A whole lot of shakin'

I didn't realize how complicated it is to calculate the magnitude of an earthquake.

Most of us are probably familiar with the Richter Scale, the one most commonly used in the media.  It was developed in 1935 by seismologist Charles Francis Richter to give a standard scale to measure the power of earthquakes.  The scale is logarithmic; each increase in one on the scale represents a ten-fold increase in intensity.  The scale is based upon the displacement amplitude on a seismograph at a distance of one hundred kilometers from the epicenter, starting with a magnitude 0 earthquake causing the needle to move with an amplitude of one micron.  The scale extends up to an unspecified "greater than 9" -- because at that point, pretty much everything in the vicinity, including the seismograph, gets completely pulverized.

When you start looking more closely, though, the problems with the scale start to become obvious.  First of all, if the measurement is being made one hundred kilometers from the epicenter, the terrain in between is a significant factor.  Tremors passing through material with a high amount of shear (such as sand or mud) will lose intensity fast, as compared to ones going through a material that is rigid (such as solid rock).  Second, the origin of the earthquake usually isn't at the epicenter, which is the point on the surface nearest the source; the origin is the hypocenter, directly underneath -- but which can be at any depth from right near the surface down to hundreds of kilometers down.  (The deepest earthquake ever recorded was a minor tremor off the island of Vanuatu in 2004, which had a hypofocus 736 kilometers deep.)  Then there's the fact that earthquakes can be of different durations -- a less powerful earthquake that lasts longer can do as much damage as a more powerful, but shorter, tremor.

Another problem is that earthquakes can result in differences in the oscillation of the waves relative to the direction they're moving.  This is largely due to the fact that there are three basic sorts of faults.  There are thrust faults or convergent faults, where two tectonic plates are moving toward each other; what happens then can be one plate being pushed underneath the other (subduction), which is what causes the quakes (and the volcanoes) in Indonesia and Japan, or the two plates kind of smashing together into a jumble, which is the process that created the Himalayas.  There are extension faults or divergent faults, where the two plates are moving apart; this usually creates smaller but more frequent quakes, and lots of volcanism as magma bubbles up from the underlying mantle.  This is happening in Iceland, and is also the cause of the Great Rift Valley in Africa, which will eventually peel off the Horn of Africa (Somalia and parts of Ethiopia, Kenya, and Tanzania) and open up a new ocean.  Last, there are strike-slip faults or transform faults, where the plates are moving in opposite directions on each side of the fault, such as the famous San Andreas Fault in California.

Map of the (known) tectonic plates [Image is in the Public Domain courtesy of NASA/JPL]

The problems with the Richter Scale have led to the development of several other scales of intensity, such as the Surface-wave Magnitude Scale (which is pretty much just what it sounds like, and doesn't take into account source depth), the Moment Magnitude Scale (which is based on the amount of energy released as measured by the amount and distance of rock moved), the Duration Magnitude Scale (which figures in how long the tremor lasts), and so on.  But these all use different numerical benchmarks, and given that the Richter Scale is more widely known, a lot of people have continued to use that one despite its downsides.

The reason all this comes up is a new study from the University of Southampton that has identified evidence of what appears to be the biggest earthquake known; an almost unimaginable 9.5 on the Richter Scale quake that happened in Chile 3,800 years ago.  Trying to find the epicenter brings up yet another problem with measuring quake intensity, because the evidence is that this particular quake originated from the rupture of a part of the thrust fault between the Nazca Plate and the South American Plate off the coast of the Atacama Desert -- a rupture that was one thousand kilometers long.

The result was a tsunami that deposited marine sediments and fossils of oceanic animals several kilometers inland, and then traveled across the Pacific Ocean and slammed into New Zealand, tossing boulders the size of cars over distances of hundreds of meters.  That region of the Atacama Desert had been inhabited prior to the quake -- astonishing considering how dry and inhospitable the place is -- but it was (understandably) abandoned by the survivors for a long while afterward.

"The local population there were left with nothing," said geologist James Goff, who co-authored the study.  "Our archaeological work found that a huge social upheaval followed as communities moved inland beyond the reach of tsunamis.  It was over a thousand years before people returned to live at the coast again, which is an amazing length of time given that they relied on the sea for food.  It is likely that traditions handed down from generation to generation bolstered this resilient behavior, although we will never know for sure.  This is the oldest example we have found in the Southern Hemisphere where an earthquake and tsunami had such a catastrophic impact on people’s lives.  There is much to learn from this."

The obvious next question is, "Could this happen again?"  The answer is not just that it could, but it will.  Probably not in the same spot, but somewhere along the many tectonic boundaries in the world.  Nor do we know when.  Earthquake prediction is very far from an exact science.  We have instruments like strain gauges to estimate the tension rock is experiencing, but that doesn't tell you what's going on deeper in the ground, nor when the rock will fracture and release that energy as an earthquake.  Predicting volcanic eruptions is much easier; vulcanologists have gotten pretty good at detecting magma movement underground, and recognizing when a volcano is likely to blow.  (This is why the ongoing hoopla about the Yellowstone Supervolcano is all hype; sure, it'll probably erupt again, but some time in the next hundred thousand years or so, and it's showing no signs of an imminent eruption.)

The Earth is a dynamic planet, and the plates on the surface are in constant motion, jostling, coming together, moving apart, a bit like ice sheets on a river when they begin to break up in the spring.  You can't help but be fascinated by the amount of power it's capable of -- a catastrophic release of energy so large that the scales we've developed to measure such things are all but incapable of expressing.

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What's the harm?

One of the questions I get asked pretty frequently, apropos of my work as a debunker and critic of woo, is "What's the harm?"  So what if people want to believe in astrology or divination or whatnot?  Surely it's harmless to check your horoscope daily or make your decisions on your latest Tarot card reading.  Just leave people alone and let them do whatever floats their boat.

The problem is, these kinds of beliefs aren't harmless.  I see three different ways in which such practices generate a potential for direct harm.  First, belief in something despite a complete lack of evidence establishes a habit of credulity; so your acceptance of something fairly benign (like astrology) can predispose you to believe something that isn't benign at all (like the claim that homeopathy is a legitimate way to treat human disease).  Once you've fallen for one bit of nonsense, the next one is that much easier to fall for.

Second, a great many of the people who are purveyors of this nonsense are in it for one reason: money.  They are happy to relieve you of your hard-earned cash in exchange for a tissue of lies.  One good example of this is faith healing, which even today brings its practitioners millions of dollars a year, ripped off from the gullible and the desperate.

Last, though, is that some forms of woo -- the ones that, like homeopathy and faith healing, claim to alleviate something real, something with an actual physical cause -- lead people to abandon practices that might actually work, and seek out what amounts to magic.  And that brings me to Christina Lopes, a self-styled "healer and life coach."

I ran into Christina Lopes over at the r/skeptic subreddit, where someone posted one of her videos along with some rather acidic commentary.  I'd never heard of her, so I decided to watch the video.

In order to save you a half-hour of your life that you'll never get back, allow me to summarize the main points.

First, she says we're all "ascending."  Our bodies, supposedly, are in the process of transforming into something "higher."  What she means by "higher" is never defined in any rigorous way, but apparently it has to do with two things -- your "light quotient," the amount of light your body can hold, and the rate at which you're vibrating.  Lopes subscribes to the idea that the faster something is vibrating, the better it is, an idea you'd think anyone would realize is false just based on sound waves.  (If you don't believe me, you listen to a guy playing a solo piccolo for an hour, and I'll listen to a guy playing a cello, and we'll see who has a headache afterward.)  Better still, consider that claim applied to the light she likes talking about so much; compare the effect on the body of very high-frequency light (e.g. gamma rays) as compared to lower-frequency light (e.g. visible light).

I know which one I'd want bombarding me.

[Image licensed under the Creative Commons Salma2789, Spirit man, CC BY-SA 4.0]

So far, nothing so different than a lot of these kinds of wacky spiritual claims.  But then she goes into the health effects of "ascension," and that's where things get dangerous.

She says that when you start "ascending," it's hard on the body.  Our cells (which she claims are sentient) "literally purge themselves of lower energy."  If she means "literally" literally, it's hard to fathom why the scientists have never detected this energy purge, since you'd think it would be measurable somehow.  But she goes on to tell us that this phase of things creates some real physical symptoms -- muscle inflammation, which "could be anywhere" including your chest, and mental agitation (disjointed, dark, or violent thoughts).  If this happens to you, she says, don't be afraid, because fear is a "dense emotion" which will just make things worse.  You should also increase water intake, because "water is a conductor of energy."  (Good idea, but for the wrong reason.)

At this point, she's moved into the realm of advice that could cause actual harm.  The symptoms she describes -- inflammation and mental agitation -- can be the result of real, and potentially serious, medical conditions.  Believing her bullshit explanation about this being just a natural result of "ascension," and nothing to worry about, means someone might forgo legitimate medical treatment, perhaps until it's far too late.  (For fuck's sake, chest pains and mental agitation are signs of a heart attack.  If you're feeling this, don't mess around with wondering if you're "ascending," get your ass to a hospital now.)

It's to be hoped that the scope of damage she's doing is limited; not only is she not especially widely-known (I couldn't find any mention of her on RationalWiki, for example), but fortunately a lot of the little aches and twinges we experience, and many of the disjointed or chaotic thoughts, are completely normal and not the sign of any dire problems.  But one person dying of cancer because he thought his symptoms were signs of "ascension," and he put off seeing a doctor, is way, way too many.

It's amazing how quickly beliefs can move from "weird but basically harmless" to "actively dangerous."  The problem is, setting aside rational thought so you can accept the former means you'll be much more likely to accept the latter without question.  All the "your body is light" and "high-frequency vibrations are good" stuff is innocuous enough; but as you can see from Lopes's video, those lead directly to "here are some real physical symptoms you shouldn't worry about."

I don't see any way to stop her from posting her videos; her advice is mostly vague enough that trying to establish culpability for harm in a legal sense would be next to impossible.  Failing that, the best we can do is to stress once again how important education in critical thinking is.  Not to mention a solid background in actual science.  If enough people call this out as the bullshit it is, purveyors of snake oil like Christina Lopes will be permanently out of a job.

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A window on deep time

The ultimate speed limit in the universe -- unbreakable, as far as our current understanding of science goes -- is the speed of light, 3x10^8 meters per second.

Most people think of spaceships when this comes up, and certainly it's easy to conceptualize this in terms of objects moving.  What might be less intuitive is that this speed limit also applies to the movement of information.  If an event occurs, the soonest we can know about it is the amount of time it takes for light to get from there to here.  So -- to use an oft-cited, if a little ridiculous, example -- if the Sun were to disappear, we wouldn't know about it for 8.317 minutes, because the Sun is 8.317 light-minutes from Earth.

So we're always looking into the past, and the farther away something is, the farther into the past we're looking.  You see the Sun as it was a little over eight minutes ago.  The distance between the Earth and Mars varies, given that both are in elliptical orbits around the Sun and moving at different angular velocities, but on average Mars is a bit under thirteen light-minutes from us, which is why the Mars rovers had to be able to sense their environment and function independently.  If here on Earth we saw through its camera that the rover was heading toward the edge of a cliff, and we sent a message saying "Stop!  Turn around!", it would be far too late.  Not only would that image have taken (again, on average) thirteen minutes to get to us, it would take another thirteen minutes for our command to get back to it.  By that time, it would be a heap of scrap metal on the bottom of the cliff.

And so on.  We see the nearest star to the Sun, Proxima Centauri, as it was 4.3 years ago.  The brightest star in the night sky, Sirius, in the constellation of Canis Major, is 8.6 light years away.  Vega, brightest star in the constellation Lyra -- the one made famous as the home of the super-intelligent aliens in the movie Contact -- is twenty-five light years away.  When we see the other side of our own galaxy, we're seeing what it looked like around a hundred thousand years ago (at which point we were in the middle of an ice age, and our distant ancestors were just on the point of leaving the African savanna).  The nearest galaxy to the Milky Way, the Andromeda Galaxy, is 2.5 million light years away -- when the light from it left its source, there weren't any modern humans, and the species Homo habilis had just mastered the use of tools.

But this ultimate speed limit means there's also a limit to how far away we can see.  The Big Bang is estimated to have happened 13.8 billion years ago, so the Cosmic Microwave Background Radiation -- the remnant radiation from only a short time after the universe formed -- has been traveling toward us for 13.8 billion years, and represents the most distant thing it's even theoretically possible to see.  There is certainly stuff farther away from us than that; for one thing, in the intervening 13.8 billion years, the universe has been continuously (although not uniformly) expanding, so the radius of the universe is way bigger than 13.8 billion light years.  But whatever is farther away than that is completely out of our reach, no matter how good our telescopes get.  Our knowledge of anything beyond the distance limit imposed by the speed of light is zero, and always will be.

That doesn't mean we can't see a long way, though.  Last week in Nature it was announced that the Hubble Space Telescope had captured a photograph of the most distant star ever seen, at 12.9 billion light years away.  The image was distorted by gravitational lensing, when the light from a luminous object passes through a region of space warped by a large mass, but the astronomers are saying the source is too small to be a galaxy or star cluster.  We know how far away it is because of its red shift, the stretching of the wavelength of light when its source is moving away from us, combined with Hubble's Law, which connects the amount of red shift with the object's distance.

The image containing Earendel [Image is in the Public Domain courtesy of NASA/JPL]

The astronomers named the star Earendel -- an Old English word meaning "morning star."  If you immediately thought of J. R. R. Tolkien when you saw this, so did I; the name of the character Eärendil in The Silmarillion was pilfered directly from Old English, of which Tolkien was a noted scholar.  Tolkien said he was struck by the word's "great beauty," and adopted it into his conlang Quenya (one of the Elvish languages in his stories).  In Quenya, Eärendil means "lover of the sea," but interestingly, at the end of The Silmarillion, when Morgoth is defeated, the last remaining Silmaril -- the phenomenally beautiful jewels created by the Elf Fëanor, that were the cause of the entire conflict in the book -- is taken by Eärendil up into the sky, where it becomes the "morning star," or Venus.  So the myth and Tolkien's story come full circle.

In any case, the fact that we can see something that far away is kind of astonishing.  When the light Hubble captured from Earendel left its surface, it was 8.4 billion years before the Earth would form.  In fact, Earendel almost certainly doesn't exist any more; the current guess is that it is (or was) a supergiant, meaning it had high temperatures and luminosity, and would have burned through its fuel long ago.  What's left of it is almost certainly a black hole.  But when that occurred is impossible to know, as the light released when it went supernova still hasn't gotten here.

But still, this is an incredible window on deep time.  I have to wonder what other amazing images we'll get to see soon when the new James Webb Space Telescope, which has better resolution than Hubble, starts sending us data this summer.  I think we've only begun to explore what is out there in the far reaches of the universe, and the far distant past.

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Puppy dog eyes

We have two dogs, our big thirty-kilogram galumphing galoot, Guinness:

And his comical sidekick, little eight-kilogram Cleo:

They are best buddies and love to be outside playing together, which is as fun for us as it is for them because watching them is so damn comical.  Cleo is about twice as fast as Guinness is, and runs in circles around him, sometimes attempting a full-on body slam that is completely unsuccessful because of this inconvenient law of physics called Conservation of Momentum.  Usually Cleo just ricochets off Guinness's side like a ping-pong ball off a boulder, but it never seems to discourage her from trying again.

Remember Chester and Spike, from Looney Tunes?

Yeah, that's Guinness and Cleo, right there.

Carol and I frequently laugh ruefully at how many times a day we say, "They are so stinkin' cute."  I mean, it's true, but it's kind of ridiculous how much they have us wrapped around their paws.  Guinness, especially, has an incredibly expressive face, and when we talk to him he gazes up at us adoringly as if he's hanging on every word we say.  The funny thing is that it doesn't, in fact, matter what exactly it is we're saying.  We could be explaining to him something like why it is not a good idea to eat the sofa, or reading to him from a text on economics for that matter, and he will still stare at us as if to say, "My god, yes!  That's genius!  I never would have thought of that!"

A paper presented last week at the annual meeting of the American Association for Anatomy has shown that this ability dogs have to communicate with their facial expressions is no accident.  Researchers Anne Burrows and Kailey Omstead of Duquesne University did a detailed comparison of mimetic muscles -- the tiny muscles in the face that allows us (and other animals) to alter our expressions -- between domestic dogs and wolves, and they found something fascinating.

To understand what's going on here you have to know a little about muscle composition.  In the broadest-brush terms, mammals have two types of skeletal muscles; fast-twitch muscles, which can contract rapidly and powerfully but aren't able to maintain sustained contraction, and slow-twitch muscles, which are much slower to react but can remain contracted for long periods.  Our upper bodies are predominantly fast-twitch muscle; this is why lifting a heavy weight with your arms is doable, but keeping it lifted for more than a few minutes is excruciatingly difficult.  On the other hand, the three big muscle groups in your upper legs -- the quadriceps, biceps femoris (hamstrings), and gluteus maximus -- have to maintain tension just to allow you to support your own body weight, but can do so for hours without fatiguing.  One of the reasons for this is that slow-twitch muscles have a protein called myoglobin, which improves the ability of the muscle to absorb oxygen from the blood; it's this protein that makes the dark meat of a chicken dark.  And notice which two muscles are dark meat -- the leg and the thigh, same as us.

Not that I'm recommending eating humans, mind you.

Anyhow, back to dogs.  The analysis by Burrows and Omstead found a striking difference in the muscle composition of dogs' faces as compared to wild wolves; dogs' mimetic muscles are predominantly fast-twitch, while wolves' are predominantly slow-twitch.  What this means is that dogs' faces are much quicker to change in expression.  Wolves do have expressions; one obvious example is the wrinkled forehead and retracted lip that signifies aggression or anger.  But domestic dogs can alter their expressions rapidly and subtly in response to the circumstances, allowing them to communicate with humans in a way few other animals can.

"Dogs are unique from other mammals in their reciprocated bond with humans which can be demonstrated though mutual gaze, something we do not observe between humans and other domesticated mammals such as horses or cats," said study co-author Anne Burrows.  "Our preliminary findings provide a deeper understanding of the role facial expressions play in dog-human interactions and communication."

This difference between dogs and their wolf cousins is almost certainly due to unwitting artificial selection by humans -- our ancestors back in the Paleolithic, when we have the first evidence of dog/human cohabitation, selected the puppies that were the most responsive to us as companions.  (At the same time, selection was going on for other features as well, such as size, color, and skill at tasks like herding or retrieving.)  Over the intervening years this selection has actually altered the composition of the muscles in our canine friends' faces, so that they're even better at communicating with us.

Which I think is amazingly cool.  But I'd better wrap this up, because Guinness just looked at me with a furrowed brow and a head tilt, which means he wants his breakfast.  You know how it goes.

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Jars, bones, and solar calendars

Today we're back to the subject of cool archaeological discoveries, thanks to a couple of loyal readers of Skeptophilia who sent me links about recent research giving us a lens into humanity's past.

The first has to do with the discovery of 65 giant sandstone jars that were found buried in Assam, in the northeastern part of India.  "Giant" is no exaggeration; these jars average three meters tall and two meters wide, and some weigh over three hundred kilograms.  Stone artifacts are notoriously hard to date accurately -- the archaeologists believe that they were created some time before 1300 C.E., but might be as much as two millennia older than that.  Just about everything about them -- who created them and why, and why they were buried in the site -- is unknown.  They must have had some pressing reason, as fashioning (and then burying) tons of sandstone into a lidded jar is no inconsequential amount of work.  But the jars haven't yielded any contents of note that might account for their creation.

But the story has an interesting legendary twist.  The Naga people, who are one of the main ethnic groups in the region, say they've stumbled upon such jars before, and found them filled with bodily remains and valuables -- i.e., that they were used in burial rituals.  However, they're insistent that they (well, their ancestors) weren't the ones who made the jars.  The jars were created, they say, by a mysterious people called the Siemi -- a race of small, dark-skinned people who dwelled in the forest, and were known to be "uncanny" and adept at magic.  In particular, they were skilled at making deo-moni, or "spirit beads," that conferred power upon the wearer.  Well, in the thirteenth century C.E., when the region was overrun by the Bodo-Kachari, the king caught some of the Siemi and wanted to know how the beads were made.  The Siemi refused, even under torture, to reveal the secret.  Infuriated, the king wiped out the entire culture, except for a few survivors who disappeared into the jungle, where they still live today, in secret.

The legend has a lot of commonality with the Irish sídhe, which is sometimes translated as "fairies" or "elves," and who are supposedly the descendants of the Tuatha Dé Danann, a magical race who were the first inhabitants of Ireland.  When the sídhe were defeated and ousted, they went into hiding, and became the "good people" of wild areas, for whom the appellation "good" is more appeasement than it is accurate, because they were tricksters and sometimes outright dangerous.  (The famous banshee -- Irish bean sí -- is one of them, and the name translates to "fairy woman")

Our second story comes to us from Peru, where a remarkable structure in the desert known as Chankillo has been found to be a solar calendar.  It's a curious-looking place, thirteen massive stones in a line down the crest of a hill, each with a slot cut into it.

[Image licensed under the Creative Commons Juancito28, Foto torres de chankillo, CC BY-SA 4.0]

Excavation of the site not only uncovered a fortified temple, but clarified the function of the towers.  They are angled so that the rising Sun shines straight down the slot of each tower in turn as the point on the horizon drifts southward in summer and northward as winter approaches.  The angle at which the sunlight at dawn strikes the slots makes the array act as an enormous sundial -- but keeping track of the day of the year rather than the hour of the day.  Scientists have suggested that careful observation of this angle could have allowed its creators to estimate the day of the year to an accuracy of a day or two on either side, a highly useful skill in an area of extremes of seasonal rainfall and drought.

The people who built Chankillo are called the Casma-Sechin culture, but they're almost a complete mystery.  The earliest traces of the Casma-Sechin are in the region of Chankillo all the way back in 7600 B.C.E., and for the next seven millennia they left a continuous (if sparse) archaeological record of pottery, textiles, and stone structures.  There are signs of hostile invasions toward the end of their rule, and evidence of complete destruction in around 100 B.C.E. -- leaving behind traces of a mysterious people about whose ethnic affinities, language, and culture we still know next to nothing.

Our final story comes to us from Hungary, where relics of an ancient civilization of conquerors have yielded secrets of their origins.  I'm not talking about the infamous Huns, who ruled much of central and eastern Europe in the fifth century C.E., but the Avars -- who were in charge afterward and for almost three times longer, only collapsing under pressure and outright attacks from the Franks (to the north and east) and the Slavs (from the south and west) in around 900 C.E.  

Despite their being well-attested in the records, nothing was known about where they came from, nor whether they were allied to another group that went by the same name in the Caucasus Mountains.  But now, a DNA analysis of bones from eight Avar graves in Hungary has found their surprising origins -- thousands of kilometers away in what is now eastern Mongolia and northern China.

"The Avars did not leave written records about their history and these first genome-wide data provide robust clues about their origins," said Choongwon Jeong of the Max Planck Institute of Evolutionary Archaeology.  "The historical contextualization of the archaeogenetic results allowed us to narrow down the timing of the proposed Avar migration.  They covered more than five thousand kilometers in a few years from Mongolia to the Caucasus, and after ten more years settled in what is now Hungary.  This is the fastest long-distance migration in human history that we can reconstruct up to this point."

What could have impelled them to haul ass across the steppe is still uncertain, but a good guess is that these are the remnants of the ruling class of the Rouran Empire, who ruled what is now the state of Xinjiang, China and much of Mongolia, only collapsing under pressure from the Turks and Chinese in the mid-sixth century C.E. -- right around the time the Avars tore into eastern Europe.

And that's this week's cool stuff from the ancient world.  And thanks to the readers who sent me the links -- keep 'em coming.  I'm always eager to learn about stuff I didn't know, and all three of these were completely new to me.

So much to know, so little time.

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Can you hear me?

Most of you have probably heard of SETI -- the Search for Extraterrestrial Intelligence.  SETI is an umbrella term that links dozens of different projects and approaches, but is most often connected to the SETI Institute, founded in 1984 specifically to address the question of whether extraterrestrial life exists, and if so, whether we could communicate with it.

Just detecting the evidence of an extraterrestrial intelligence (assuming there is any) is fraught with difficulties.  To begin with the most glaring problem, there are an estimated 250 billion stars in the Milky Way alone, which makes for a hell of a survey area.  And even if you start by looking only at the relatively nearby ones, there's still the question of what exactly you're looking for.  Radio wave signals are an obvious choice, and we have radio telescopes that do exactly that, but to start with, that's an awfully broad band of frequencies (between 300 and 3,000 kHz).  Even to pick it up would mean not only listening to the right region of space, but being tuned to the right frequency at the right time.

But there are other problems.  Suppose there is an intelligent civilization on a star 25 light years from us, and they're sending out a radio signal of some sort.  There are two possibilities, of which the first is that the signal comes from their own intraplanet communications, like the oft-discussed bubble of transmissions from our early radio and television, which is currently carrying snippets of I Love Lucy and Gilligan's Island that are sweeping past planets and stars seventy-odd light years away.  The second is that the signal is a deliberately-deployed beacon, an interstellar lighthouse specifically for communication with other civilizations.

Each of these presents its own problems.  In the first case, the bubble of radio transmissions gets fainter and fainter as it expands, according to the inverse-square law of intensity.  So as funny as it is to think of some extraterrestrials on the third planet of Vega judging humanity by The Beverly Hillbillies, my suspicion is that by the time it arrived the signal would be so faint that it would be nearly impossible to detect.  (And that's not even considering degradation of the signal from passing through interstellar dust and gas.)

The second sounds more promising, but it too has a difficulty.  If you're beaming a signal toward another star, you get an improvement in intensity because the logical way to do it is to collimate the beam as tightly as possible.  You're still subject to the inverse-square law, but a tightly-collimated beam has such a narrow cross-section and high intensity that it could retain its power for a great deal longer.  (Consider that even back in 1962, the Lunar Laser Ranging experiment successfully collimated a laser tightly enough that they were able to reflect it from the Moon, and detect the reflected pulse back here on Earth 2.6 seconds later.)  But the narrower your beam, the smaller the area of your potential target.  You would have to have a good reason to choose a particular star, or at least a region of space, or your signal would miss detection entirely.

So broad signal/low intensity, narrow signal/smaller sample size.  There doesn't seem to be any way around those equal-and-opposite problems.

There's also the difficulty of how exactly you could encode a message that would be understandable to a non-human intelligence.  Once the signal is received, how do you make sure the aliens can figure out what it's saying?  This question has most recently been tackled by a team led by Jonathan Jiang of NASA's Jet Propulsion Laboratory, and this is in fact why the topic comes up.  Jiang has made a proposal to send out a message aimed toward the densest patch of stars in the night sky, in the direction of the galactic center in the constellation Sagittarius.  To be successful such message would have to contain enough information to (1) tell its recipients that it's not just an anomalous radio blip from a natural source, (2) give an indication of how to translate it, and (3) tell the extraterrestrials a little about where and who we are.

Jiang's proposal addresses all three.  It first contains an easily-deciphered binary code that links to our base-10 counting system, and lists off the first 24 prime numbers.  (Shades of the wonderful movie Contact, in which SETI researcher Ellie Arroway recognized that there is no naturally-occurring process that would produce blips in prime-number groups.)  Once that (hopefully) convinces the aliens that we're relatively intelligent, the message goes on to communicate our understanding of time (using a standard time interval -- the spin-flip transition of hydrogen -- that would hopefully be known to any technological species).  There would be information using this universal clock telling when the signal was sent, which would tell the recipient how far away we are.  Last, there would be a binary-encoded sketch of two humans, and some basic information about our biology and biochemistry, reminiscent of the gold plaques placed on Pioneer 10 and Pioneer 11 when they were launched in (respectively) 1972 and 1973.

[Image is in the Public Domain courtesy of NASA/JPL]

There's also the question, of course, of whether alerting the aliens to our presence (and giving them directions for how to get here, no less) would be a good thing.  Back in 2011, physicist Stephen Hawking warned us that first contact might not be quite as cheery as it was in Star Trek.  "We only have to look at ourselves to see how intelligent life might develop into something we wouldn’t want to meet," Hawking said.  "I imagine they might exist in massive ships, having used up all the resources from their home planet.  Such advanced aliens would perhaps become nomads, looking to conquer and colonize whatever planets they can reach.  If aliens ever visit us, I think the outcome would be much as when Christopher Columbus first landed in America, which didn’t turn out very well for the Native Americans...  They could be billions of years ahead of us technologically.  If so, they will be vastly more powerful and may not see us as any more valuable than we see bacteria."

Which is both humbling and scary.  The positive side of all this is that even if the aliens do turn out to be hostile, they're still very far away.  Let's say that there is intelligent life on a planet orbiting Gliese 581 (the home of the first Earth-like planet ever discovered).  Gliese 581 is 20.4 light years away, so it's in our general neighborhood.  If we sent a signal to them saying hello, they'd get it 20.4 years from now, and we'd receive their response in (minimally) 40.8 years.  If instead of just sending a radio response back they were offended by our sending them biochemistry and pictures of naked people, and launched an attack fleet, it'd be even longer before they arrived here.  So even if they're hostile, we're safe for some time.

That's assuming that they haven't found some way to overcome the light-speed barrier and get here at superluminal velocities.  In that case, we might well be fucked.

But, like Hawking, I still think we should do it.  Finding out we're not alone in the cosmos would be the most stupendous discovery humans have ever made.  Jiang and his team don't have a proposed date for beaming out our "Can you hear me?" message, but there's no reason why it couldn't be done soon.  And if it does reach an extraterrestrial intelligence, we'll just have to cross our fingers and hope it's not the Daleks, Stenza, Sontarans, or the Crystalline Entity.

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A botanical mystery

One of the most pernicious tendencies in human thought is our arrogance.  The attitude that we know all there is to know, understand the universe, have it all figured out, has led to more oversights, blunders, and outright idiocy than anything else I can think of.

What's striking is how often our intuition about things turns out to be wrong.  Consider, for example, the following question: of all the species currently alive on Earth, what percent of them are known to science -- identified, observed, collected, or studied?

The best estimate we have, from a 2011 study that appeared in PLoS Biology, blew my mind, and as a 32-year veteran of teaching biology, I was ready for an answer lower than my expectation.  You ready?

Fourteen percent.

The study estimated the total number of species on Earth at 8.7 million, 86% of which are unknown to science.  This is staggering.  We are fooling around with our climate and ecosystems, bulldozing our way through our own living space, and potentially destroying millions of species we didn't even know existed.

To be fair, our ignorance about the organisms we share the planet with is at least in part not our fault.  If, like me, you live in a comfortable home with amenities and no particular need to venture off into the wilderness, it would be easy to think that our familiar surroundings are all there is.  The truth is a little humbling, and far more interesting.  I remember my first trip to Hawaii, back in 2003, when we spent our time on the lovely island of Kauai.  While we were there, we took a boat trip out to the Na Pali Coast, a stunning terrain that has a few narrow sandy beaches, but almost immediately beyond them wrinkles up into mountains that are in places damn near vertical.

Carol and I at Na Pali

The guide on the boat told us something that I found astonishing; large parts of Waimea Canyon and Koke'e Parks, which lie inland from Na Pali, are completely unexplored.  Not only is it too steep for roads to be built, you can't even land a helicopter.  Hiking might be possible, but it's densely forested.  The combination has made the interior of these parks one of the few places in the United States where we can say with fair confidence that no human being has ever stood.

Add to that the fact that even more unexplored than some of the remote terrestrial regions are the deep oceans.  I've heard it said we know more about the terrain of the Moon than we do about the floor of the deep ocean -- I don't know if that's true, but it sure sounds plausible.

I'd like to consider, though, a more positive thought; that our lack of knowledge of other species on Earth means there is a lot out there that we could still potentially learn.  And sometimes that happens through unexpected channels.  In fact, the reason this whole topic comes up is because of an article last week in Atlas Obscura about a British botanist and biological artist named Marianne North (24 October 1830-30 August 1890), who traveled all over the world painting native plants in intricate detail -- and who captured an image of at least one plant nobody could identify.

The painting in question was made in Sarawak, one of two states of Malaysia that are on the island of Borneo.  Sarawak is a bit like Kauai; inhabited at the perimeter, but with an inland of rugged terrain and dense, nearly impenetrable forest.  Well, this kind of thing didn't stop North, who made some exquisite paintings of plants in Sarawak, including this one:

[Image is in the Public Domain]

The plant with the blue berries was unidentified -- some botanists thought it might be a member of the tropical genus Psychotria (in the coffee family, Rubiaceae).  But something about that didn't ring true.  None of the 1,582 catalogued species of Psychotria has blue berries -- all the known ones are red or pink -- and the arrangement of the leaves didn't look quite right.  So either (1) this one was an anomaly, (2) North painted the plant inaccurately, or (3) the identification was wrong.

Option (1) was a little far-fetched, but not outside the realm of possibility.  Option (2) struck most knowledgeable people as outright impossible; North was known for her absolute painstaking attention to minute detail.  So botanist and illustrator Tianyi Yu decided (3) had to be correct.  But how to find a single species of plant in an overgrown wilderness on the island of Borneo, which had avoided detection by other scientists for over a century?

Yu had a brainstorm; maybe it hadn't completely flown under the radar.  He decided to spend some time in the herbarium at Kew Gardens.  If you are ever in England, Kew is a must-see; it is home to one of the most amazingly complete collection of plants in the world, and is also stunningly beautiful, especially in spring and summer.  The herbarium contains collections of preserved plants stretching back to its founding in the middle of the nineteenth century, and currently houses over eight million specimens.

So saying it was a needle in a haystack is an understatement.  Yu had one thing going for him; North had been not only a meticulous artist, she was also conscientious about writing down where her paintings had been made.  This one was labeled "Matang Forest, Sarawak," and since the Kew specimens are catalogued not only by species but by location, it significantly narrowed down Yu's search.

And he found it.  A sprig of it was collected in 1973 and sent back to Kew, but was unidentified.  Yu studied both the specimen and North's painting, and concluded that it was a member of the genus Chassalia -- also in Rubiaceae, so the guess of Psychotria hadn't been that far off.

Further analysis by botanists confirmed Yu's surmise.  As the person who identified it as a previously-unrecorded species, Yu was given the honor of naming it.

And last year, it went down in the taxonomic records as Chassalia northi, in recognition of Marianne North's contributions to the field of botany.

So out there on the island of Borneo is a little shrub with white flowers and blue berries that we now have a name for because of a nineteenth-century adventurer/scientist/artist, a happenstance collection from 1973, and a diligent modern botanist determined to put the pieces together.  Just showing that we can still pick away at the sphere of our own ignorance -- but only if we are first willing to admit that there is a lot we still don't know about the world we live in.

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