?  They can't talk to each other.  But it runs deeper than that.  When the aforementioned cosmic microwave background radiation formed, on the order of 300,000 years after the Big Bang, those objects were already causally disconnected.  And the process that produced the radiation is thought to have been essentially random (it's called decoupling, and it occurred when the average temperature of the universe decreased enough to free photons from the plasma and send them streaming across space).

The key here is the word average.  Just as a microwaved cup of coffee could have an average temperature of 80 C but have spots that are cooler and spots that are hotter, the fact that the average temperature of the universe had cooled sufficiently to release photons doesn't mean it happened everywhere simultaneously, leaving everything at exactly the same temperature.  In fact, the great likelihood is that it wouldn't.  And since at that point there were already causally disconnected regions of space, there is no possible way they could interact in such a way as to smooth out the temperature distribution -- sort of like what happens when you stir a cup of coffee.

And yet one of the most striking things about the cosmic microwave background radiation is that it is very nearly isotropic.  The horizon problem points out how astronomically unlikely that is (pun intended) if our current understanding is correct.

One possible explanation is called cosmic inflation -- that a spectacularly huge expansion, in the first fraction of a second after the Big Bang, smoothed out any irregularities so much that everywhere did pretty much decouple at the same time.  The problem is, we still don't know if inflation happened, although work by Alan Guth (M.I.T.), Andrei Linde (Stanford), and Paul Steinhardt (Princeton) has certainly added a great deal to its credibility.

So as is so often the case with science, solving one question just led to several other, bigger questions.  But that's what's cool about it.  If you're interested in the way the universe works, you'll never run out of things to learn -- and ways to blow your mind.

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

Getting into the spirit

So it's Black Friday, wherein we Americans follow up a day set aside to give thanks for everything we have with a day set aside to trample each other to death trying to save money on overhyped garbage we really don't need.

Me, I stay right the hell away from stores on Black Friday.  I hate shopping in any case, and the rabid crowds only make it worse.  Plus, today marks the first day of the Little Drummer Boy Challenge, a yearly contest in which participants see how long they can make it into the Christmas season without hearing "The Little Drummer Boy," which ranks right up there with "Frosty the Snowman" and "Santa Claus is Comin' to Town" as the most annoying Christmas carol ever written.  This song not only is irritating as hell, it also has what must be the most ridiculous plot line ever dreamed up, involving a kid who comes up to a pair of new parents with a peacefully sleeping newborn baby, and the kid thinks, "You know what these people need?  A drum solo."

Frankly, I'm surprised Joseph didn't smack him.  Pah-rum-puh-pum-POW, you odious little twerp.

I've participated in this contest for nine years, and haven't made it to Christmas Day undefeated yet.  My most ignominious loss occurred a few years ago, when I was taken out of the competition by a clerk in a hardware store who didn't even know all of the freakin' words, and kept having to la-la bits of it:

Come they LA LA pah-rum-puh-pum-pum
A newborn LA LA LA pah-rum-puh-pum-pum
Our LA LA gifts we bring pah-rum-puh-pum-pum
LA LA before the king pah-rum-puh-pum-pum, rum-puh-pum-pum, rum-puh-pum-pum

And so on and so forth.  He was singing it with hearty good cheer, so I felt kind of guilty when I realized that he'd knocked me out of the game and blurted out, "Are you fucking kidding me?" a little louder than I intended, eliciting a shocked look from the clerk and a significant diminishment in the general Christmas spirit amongst those around me.

Thomas Couture, The Drummer Boy (1857) [Image is in the Public Domain]

And of course, the Christmas season wouldn't be complete without the Fox News types ramping up the whole imaginary War on Christmas thing.  We atheists have allegedly been waging this war for what, now... twenty years?  Twenty-five?  And yet if you'll look around you, just like the Grinch's attempt at banishing Christmas from Whoville, the holiday season still goes right on, pretty much exactly as it did before.

Oops!  Shouldn't say "holiday," because that's part of the War on Christmas, too, even though the word "holiday" comes from "holy day" and therefore is also religious.  This is a point that seems to escape a lot of the Fox News and Newsmax commentators and their ilk, but to be fair, "grip on reality" has never been their forte anyhow.  This year, for example, the rage-of-the-season has been triggered by we Godless Liberal Democratic Unpatriotic Snowflakes somehow inducing Starbucks to put out holiday cups that have designs of hearts and stars instead of having Christmas trees or presents or whatnot, a decision which apparently is Very Naughty In God's Sight.  One furious ex-customer shrieked, "Starbucks REMOVED CHRISTMAS from their cups because they hate Jesus!!!", because apparently all it takes to defeat their all-powerful and omnipotent God is to change the design on some disposable paper cups.

What is wryly amusing about all of this is that I'm one of the aforementioned liberal atheists, and I love the holidays.  We had a nice turkey-and-stuffing dinner yesterday with my brother-in-law and his family for Thanksgiving, and I'm already putting together some gifts for friends and family for Christmas and looking forward to putting up a tree.  So it might come as a surprise to Fox News et al. that in December I tell people "Merry Christmas" at least as often as I say "Happy Holidays." Basically, if someone says "Merry Christmas" to me, I say it back to them; if they say, "Happy Holidays," I say that.  Likewise "Happy Hanukkah," "Happy Kwanzaa," "Blessed Solstice," "Merry Festivus," or "Have A Nice Day."

You know why?  If people speak kindly to me, I reciprocate, because I may be a liberal and an atheist, but I am not an asshole.  So I guess that's three ways in which I differ from the commentators over at Fox News.

Basically, be nice to me, I'll be nice to you.  Unless you're singing "The Little Drummer Boy."  I'm sorry, but my tolerance does have its limits.

In any case, mostly what I plan to do today is to sit around recovering from the food-and-wine-induced coma in which I spent most of yesterday evening.  So however you choose to observe the day and the season, I hope you enjoy it, whether you get into the spirit of it or pretty much ignore the whole thing.

Pah-rum-puh-pum-pum.

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

Dreaming the past

My novel In the Midst of Lions opens with a character named Mary Hansard -- an ordinary forty-something high school physics teacher -- suddenly realizing she can see the future.

More than that, really; she now has no reliable way of telling the future from the past.  She "remembers" both of them, and if she has no external context by which to decide, she can't tell if what's in her mind occurred in the past or will occur in the future.  Eventually, she realizes that the division of the passage of time she'd always considered real and inviolable has changed.  Instead of past, present, and future, there are now only two divisions: present and not-present.  Here's how she comes to see things:

In the past two months, it felt like the universe had changed shape.  The linear slow march of time was clean gone, and what was left was a block that was unalterable, the people and events in it frozen in place like butterflies in amber.  Her own position in it had become as observer rather than participant.  She could see a wedge of the block, extending back into her distant past and forward into her all-too-short future.  Anything outside that wedge was invisible...  She found that it completely dissolved her anxiety about what might happen next.  Being not-present, the future couldn’t hurt her.  If pain lay ahead of her, it was as removed from her as her memories of a broken arm when she was twelve.  Neither one had any impact on the present as it slowly glided along, a moving flashlight beam following her footsteps through the wrecked cityscape.

 I found myself thinking about Mary and her peculiar forwards-and-backwards perception while I was reading physicist Sean Carroll's wonderful and mind-blowing book From Eternity to Here: A Quest for the Ultimate Theory of Time, which looks at the puzzling conundrum of what physicists call time's arrow -- why, when virtually all physical laws are time-reversible, there is a clear directionality to our perceptions of the universe.  A classic example is the motion of billiard balls on a table.  Each ball's individual motion is completely time-reversible (at least if you discount friction with the table); if you filmed a ball rolling and bouncing off a bumper, then ran the recording backwards, it would be impossible to tell which was the original video and which was the reversed one.  The laws of motion make no differentiation between time running forward and time running backward.

But.

If you played a video of the initial break of the balls at the beginning of the game, then ran the recording backwards -- showing the balls rolling around and after a moment, assembling themselves back into a perfect triangle -- it would be blatantly obvious which was the reversed video.  The difference, Carroll explains, is entropy, which is a measure of the number of possible ways a system can exist and be indistinguishable on the macro level.  What I mean by this is that the racked balls are in a low-entropy state; there aren't that many ways you can assemble fifteen balls into a perfect equilateral triangle.  On the other hand, after the break, with the balls scattered around the table seemingly at random -- there are nearly an infinite number of ways you can have the balls arranged that would be more or less indistinguishable, in the sense that any of them would be equally likely to occur following the break.  Given photographs of thousands of different positions, not even Commander Data could determine which one was the pic taken immediately after the balls stopped moving.

Sure, it's possible you could get all the balls rolling in such a way that they would come to rest reassembled into a perfect triangle.  It's just extremely unlikely.  The increase in entropy, it seems, is based on what will probably happen.  There are so many high-entropy states and so few low-entropy states that if you start with a low-entropy arrangement, the chances are it will evolve over time into a high-entropy one.  The result is that it is (very) strongly statistically favored that entropy increases over time.  

The Arrow of Time by artist benpva16 [Image licensed under the Creative Commons Creative Commons BY-NC-ND 3.0 license: creativecommons.org/licenses/b…]

The part of the book that I am still trying to parse is chapter nine, "Information and Life," where he ties the physical arrow of time (an example of which I described above) with the psychological arrow of time.  Why can't we all do what Mary Hansard can do -- see the past and future both -- if the only thing that keeps us knowing which way is forward and which way is backward is the probability of a state's evolution?  After all, there are plenty of cases where entropy can locally go down; a seed growing into a tree, for example.  (This only occurs because of a constant input of energy; contrary to what creationists would have you believe, the Second Law of Thermodynamics doesn't disprove evolution, because living things are open systems and require an energy source.  Turn off the Sun, and entropy would increase fast.)

So if entropy actually explains the psychological arrow of time, why can I remember events where entropy went down -- such as yesterday, when I took a lump of clay and fashioned it into a sculpture?

Carroll's explanation kind of made my mind blow up.  He says that our memories themselves aren't real reflections of the past; they're a state of objects in our environment and neural firings in our brain in the present that we then assemble into a picture of what we think the past was, based on our assumption that entropy was lower in the past than it is now.  He writes:

So let's imagine you have in your possession something you think of as a reliable record of the past: for example, a photograph taken of your tenth birthday party.  You might say to yourself, "I can be confident that I was wearing a red shirt at my tenth birthday party, because this photograph of that event shows me wearing a red shirt."...

[Is] the present macrostate including the photo... enough to conclude with confidence that we were really wearing a red shirt at our tenth birthday party?

Not even close.  We tend to think that [it is], without really worrying about the details too much as we get through our lives.  Roughly speaking, we figure that a photograph like that is a highly specific arrangement of its constituent molecules.  (Likewise for a memory in our brain of the same event.)  It's not as if those molecules are just going to randomly assemble themselves into the form of that particular photo -- that's astronomically unlikely.  If, however, there really was an event in the past corresponding to the image portrayed in the photo, and someone was there with a camera, then the existence of the photo becomes relatively likely.  It's therefore very reasonable to conclude that the birthday party really did happen in the way seen in the photo.

All of those statements are reasonable, but the problem is that they are not nearly enough to justify the final conclusion...  Yes, the photograph is a very specific and unlikely arrangement of molecules.  However, the story we are telling to "explain" it -- an elaborate reconstruction of the past, involving birthday parties and cameras and photographs surviving essentially undisturbed to the present day -- is even less likely than the photo all by itself...

Think of it this way: You would never think to appeal to some elaborate story in the future to explain the existence of a particular artifact in the present.  If we ask about the future of our birthday photo, we might have some plans to frame it or whatnot, but we'll have to admit to a great deal of uncertainty -- we could lose it, it could fall into a puddle and decay, or it could burn in a fire.  Those are all perfectly plausible extrapolations of the present state into the future, even with the specific anchor point provided by the photo here in the present.  So why are we so confident about what the photo implies concerning the past?

The answer, he says, is that we're relying on probability and the likelihood that the past had lower entropy -- in other words, that the photo didn't come from some random collision of molecules, just as our surmise about the billiard balls' past came from the fact that a perfect triangular arrangement is way less likely than a random one.  All we have, Carroll says, is our knowledge of the present; everything else is an inference.  In every present moment, our reconstruction of the past is a dream, pieced together using whatever we're experiencing at the time.

So maybe we're not as different from Mary Hansard, with her moving flashlight beam gliding along and spotlighting the present, as I'd thought.

Mind = blown.

I'm still not completely convinced I'm understanding all the subtleties in Carroll's arguments, but I get enough of it that I've been thinking about it ever since I put the book down.  But in any case, I'd better wrap this up, because...

... I'm running short on time.

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

The phantom touch illusion

It seems like every time researchers look further into our sensory-perceptive systems, we have another hole punched in our certainty that what we think we're perceiving is actually real.

We've looked at optical illusions -- and the fact that dogs fall for 'em, too.  We've considered two kinds of auditory illusions, the postdictive effect and the McGurk effect.  Sometimes we see patterns of motion in still objects -- and illusory "impossible" motion that our brains just can't figure out.  A rather simple protocol convinced test subjects their hands had turned to stone.  Stimulating a particular clump of neurons in the brain made patients see the doctor's face as melting.  We can even be tricked into feeling like we're controlling a second body, that just happens to be invisible.

As eminent astrophysicist Neil deGrasse Tyson put it, "The human brain is rife with ways of getting it wrong."  Honestly, at this point it's a wonder we trust anything we perceive -- and yet you still hear people say "I saw it with my own eyes" as if that somehow carried any weight at all.  Add to that all the problems with the reliability of memory, and you have to ask why eyewitness accounts are still considered the gold standard of evidence.

If you needed more proof of this, take a look at some research that came out last week from Ruhr-Universität Bochum into what happens when a person watches a virtual-reality avatar of their own body.  Participants were suited up in VR gear, and after a period of acclimation -- during which they got used to their avatar's arms and hands moving as their own did -- they were instructed to use a virtual representation of a stick to touch their avatar's hand.  Nearly all of the subjects reported feeling a sensation of touch, or at least a tingling, at the spot the virtual stick appeared to touch.

[Image licensed under the Creative Commons Samuel Zeller samuelzeller, VR (Unsplash VK284NKoAVU), CC0 1.0]

The researchers decided to check and see if the sensation occurred simply by drawing awareness to the hand, so they did the same thing only using a virtual laser pointer -- and no feeling of touch occurred.

Apparently all it took was convincing the subjects they were being touched to stimulate the sensation itself.

"The phantom touch illusion also occurs when the subjects touched parts of their bodies that were not visible in virtual reality," said study co-author Marita Metzler.  "This suggests that human perception and body sensation are not only based on vision, but on a complex combination of many sensory perceptions and the internal representation of our body."

The whole thing brings to mind a conversation I had with an acquaintance, a Ph.D. in philosophy, some years ago about the impossibility of proving materialism.  I'd always considered myself a hard-nosed materialist, but her stance was that no one could prove the external world was real.  I shot back with a snarky, "Well, that works until someone throws a rock at your head.  Hard to deny the rock isn't real after that."  She patiently responded, "No.  What is real are the sensations you experience -- the shock, the pain, the adrenaline rush.  Possibly a period of loss of consciousness.  You're still locked inside your own skull, and the only thing you have access to are your own thoughts and feelings.  Those are all you can be certain are real experiences -- and even those might well be false or misleading."

Well, it was a fair knockout (pun intended), and I still haven't really come up with a rejoinder.  Not that this is surprising; philosophers have been discussing the whole materialism vs. idealism thing for centuries, and haven't really settled it to anyone's satisfaction.  And since the time of that argument, I've found more and more evidence that we experience through our sensory-perceptive apparatus only the barest fraction of what's out there -- what neuroscientist David Eagleman calls our umwelt -- and even that part, we see inaccurately.

Kind of humbling, isn't it?  Think about that next time someone starts acting so all-fired certain about their own perceptions, memories, experiences, and opinions.  The more you know, they more you should realize that none of us should be sure of anything.

But after all, doubt isn't a bad place to start.  I'll end as I did yesterday, with a quote from the brilliant physicist Richard Feynman: "The first principle is that you must not fool yourself; and you are the easiest person to fool."

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

A light into shadow

I think my love of science comes from the joy of unlocking one at a time the pieces of the universe that were mysteries.  It's why I'm such a dilettante -- someone who, as an acquaintance once described me, has knowledge a light year across and an inch deep.  I find it all fascinating.  I was never able to focus on one thing long enough to really become an expert.  I'd start in one direction, but in short order I'd say, "Oh, look, something shiny!" and take off on some unrelated tangent.

I may not have much in the way of academic credentials, but it makes me a force to be reckoned with when playing Trivial Pursuit.

It's okay, really.  I enjoy the fact that my brain makes up for in breadth what it lacks in depth.  Which is why last week we had posts about astronomy, geology, glaciology, paleontology, and cosmology, and today we're on to archaeology.

Because of my love of mysteries, I've always been drawn to trying to understand civilizations whose relics are scanty or poorly-understood.  The Incas, Aztecs, and Mayas.  The ancestors of the First Nations of North America.  The Songhai Empire and the kingdoms of Benin, Congo, and Aksum in Africa.  The ancient history of Southeast Asia and Australia.  And while European history is generally considered to be well-studied and accessible, that's because most of the focus is on the Romans, Greeks, and Norse, who left extensive written records.  The Celts, Slavs, and the southern Germanic tribes, for whom we have far fewer extant records (and many of those were penned by conquering cultures which took few pains to represent them fairly or accurately), have an ancient history that is largely lost to the shadows of time.

Or... maybe not entirely lost.

Archaeologists are now using sophisticated technological tools to discern traces of long-gone settlements, recovering traces of civilizations that have been up till now complete ciphers.  The reason this comes up is a study by a team from University College Dublin, working with colleagues in Serbia and Slovenia, which used aerial photography to piece together the remnants of 3,500 year old settlements in the southern Carpathian Basin -- and found that the area was as thickly-settled as many of the far better known cultures who were at their height around the same time.

"Some of the largest sites, we call these mega-forts, have been known for a few years now, such as Gradište Iđoš, Csanádpalota, Sântana or the mind-blowing Corneşti Iarcuri enclosed by thirty-three kilometers of ditches and eclipsing in size the contemporary citadels and fortifications of the Hittites, Mycenaeans or Egyptians,” said UCD archaeologist Barry Molloy, who led the study.  "What is new, however, is finding that these massive sites did not stand alone, they were part of a dense network of closely related and codependent communities.  At their peak, the people living within this lower Pannonian network of sites must have numbered into the tens of thousands...  Uniquely for prehistoric Europe, we are able to do more than identify the location of a few sites using satellite imagery but have been able to define an entire settled landscape, complete with maps of the size and layout of sites, even down to the locations of people’s homes within them. This really gives an unprecedented view of how these Bronze Age people lived with each other and their many neighbors."

One of the circular hill-forts discovered through analysis of aerial photographs

Of course, this sets the imagination running.  Like the Australian fossilized bird footprints we looked at yesterday, these remnants only tell you so much, in this case tantalizing clues about how their cities were laid out, coupled with hypothesizing the purposes of buildings for which we only have traces of foundations.  But deeper information about the societies who lived there, their political and social structure, religious beliefs, and languages -- the relics we have are silent on all of that.  Who these people were, we can only speculate.

Still, it's a remarkable achievement.  "1200 BC was a striking turning point in Old World prehistory, with kingdoms, empires, cities, and whole societies collapsing within a few decades throughout a vast area of southwest Asia, north Africa, and southern Europe," Molloy said.  "It is fascinating to discover these new polities and to see how they were related to well-known influential societies yet sobering to see how they ultimately suffered a similar fate in wave of crises that struck this wider region."

And for me, looking at it from the outside, it's wonderful to cast some light into the shadows of a culture that heretofore was completely mysterious.  Knowing them, even if only a little, is thrilling.  I'll end with a quote from the inimitable Richard Feynman, from his book The Pleasure of Finding Things Out:

Fall in love with some activity, and do it!  Nobody ever figures out what life is all about, and it doesn’t matter.  Explore the world.  Nearly everything is really interesting if you go into it deeply enough.  Work as hard and as much as you want to on the things you like to do the best.  Don’t think about what you want to be, but what you want to do.

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