The smell of time passing

We once owned a very peculiar border collie named Doolin.  Although from what I've heard, saying "very peculiar" in the same breath as "border collie" is kind of redundant.  The breed has a reputation for being extremely intelligent, hyperactive, job-oriented, and more than a little neurotic, and Doolin fit the bill in all respects.

As far as the "intelligent" part, she's the dog who learned to open the slide bolts on our fence by watching us do it only two or three times.  I wouldn't have believed it unless I'd seen it with my own eyes.  She also took her job very seriously, and by "job" I mean "life."  She had a passion for catching frisbees, but I always got the impression that it wasn't because it was fun.  It was because the Russian judge had only given her a 9.4 on the previous catch and she was determined to improve her score.

There were ways in which her intelligence was almost eerie at times.  I was away from home one time and called Carol to say hi, and apparently Doolin looked at her with question marks in her eyes.  Carol said, "Doolin, it's Daddy!"  Doolin responded by becoming extremely excited and running around the house looking in all of the likely spots -- my office, the recliner, the workshop -- as well as some somewhat less likely places like under the bed.  When the search was unsuccessful, apparently she seemed extremely worried for the rest of the evening.

Not that this was all that different from her usual expression.

One thing that always puzzled us, though, was her ability to sense when we were about to get home.  Doolin routinely went to the door and stood there on guard before Carol's car pulled into the driveway.  She did the same thing, I heard, when I was about to arrive.  In each case, there was no obvious cue that she could have relied on; we live on a fairly well-traveled stretch of rural highway and even if she heard our cars in the distance, I can't imagine they sound that different from any of the other hundreds of cars that pass by daily.  And my arrival time, especially, varied considerably from day to day, because of after-school commitments.  How, then, did she figure out we were about to get home -- or was it just dart-thrower's bias again, and we were noticing the times she got it right and ignoring all the times she didn't?

According to Alexandra Horowitz, a professor of psychology at Barnard University, there's actually something to this observation.  There are hundreds of anecdotal accounts of the same kind of behavior, enough that (although there hasn't been much in the way of a systematic study) there's almost certainly a reason behind it other than chance.  Horowitz considered the well-documented ability of dogs to follow a scent trail the right direction by sensing where the signal was weakest -- presumably the oldest part of the trail -- and heading toward where it was stronger.  The difference in intensity is minuscule, especially given that to go the right direction the dog can't directly compare the scent right here to the scent a half a kilometer away, but has to compare the scent here to the scent a couple of meters away.

What Horowitz wondered is if dogs are using scent intensity as a kind of clock -- the diminishment of a person's scent signal after they leave the house gives the dog a way of knowing how much time has elapsed.  This makes more sense than any other explanation I've heard, which include (no lie) that dogs are psychic and are telepathically sensing your approach.  Biological clocks of all kinds are only now being investigated and understood, including how they are entrained -- how the internal state is aligned to external cues.  (The most obvious examples of entrainment are the alignment of our sleep cycle to light/dark fluctuations, and seasonal behaviors in other animals like hibernation and migration in response to cues like decreasing day length.)

So it's possible that dogs are entraining this bit of their behavior using their phenomenally sensitive noses.  It'll be interesting to see what Horowitz does with her hypothesis; it's certainly worth testing.  Now, I need to wrap this up because Guinness's biological clock just went off and told him it was time to play ball.  Of course, that happens about fifty times a day, so there may not be anything particularly surprising there.

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The magnetic fingerprint

Back in 1963, Frederick Vine and Drummond Matthews came up with a groundbreaking idea (pun very much intended); that the Earth's crust is divided into a bunch of chunks called plates that are all moving relative to each other, and that this is what causes virtually all earthquakes and volcanoes.

The main evidence for this dramatic paradigm shift in our understanding of how geology works came from the discovery on the ocean floor of regions of hardened lava that have opposite magnetic signatures.  When molten rock freezes, tiny magnetic particles that were free to move when they were in a liquid become locked into place, acting like billions of little compass needles recording the direction of the Earth's magnetic field at the time.  As you undoubtedly know, the positions of the magnetic poles flip, on average every three hundred thousand years (although the actual intervals vary greatly, for reasons that are still unknown).  So the rocks Vine and Matthews studied, on either side of the Mid-Atlantic Ridge, which showed symmetrically-arranged parallel stripes of magnetic signatures, showed that new oceanic crust was being formed all the time at the ridge, driving the plates apart and gradually widening the Atlantic Ocean.

Well, it turns out that lava isn't the only thing that can record what the magnetic field is doing.  According to a study last week in Proceedings of the National Academy of Sciences, so can pottery.

When clay is fired, its chemical structure changes, fusing into ceramic.  Different clays fire to different temperatures; in our kiln we fire our work to 1220 C (2232 F), which works for the clays classified as stonewares and mid-fire porcelains.  If we were to fire a high-fire porcelain to that temperature, it would still be brittle and not water-tight; fire an earthenware clay to that temperature, and it (literally) would melt.  (The difference is in the formulation of the clay, which is a complex subject about which I am still learning.)

But when you fire any clay to the correct temperature for that type, it effectively turns to stone.  The particles fuse together, giving it strength and resistance to breaking.  And this has the effect of locking into place any magnetic particles the clay may contain -- same as with Vine and Matthews's solidified lava on the ocean floor.

White stoneware vase with a cobalt splatter glaze

The reason this topic comes up is the discovery by a research team out of University College London of the fact that some earthenware bricks dating to the reign of Nebuchadnezzar II of Babylon (605-562 B.C.E.) show a magnetic particle pattern indicating a strange and sudden surge in the strength of the magnetic field -- something that has been nicknamed the Levantine Iron Age Geomagnetic Anomaly.

"It is really exciting that ancient artifacts from Mesopotamia help to explain and record key events in Earth history such as fluctuations in the magnetic field," said study co-author Mark Altaweel.  "It shows why preserving Mesopotamia’s ancient heritage is important for science and humanity more broadly."

Noting this odd magnetic fingerprint -- the cause of which is as yet unexplained -- has another added benefit; once they've identified it in items of known age (as with the bricks, that had an identifying stamp), it can be used to date ceramic items that have no such marks.

It makes me wonder what kind of record I'm creating in my own pottery.  When we have pieces with too many flaws to be worth keeping, we shatter them against the cement wall along the back of our house (there's now a pile of pottery shards at the base of the wall).  We think of it as our ongoing effort to confuse future archaeologists.  But supposing they do piece together some of our failed attempts at bowls and mugs and various sculptures, maybe they'll find out something more than our dubious skill at making pottery -- but what the Earth itself was doing in 2023.

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Lords of the air

Ever since I was a kid, my favorite group of dinosaurs has been the pterosaurs.

These are one of the six groups of animals that independently evolved flight, or at least significant capacity for gliding (the others are insects, birds, bats, flying squirrels, sugar gliders, and colugos).  They had incredible diversity at their height, during the Jurassic and Cretaceous Periods, from the pint-sized Sordes pilosus (with a sixty-centimeter wingspan) to the almost unimaginably huge Quetzalcoatlus northropi (with a ten-meter wingspan, as big as a light plane).

Most of them were probably clumsy on the ground -- it's hard to imagine how Quetzalcoatlus got off the ground -- but in the air, they were nimble, maneuverable, and fast.  The smaller ones were probably insect-eaters; the larger ones likely fed on fish, although a terrestrial diet of small reptiles and mammals is also possible. 

What brings all this up is the discovery of a new species of pterosaur, one of dozens that have been identified from the Jehol Biota, a stupendous fossil deposit in northeastern China near Huludao.  This fossil bed has produced not only pterosaurs but incredibly well-preserved species of prehistoric birds and other vertebrates -- it's like a tapestry of late Cretaceous animal life.

"Pterosaurs comprise an important and enigmatic group of Mesozoic flying reptiles that first evolved active flight among vertebrates, and have filled all aerial environmental niches for almost 160 million years," said Xiaolin Wang, of the Institute of Vertebrate Paleontology and Paleoanthropology at the Chinese Academy of Sciences, who co-authored the paper describing the discovery.  "Despite being a totally extinct group, they have achieved a wide diversity of forms in a window of time spanning from the Late Triassic to the end of the Cretaceous period.  Notwithstanding being found on every continent, China stands out by furnishing several new specimens that revealed not only different species, but also entire new clades."

This includes the newly-discovered Meilifeilong youhao, belonging to the family Chaoyangopteridae, which is represented at the site by two other species that have been found nowhere else.

Meilifeilong looked like something out of a nightmare, if the artist's reconstruction is accurate (and probably even if it isn't):

[Image courtesy of artist Maurilio Oliveira]

The name means "beautiful flying dragon," which I doubt is what I'd say if I saw one, but what I'd say is borderline unprintable so we'll leave it at that.

It's astonishing to think of how long these creatures ruled the skies -- from the late Triassic until the very end of the Cretaceous, a time span of around 160 million years.  Had change not come in the form of the Chicxulub Meteorite collision, they might well still be here, soaring on thermals above our forests and lakes and oceans, the undisputed lords of the air.  And even if we now know them only from fossils, they still can't help but impress.

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The train to CrazyTown

It always astonishes me how much it takes for people to say to some nonsense-spouting pseudo-pundit, "You are nuttier than squirrel shit, and I am no longer listening to anything you say."

Or, more accurately, I don't know how much it takes, because it almost never happens.  Once people have decided they like someone's views, it seems like it's damn near impossible to get them to change their minds.  Said pundit could go on national television and say, "Scientists have found that the mantle of the Earth is not made of molten magma, it's made of my Grandma Betty's Special Tasty Banana Pudding," and I swear, 95% of the followers would just nod along as if this was a revelation from the Lord Almighty Himself.

It may come as a significant surprise that for once, I'm not talking about Donald Trump.  No, this time the person who has given strong evidence that he's been doing sit-ups underneath parked cars is Tucker Carlson, disgraced ex-Fox News commentator, who despite being too obnoxiously racist even for Fox, is still somehow finding venues for his insane vitriol.  (One of them, unsurprisingly, is The Social Media Platform Formerly Known As Twitter, because Elon Musk appears to be as much of a bigot as Carlson, if arguably a bit saner.)

The latest missive from Tucker Carlson, though, amazingly has nothing to do with how brown-skinned immigrants are coming for all of us white people.  It concerns UFOs (or UAPs, as I guess we're now all supposed to call them), and springboards off the kerfuffle the last few months about government cover-ups of what David Grusch elliptically referred to as "non-human biological entities."  (Fer cryin' in the sink, if you mean the A-word, say the A-word.  And yes, I'm being deliberately ironic by not saying the A-word myself.)

[Image is in the Public Domain]

Carlson, though, has no such sense of delicacy, but he thinks they're not extraterrestrial species -- at least in the conventional sense.  Here's what he said, as part of a two-hour interview which I made it through about fifteen minutes of, before my forehead hurt so much from faceplanting that I decided discretion is the better part of valor and gave up:

It’s my personal belief based on a fair amount of evidence that they’re not aliens.  They’ve always been here, and I do think it’s spiritual,  There are forces that aren’t human that do exist in a spiritual realm of some kind, that we cannot see, and that when you think about it, will sorta make you think we live in an ant farm...  I do know that informed people have said that the U.S. government has an agreement with these entities.

The whole thing smacks of the "prison planet" hypothesis, whose most vocal supporter is Ellis Silver, about whom I wrote here at Skeptophilia a while back.  The idea is that humans evolved elsewhere in the universe, and our ancestors were transported to Earth because we're so violent, and we're stuck here until we learn our lesson.  (Given recent world events, we don't seem to be catching on very quickly.)

In any case, Carlson takes it a step further, hybridizing Silver's ideas with the Book of Enoch and various episodes of The X Files to create a new brand of batshittery all his own.  In short, he seems to have taken on a job as conductor of the Express Train to CrazyTown, and a significant slice of Americans are just thrilled to hop on board.

So I encourage you to watch the interview (linked above), if you've got the stomach for it.  Myself, I have a hard time watching Tucker Carlson even with the sound turned off, because in my opinion he's only beaten out narrowly by Ted Cruz in the contest for the World's Most Punchable Face.  But given that Carlson has been floated seriously as a contender for the vice presidential choice for whomever the Republican nominee is for president in 2024, and a possible candidate for president in his own right in 2028, it behooves us all to be aware that he appears to be a few fries short of a Happy Meal.  To quote skeptic Jason Colavito, "That a leading contender for high office and one of the most influential figures on the right believes in some variation of Nephilim Theory is depressing.  That a powerful network of advocates has infiltrated both political parties to spread ancient mythology as though it were scientific revelation, and government and media cheer them on, is terrifying."

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The forbidden light

In the early nineteenth century, two scientists -- Joseph von Fraunhofer and Charles Wheatstone -- independently observed something strange; if you heated up samples of various elements, they emitted a light spectrum that contained strong peaks at certain frequencies, showing up as bright lines instead of a continuous rainbow of colors.

It quickly became obvious that this property could be used to identify the presence of different elements in mixed samples.  In fact, helium was discovered when French astronomer Georges Rayet found emission lines in the solar spectrum that didn't correspond to any other known element, making it the only element in the periodic table first detected somewhere other than on Earth.  (The name helium comes from the Greek Ἥλιος, meaning the Sun.)

Figuring out why this phenomenon occurred, though, took almost a hundred years.  The explanation, due in large part to the work of Danish physicist Niels Bohr, has to do with the fact that the electron shells in atoms are quantized -- there are only certain allowed energy levels, so an atom has to absorb a particular frequency of light in order for one of its electrons to jump to the next level (or, conversely, to drop to a lower level, the atom has to emit a photon of a particular frequency).  This simultaneously explained the specificity of emission spectra and the odd phenomenon of absorption spectra, where broad-spectrum light passing through transparent substances shows dark lines where certain frequencies are absorbed, effectively subtracting them from the beam.

So each element has its own distinctive "fingerprint" of spectral lines, which is how researchers here on Earth can determine the chemical composition of distant stars, and even the constituents of the atmospheres of exoplanets.

The emission spectrum of iron [Image is in the Public Domain]

However -- as usual -- even this rather complex model has some unexpected twists.

Very rarely, the electrons in atoms will undergo forbidden transitions, resulting in light being emitted that should not be possible from the element in question.  (A simple analogy is if you were climbing a staircase, and somehow were able to go up by one-and-three-quarters steps.)  These transitions are highly unstable (just as your attempted ascent would be), and the electron almost instantaneously collapses back into one of the allowed energy states, but when it does so the atom emits a frequency of light you wouldn't expect.  So these aren't so much forbidden as they are extremely improbable; in ordinary situations, their contribution to the light spectrum is vanishingly small.

But in very high energy conditions, where the electrons are bouncing all over the place millions of times per second, you begin to see a significant contribution from forbidden transitions.

The reason this comes up is because of a study of a Seyfert galaxy named MCG 01-24-014.  Seyfert galaxies, named after American astronomer Carl Keenan Seyfert who studied them extensively, look superficially like ordinary spiral galaxies, but have an active galactic nucleus.  This latter name is a massive understatement, mostly because astronomers shy away from calling something "Holy Shit This Thing Is Super Bright, No Really You Have No Idea How Bright It Is."  The center bit of a Seyfert galaxy has a luminosity equal to the luminosity of all the stars of the Milky Way put together, and is thought to be the result of large quantities of material falling rapidly into a supermassive black hole.  Most of the light emitted is outside of the visible spectrum -- thus their ordinary appearance through a telescope -- but when viewed in other frequency ranges, it becomes obvious how weird they are.  

The Circinus Galaxy, one of the best-studied Seyfert galaxies [Image is in the Public Domain courtesy of NASA/JPL]

And MCG 01-24-014 is really peculiar -- emitting far more light from forbidden transitions than even an average Seyfert galaxy would.  So whatever is powering its galactic core is running full-throttle.

The forbidden light of Seyfert galaxies provides us with yet another example of "you think you understand, then nature throws you a curve ball."

Sometimes you hear the criticism levied at scientists that all the technical details somehow take away from the wonder of simply looking up and delighting at the beauty of the night sky.  I can't speak for anyone else, but for me, the exact opposite is true.  I can still go outside on a clear winter's night and look up at my favorite naked-eye astronomical object -- the Pleiades -- and fully appreciate how lovely it is, but my enjoyment is increased further by knowing that it's a cluster of recently-formed hot blue supergiant stars inside the wispy strands of a reflection nebula.  

Understanding and appreciation shouldn't be inversely proportional.  The more I know, the more I wonder at the beauty, complexity, and strangeness of this universe in which we live.  The only frustrating part about it all is the limitation of my mind in comprehending it all.

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A piece of the puzzle

Given how thoroughly explored the world seems to be, it's easy to assume that we've found pretty much everything there is to be found.  Yeah, we continue to stumble across small, obscure, well-hidden stuff -- frog species living in the deep parts of the rain forest, fossils buried under meters of sedimentary rock, a cache of flint tools out in the middle of the steppe.  That sort of thing.

The fact that sometimes we find something big and flashy sitting, as it were, right under our noses should give everyone hope that we are far from understanding everything there is to understand, and that we're not yet down to the level of simply cleaning up the minuscule details.

The latest example of this continues along the archaeological path we've been following for the past week or so, and looks at the discovery of a huge intact mosaic, made over two millennia ago, in Rome.  Not just in Rome, but on Palatine Hill, surely one of the best-studied, most thoroughly excavated historical sites in the world.

The mosaic, which has been described as "a jewel" by archaeologists, is estimated to be about 2,300 years old.  It was constructed of a variety of materials, including chips of marble and travertine, shells, pearls, coral, and pieces of a rare and expensive blue-green glass paste thought to have been imported from Alexandria, Egypt.  (The latter, Egyptian blue faience, is a semi-vitrified, or sintered, opaque quartz material colored with calcium copper silicate -- the exact recipe for which was a closely-guarded secret known only to a handful of master artisans.)

So whoever commissioned the mosaic -- at this point, unknown -- had money to burn.  The design appears to commemorate land and naval victories that were probably funded (if not actively led) by the project's patron.  There are also intricate decorative motifs, and fanciful representations of mythical creatures, including sea monsters swallowing enemy ships.  The wall holding the mosaic is thought to have been part of a large, ornate banquet hall.

A detail of the Palatine Hill mosaic [Image courtesy of photographer Emanuele Antonio Minerva]

“This banquet hall, which measures 25 square meters (270 square feet), is just one space within a domus (the Latin word for house) spread on several floors," said lead researcher Alfonsina Russo, head of Rome's Colosseum Archaeological Park.  "In ancient times, when powerful noble families inhabited the Palatine Hill, it was customary to use rich decorative elements as a symbol to show-off opulence and high social rank...  We have also found lead pipes embedded within the decorated walls, built to carry water inside basins or to make fountains spout to create water games."

Further excavation into the site might not only turn up more artifacts, but could reveal who had the structure built -- likely a Roman senator.  "The person was so rich they could afford to import such precious elements from across the empire to decorate this mansion," Russo said.  "We have found nothing so far to shed light on their identity, but we believe more research might enable us to pinpoint the noble family."

It will be fascinating to see what else the researchers find out about this site, occupied by a fabulously wealthy Roman at the height of the Roman Republic.  (When this was built -- if estimates of its age are correct -- the Empire was still in the future; the first Roman Emperor, Octavian/Augustus, was born in 63 B.C.E., at which point this mosaic would already have been over two hundred years old.)

So this should provide some incentive for people to keep looking.  We are far from finding everything there is to find, even here on the Earth's surface, much less out in space.  And whatever new bits we come across -- like this mosaic, hidden beneath one of the most famous archaeological sites in the world -- will add one more piece to the puzzle of the complex and beautiful universe in which we live.

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Walkabout

A couple of days ago, a long-time reader of (and frequent contributor of topics for) Skeptophilia sent me an email saying "Time to get your Archaeo-Geek excited!", with a link to a study about archaeological finds in Australia.  I was really confused at first because I read "Geek" as "Greek" and was puzzled about how there could be an ancient Greek settlement in Australia. 

I need new glasses.

Anyhow, once I got that sorted, I found that the actual research was pretty amazing.  A team of archaeologists led by Kasih Norman of Griffith University has discovered artifacts dating back to the Late Pleistocene Epoch -- on the order of twenty thousand years ago -- indicating a large human population living in a thriving ecosystem, with rolling hills and a large freshwater lake, all of which are now at the bottom of the Gulf of Carpentaria.

The authors write:

The submerged Northwest Shelf of Sahul (the combined landmass of Australia and New Guinea at times of lower sea level) was a vast area of land in the Late Pleistocene that connected the Australian regions of the Kimberley and western Arnhem Land during times of lower sea level than today.  The shelf extends >500 km northwest from the modern-day shoreline with a now-submerged landmass of ∼400,000 km2, an area more than 1.6 times larger than the United Kingdom.  The region might have been an area of initial entry for the peopling of Sahul.  Irrespective of the precise locations people used to disperse into Sahul, the Northwest Shelf is adjacent to the oldest known archaeological sites in Australia , and might have been one of the first inhabited landscapes on the continent.  Archaeological evidence for Late Pleistocene use of the continental shelves of Sahul by the First Australians is demonstrated on multiple large islands that are remnant portions of the continental margin, including Barrow Island, Kangaroo Island, Hunter Island, and Minjiwarra (Stradbroke Island).

The distribution of artifacts, which include stone axes, flint tools, and arrowheads, indicate at east two major pulses of settlement, which is cool because it lines up with what we know about the linguistics of the region.  The majority of the indigenous languages of northern and central Australia -- 306 of the 400 recorded native languages -- belong to the Pama-Nyungan family, which is (as a group) a linguistic isolate, related to no other known language group.  The rest are scattered clusters of unrelated languages, indicative of arrivals at different times or from different places, apparently when the Gulf of Carpentaria was mostly dry land and you could walk from New Guinea to Australia without getting your feet wet.

Eventually, of course, as we were coming out of the last ice age, the sea level rose and gradually that block of lowlands filled in from both sides, isolating Australia from the islands to the north and halting the walkabout that allowed for easy settlement.  But at its height, the archaeologists believe the now-submerged region could have been home to between fifty and five hundred thousand people.

"[Sea level rise] likely caused a retreat of human populations, registering as peaks in occupational intensity at archaeological sites," the authors write.  "Those who funneled into an archipelago on the shelf would go on to become the first maritime explorers from Wallacea [what is now the islands of eastern Indonesia], creating a familiar environment for their maritime economies to adapt to the vast terrestrial continent of Sahul."

Further research into the archaeology, topography, and paleoecology of the region is sure to turn up more information about a landscape that has altered dramatically in the last fifteen-thousand-odd years.  It also spurs researchers to look at other regions flooded by sea level rise -- like Doggerland, now beneath the turbulent waters of the North Sea -- perhaps to recover more clues about where and how our distant ancestors lived.

"Now submerged continental margins clearly played an important role in early human expansions across the world," the researchers write.  "The rise in undersea archaeology in Australia will contribute to a growing worldwide picture of early human migration and the impact of climate change on Late Pleistocene human populations."

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