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

Monday, October 26, 2020

Five dozen trips

Dear Skeptos...

After today I'm taking a quick break -- this will be my only post this week.  I'll be back on Monday, November 2.  Until then, please keep topic suggestions coming!

cheers,

Gordon

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

Today is my sixtieth birthday.

I'm not a big believer in the significance of milestones, but this one seems to be pretty major.  Partly, it's my incredulity over turning sixty when I don't feel sixty.  Well, in some ways I do; I've got more aches and pains and minor physical issues than I used to.  Fortunately, at this point, nothing at all serious.  I've got some gray, especially in my facial hair, so I keep it trimmed really short to minimize the impact.  I have a few more wrinkles and laugh lines.  I need reading glasses (either that, or my conjecture that everyone is printing in smaller and smaller fonts is correct).  My stamina for running is less than it used to be.

Overall, though, I can't complain.  I've made it here relatively unscathed.

What sixty looks like

Part of that is good luck, and part is good genes.  I come from a family of long-lived people.  My parents both made it to 83, and my dad especially looked a consistent ten years younger than he actually was, pretty much his whole life.  His mom, my beloved Grandma Bertha, lived to 93, and her eccentric Aunt Clara died at 101.  (Great Aunt Clara was almost completely blind during the last ten years of her life, but still walked daily around her home town of Wind Ridge, Pennsylvania with her red-tipped cane.  The story is that she made a point of whapping people she didn't like with her cane as she passed them.  "Accidentally."  Just showing that irascibility runs in my father's family as well as longevity.)

So as far as genetics goes, I got dealt a pretty good hand.

I also attribute some of it, though, to the fact that I still have the sense of humor of a twelve-year-old.  Nothing keeps you young like retaining your ability to laugh at fart jokes.

Looking back, it's been a wild ride.  I've come a long way in sixty years, both literally and figuratively.  I've been lucky enough to have the opportunity to travel to exotic places like Ecuador and Trinidad and Malaysia.  I live in upstate New York, which I would put in contention for the most beautiful place in the world.  I have two sons I'm proud of.  Despite off-the-scale shyness and social anxiety I'm happily married to the love of my life.  I'm a published author with fifteen books to my name.  I just retired a couple of years ago after a 32-year career teaching science to teenagers, a vocation that was some combination of challenging, fun, frustrating, and exhilarating -- truly a job where you never know what's going to happen next.  With the support of family and friends, two years ago I finally came out publicly as bisexual, shedding decades of shame and fear and finally stepping into the light and saying, "This is who I am."  I've learned a lot about myself and others, especially the deep, aching truth of what a family friend told me when I was six: "Always be kinder than you think you need to be, because everyone you meet is fighting a terrible battle that you know nothing about."  Through it all, I've come out mostly happy, mostly healthy, and entirely glad to be where I am.

I am an incredibly lucky man.

Still, it's a little mind-boggling that I've made five dozen trips around the Sun.  It's hard to fathom that it's been that long.  When someone says "twenty years ago," I immediately think, "1980?"  No, that's forty years ago.  Twenty years ago is 2000.  Today's twenty-year-olds were infants when 9/11 happened.  So many of the things I think of as high-magnitude historical events -- the explosion of the Space Shuttle Challenger, the start of the Gulf War, the Exxon Valdez oil spill, the launch of the Hubble Space Telescope, the development of the World Wide Web and email, the breakup of Yugoslavia and the siege of Sarajevo, the Oklahoma City bombing, the signing of the Good Friday Agreement that officially ended the Irish "Troubles" -- all happened before today's twenty-year-olds were born.

I can't fool myself.  I haven't been young for quite some time.  It brings back memories of my grandma, then about eighty, dropping into her favorite rocking chair with a groan, then cocking an eyebrow at me and saying, "You know, Gordon, I'm no spring chicken any more."  I'd usually grin and say, "Grandma, when were you a spring chicken?"  To which she'd retort something like, "Last Thursday, you little pipsqueak.  Now fix me a martini."  And we'd both crack up.

Then I'd fix her a martini.

That's the kind of eighty-year-old I want to be.

I guess there's no avoiding aging, although I do think a lot of it boils down to attitude.  You can't escape the physical stuff completely, although you can ameliorate it by staying active; I'm glad I'm still a runner, and I suspect that I'd be in way worse shape than I am if I'd become sedentary.  But I'm damned if I'll let it get me down.  I remember a friend of mine turning sixty, and he went into a serious depression -- it was so much harder than fifty, he said, "because there's no doubt you're past halfway.  Some people make it to a hundred, but almost no one makes it to a hundred and twenty."

Which might be true, but it's not going to stop me from trying.

So anyhow: happy birthday to me.  Despite my friend's hang-dog attitude, here's to the next five dozen trips.  Maybe my attitude is a little like the guy who fell off the roof of a skyscraper, and as he passes the twentieth floor, someone yells out of a window at him to ask how he's doing, and he shrugs and says, "So far, so good."

But it's better than the alternative.  Much better to relax, enjoy the view, and have a martini.

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

Have any scientifically-minded friends who like to cook?  Or maybe, you've wondered why some recipes are so flexible, and others have to be followed to the letter?

Do I have the book for you.

In Science and Cooking: Physics Meets Food, from Homemade to Haute Cuisine, by Michael Brenner, Pia Sörensen, and David Weitz, you find out why recipes work the way they do -- and not only how altering them (such as using oil versus margarine versus butter in cookies) will affect the outcome, but what's going on that makes it happen that way.

Along the way, you get to read interviews with today's top chefs, and to find out some of their favorite recipes for you to try out in your own kitchen.  Full-color (and mouth-watering) illustrations are an added filigree, but the text by itself makes this book a must-have for anyone who enjoys cooking -- and wants to learn more about why it works the way it does.

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



Saturday, October 24, 2020

What doesn't kill you

In evolutionary biology, it's always a little risky to attribute a feature to a specific selective pressure.

Why, for example, do humans have upright posture, unique amongst primates?  Three suggestions are:

  • a more upright posture allowed for longer sight distance, both for seeing predators and potential prey
  • standing upright freed our hands to manipulate tools
  • our ancestors mostly lived by the shores of lakes, and an ability to wade while walking upright gave us access to the food-rich shallows along the edge

So which is it?  Possibly all three, and other reasons as well.  Evolution rarely is pushed in a particular pressure by just one factor.  What's interesting in this case is that upright posture is a classic example of an evolutionary trade-off; whatever advantage it gave us, it also destabilized our lumbar spines, giving humans the most lower back problems of any mammal (with the possible exceptions of dachshunds and basset hounds, who hardly got their low-slung stature through natural selection).

Sometimes, though, there's a confluence of seeming cause and effect that is so suggestive it's hard to pass up as an explanation.  Consider, for example, the rationale outlined in the paper that appeared this week in Science Advances, called "Increased Ecological Resource Variability During a Critical Transition in Hominin Evolution," by a team led by Richard Potts, director of the Human Origins Program of the Smithsonian Institution.

What the paper looks at is an oddly abrupt leap in the technology used by our distant ancestors that occurred about four hundred thousand years ago.  Using artifacts collected at the famous archaeological site Olorgesailie (in Kenya), the researchers saw that after a stable period lasting seven hundred thousand years, during which the main weapons tech -- stone hand axes -- barely changed at all, our African forebears suddenly jumped ahead to smaller, more sophisticated weapons and tools.  Additionally, they began to engage in trade with groups in other areas, and the evidence is that this travel, interaction, and trade enriched the culture of hominin groups all over East Africa.  (If you have twenty minutes, check out the wonderful TED Talk by Matt Ridley called "When Ideas Have Sex" -- it's about the cross-fertilizing effects of trade on cultures, and is absolutely brilliant.)

Olorgesailie, Kenya, where our distant ancestors lived [Image licensed under the Creative Commons Rossignol Benoît, OlorgesailieLandscape1993, CC BY-SA 3.0]

So what caused this prehistoric Great Leap Forward?  The Potts et al. team found that it coincides exactly with a period of natural destabilization in the area -- a change in climate that caused what was a wet, fertile, humid subtropical forest to change into savanna, a rapid overturning of the mammalian megafauna in the region (undoubtedly because of the climate change), and a sudden increase in tectonic activity along the East African Rift Zone, a divergent fault underneath the eastern part of Africa that ultimately is going to rip the continent in two.

The result was a drastic decrease in resources such as food and fresh water, and a landscape where survival was a great deal more uncertain than it had been.  The researchers suggest -- and the evidence seems strong -- that the ecological shifts led directly to our ancestors' innovations and behavioral changes.  Put simply, to survive, we had to get more clever about it.

The authors write:

Although climate change is considered to have been a large-scale driver of African human evolution, landscape-scale shifts in ecological resources that may have shaped novel hominin adaptations are rarely investigated.  We use well-dated, high-resolution, drill-core datasets to understand ecological dynamics associated with a major adaptive transition in the archeological record ~24 km from the coring site.  Outcrops preserve evidence of the replacement of Acheulean by Middle Stone Age (MSA) technological, cognitive, and social innovations between 500 and 300 thousand years (ka) ago, contemporaneous with large-scale taxonomic and adaptive turnover in mammal herbivores.  Beginning ~400 ka ago, tectonic, hydrological, and ecological changes combined to disrupt a relatively stable resource base, prompting fluctuations of increasing magnitude in freshwater availability, grassland communities, and woody plant cover.  Interaction of these factors offers a resource-oriented hypothesis for the evolutionary success of MSA adaptations, which likely contributed to the ecological flexibility typical of Homo sapiens foragers.

So what didn't kill us did indeed make us stronger.  Or at least smarter.

Like I said, it's always thin ice to attribute an adaptation to a specific cause, but here, the climatic and tectonic shifts occurring at almost exactly the same time as the cultural ones seems far much to attribute to coincidence. 

And of course, what it makes me wonder is how the drastic climatic shifts we're forcing today by our own reckless behavior are going to reshape our species.  Because we're not somehow immune to evolutionary pressure; yes, we've eliminated a lot of the diseases and malnutrition that acted as selectors on our population in pre-technological times, but if we mess up the climate enough, we'll very quickly find ourselves staring down the barrel of natural selection once again.

Which won't be pleasant.  I'm pretty certain that whatever happens, we're not going extinct any time soon, but the ecological catastrophe we're increasingly seeming to be facing won't leave us unscathed.  I wonder what innovations and adaptations we'll end up with to help us cope?

My guess is whatever they are, they'll be even more drastic than the ones that occurred to our kin four hundred thousand years ago.

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

Have any scientifically-minded friends who like to cook?  Or maybe, you've wondered why some recipes are so flexible, and others have to be followed to the letter?

Do I have the book for you.

In Science and Cooking: Physics Meets Food, from Homemade to Haute Cuisine, by Michael Brenner, Pia Sörensen, and David Weitz, you find out why recipes work the way they do -- and not only how altering them (such as using oil versus margarine versus butter in cookies) will affect the outcome, but what's going on that makes it happen that way.

Along the way, you get to read interviews with today's top chefs, and to find out some of their favorite recipes for you to try out in your own kitchen.  Full-color (and mouth-watering) illustrations are an added filigree, but the text by itself makes this book a must-have for anyone who enjoys cooking -- and wants to learn more about why it works the way it does.

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



Friday, October 23, 2020

The astronomical pogo stick

It's all too easy lately to find reasons to criticize humans.  I'm guilty of contributing to it myself, by my focus on pseudoscientific nonsense; you can jump from "some humans do stupid stuff" to the cynical "all humans are irreparably stupid" without even realizing it.

It's worthwhile focusing instead on our accomplishments, some of which are downright amazing.  This year, I think we all need something to cheer us up and make us feel a little more optimistic about our potential as a species.  So today we're going to look at: the mind-blowing reconnaissance mission NASA has undertaken to collect, and bring back to Earth, material from the asteroid Bennu.

Bennu is interesting from a number of standpoints.  It's a carbonaceous asteroid, meaning it is high in the carbon-containing compounds that were probably abundant in the early Earth's atmosphere -- carbon dioxide and monoxide, methane, and hydrogen cyanide.  Because these were the raw materials from which the first biochemicals were synthesized, it's of serious interest to people like me who are obsessed with the possibilities of extraterrestrial life.  Astronomers tend to be more curious about Bennu because its composition is thought to be very similar to the material from which the Solar System originally coalesced, so learning about it might give us a lens into our region of the galaxy's very distant past.

And if you needed another reason, Bennu is one of the asteroids which periodically crosses the Earth's orbit, making it high on the list of eventual Earth strikes.  (Not to worry: it's not going to hit the Earth, or anything else, for at least another two hundred years, and the current surmise is that it's much more likely to hit Jupiter than it is to hit Earth.)

So in 2016, NASA launched the OSIRIS-REx mission, which first did a near pass and mapped out its surface to look for good spots for rock collecting, and then on the second encounter -- which happened three days ago -- dropped onto the asteroid with a maneuver that looked like someone bouncing on a pogo stick.  The six-second contact stirred up material from the surface, which was sucked into a collector.  OSIRIS-REx then zoomed back off into space for its return voyage to Earth, carrying what scientists hope is a sixty-gram sample of the surface of the asteroid.

Okay, that's already impressive, right?  If you want your mind boggled further, consider this:

OSIRIS-REx's trip (one way) from Earth to Bennu covered about 820 million kilometers.  The asteroid's diameter is about 530 meters; the spacecraft's is a little under seven meters.  I did a bit of back-of-the-envelope calculation, and discovered that our ability to hit Bennu from this distance is equivalent to hitting a target the size of a bacterium with a bullet the size of a virus -- from a kilometer away.

Oh, and it's hardly standing still.  Bennu is a fast-moving target, zooming along at 28 kilometers per second.

If that doesn't impress you, I can't imagine what would.

OSIRIS-REx's sampling arm, seconds before impact on asteroid Bennu on October 20, 2020 [Image is in the Public Domain courtesy of NASA/JPL]

"The spacecraft did everything it was supposed to do," said mission principal investigator Dante Lauretta of the University of Arizona.  "I can’t believe we actually pulled this off."

His elation and incredulity are understandable considering all of the things that could have gone wrong, and how slight the error would have to be to result in the spacecraft either plunging into a destructive crash or else missing the asteroid entirely.  And at that point, OSIRIS-REx had to function perfectly on its own -- at that distance, radio signals traveling at the speed of light take over eighteen minutes to reach Earth, and (even assuming an instantaneous response by NASA scientists) another eighteen to send back a command like "NO NO NO DON'T DO THAT!"

By that time, the spacecraft would either be rubble or else zooming away into space, and away from the target.

So the mission went off without a hitch.  Well, the first half of it -- they still have to get OSIRIS-REx back to Earth safely.  But I'd say given how flawless the first bit was, there's a good chance they'll accomplish the whole shebang, and we'll have some really interesting stuff to study.

When you consider things like this, it's reassuring -- the capacity for human accomplishment is limitless.  Yes, I know there's still idiotic stuff going on down here.  But I'm not ready to give up on humanity yet.  I find the OSIRIS-REx mission incredibly inspirational.

Gives me hope that there may be a bright future for our species yet.

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

Have any scientifically-minded friends who like to cook?  Or maybe, you've wondered why some recipes are so flexible, and others have to be followed to the letter?

Do I have the book for you.

In Science and Cooking: Physics Meets Food, from Homemade to Haute Cuisine, by Michael Brenner, Pia Sörensen, and David Weitz, you find out why recipes work the way they do -- and not only how altering them (such as using oil versus margarine versus butter in cookies) will affect the outcome, but what's going on that makes it happen that way.

Along the way, you get to read interviews with today's top chefs, and to find out some of their favorite recipes for you to try out in your own kitchen.  Full-color (and mouth-watering) illustrations are an added filigree, but the text by itself makes this book a must-have for anyone who enjoys cooking -- and wants to learn more about why it works the way it does.

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



Thursday, October 22, 2020

Lines of sight

What amazes me about so many crazy claims is that you get the impression that the people making them didn't even try to find a natural explanation.

It's one thing to speculate wildly about a phenomenon for which science is still searching for explanations.   Déjà vu, for example, is one experience that virtually everyone shares, and for which no convincing explanation has yet been found.  It's no wonder that it's fertile ground for people who prefer to ascribe such occurrences to the paranormal.

But in other cases, there is such a simple, convincing natural explanation that you have to wonder why the claimant isn't going there.   Such, for example, is the suggestion over at the phenomenally bizarre quasi-religious site The Watchman's Cry that geographical locations on the Earth that have been the sites of disasters (natural or manmade) fall along connecting lines, making some sort of mystical, meaningful pattern.

The article starts out with a bang, with the phrase, "Several months ago, I had four prophetic dreams which took place on the same night."  Four precognitive dreams is pretty impressive, I have to say, especially since most skeptics don't think precognition occurs at all.  Be that as it may, these dreams involved train wrecks, which is ironic, because that is what the rest of the site turns out to be.

Both literally and figuratively.

The site goes into great detail about various train derailments, and how if you connect them by lines (great circles, to be more precise), those lines then go around the Earth and connect to other sites that have had bad things happen.  These then intersect other such great circles, which go other interesting places, and so on.



[Image is in the Public Domain]

It's just ley lines all over again, isn't it?  If your search parameters are wide enough -- basically, "anywhere that anything bad has happened in the past two centuries" -- you can find great circles that link them up.  Which is entirely unsurprising.  I could draw a great circle anywhere on Earth and pretty much guarantee that I'll find three or more sites near it that had some kind of natural or manmade calamity in the past two centuries.  The Earth is a big place, and there are lots of calamities to choose from.

But what gets me most about this guy is that he doesn't even seem to understand that given the fact that the Earth is a sphere (an oblate spheroid, to be precise, but let's not get technical), a given point on Earth has an infinite number of great circles passing through it.  Just as two points on a plane define a line, two points on a sphere define a great circle.  And his lack of grasp of simple geometry becomes apparent when he tells us that it's amazing that two intersecting great circles (ones connecting Houston, Texas to train derailment sites in Rosedale, Maryland and Bear Creek, Alabama, respectively) were "only 900 feet apart."

How can you say that two intersecting lines are any specific distance apart?  If they intersect, they are (at that point) zero feet apart.  Farther from the intersection, they are farther apart.  Because that's how intersection works.

But the author of this site trumpets this statement as if it were some kind of epiphany.  It's like being excited because you found a triangle that had three sides.

I'll leave you to explore the site on your own, if you're curious to see more of this false-pattern malarkey, but suffice it to say that there's nothing at all mystical going on here.  He's adding geometry to coincidence and finding meaning, and it's no great surprise that it turns out to be the meaning he already believed going into it.

So like the ley lines people, this guy doesn't seem to be trying very hard to see if there's a natural explanation that sufficiently accounts for all of the facts, a tendency I have a hard time comprehending.  Why are people attracted to this kind of hokum?  Science itself is a grand, soaring vision, telling us that we are capable of understanding how the universe works, from the realm of the enormous to the realm of the unimaginably small.  With a little work, you can find out the rules that govern everything from galaxies to quarks.

But that, apparently, isn't enough for some people.

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

Have any scientifically-minded friends who like to cook?  Or maybe, you've wondered why some recipes are so flexible, and others have to be followed to the letter?

Do I have the book for you.

In Science and Cooking: Physics Meets Food, from Homemade to Haute Cuisine, by Michael Brenner, Pia Sörensen, and David Weitz, you find out why recipes work the way they do -- and not only how altering them (such as using oil versus margarine versus butter in cookies) will affect the outcome, but what's going on that makes it happen that way.

Along the way, you get to read interviews with today's top chefs, and to find out some of their favorite recipes for you to try out in your own kitchen.  Full-color (and mouth-watering) illustrations are an added filigree, but the text by itself makes this book a must-have for anyone who enjoys cooking -- and wants to learn more about why it works the way it does.

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



Wednesday, October 21, 2020

The gospel according to Tolkien

Markus Davidsen, a Ph.D. candidate in Religious Studies at Leiden University in the Netherlands, thought he'd write his dissertation about people who believe that the Jedi religion, made famous by Star Wars, is real.  But after he began his research, he seems to have decided that that was just too silly a topic to research, so he changed his mind.

And decided to research people who believe that the religious schema from J. R. R. Tolkien's Lord of the Rings is real, instead.

Yes, we're talking Elves, and the whole Valar and Maiar thing from The Silmarillion.  And that there have been a series of massive cataclysms, including the one caused by Fëanor forging the Silmarils (a battle which "reshaped Middle-Earth"), and one that sank the continent of Númenor, not to mention the more famous Battle of Five Armies (from The Hobbit) and Battle of the Pelennor Fields (from The Return of the King).  All of which, mysteriously, have left no archaeological traces whatsoever.

But that's not all.  Many of these people think that they are Elves.  Or descended from the Valar.  And there are enough such folks that Davidsen was inundated with requests to participate in his research.  When asked how he found Latter-Day Elves, Davidsen responded, "Actually, they found me.  My graduation thesis on Jedis won a prize and that generated lots of publicity in Mare [the official newspaper of Leiden University] too.  As a result, those people got in touch with me: one group of Tolkien followers would put me in touch with another and it snowballed from there. The groups turned out to be quite diverse too, so I could compare them to each other."

[Image licensed through the Creative Commons Giorgio Minguzzi from Italy, Elf, Tolkien (5503256855), CC BY-SA 2.0]

Allow me to emphasize; these were not some folks playing role-playing games, a sort of Middle-Earth version of the Society for Creative Anachronism.  These people are serious.

And of course, what would a religion be without schisms and squabbling?  "There are those who swear that they themselves are descended from Elves and accordingly have Elvish genes," Davidsen says.  "That’s some claim, and taking it too far for the people who only claim to have Elvish souls and who dissociate themselves from that group."

Others, Davidsen says, go right to the top, worship-wise.  "Yet another group say they not remotely related to Elves, but that there is another world in which the Valar exist," he said.  "They use rituals to try and contact the Valar.  Some draw a circle on the ground, spiritually cleanse it and then evoke the Valar while others go on a kind of shamanic journey with their spirits travelling to another world."

Right.  Okay.  Because it's not like Tolkien made the whole thing up, or anything.

Davidsen, fortunately, agrees.  On the other hand, he says, "This kind of religion isn’t any dafter than other faiths, we’re just used to that particular madness.  We think it’s normal for Catholics to consume the flesh and blood of their God, but when the modern vampire movement says they draw powers from blood, we think they’re loonies.  It’s not really fair.  Buddhism dictates that some people have a Buddha nature, which is not essentially different from the Tolkien-esque idea of having an Elvish nature."

Which is spot-on, even if predictably I think it's all a lot of lunacy.  I tend to agree with Stephen F. Roberts, who said the following to a devout Christian: "I contend we are both atheists.  I just believe in one fewer god than you do.  When you understand why you dismiss all the other possible gods, you will understand why I dismiss yours."

Now, understand, as religions go, Tolkienism (or whatever it's called) at least has one selling point; it's got a beautiful narrative.  If I was forced to choose a fictional world to live in, Middle-Earth would come near the top.  It's got a grandeur, a breadth of scope, like no other fantasy world I've ever read about, and (best of all) the good guys win.

Which is more than you can say for the world of, say, the Lovecraftian mythos.  There, you do everything you can to worship Yog-Sothoth, or whoever, and for your devotion you get your arms ripped off and your face melted.  That's one fictional religion I'm glad isn't real.

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

Have any scientifically-minded friends who like to cook?  Or maybe, you've wondered why some recipes are so flexible, and others have to be followed to the letter?

Do I have the book for you.

In Science and Cooking: Physics Meets Food, from Homemade to Haute Cuisine, by Michael Brenner, Pia Sörensen, and David Weitz, you find out why recipes work the way they do -- and not only how altering them (such as using oil versus margarine versus butter in cookies) will affect the outcome, but what's going on that makes it happen that way.

Along the way, you get to read interviews with today's top chefs, and to find out some of their favorite recipes for you to try out in your own kitchen.  Full-color (and mouth-watering) illustrations are an added filigree, but the text by itself makes this book a must-have for anyone who enjoys cooking -- and wants to learn more about why it works the way it does.

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



Tuesday, October 20, 2020

The swing of a pendulum

 Physicists have a serious problem.

Back in the mid-1970s, astrophysicist Vera Rubin made an interesting discovery.  She had initially been interested in quasars, but moved away from that because the subject was "too controversial" -- and landed herself in the midst of one of the biggest scientific controversies to hit the field since the discovery of the quantum nature of reality back in the 1920s and 1930s.

She was looking at the rotation rates of galaxies, and found something curious; based on what was known about gravitational interactions between massive objects, the outer fringes of every galaxy she studied were moving at the "wrong" velocity.  The outermost stars were moving far faster than the model predicted, suggesting there was some unseen mass increasing the gravitational field and whirling the edges of the galaxy around faster than the visible matter could have.

And it wasn't by a small margin, either.  Rubin's calculations suggested that there was five times the unseen stuff as there was all of the visible matter in the galaxy put together.  This was way too much to be accounted for by something like diffuse dust clouds or other agglomerations of non-luminous, but completely ordinary, matter.  Rubin nicknamed the invisible stuff dark matter, more or less as a placeholder name until the physicists could figure out what the stuff was, something most researchers figured would be accomplished in short order.

Almost fifty years later, we still are hardly any further along.  Better measurements have confirmed that there is way more dark matter than ordinary matter; Rubin's estimate was spot-on, and current data indicates that 27% of the universe's total mass is dark matter, as compared to only 5% ordinary matter.  (The other 68% is an even more mysterious thing called dark energy, about which the astrophysicists are even more completely, um, in the dark.)

Every attempt to figure out the nature of dark matter -- or even to detect it by anything else but its gravitational effects on the galactic scale -- has resulted in failure.  The leading candidate, called weakly interacting massive particles (WIMPs), has been the subject of repeated detection attempts, and every single one of them has generated "null results."

Which is science-speak for "bupkis."

At some point, you have to wonder if the scientists are going to give the whole thing up as a bad job.  The problem is, if that happens you have 95% of the universe made of stuff we can't account for, which isn't a state of affairs anyone is happy with.

So a team at the National Institute of Standards and Technology is giving dark matter one more chance to show itself, using the only way in which we're certain it interacts with ordinary matter -- gravity.

The trouble is, gravity is a really weak force.  It's only a big player in our lives because we live on a massive chunk of rock, big enough to have a significant gravitational field.  Of the four fundamental forces -- gravity, electromagnetism, and the weak and strong nuclear forces -- gravity is weaker than the next in line (electromagnetism) by a factor of 10 to the 36th power.

So gravity is 1,000,000,000,000,000,000,000,000,000,000,000,000 times weaker than the electromagnetic force that holds molecules together, generates static electricity, and toasts your bread in the morning.

How on earth could you detect something that small, when even a trace of a stray electrical field could overwhelm it by many orders of magnitude?  The NIST scientists think they have the answer: an array of over a billion tiny, incredibly sensitive pendulums, each only a millimeter long, shielded and then cooled to near absolute zero to minimize interference from other forces.

[Image licensed under the Creative Commons Ben Ostrowsky, Foucault's Pendulum, CC BY 2.0]

There are four possibilities of what could happen to the array:

  • Nothing.  Then we're back to the drawing board.
  • Motion of one or two pendulums only.  This is probably due to interaction with an ordinary matter particle, which would hit a pendulum and stick, causing it to swing but leaving the ones around it unaffected.
  • Chaotic or random movement in a number of the pendulums.  This "noise" would most likely be caused by a fluctuation in an electric field -- i.e. the array wasn't well enough shielded.
  • A coordinated "ripple" passing through the detector, setting more or less a straight line of the pendulums swinging.  This, the researchers say, would be the signal of a dark matter particle zooming through the array, and its gravitational ripple streaking across in a specific direction.

Of course, even if the best possible outcome -- option #4 -- occurs, it still doesn't tell us what dark matter is.  After all, Vera Rubin's research in the 1970s showed that it interacts gravitationally with ordinary matter (i.e., we already knew that).  But at least we'll have a demonstration that it exists, that we're not looking at something like the nineteenth century's luminiferous aether, the mysterious substance that supposedly was the medium through which light waves propagated, and was shown not to exist by the Michelson-Morley interferometer experiment (and the nature of light propagation ultimately explained by Einstein and others, decades later).

So I'll be eagerly awaiting the outcome.  Right now, the array is still in development, so it will be a while before we can expect results.  But if it generates positive results, it'll be the first conclusive demonstration that we're talking about something detectable right here on Earth, not just by its effects on distant galaxies.

Of course, that still leaves us with the other 68% unknown stuff to explain.

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

Have any scientifically-minded friends who like to cook?  Or maybe, you've wondered why some recipes are so flexible, and others have to be followed to the letter?

Do I have the book for you.

In Science and Cooking: Physics Meets Food, from Homemade to Haute Cuisine, by Michael Brenner, Pia Sörensen, and David Weitz, you find out why recipes work the way they do -- and not only how altering them (such as using oil versus margarine versus butter in cookies) will affect the outcome, but what's going on that makes it happen that way.

Along the way, you get to read interviews with today's top chefs, and to find out some of their favorite recipes for you to try out in your own kitchen.  Full-color (and mouth-watering) illustrations are an added filigree, but the text by itself makes this book a must-have for anyone who enjoys cooking -- and wants to learn more about why it works the way it does.

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



Monday, October 19, 2020

Knots, twists, and meaning

One of the most curious relics of the past, and one which is a persistent mystery, is the quipu (also spelled khipu) of Andean South America.

A quipu is a linked series of knotted, dyed cotton strings, and were apparently some kind of meaningful device -- but what their meaning was is uncertain, thanks to the thoroughness and determination of Spanish priests in the sixteenth century to destroy whatever they could of the "pagan" Inca culture.  The result is, there are only 751 of them left, which is a pretty small sample if you're interested in decipherment.

An Incan quipu in the Larco Museum, Lima, Peru [Image licensed under the Creative Commons Claus Ableiter nur hochgeladen aus enWiki, Inca Quipu, CC BY-SA 3.0]

A number of attempts have been made to understand what the patterns of knots meant, but none of them have really panned out.  Some of the possibilities are that they were devices for enumeration, perhaps something like an abacus; a literary device for recording history, stories, or genealogies; or census data.

In fact, the jury's still out on whether they encode linguistic information at all.  An anthropologist named Sabine Hyland has suggested that they do; the color, position of knots, and even the ply of the string combine in 95 different ways to represent a syllabic writing system, she says, and claims that they were intricate family records.  If she's right, the burning of the Incan quipus represents a horrific eradication of the entire cultural history of a people -- something the invading Europeans were pretty good at.

The reason the topic comes up is because of a paper that came out last week in Nature Communications that has a striking parallel to the quipu.  The paper, titled "Optical Framed Knots as Information Carriers," by Hugo Larocque, Alessio d'Errico, Manuel Ferrer-Garcia, and Ebrahim Karimi (of the University of Ottawa), Avishy Carmi (of Ben-Gurion University), and Eliahu Cohen (of Bar Ilan University), describes a way of creating knots in laser light that could be used to encode information.  The authors write:

Modern beam shaping techniques have enabled the generation of optical fields displaying a wealth of structural features, which include three-dimensional topologies such as Möbius, ribbon strips and knots.  However, unlike simpler types of structured light, the topological properties of these optical fields have hitherto remained more of a fundamental curiosity as opposed to a feature that can be applied in modern technologies.  Due to their robustness against external perturbations, topological invariants in physical systems are increasingly being considered as a means to encode information.  Hence, structured light with topological properties could potentially be used for such purposes.  Here, we introduce the experimental realization of structures known as framed knots within optical polarization fields.  We further develop a protocol in which the topological properties of framed knots are used in conjunction with prime factorization to encode information.
"The structural features of these objects can be used to specify quantum information processing programs," said study lead author Hugo Larocque, in an interview in Science Daily.  "In a situation where this program would want to be kept secret while disseminating it between various parties, one would need a means of encrypting this 'braid' and later deciphering it.  Our work addresses this issue by proposing to use our optical framed knot as an encryption object for these programs which can later be recovered by the braid extraction method that we also introduced.  For the first time, these complicated 3D structures have been exploited to develop new methods for the distribution of secret cryptographic keys.  Moreover, there is a wide and strong interest in exploiting topological concepts in quantum computation, communication and dissipation-free electronics.  Knots are described by specific topological properties too, which were not considered so far for cryptographic protocols."

A few of the research team's knotted beams of light

I have to admit that even given my B.S. in physics, most of the technical details in this paper went over my head so fast they didn't even ruffle my hair.  And I know that any similarity between optical framed knots and the knots on quipus is superficial at best, but even so, the parallel jumped out at me immediately.  Just as the Incas (probably) used color, knot position and shape, and ply of the string to encode information, these scientists have figured out how to encode information using intensity, phase, wavelength, polarization, and topological form to do the same thing.

Which is pretty amazing.  I know the phrase "reinventing the wheel" is supposed to be a bad thing, but here we have two groups independently (at least, as far as I know) coming up with analogous solutions for the same problem -- how to render information without recourse to ordinary symbology and typography.

Leaving me awestruck, as always, by the inventiveness and creativity of the human mind.

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

Have any scientifically-minded friends who like to cook?  Or maybe, you've wondered why some recipes are so flexible, and others have to be followed to the letter?

Do I have the book for you.

In Science and Cooking: Physics Meets Food, from Homemade to Haute Cuisine, by Michael Brenner, Pia Sörensen, and David Weitz, you find out why recipes work the way they do -- and not only how altering them (such as using oil versus margarine versus butter in cookies) will affect the outcome, but what's going on that makes it happen that way.

Along the way, you get to read interviews with today's top chefs, and to find out some of their favorite recipes for you to try out in your own kitchen.  Full-color (and mouth-watering) illustrations are an added filigree, but the text by itself makes this book a must-have for anyone who enjoys cooking -- and wants to learn more about why it works the way it does.

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