The rhythmic brain

Regular readers of Skeptophilia know that I've been a musician for a very long time.  I started on the flute when I was a teenager, more or less self-taught.  In my twenties, for several years while I lived in Seattle, I was fortunate enough to study the classical flute repertoire with a brilliant flutist and teacher named Margaret Vitus, who did wonders for my technique.  Shortly after that I became fascinated with Celtic music (due in no small measure to the wonderful radio program The Thistle & Shamrock, which thirty-some-odd years later is still going strong), and was for years part of a Celtic music quartet called Taradiddle that performed at the Seattle Folklife Festival four years running.

Along the way, though, I fell in love with Balkan music.  I'm not sure why it was such a draw for me -- I don't have a drop of eastern European blood and certainly hadn't heard it growing up.  But something about Bulgarian, Serbian, and Macedonian music was absolutely magnetic, and still is.

[Image is licensed under the Creative Commons Walter from Tampa/St Petersburg, Florida, Serb Fest DSC 1084 pp (31031644011), CC BY 2.0]

A lot of it was the asymmetrical rhythms.  People who are unfamiliar with this style of music often can't figure out how to count it or tap their feet to it, because it has rhythms you almost never hear in western music.  For example, what time signature would you say this tune is in?  (Listen to it before reading further, and see if you can figure it out.)

Ready for the answer?

It, like all kopanicas (pronounced ko-pa-neetsa; the kopanica is a Balkan dance, so they all have the same time signature) is in 11/16.  But you don't have to count up to 11 and then start over from 1; Balkan music is in combinations of 2s and 3s.  The 2s are the short, quick dance steps, and the 3s the longer steps; and a kopanica has the form of quick-quick-slow-quick-quick.  An easy way to count it out is to use a two-syllable word (I use apple) and a three-syllable word (I use cinnamon) to represent the 2s and 3s respectively.

So a kopanica is apple-apple-cinnamon-apple-apple.  Pretty tasty.  You might want to go back and listen again, and see if you can count it out.

11/16 isn't the craziest it gets, though.  The Macedonian tune and dance "Dvajspetorka" is in 25/16.  (Broken up 3-2-2, 3-2-2, 2-2-3-2-2.)

Okay, it's not as hard as it sounds.  Really it isn't.

This weird rhythmic stuff comes up because of a study that came out last week in the journal Neuropsychologia that looked at fMRI studies of three groups of people -- musicians trained in the western European classical tradition, musicians trained in the Japanese classical tradition, and non-musicians.  In particular they were looking for responses in a part of the left hemisphere that is associated with processing auditory rhythm.

Unsurprisingly, both groups of trained musicians showed greater responsiveness in that part of the brain than non-musicians.  What was more interesting, though, was that the western and Japanese musicians didn't respond the same way, especially to asymmetrical beat patterns.  Most western classical music has until recently confined itself to symmetrical 2-, 3-, or 4-beat patterns; this is why the exceptions stand out, like the movement "Mars" from Gustav Holst's The Planets, which is in 5/4; and brilliant lunacy like Igor Stravinsky's The Rite of Spring.  (The joke amongst musicians is that when Stravinsky was asked what time signature The Rite of Spring was in, he responded, "Yes.")

Classical Japanese music, however, such as the music used in Noh and Kabuki, often use beat-lengthening, called ma (間), which sounds pretty peculiar to a lot of western ears, as if the stretched beats were random.  They're not, of course, any more than the 25/16 rhythm of "Dvajspetorka" is; it's just not rhythmically like what most of us are used to.  And the musicians trained in classical Japanese music responded to that as a natural, comprehensible rhythm, whereas the musicians trained in western classical music did not.

"We expected that musicians would exhibit strong statistical learning of unfamiliar rhythm sequences compared to non-musicians," said study lead author Tatsuya Daikoku, of the University of Tokyo, in a press release.  "This has been observed in previous studies which looked at responses to unfamiliar melodies. So this in itself was not such a surprise.  What is really interesting, however, is that we were able to pick out differences in the neural responses between those trained in Japanese or Western classical music."

So our brains really do respond differently to music that we grok.  I'd love to see if the same holds true for Balkan musicians as compared to musicians from other cultures; I know that there are talented musician friends of mine who listen to Balkan music with a puzzled frown, and never can quite catch hold of what the rhythm is doing, even once it's explained.  But it does show that learning can modulate what's happening all the way down to the neural level.

All of which wants me to get my flute out and play some wacky Bulgarian tunes.  Like a neat one called "Nenadova Igra," which is in 9/8.  But it's not three 3s; no, that'd be too simple.  It's 2-2-2-3.  Apple-apple-apple-cinnamon.

Because of course it is.

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This week's Skeptophilia book recommendation of the week is about as cutting-edge as you can get, and is as scary as it is fascinating.  A Crack in Creation: Gene Editing and the Unthinkable Power to Control Evolution, by Jennifer Doudna and Samuel Sternberg, is a crash course in the new genetic technology called CRISPR-Cas9 -- the gene-editing protocol that Doudna herself discovered.  This technique allows increasingly precise cut-and-paste of DNA, offering promise in not just treating, but curing, deadly genetic diseases like cystic fibrosis and Huntington's disease.

But as with most new discoveries, it is not without its ethical impact.  The cautious are already warning us about "playing God," manipulating our genes not to eliminate disease, but to enhance intelligence or strength, to change personal appearance -- or personality.

A Crack in Creation is an unflinching look at the new science of gene editing, and tries to tease out the how much of what we're hearing is unwarranted fear-talk, and how much represents a genuine ethical minefield.  Doudna and Sternberg give the reader a clear understanding of what CRISPR-Cas9 is likely to be able to do, and what it won't, and maps out a direction for the discussion to take based on actual science -- neither panic and alarmism, nor a Panglossian optimism that everything will sort itself out.  It's a wonderful introduction to a topic that is sure to be much in the news over the next few years.

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

"Nurse Black"

We had a hellacious thunderstorm last night, and while listening to the rumbling, the rain falling, and the wind howling, I was reminded of a passage from my most recently-completed novel, The Communion of Shadows (scheduled for publication in 2022).  It's about four friends who gather on a thundery night and start telling ghost stories, since a night during a storm seems somehow appropriate for that time-honored activity.

One of the characters, though, is of the prosaic sort, and says, "Why would ghosts want to walk in weather like this?  I don't want to be out in a thunderstorm while I'm alive, why would that change after I'm dead?"

Which seems like good logic, doesn't it?  We attribute all sorts of tendencies to ghosts, without having much in the way of actual evidence.  They stick around if they have unfinished business or want revenge on someone, are more likely to appear if they died tragically, and for some reason are usually seen wearing the clothes they died in.  (So I suppose it's pretty likely I'll spend eternity in a disreputable pair of cargo shorts and no shirt.)

Despite my general reluctance to believe in ghosts -- the evidence still seems to me regrettably slim -- I love a good scary story, and have been an aficionado of books with names like Twenty True Tales of Terror since childhood.  One of the scariest ones I've ever run into can be found in its entirety in John Canning's wonderful collection 50 Great Ghost Stories, which (according to the message written into the front cover that says "October 29, 1977... Mon Cher Ami... mieux vaut tard que jamais!... Amelia") I received from a family friend as a gift three days after my 17th birthday.

I read the whole thing voraciously, as I was wont to do with such books.  But none of the stories has stuck with me like the nineteenth-century English tale of Nurse Black.

The story comes from the (real) English theater figures of Charles Kean and his wife, Ellen, but the central characters are Ellen's sister, Ann, and her publisher husband, John Kemble Chapman.  John and Ann and their eleven children lived in London in the 1850s, but London of the time was a polluted, disgusting-smelling, crime-ridden place, so they decided to find a country home that was a healthier place to raise children.

They settled on a home in Cheshunt, Hertfordshire.  It was spacious and picturesque, and at the time already about two hundred years old.  But it seemed ideal, and in due time the home was purchased, and the family moved in.

And for a while, nothing untoward happened.

It was only when the Chapmans were expecting guests that the first events occurred that were eventually to impel them to sell their house.  For wealthy individuals, John and Ann were unusual in their time in that they employed few servants.  Ann was a practical, strong-minded individual, and preferred to see to the household chores herself.  So one day, she was making up the bed in the "Oak Bedroom," a room that had been left unoccupied for guests, when she realized that she was not alone.

Standing near the window was a young woman in antiquated dress, wearing a white shawl over a silk petticoat.  The woman was looking out of the window with an eager expression, as if she were expecting someone, and did not seem to be paying any attention to Ann.  But Ann herself was seized with a sudden panic; she knew, she said afterwards, that it was not some stranger who had wandered into the house unnoticed.  "I felt," she told her brother-in-law Charles Kean, "as if I was seeing something I ought not to have seen."  So she put her hands over her eyes for a moment.

When she removed them, the figure was gone.

Ann chalked the apparition up to fatigue and nerves, and was able to convince herself for a time that she'd been a victim of her own imagination.

Then a few days later, a young woman who had been hired to look after the youngest of the Chapman children came running upstairs in hysterics, saying that she had been taking the trash out through a back room, and had seen a face staring at her through a window.  The face, she said, was of an old woman, "hideously ugly" and with "an expression of awful malignance," wearing a nightcap.

With some difficulty, Ann was able to calm down the nursery maid, convincing her that it had been a trick of the light -- until three days later, when Maria Chapman, one of Ann's older daughters, told her that she had been scared during the night when she had awakened to find a "very ugly lady wearing a cap" who was peering around the edge of her bedroom door at her.

During this entire time, John Chapman had been away on business in London, and it's to be imagined that Ann was looking forward to his return.  But before he got back, she did something that I have to say I find impressive -- with the help of their few servants, she went over the entire house from stem to stern.  Every closet, cabinet, cupboard, and corner was investigated, to see if there was any evidence of someone hiding in the house without the owners' knowledge.  They found nothing -- but as Ann was going down the staircase away from the Oak Bedroom, she heard footsteps following her.

She turned around.  The staircase was empty.

John came home a few days later, and by this time Ann was so thoroughly unnerved that she told her husband everything.  Knowing her to be steady, reliable, and intelligent, John believed what she said, and instituted a second (fruitless) search of the house.  And he was to get his own evidence shortly thereafter, as events accelerated.  Footsteps began to follow him everywhere he went -- "soft, steady, infinitely menacing."  He took to carrying a loaded pistol with him.  Then most of their servants quit when during their meal, a door opened and closed -- to admit no one.

One of the only remaining servants, a Mrs. Tewin, promised to sleep in the same room with Ann Chapman the next time John had to be away.  And this was to precipitate one final incident, that induced the Chapmans to leave.

In the middle of the night, Ann Chapman awoke to hear Mrs. Tewin moaning, "Wake me.  Wake me."  Ann ran to her bedside, and shook the servant awake.  Upon coming to full consciousness, Mrs. Tewin said she'd been dreaming, and had been aware it was a dream -- but had been unable to wake up.

In the dream, Mrs. Tewin said, she was in the Oak Bedroom.  Standing near the window was a young woman in an old-fashioned white robe, with long, disheveled dark hair.  Across the room, near the fireplace, was an ugly old woman "with an evil expression," wearing a gray nightcap over scanty, wispy hair, seated in a rocking chair.

"What have you done with the child, Emily?" the old woman asked, in a sneering, mocking voice.  "What have you done with the child?"

"Oh, I did not kill it," the girl replied.  "He was preserved, and grew up and joined a regiment and went to India."

At this point, the young woman noticed Mrs. Tewin, seemingly for the first time, and said to her, "I have never spoken to a mortal before.  But I will tell you everything.  My name is Miss Black.  This old woman is Nurse Black.  Black is not her family name, but we call her that because she has been so long in the family..."

But here, the old woman stood, and went to Mrs. Tewin and put her hand on the servant's shoulder.  The pain was excruciating, but she could not wake up.  This is when she began crying out, and called for Ann Chapman to wake her.

The next morning, Ann went into the village of Cheshunt to make inquiries, and was able to find out from an old inhabitant that many years earlier, the home had been inhabited by a Mrs. Ravenhall, who had had a niece named Emily Black.  But nothing else was recalled about them.

The Chapmans were becoming increasingly desperate to find out what was going on, and Ann (who was either incredibly courageous or else completely crazy) decided to spend a night in the Oak Bedroom, which seemed to be the epicenter of the haunting.  And late at night, she woke to see once again the figure of the young woman, this time wringing her hands and looking down at a particular spot on the floor.  The next day, she even went to the length of calling in a carpenter to pry up the floorboards at that particular spot.

Underneath was a hollowed-out space -- but it was empty.

At this point, the Chapmans had had enough, and put the house up for sale.  What happened afterwards -- who bought it, and if they had similarly uncanny experiences -- was not recorded in the story.

I think what appeals to me about this story is the open-endedness of it.  All of us have heard scary stories of the urban legend variety; the driver who picked up a beautiful hitchhiker late at night, loaned her his jacket, and afterwards finds out that she matches the description of a dead girl from the nearby village, and he finds his missing jacket folded up on her grave.  Those have always struck me as too neat, too pat, to be believable (even when I was in my much more gullible youth).  But the Nurse Black story has no easy tie-up, and is full of loose ends -- the Chapmans never did figure out who the ghosts were, what their story was, why they haunted the place.  Even the hollow space under the floorboards, which could have provided an easy way to give a punch line, was empty.

Now, it's not that I actually believe it, mind you.  Charles Kean, who enjoyed many a glass of brandy while scaring the absolute shit out of his friends with the tale, was a thespian, and presumably knew how to spin a good yarn, so I strongly suspect that he was embellishing a much more prosaic story, or else made it up entirely.  But the twisty, unresolved messiness of the tale has the ring of truth, I have to admit, and for me that makes it a hundred times scarier.

Man, it should be true.

So there you have it.  One of my favorite ghost stories.  And whether you're a doubter or a true believer or don't much care either way, it's important to approach whatever claims you're considering with a skeptical mind.  Keep reading, keep thinking, keep investigating, keep confronting your own biases, keep asking good questions.  So if on the next thundery evening you hear footsteps behind you on the stairs, just say, "Emily Black, is that you?"

Maybe you'll get an answer.

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This week's Skeptophilia book recommendation of the week is about as cutting-edge as you can get, and is as scary as it is fascinating.  A Crack in Creation: Gene Editing and the Unthinkable Power to Control Evolution, by Jennifer Doudna and Samuel Sternberg, is a crash course in the new genetic technology called CRISPR-Cas9 -- the gene-editing protocol that Doudna herself discovered.  This technique allows increasingly precise cut-and-paste of DNA, offering promise in not just treating, but curing, deadly genetic diseases like cystic fibrosis and Huntington's disease.

But as with most new discoveries, it is not without its ethical impact.  The cautious are already warning us about "playing God," manipulating our genes not to eliminate disease, but to enhance intelligence or strength, to change personal appearance -- or personality.

A Crack in Creation is an unflinching look at the new science of gene editing, and tries to tease out the how much of what we're hearing is unwarranted fear-talk, and how much represents a genuine ethical minefield.  Doudna and Sternberg give the reader a clear understanding of what CRISPR-Cas9 is likely to be able to do, and what it won't, and maps out a direction for the discussion to take based on actual science -- neither panic and alarmism, nor a Panglossian optimism that everything will sort itself out.  It's a wonderful introduction to a topic that is sure to be much in the news over the next few years.

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

Black as the night

You wouldn't think that fish living three miles deep in the ocean, far beneath the level that sunlight can penetrate, would worry much about being seen.

Well, I'm not sure they're worried, exactly.  But they still have the problem that if they do somehow get seen, they're likely to get eaten.

This lies at the heart of the reason that bioluminescence exists in the deep ocean.  You probably know that bioluminescence is the ability of some organisms to use chemical reactions in their bodies to emit light.  (Fireflies are a common example.)  In the deep ocean, it was thought the main reason animals might do this is to create a lure; the illuminated "fishing pole" of the grotesque angler fish brings in curious smaller fish, which then get turned into lunch.

[Image licensed under the Creative Commons Masaki Miya et al., Bufoceratias, CC BY 2.0]

There are other functions for light-emitting structures besides lures.  Squid that live in shallow water have ink they squirt into the water then they're attacked, creating a dark cloud to confuse the predator, thus allowing the squid to escape.  But if you live at a depth where its perpetually dark, black ink is fairly useless; so there are deep-sea squid that emit luminescent ink, creating a burst of light to startle the predator and give the would-be dinner a chance to live for another day.

Last week in Current Biology, though, there was a paper wherein I learned about another reason for bioluminescence in the deep ocean.  In "Ultra-black Camouflage in Deep-Sea Fishes," by Alexander L. Davis, Sönke Johnsen, and Karen J. Osborn (Duke University), Kate N. Thomas (The London Museum of Natural History), Freya E. Goetz (Smithsonian National Museum of Natural History), and Bruce H. Robison (Monterey Bay Aquarium Research Institute), we read about fish like the evocatively-named fangtooth, Pacific blackdragon, and black swallower, whose skin is amongst the blackest naturally-occurring substances, reflecting less than 0.5% of the light the falls on it.

But as with the squid ink, why bother to evolve such dark skin if there's no light there to reflect?  The answer turns out to be that there is light there to reflect; the bioluminescence emitted by other predatory fish.  If you're in the complete darkness, even the reflection of a tiny amount of light from your body might give away your position.  So this is a third reason for deep-sea bioluminescence; not as a lure, nor a distraction, but as a searchlight.

These fish, however, are so dark that even in bright sunlight they look like black silhouettes, as study co-author Karen Osborn found out when she tried to photograph them.  This confers a significant advantage over other fish, even if there's only a marginal difference in the skin blackness.  The authors write:

At low light levels, as is the case with a fish reflecting <2% of an already dim source (i.e., a bioluminescent flash, lure, glow, or searchlight), against the black deep-sea background, the model predicts that the sighting distance is proportional to the square root of the number of photons being reflected back to the viewer.  Using this relationship, we find that reducing skin reflectance from 2% to 1% reduces sighting distance by 29% and that decreasing further to 0.5% or 0.05% reflectance reduces sighting distance by 50% and 84%, respectively.  Because visual predators typically search a volume of space, and this reduction in sighting distance is linear, the camouflage benefits of ultra-black skin may be even greater than the reduction in sighting distance calculated here.  Given the small size of the fishes studied here, it is likely that predator-prey interactions occur over short distances, where even small differences in sighting distance can have meaningful effects on interaction outcomes.

I've read that we know less about the abyssal regions of the ocean than we do about the surface of the Moon.  I don't know if that's true -- it's a little hard to quantify what we don't know about something -- but what's certain is that the deep ocean harbors some astonishingly weird creatures.  I'll end with a quote from H. P. Lovecraft, in whose writings the ocean represents everything that is dark and mysterious about the universe: "But more wonderful than the lore of old men and the lore of books is the secret lore of ocean...  The process of delving into the black abyss is to me the keenest form of fascination."

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This week's Skeptophilia book recommendation of the week is about as cutting-edge as you can get, and is as scary as it is fascinating.  A Crack in Creation: Gene Editing and the Unthinkable Power to Control Evolution, by Jennifer Doudna and Samuel Sternberg, is a crash course in the new genetic technology called CRISPR-Cas9 -- the gene-editing protocol that Doudna herself discovered.  This technique allows increasingly precise cut-and-paste of DNA, offering promise in not just treating, but curing, deadly genetic diseases like cystic fibrosis and Huntington's disease.

But as with most new discoveries, it is not without its ethical impact.  The cautious are already warning us about "playing God," manipulating our genes not to eliminate disease, but to enhance intelligence or strength, to change personal appearance -- or personality.

A Crack in Creation is an unflinching look at the new science of gene editing, and tries to tease out the how much of what we're hearing is unwarranted fear-talk, and how much represents a genuine ethical minefield.  Doudna and Sternberg give the reader a clear understanding of what CRISPR-Cas9 is likely to be able to do, and what it won't, and maps out a direction for the discussion to take based on actual science -- neither panic and alarmism, nor a Panglossian optimism that everything will sort itself out.  It's a wonderful introduction to a topic that is sure to be much in the news over the next few years.

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

Blink of an eye

I know I often write about strange and unexpected discoveries out there in the universe in the context of how much more we have to learn, but even by those standards, the discovery announced by astrophysicists at the Massachusetts Institute of Technology this week was bizarre.

Most everyone knows about black holes -- stellar remnants that have collapsed to a density that they warp space/time into a closed surface.  The usual way this is put is that their gravitational pull is so strong even light isn't fast enough to escape, but that's not really that accurate; light is massless and therefore photons exert (and feel) no gravitational pull.  However, they are constrained to follow the lines of space/time they're traveling through, just as cars can take whatever road their drivers choose, but are still constrained to stay on the surface of the Earth's sphere.

Around a black hole, the fabric of space is so distorted that it's a bit like an infinitely-deep well.  Once inside the black hole's event horizon, there's no escape.  Weirder still, since not only space but time is affected by such a mass, to an outside observer watching an object falling into a black hole, it would seem to take an infinite amount of time.  The closer it got, the slower it would move, until it finally paused, forever, on the surface of the event horizon.  (Due to the vagaries of general relativity, this wouldn't help the hapless space traveler falling into a black hole.  Time would run at the regular speed for him/her, and in a very finite amount of time, the spaceship and everything and everyone in it would get ripped to shreds by the tidal forces exerted by the black hole's mass.)

[Image licensed under the Creative Commons User:Alain r, BH LMC, CC BY-SA 2.5]

It's this last bit that's germane to this week's announcement.  Black holes are black (duh), even light can't escape, so how do we see them?  It's because of material that's falling toward them.  Black holes tend to form accretion disks of stuff circling the central singularity at a high rate of speed, and the acceleration of this disk causes it to emit x-rays.  (In fact, the first black hole ever observed, Cygnus X-1, was given that name because it was the first x-ray source found in the constellation Cygnus.)

So we see the black hole by its brilliant x-ray "corona."  Generally, the larger the black hole, the bigger the accretion disk and the brighter it is; the center of the Milky Way, the object called Sagittarius A*, has a radius of 22 million kilometers, and parts of its accretion disk are being whirled about at thirty percent of the speed of light.

1ES 1927+654 is another such supermassive galactic nucleus, but its behavior is even weirder than our own.  In March 2018 it flashed -- its luminosity suddenly jumped by forty percent.  Keep in mind that these things are already phenomenally luminous, so such a jump is stupendous by anyone's estimate.  "This was an AGN [active galactic nucleus] that we sort of knew about, but it wasn't very special," said MIT astronomer Erin Kara.  "Then they noticed that this run-of-the-mill AGN became suddenly bright, which got our attention, and we started pointing lots of other telescopes in lots of other wavelengths to look at it."

That's why Kara and her team were watching when 1ES 1927+654 suddenly -- and completely -- disappeared.

Put more accurately, it became undetectable.  Something had apparently vaporized its corona completely, causing the x-ray emissions to stop.  The most amazing thing is how fast it happened -- an astronomical blink of an eye.  "We expect that luminosity changes this big should vary on timescales of many thousands to millions of years," said Kara.  "But in this object, we saw it change by 10,000 over a year, and it even changed by a factor of 100 in eight hours, which is just totally unheard of and really mind-boggling."

Here's what they think happened.

Something disrupted the accretion disk, possibly a large star that got caught in the black hole's gravitational well and was shredded by tidal forces as it approached.  That's a lot of material to throw into the accretion disk at once, and the star's own gravity destabilized the disk.  As an analogy, imagine a small whirlpool, like water going down a drain.  If you pour something like a dye into it slowly, it gets pulled in and incorporated smoothly.  But drop a gallon of dye into the whirlpool suddenly, and it disrupts the whirlpool completely, turning it into turbulent chaos.

That's what is thought to have happened here.  The shredding of the star is what created the flash we detected two years ago, then as the remnants plunged into the accretion disk, it blew the disk apart, and a lot of the material simply dropped into the black hole.  The acceleration of the material around the black hole is what causes the corona -- so when that's gone, the x-rays stop, and the black hole becomes undetectable.

The astronomers believe that the black hole's luminosity will "turn back on" as material around it begins to whirl around again, but the honest truth is that no one knows what it'll do next.  "We want to keep an eye on it," Kara said.  "It's still in this unusual high-flux state, and maybe it'll do something crazy again, so we don't want to miss that."

So that's our "you thought outer space was weird before" story for today.  Once again illustrating that we really are only on the beginning of our journey toward understanding the universe we live in.  If you keep your eyes on the stars, you will never lack for something to fascinate and startle you.

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This week's Skeptophilia book of the week is for anyone fascinated with astronomy and the possibility of extraterrestrial life: The Sirens of Mars: Searching for Life on Another World, by Sarah Stewart Johnson.

Johnson is a planetary scientist at Georgetown University, and is also a hell of a writer.  In this book, she describes her personal path to becoming a respected scientist, and the broader search for life on Mars -- starting with simulations in the most hostile environments on Earth, such as the dry valleys of central Antarctica and the salt flats of Australia, and eventually leading to analysis of data from the Mars rovers, looking for any trace of living things past or present.

It's a beautifully-told story, and the whole endeavor is tremendously exciting.  If, like me, you look up at the night sky with awe, and wonder if there's anyone up there looking back your way, then Johnson's book should be on your reading list.

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

The bones speak

Yesterday I ran into two unrelated studies that are kind of interesting in juxtaposition.

The first was in the journal Heritage Science, and was authored by a team led by Kaare Lund Rasmussen of the University of Southern Denmark.  It describes analysis of bones taken from 17th century Franciscan friaries in Italy and Denmark, looking specifically at trace element levels as an indicator of wealth, diet, medical treatments, and pollutants. 

The similarities were as fascinating as the differences.  In both places, bones from tombs of wealthy patrons were lower in strontium and barium than were bones from the cloisters, where the rank-and-file monks were buried.  This was likely due to the better (and more meat-rich) diet of nobles; ordinary folks ate a great deal more in the way of cereals and grains, which tend to have higher amounts of those trace elements.

On the other hand, the Italian bones had over twenty times the amount of copper that the Danish bones, regardless of social standing.  This was almost certainly because of cookware traditions; there was a long history of Italians of all classes using copper cook pots and storage vessels, whereas the Danes rarely did.

Lead followed the opposite pattern from strontium and barium; the wealthier people had higher amounts of lead in their bones, regardless of where they were from.  Rich people had pewter vessels and serving ware, earthenware coated with lead-based glazes, and (in some cases) lead water intake pipes for indoor plumbing and lead sheets on the roofs of their houses.  Plus -- something that I'd never heard of -- fine wine sometimes had added lead salts, put in to stop it from spoiling.

It worked, apparently, with the downside that if you drank it, you got lead poisoning.

I guess you can't have everything.

Mercury was an interesting one.  Mercury-based "medicine" was used to treat leprosy and syphilis in the Middle Ages.  Like the lead/wine-spoilage thing, the medicine worked only in the sense that you died, after which you no longer had leprosy or syphilis.  What the researchers found was that in Italian bones, the greater the socioeconomic status, the higher the likelihood of having mercury in the bone tissue; not, apparently, that the lower classes didn't get syphilis or leprosy, but that they had less access to treatment when they did.  Danish bones, however, showed no such trend.  The availability of medical treatment for the Danes was much more even-handed -- although, as I pointed out, that was not necessarily a good thing.

It's fascinating that we can analyze four-hundred-year-old bones and make some shrewd guesses about the cultural and social context their former owners lived in.  What they had to contend with -- good and bad -- left a clear record in their graves, still discernible four centuries later.

Then there's the second study, which appeared this week in the journal Environmental Hazards.  Entitled "Gulf Coast Parents Speak: Children's Health in the Aftermath of the Deepwater Horizon Oil Spill," by Jaishree Beedasy, Elisaveta Petkova, and Jonathan Sury (of Columbia University), and Stephanie Lackner (of the University of Madrid), the paper describes a study of 720 families in the part of coastal Louisiana hit by the spill, looking particularly at children's health as a function of proximity.  Turns out 60% of parents reported their children having health and/or psychological/emotional problems following exposure, and those who had come into direct physical contact with the spilled oil showed a 4.5 times higher rate of problems than those who had not.

[Image is in the Public Domain]

As the press release about the study in Science Daily put it:

Although natural disasters don't discriminate, they do disproportionately harm vulnerable populations, such as people of color and people with lower incomes.  Children are another vulnerable group, because their coping and cognitive capacities are still developing, and because they depend on caregivers for their medical, social, and educational needs.  A growing body of evidence demonstrates that disasters are associated with severe and long-lasting health impacts for children.

Having just read the story about the Danish and Italian bones, what it immediately got me thinking was, what will future archaeologists say about us when they unearth and analyze our bones?  Will they be able to detect traces of our self-poisoning reliance on fossil fuels?  Will the years from 2016 to 2020 show an uptick in pollutants because of Donald Trump's systematic weakening of environmental protections in favor of zero restrictions on industry and corporate interests?

What will that say to them about our priorities as a society?

Sorry to end on an elegiac note, but since we started with bones buried in cloisters, I suppose it's natural enough.  People eventually wised up to the point that they stopped using lead water intake pipes and cookware, and stopped treating diseases with mercury salts.  They did that, by the way, because of science -- the patient study of cause-and-effect that linked lead and mercury to chronic poisoning.  Let's hope that humanity today starts listening to the scientists today who are warning us about climate change and the health effects of pollution.

Otherwise our distant descendants will make the same judgments of our intelligence as we do of the medievals who put lead compounds in their bottles of wine.

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This week's Skeptophilia book of the week is for anyone fascinated with astronomy and the possibility of extraterrestrial life: The Sirens of Mars: Searching for Life on Another World, by Sarah Stewart Johnson.

Johnson is a planetary scientist at Georgetown University, and is also a hell of a writer.  In this book, she describes her personal path to becoming a respected scientist, and the broader search for life on Mars -- starting with simulations in the most hostile environments on Earth, such as the dry valleys of central Antarctica and the salt flats of Australia, and eventually leading to analysis of data from the Mars rovers, looking for any trace of living things past or present.

It's a beautifully-told story, and the whole endeavor is tremendously exciting.  If, like me, you look up at the night sky with awe, and wonder if there's anyone up there looking back your way, then Johnson's book should be on your reading list.

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

Meadow management

My wife and I live on a 3.5 acre bit of land in the hills of upstate New York.  We're lucky to have that kind of space, and the place itself is beautiful; it's crossed by a little stony-bedded creek, and has a swimmable pond and lots of big old trees for shade.

And lots of lawn.  At least it did when we moved in here eighteen years ago.  We've been gradually doing battle with the lawn for most of that eighteen years.  We replaced some with gardens -- which was a net loss of discretionary time, since weeding a garden takes a great deal more time than mowing an equal-sized piece of lawn.  My wife got the idea of replacing a lot of the grass in the back yard with clover, and she was helped out in that endeavor by our large galumphing dog Guinness, who essentially does a hockey stop whenever he's chasing his tennis ball, tearing up large strips of turf and thus earning himself the nickname "Skidmark."  But the clover's finally taken hold in a big way, and it not only looks great and needs way less mowing, it's a happy place for the honeybees.

That last bit was our incentive for turning a chunk of our front yard into a meadow.  A wonderful local nursery, The Plantsmen, specializes in native wildlife-friendly plants, so a couple of months ago we went down and came back with my Honda Element packed with such unusual finds as blue-stemmed goldenrod (Solidago caesia), nannyberry (Viburnum lentago), American scarlet elderberry (Sambucus racemosa), two different kinds of bergamot (Monarda spp.), fragrant sumac (Rhus aromatica), serviceberry (Amelanchier canadensis), and in a corner that has a permanent spring, the charming and water-loving buttonbush (Cephalanthus occidentalis).

The Meadow thus far.  Okay, it doesn't look like much yet, but just you wait until our plants have a couple years' growth behind them.

The reason this topic comes up is because of a study that came out this week in the journal Biological Conservation about the role of verges in preserving valuable pollinators and beneficial insects.  Verges, they tell us, are hotspots for flowers and pollinators, often containing a dramatic diversity of different species (not all of which are native, of course; but then, neither is the white clover we seeded in our back yard, and I still consider it to be on balance a beneficial plant).  

Of course, roads themselves are a necessary evil, replacing and fragmenting habitat, not to mention the never-ending problem of roadkill.  (Don't just think of mammals, here; think of the number of insects killed yearly by windshield collisions, and keep in mind that even the National Pesticide Information Center says that 97% of insect species are neutral with respect to humanity, or else actively beneficial).  So given that roads aren't going anywhere, the best thing to do is to figure out how to maximize whatever's positive about them, and minimize the negative ecological impact.

Verges seem to be the biggest positive feature, as long as they're managed properly.  The key, says the researchers (a group led by environmental scientist Benjamin Phillips of the University of Exeter), is to mow as infrequently as is practical for the spot.  Surprisingly, "don't mow at all" turns out to be a bad idea.  The authors write:

An observational study of 19 road verges in the UK found that mown verges (cut once between May and August, cuttings not removed) had on average 67% fewer flowers and 61% fewer pollinators across the summer than unmown verges, experimentally manipulated mowing frequency (cuts/year: 0, 1 (early autumn) or 2 (early summer and early autumn)) and removal of cuttings (left in the verge or removed) in a single road verge (with a species-rich plant community) in the Netherlands.  Increasing the number of cuts from 0 to 1 cut resulted in 3.5 times greater flower density and 2 times greater flower species richness, but no significant effect on pollinator density, though increasing from 1 to 2 cuts/year resulted in 3.5 times greater pollinator density.

This is good information for our own little meadow, because I wasn't sure if we should mow at all, but it sounds like it's a good idea; in our case, not only for the pollinators, but because in our area, completely stopping mowing is a good way to turn a meadow into a tangle of walnut saplings and nasty, fast-growing exotics like Tatarian honeysuckle and multiflora rose.

So it sounds like mowing once or twice -- maybe once in spring and once in fall -- might be the way to go.  That way the plants that die all the way back to the ground in the winter (like the goldenrod and bergamot) will get a fresh start each year, and we won't have competitors for the woody shrubs (such as the sumac, nannyberry, serviceberry, and elderberry).

I can't mow near where the buttonbush is, however, because the spring keeps that piece of the lawn soggy, and if I try to mow it our lawn mower sinks up to the axle and then I have to tow it out with my car.

Yes, that's the voice of experience, right there.

In any case, this paper was nicely timed from my perspective, as I was wondering what I'd do after the first frost when everything starts to die back.  Since we planted as we did to encourage the bees and butterflies, it's good to know that there's some solid scientific research to back up our choice of how to handle it.

With luck, in a couple of years we'll have something really beautiful to enjoy -- and a nice habitat for wildlife, as well.

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This week's Skeptophilia book of the week is for anyone fascinated with astronomy and the possibility of extraterrestrial life: The Sirens of Mars: Searching for Life on Another World, by Sarah Stewart Johnson.

Johnson is a planetary scientist at Georgetown University, and is also a hell of a writer.  In this book, she describes her personal path to becoming a respected scientist, and the broader search for life on Mars -- starting with simulations in the most hostile environments on Earth, such as the dry valleys of central Antarctica and the salt flats of Australia, and eventually leading to analysis of data from the Mars rovers, looking for any trace of living things past or present.

It's a beautifully-told story, and the whole endeavor is tremendously exciting.  If, like me, you look up at the night sky with awe, and wonder if there's anyone up there looking back your way, then Johnson's book should be on your reading list.

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

Collision of galaxies

When I was an undergraduate at the University of Louisiana, I and several of my friends were blown away by the original series Cosmos, written and narrated by Carl Sagan.

Monday mornings, we gathered in the student lounge, eagerly discussing whatever mind-blowing filigree of physics had been the subject of that week's episode.  I still recall one of the ones that made the biggest impression on me -- the tenth episode, "The Edge of Forever," which included, among many other things, wonderful simulations of the motion of stars within a galaxy, and what happens when two galaxies collide.  (You can watch a clip of it here.)  The simulations were (at the time) state-of-the-art, and certainly enough to blow the mind of a sophomore physics student like myself; what struck me most was that galaxies aren't rigid, and their constituent stars don't "hang together," but move independently around the massive black hole at the galactic core.  This can settle down into a shape that seems pretty stable -- such as the spiral pattern of the Milky Way -- or it can destabilize, flinging stars out into space, exploding the galaxy and scattering its pieces across hundreds of thousands of light years.

Sagan, of course, put it best: "A galaxy is a fluid made of a billion suns, all bound together by gravity."

When galaxies collide, it disrupts both completely; at the same time, collisions between the stars themselves are extremely uncommon.  However big the stars are, they're still minuscule with respect to the galaxies that contain them.  It's like the atoms writ large, isn't it?  The seemingly solid matter around you is made up of tiny charged particles interacting through the force of electromagnetism, but in between those particles is... nothing.  Matter is mostly empty space, and only seems solid because you're feeling the mutual repulsion of the electrons in your fingers and the electrons on the surface of whatever you're touching.  Likewise, most of interstellar space is very close to nothing, and the galaxies themselves are made up of particles (stars) interacting through a different force (gravity), and separated by vast, empty voids.

Makes you almost think that the pagans might have been on to something with their dictum of "As above, so below."

Map of the Milky Way, as it would look from above the galactic disk [Image licensed under the Creative Commons 鄭興武和馬克 裡德（Mark J. Reid）銀河系棒和旋臂結構遺產性巡天(BeSSeL)項目組/南京大學/哈佛-斯密松天體物理中心., Milky Way large, CC BY-SA 4.0]

This topic, and my reminiscences of Cosmos, come up because of a paper in Nature Astronomy last week called "Evidence for a Vast Prograde Stellar Stream in the Solar Vicinity," by a team led by astronomer Lina Necib of the California Institute of Technology.  What this paper tells us is something stunning; there is a streamer of stars in the Milky Way that started out somewhere else, and collided with our galaxy.  Rather fortunately, apparently the angle and velocity with which the streamer hit were more or less the same direction the original galaxy was turning, so these stars simply got sucked in, like some bits of debris going down a whirlpool.

The streamer has been named Nyx, after the Greek goddess of the night.  250 stars have been identified as being part of Nyx.  "The two possible explanations here are that they are the remnants of a [galactic] merger, or that they are disk stars that got shaken into their new orbits because of a collision with the disk of the Milky Way," said study lead author Lina Necib, in an interview with CNN.  The likelihood, though, is the former, something that is expected to be confirmed by chemical analysis of the constituent stars.  "Galaxies form by swallowing other galaxies," Necib said. "We've assumed that the Milky Way had a quiet merger history, and for a while it was concerning how quiet it was because our simulations show a lot of mergers.  Now, we understand it wasn't as quiet as it seemed.  We're at the beginning stages of being able to really understand the formation of the Milky Way."

I think it's stunning that we can figure out this sort of thing at all -- that 250 out of the estimated 250 billion stars in the Milky Way started out somewhere else in the universe.  I think that's pretty damn impressive.  "This particular structure is very interesting because it would have been very difficult to see without machine learning," Necib said.  "I think we reached a point in astronomy where we are not data limited anymore.  This project is an example of something that would have not been possible a few years ago, the culmination of developments in data with Gaia, high resolution simulations, and machine learning methods."

How pleased and amazed Carl Sagan would have been.  He went a long way toward bringing the wonders of the universe, from the largest scales to the smallest, to laypeople.  He certainly blew the minds of me and my friends, and that was back in 1980.  Necib's comment, that we're still at the beginning of being able to understand the formation of galaxies, tells us that we have a long way still to go -- and that many, many more eye-opening discoveries are sure to come our way in the next years.

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This week's Skeptophilia book of the week is for anyone fascinated with astronomy and the possibility of extraterrestrial life: The Sirens of Mars: Searching for Life on Another World, by Sarah Stewart Johnson.

Johnson is a planetary scientist at Georgetown University, and is also a hell of a writer.  In this book, she describes her personal path to becoming a respected scientist, and the broader search for life on Mars -- starting with simulations in the most hostile environments on Earth, such as the dry valleys of central Antarctica and the salt flats of Australia, and eventually leading to analysis of data from the Mars rovers, looking for any trace of living things past or present.

It's a beautifully-told story, and the whole endeavor is tremendously exciting.  If, like me, you look up at the night sky with awe, and wonder if there's anyone up there looking back your way, then Johnson's book should be on your reading list.

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