Homing in on Tatooine

I remember the first time I ran into the concept that the Earth's relatively circular orbit might not be universal amongst the planets out there in the universe.

I shudder to admit that it was on the generally abysmal 1960s science fiction series Lost in Space.  The brave crew of the Jupiter 2 are stranded on a strange planet, and initially the whole place seems to be a frozen wasteland.  But after a journey via their "chariot" (as they call their tank-like wheeled transport vehicle), they find the temperature is seesawing wildly -- at first it seems to be heading to cold temperatures that will eliminate all possibility of life, but unexpectedly the mercury begins to rise, and what was a crossing on solid ice turns into a treacherous sea voyage (the chariot, fortunately, has amphibious capabilities).

The explanation we're given is that the planet they're on has a very elliptical orbit, so it experiences huge temperature changes.  Unfortunately, the writers of the show apparently did not understand that there's a difference between a planet's rotation and its revolution, so they depict the excruciatingly hot temperatures when the planet is at its perigee as only lasting a minute or two, so all the Robinsons had to do was hide under a reflective shelter for a little bit to avoid getting cooked.

So good idea, lousy execution, which can be said of much of that series.

A more fundamentally startling change in my perception of what it'd look like on another planet occurred when I saw Star Wars for the first time, and hit the iconic scene where Luke is looking toward the horizon as sunset occurs on Tatooine -- and there are two suns in the sky.  Tatooine, it seems, orbits a binary star -- something I'd honestly never thought about before then.

Being a science nerd type, I wondered what the shape of a planet's orbit would be if it were moving around two centers of gravity, and found pretty quickly that my rudimentary knowledge of Newton's Laws and Kepler's Law were insufficient to figure it out.

Turns out I wasn't alone; physicists have been wrestling with the three-body problem for a couple of hundred years, and there is no general solution for it.  Three objects orbiting a common center of gravity results in a chaotic system, where the paths of each depend strongly on initial conditions (and some configurations are unstable and result in either collisions or one of the objects being ejected from the system).

It is known, however, that there are points in a three-body system called Lagrange points (after their discoverer, the French mathematician and astronomer Joseph-Louis Lagrange) which result in a stable configuration in which each of the orbiting bodies stays in the same locked position relative to the other, so the entire system seems to turn as one.  Some of the moons of Jupiter (the so-called Trojan moons) sit at the Lagrange points for that system, a pattern that seems to be stable indefinitely.  (Note that from the Earth perspective, an object at the L3 Lagrange point would never be visible -- leading conspiracy wackos to postulate that it could be a place for alien spacecraft to be hiding.)

[Image licensed under the Creative Commons Xander89, Lagrange points simple, CC BY 3.0]

Things only get worse when you add additional objects.  The only way to approximate the configuration of the orbits is to input the specific initial parameters and use computer modeling software to determine a solution; there is no general set of equations to predict what it will look like.

What brings this up is a paper this week in The Astrophysical Journal that went beyond the theoretical, and found actual data from binary star systems with planets to see what the various orbits looked like.  In "The Degree of Alignment between Circumbinary Disks and Their Binary Hosts," by a team led by Ian Czekala of the University of California - Berkeley, we read about new observations from the Atacama Large Millimeter/submillimeter Array (ALMA), which tells us that not only might objects orbiting a binary star exhibit chaotic paths, they might not all orbit in the same plane.

Because of the way planets form -- coalescence of dust and debris from a flat ring surrounding the host star -- planetary systems seem mostly to be aligned with each other.  In our own Solar System, the eight planets all orbit within seven degrees of the Earth's orbital plane (excluding, sadly, Pluto, which still hasn't recovered its planet status, and has an orbital tilt of just over seventeen degrees).

But apparently there are exceptions.  Some binary stars have planets that orbit in a highly tilted ellipse with respect to the orbit of the two stars around their own center of mass.  How this could happen -- whether the planets condensed from a ring that was already tilted for some reason, or that the three-body chaos warped the orbits after formation -- isn't known.  "We want to use existing and coming facilities like ALMA and the next generation Very Large Array to study disk structures at exquisite levels of precision," study lead author Czekala said, "and try to understand how warped or tilted disks affect the planet formation environment and how this might influence the population of planets that form within these disks."

Which is pretty cool.  While it won't solve the more general difficulty of the three-body problem (and the four-, five-, six-, etc. body problems), it will at least give some empirical data to go on with which to analyze other systems ALMA finds.

So we're homing in on Tatooine.  For what it's worth, it looks like the overall situation might be more similar to Star Wars than it is to Lost in Space.

Which is a good thing in a variety of respects.

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

Any guesses as to what was the deadliest natural disaster in United States history?

I'd speculate that if a poll was taken on the street, the odds-on favorites would be Hurricane Katrina, Hurricane Camille, and the Great San Francisco Earthquake.  None of these are correct, though -- the answer is the 1900 Galveston hurricane, that killed an estimated nine thousand people and basically wiped the city of Galveston off the map.  (Galveston was on its way to becoming the busiest and fastest-growing city in Texas; the hurricane was instrumental in switching this hub to Houston, a move that was never undone.)

In the wonderful book Isaac's Storm, we read about Galveston Weather Bureau director Isaac Cline, who tried unsuccessfully to warn people about the approaching hurricane -- a failure which led to a massive overhaul of how weather information was distributed around the United States, and also spurred an effort toward more accurate forecasting.  But author Erik Larson doesn't make this simply about meteorology; it's a story about people, and brings into sharp focus how personalities can play a huge role in determining the outcome of natural events.

It's a gripping read, about a catastrophe that remarkably few people know about.  If you have any interest in weather, climate, or history, read Isaac's Storm -- you won't be able to put it down.

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

Thy fearful symmetry

For some of the most fundamental aspects of life, it's uncertain whether or not evolution was constrained.

This has huge implications for the search for extraterrestrial life, and whether or not we'd recognize it if we saw it.  One I've dealt with here before is the fact that terrestrial life is based on carbon -- but is that necessarily true everywhere?  Sure, carbon's pretty cool stuff, with its four snazzy valence electrons and all, but maybe there are other ways to build functional organic molecules.

What about oxygen?  Even here on Earth, we have living things that get by just fine without it; they're the anaerobes, and include such familiar fermenters as yeast and Lactobacillus acidophilus (the bacteria responsible for yogurt), and such bad guys as the causative agents of tetanus, botulism, and gangrene.  Being aerobic certainly seems like a great innovation -- it increases the efficiency of a cell's energy utilization by a factor of 18 -- but it certainly isn't a requirement.  In fact, probably the most common life form on Earth, individual for individual, are methanogens -- deep sea-floor bacteria that metabolize anaerobically and produce methane as a waste product.  By some estimates, methanogens may outnumber all other living things on Earth put together.

So maybe anaerobic respiration isn't as efficient as aerobic respiration, but apparently it works well enough.

There are other features that deserve consideration, too.  How many of the things we take for granted about animal life are ubiquitous not because they were the result of strong natural selection, but simply because one of our ancestors had those features and happened to be the one that survived?  I'm guessing that having the sensory organs, central processing unit (brain), and the mouth clustered together at the anterior end of the animal will turn out to be common; it makes sense to have your perceptive equipment and your feeding apparatus pointing basically in the direction you're most likely to move.  And speaking of movement, that's probably going to turn out to be fairly uniform everywhere, because there aren't that many ways to fashion an appendage for walking, flying, or swimming.

But what about symmetry?  The vast majority of animals are bilaterally symmetric, meaning that there's only one axis of symmetry that divides the animal into mirror-image halves.  (A few have radial symmetry, where any line through the center works -- jellyfish being the most obvious example.)  Even animals like starfish, that seem to have some weird five-way symmetry, are actually bilateral, which is obvious if you look at starfish larva, and in fact is given away by the position of the sieve plate (the opening through which they draw in water), which is off-center.

True multiple-line symmetry doesn't seem to exist in the animal world, and even in science fiction most aliens are depicted as being nicely bilateral.  An exception are the Antarctic Elder Things, an invention of H. P. Lovecraft, which have pentaradial symmetry, if you don't count the wings -- further illustrating that as unpleasant a person as Lovecraft evidently was, he had a hell of an imagination.

[Image licensed under GNU Free Documentation; original available at http://vixis24m.deviantart.com/art/The-Elder-Thing-39576904]

So are most animals bilateral because it's got some kind of selective advantage, or simply because we descend from bilateral creatures who survived well for other reasons?  In other words, is it selected for, or an accidental neutral mutation?

The reason all this comes up is because of a discovery in South Australia described in a paper that came out this week in Proceedings of the National Academy of Sciences.  Paleontologists have discovered a fossil half the size of a grain of rice that is over half a billion years old, and is the oldest truly bilateral animal ever found -- meaning what we're looking at may be a very close cousin to the ancestor of all the current bilateral animals on Earth.

In "Discovery of the Oldest Bilaterian from the Ediacaran of South Australia," by Scott D. Evans and Mary L. Droser (of the University of California-Riverside), Ian V. Hughes (of the University of California-San Diego), and James G. Gehling (of the South Australia Museum Department of Paleontology), we read about Ikaria wariootia, a teardrop-shaped critter whose unprepossessing appearance belies its significance.  This tiny little proto-worm might actually be our great-great-great (etc. etc. etc.) grandparent.

Not only was it bilateral, it had a throughput digestive system (two openings, one-way flow of material), another innovation that has turned out to be pretty important.  "One major difference with a grain of rice is that Ikaria had a large and small end," said study lead author Scott Evans, in an interview with The Guardian.  "This may seem trivial but that means it had a distinct front and back end, which is the kind of organization that leads to the variety of things with heads and tails that are around today."

Of course, this doesn't solve the question of whether bilateral symmetry is constrained or not.  My guess is that if it turns out to be, it will be because mirror-symmetry is easier to produce genetically.  A lot of the homeotic genes (genes that guide the development of overall body plan) work by creating a gradient of some protein or another, so the polarity of structures is established (head here, butt there, and so forth).  It might simply be easier to establish a one-way gradient, with a high on one end and a low on the other, than one with multiple highs and lows arranged symmetrically.

Although we do manage to do a five-point gradient in the development of our fingers and toes, so it's doable, it just may not be common.

In any case, here we have a creature that may be the reason we're arranged bilaterally, whether or not it gives us any sort of advantage.  Kind of humbling that we might come from a millimeter-wide burrowing scavenger.  I guess that's okay, though, if it'll keep humanity from getting any more uppity than it already is.

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

Any guesses as to what was the deadliest natural disaster in United States history?

I'd speculate that if a poll was taken on the street, the odds-on favorites would be Hurricane Katrina, Hurricane Camille, and the Great San Francisco Earthquake.  None of these are correct, though -- the answer is the 1900 Galveston hurricane, that killed an estimated nine thousand people and basically wiped the city of Galveston off the map.  (Galveston was on its way to becoming the busiest and fastest-growing city in Texas; the hurricane was instrumental in switching this hub to Houston, a move that was never undone.)

In the wonderful book Isaac's Storm, we read about Galveston Weather Bureau director Isaac Cline, who tried unsuccessfully to warn people about the approaching hurricane -- a failure which led to a massive overhaul of how weather information was distributed around the United States, and also spurred an effort toward more accurate forecasting.  But author Erik Larson doesn't make this simply about meteorology; it's a story about people, and brings into sharp focus how personalities can play a huge role in determining the outcome of natural events.

It's a gripping read, about a catastrophe that remarkably few people know about.  If you have any interest in weather, climate, or history, read Isaac's Storm -- you won't be able to put it down.

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

Diamonds in the rough

Sure, diamonds are pretty and sparkly and rare and valuable, but do you know how they form?  Because that's honestly the coolest thing about them.

Diamonds are found in geological formations called kimberlite pipes.  This is a structure shaped like a long, narrow ice cream cone, extending downward into the Earth (how far downward we'll get to in a moment), and characterized by some rocks and minerals you usually don't find lying around -- chromium-rich pyrope garnets, forsterite, and various types of ultramafic (low-silica igneous) rocks that break down to a very specific kind of clay.  Jewel hunters long ago figured out that diamonds were likely to be found in association with these rocks and minerals, and used those as indicators of where to look -- such as the diamond-rich Kimberly region of South Africa (which gave its name to kimberlite), a couple of spots in Greene and Indiana Counties, Pennsylvania, and the Udachnaya area of Siberia.

[Image licensed under the Creative Commons Rob Lavinsky, iRocks.com – CC-BY-SA-3.0]

All of that's just background, though.  Here's the cool part, if (like me) you like things that are big and powerful and scary and can kill you.

Geologists discovered more or less simultaneously that the composition of kimberlite pipes is consistent with magma found in the (very) deep mantle, and that known kimberlite pipes extend a (very) long way down.  The best models indicate that the eruption that forms them starts on the order of four hundred kilometers below the surface of the Earth, making it the deepest known volcanic feature.

No one knows what triggers the eruption to begin.  It seems to be a rare occurrence, whatever it is.  Fortunately.  Because once it starts, and the magma moves upward through the mantle, the drop in pressure makes dissolved gases bubble out, rather like popping the cork off a bottle of champagne.  This speeds up the movement, which lowers the pressure more, so more gas bubbles out, and so on and so forth.  Also -- gases expand as the pressure drops, so the higher it rises, the more volume it displaces.

The result is what's called a diatreme.  What seems to happen is that with no warning, there's a Plinian eruption -- the same sort that destroyed Pompeii and Herculaneum -- but moving at supersonic speeds.  Imagine what it must look like -- from a distance, preferably -- everything is calm, then suddenly a several-kilometer-wide chunk of land gets blown up into the stratosphere.  The conical hole left behind fills with material from the deep mantle (thus its odd composition by comparison to other igneous rocks).  Give it a few million years, and weathering results in the characteristic clay found in a typical kimberlite.

So what's all this got to do with diamonds?

Well, in the intense heat and pressure of the eruption, some of the carbonate ions in minerals in the magma are reduced to elemental carbon, and that carbon is compressed to the point that its crystalline structure changes to a hexoctahedral lattice.  The result is a transparent crystal that looks nothing like the soft, black, powdery stuff we picture when we think of carbon.  (Further illustrating that bonding pattern is everything when it comes to physical properties.)

The reason all this comes up is a discovery described in a press release from the University of British Columbia that I found out because of a friend and loyal reader of Skeptophilia.  Kimberlite pipes are not only unusual, they differ from each other, so the composition of each acts as a geological fingerprint.  So when a UBC geologist named Maya Kopylova tested samples of a kimberlite on Baffin Island, she found that its composition was inconsistent with the rocks of the nearby geological province -- the nearest rocks it matched were in Labrador, almost two thousand kilometers away.

This was sufficient to identify it as part of the North American craton, a (relatively) stable piece of continental crust that currently extends from eastern Canada, through southern Greenland, and over to Scotland.  (It was torn into chunks when the Mid-Atlantic Rift Zone formed on the order of two hundred million years ago, breaking up what was the supercontinent of Pangaea.)

How a chunk of a billion-year-old craton ended up two thousand kilometers away is uncertain, but it does give us a lens into how the continents have shifted during geologic history.  "The mineral composition of other portions of the North Atlantic craton is so unique there was no mistaking it,"  Kopylova said.  "It was easy to tie the pieces together.  Adjacent ancient cratons in Northern Canada—in Northern Quebec, Northern Ontario and in Nunavut—have completely different mineralogies...  Finding these 'lost' pieces is like finding a missing piece of a puzzle.  The scientific puzzle of the ancient Earth can’t be complete without all of the pieces."

Cool, too, that the discovery was made using remnants of what is very likely to be one of the most unpredictable and violent geological events on Earth.  (Okay, the formation of igneous traps is worse.  But still, kimberlites should surely come in second.)  The universe never ceases to fascinate me, and I'm always struck by the fact that no matter how much you know, there's always more to find out.

More, too, to worry about.  Although considering the current state of affairs, a supersonic volcanic eruption might actually lighten everyone's mood.

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

Any guesses as to what was the deadliest natural disaster in United States history?

I'd speculate that if a poll was taken on the street, the odds-on favorites would be Hurricane Katrina, Hurricane Camille, and the Great San Francisco Earthquake.  None of these are correct, though -- the answer is the 1900 Galveston hurricane, that killed an estimated nine thousand people and basically wiped the city of Galveston off the map.  (Galveston was on its way to becoming the busiest and fastest-growing city in Texas; the hurricane was instrumental in switching this hub to Houston, a move that was never undone.)

In the wonderful book Isaac's Storm, we read about Galveston Weather Bureau director Isaac Cline, who tried unsuccessfully to warn people about the approaching hurricane -- a failure which led to a massive overhaul of how weather information was distributed around the United States, and also spurred an effort toward more accurate forecasting.  But author Erik Larson doesn't make this simply about meteorology; it's a story about people, and brings into sharp focus how personalities can play a huge role in determining the outcome of natural events.

It's a gripping read, about a catastrophe that remarkably few people know about.  If you have any interest in weather, climate, or history, read Isaac's Storm -- you won't be able to put it down.

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

The power of models

I get that scientific terminology can be daunting.  Scientists, and therefore scientific papers, have become so specialized that unless you are an expert, the vocabulary by itself can be an overwhelming barrier to understanding.  That only gets worse in disciplines like physics and chemistry, where complex mathematics throws another spanner into the works.  I have a B.S. in physics, enough credits for a second major in biology, and a minor in math, and am reasonably articulate, but just about every academic paper I've ever seen loses me within a couple of paragraphs, except for the two areas I know best -- population genetics and evolutionary biology.

So I'm not expecting laypeople to become experts in scientific jargon.  But there are two words I really wish everyone would familiarize themselves with -- theory and model.

Confusion over the first one is what gives rise to the "it's only a theory" *shrug* reaction a lot of people have when discussing the theory of evolution.  Theory, in scientific discussions, does not mean "a wild guess that could as easily be wrong as right."  In scientific parlance, a theory is an explanation of a natural phenomenon that has passed repeated tests and makes predictions that are in good accordance with the data.  This is why intelligent design creationism isn't a theory; it makes no predictions.  If things get complex, it defaults to "God did it," and the conversation ends.

In science, a model is a representation of a natural object, system, or phenomenon, often idealized or simplified, that can then be manipulated -- once again, to see if the results are consistent with observed data from the real world.  As an example, the computerized three-dimensional maps of the climate are models, breaking up the atmosphere into thousands of cubical regions and the land and ocean into square blocks of area, with specifications for atmospheric composition, heat absorption capacity for land and water, solar radiation input, and so on.  The software can take the known input parameters and then run a simulation to see if what comes out matches what we actually know of the real climate data (and they have, to a startling degree of accuracy, something that is simultaneously impressive and terrifying).

The problem with the idea of modeling is that to an outside observer, it may look like the scientists are just messing around -- playing Sims with the world, with no particular expectation that what they're doing has anything in common with reality.  This, of course, is the opposite of the truth -- if a model doesn't align very well with the natural world, it's rightly abandoned for one that works better.

Even models that seem to be a little bit out there are only retained because they describe a known part of the universe sufficiently well that their predictions can be useful for describing something not yet understood.  Take, for example, the paper last week in Proceedings of the National Academy of Sciences that used what's known about biochemistry to make a stab at the configuration and composition of the earliest proteins, molecules that were around 3.5 billion years ago -- produced abiotically before there were any living things on Earth.

In "Small Protein Folds at the Root of an Ancient Metabolic Network," Hagai Raanan, Saroj Poudel, Douglas Pike, Vikas Nanda, and Paul Falkowski, of Rutgers University, describe a sophisticated computer simulation that took what we know about the chemistry that is common to all living organisms (such as using oxidation/reduction reactions to power metabolism) and combined it with what is surmised about the conditions on the early Earth, and used it to infer what the earliest energy-transfer proteins looked like.  The authors write:

Life on Earth is driven by electron transfer reactions catalyzed by a suite of enzymes that comprise the superfamily of oxidoreductases (Enzyme Classification EC1).  Most modern oxidoreductases are complex in their structure and chemistry and must have evolved from a small set of ancient folds.  Ancient oxidoreductases from the Archean Eon between ca. 3.5 and 2.5 billion years ago have been long extinct, making it challenging to retrace evolution by sequence-based phylogeny or ancestral sequence reconstruction.  However, three-dimensional topologies of proteins change more slowly than sequences.  Using comparative structure and sequence profile-profile alignments, we quantify the similarity between proximal cofactor-binding folds and show that they are derived from a common ancestor.  We discovered that two recurring folds were central to the origin of metabolism: ferredoxin and Rossmann-like folds.  In turn, these two folds likely shared a common ancestor that, through duplication, recruitment, and diversification, evolved to facilitate electron transfer and catalysis at a very early stage in the origin of metabolism.

Here's one of the ancestral proteins the model generated:

Now, maybe you see this as a bunch of hand-waving in an intellectual vacuum.  After all, we have no way of going back 3.5 million years and checking to see if the model is correct.  But the key thing is that this was created within parameters of how we know proteins work, and what we see in the energy-transfer proteins of current organisms.  This model was very much constrained by reality -- meaning that its results have a really good chance of being accurate.

Further, like any good model (or theory, for that matter), it generates predictions -- in this case, what we might look for as a signature of emerging life on other planets.  "In the realm of deep-time evolutionary inference," the authors write, "we are necessarily limited to deducing what could have happened, rather than proving what did happen...  Ultimately, our goal is for the proposed effort to inform future NASA missions about detection of life on planetary bodies in habitable zones.  Our effort provides a unique window to potential planetary-scale chemical characteristics that might arise from abiotic chemistry, which must be understood if we are to recognize unique biosignatures on other worlds."

So models and theories aren't guesses, they're real-world descriptions, and the best ones give us deep insight into the workings of the universe.  As such, they are part of the scientist's stock-in-trade -- and essential to understand for laypeople who would like to know what's happening on the cutting edge of research.

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

Any guesses as to what was the deadliest natural disaster in United States history?

I'd speculate that if a poll was taken on the street, the odds-on favorites would be Hurricane Katrina, Hurricane Camille, and the Great San Francisco Earthquake.  None of these are correct, though -- the answer is the 1900 Galveston hurricane, that killed an estimated nine thousand people and basically wiped the city of Galveston off the map.  (Galveston was on its way to becoming the busiest and fastest-growing city in Texas; the hurricane was instrumental in switching this hub to Houston, a move that was never undone.)

In the wonderful book Isaac's Storm, we read about Galveston Weather Bureau director Isaac Cline, who tried unsuccessfully to warn people about the approaching hurricane -- a failure which led to a massive overhaul of how weather information was distributed around the United States, and also spurred an effort toward more accurate forecasting.  But author Erik Larson doesn't make this simply about meteorology; it's a story about people, and brings into sharp focus how personalities can play a huge role in determining the outcome of natural events.

It's a gripping read, about a catastrophe that remarkably few people know about.  If you have any interest in weather, climate, or history, read Isaac's Storm -- you won't be able to put it down.

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

Meet Wonderchicken

Since Jurassic Park, it hasn't been news to most people that birds are dinosaurs.  The evidence from skeletal analysis is unequivocal; not only is your average little garden sparrow a dinosaur, it's close cousin to one of the most famous prehistoric animals, the fearful Velociraptor.  (Which apparently was a pack hunter, but probably wasn't smart enough to figure out how to unlatch a freezer door, so take what you see in the movies with a grain of salt or two.)

The mystery is why the ancestors of modern birds survived, and all of the other dinosaur lineages died out.  The old saw of "the dinosaurs were dying out anyhow, and the meteorite impact finished 'em off" is almost certainly untrue; the dinosaurs were apparently doing just fine when Chicxulub hit, flash-frying anything nearby and causing global havoc (and nearly simultaneously the colossal Deccan Traps volcanic eruptions occurred -- geologists are still debating whether those two events are causally linked).

But whatever the cause(s), the dinosaurs were clearly doing well, then whammy.  And, for what it's worth, they'd been pretty much in charge of the world for the entire Mesozoic Era, a time span of 180 million years (and to put that in perspective, that's over a hundred times longer than Homo sapiens has been in ascendancy).  It's probable that the reason most of the best-known species of dinosaurs became extinct is that when conditions suddenly become dire, the two groups to suffer most are the large species and the extreme specialists, both of whom are intolerant to a rapidly changing environment.  But hard evidence of this, in the form of fossils from right around the time of the end-Cretaceous Extinction, have been few and far between.

This week a paper in Nature added a new piece to the puzzle -- a fossil bird from 66.7 million years ago, only 700,000 years before Chicxulub et al. said finis to the Age of the Dinosaurs.  So here we have in hand a species that probably made it through the bottleneck -- because it looks like what may well be the common ancestor between galliform birds (chickens and turkeys) and waterfowl.

In "Late Cretaceous Neornithine from Europe Illuminates the Origins of Crown Birds," by Daniel Field, Juan Benito, and Albert Chen (of Cambridge University), John Jagt (of Natuurhistorisch Museum Maastricht in the Netherlands), and Daniel Ksepka (of the Bruce Museum of Greenwich, Connecticut), we read about read about a fascinating find that the researchers have dubbed "Wonderchicken:"

Our understanding of the earliest stages of crown bird evolution is hindered by an exceedingly sparse avian fossil record from the Mesozoic era.  The most ancient phylogenetic divergences among crown birds are known to have occurred in the Cretaceous period, but stem-lineage representatives of the deepest subclades of crown birds—Palaeognathae (ostriches and kin), Galloanserae (landfowl and waterfowl) and Neoaves (all other extant birds)—are unknown from the Mesozoic era.  As a result, key questions related to the ecology, biogeography, and divergence times of ancestral crown birds remain unanswered.  Here we report a new Mesozoic fossil that occupies a position close to the last common ancestor of Galloanserae and fills a key phylogenetic gap in the early evolutionary history of crown birds.  Asteriornis maastrichtensis, gen. et sp. nov., from the Maastrichtian age of Belgium (66.8–66.7 million years ago), is represented by a nearly complete, three-dimensionally preserved skull and associated postcranial elements.  The fossil represents one of the only well-supported crown birds from the Mesozoic era, and is the first Mesozoic crown bird with well-represented cranial remains.  Asteriornis maastrichtensis exhibits a previously undocumented combination of galliform (landfowl)-like and anseriform (waterfowl)-like features, and its presence alongside a previously reported Ichthyornis-like taxon from the same locality provides direct evidence of the co-occurrence of crown birds and avialan stem birds.  Its occurrence in the Northern Hemisphere challenges biogeographical hypotheses of a Gondwanan origin of crown birds, and its relatively small size and possible littoral ecology may corroborate proposed ecological filters that influenced the persistence of crown birds through the end-Cretaceous mass extinction.

This fossil is pretty spectacular -- and unique.  "It shows a never previously seen mashup of ducklike and chickenlike features," said study lead author Daniel Field, a vertebrate paleontologist at the University of Cambridge.  "It’s like a turducken."

This pushes forward the date estimated for the last common ancestor of all modern birds, previously estimated by molecular clock data as between 139 and 89 million years ago.  Asteriornis is a very close ally to the ancestor of two large bird groups, so it could be that true birds evolved much closer to the end-Cretaceous Extinction than we'd previously thought.

So I'm sure you're wondering what Wonderchicken looked like.  Here's an artist's reconstruction (art by Phillip Krzeminski):

Recognizably a bird, isn't it?  Not some scary toothy flying dinosaur like Archaeopteryx.  Poor thing, little did it know that hard times were coming, although maybe knowing its descendants would be some of the survivors would have cheered it up.

And its relevance was obvious the moment the team saw the results of the computerized tomography of the skull.  "The timeline was: See the skull, scream ‘Holy shit,’ give my Ph.D. student a high five, and then start calling it the Wonderchicken," Field said, in an interview with Science News.

Wonderchicken was about the size of a modern quail, further supporting the conjecture that small size was a factor in surviving the bottleneck.

So that's another piece in the evolutionary puzzle, and something to think about next time you fill the birdfeeders for the local chickadees.  Modern biodiversity has been mostly shaped by evolution, but random and unpredictable natural disasters played their own role in determining who the winners and losers would be.  And here we have hard evidence of one of the winners -- an unprepossessing bird from right before one of the biggest catastrophes the Earth has ever seen.

Wonderchicken, indeed.

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

This week's Skeptophilia book recommendation of the week is a classic -- Martin Gardner's wonderful Did Adam and Eve Have Navels?

Gardner was a polymath of stupendous proportions, a mathematician, skeptic, and long-time writer of Scientific American's monthly feature "Mathematical Games."  He gained a wonderful reputation not only as a puzzle-maker but as a debunker of pseudoscience, and in this week's book he takes on some deserving targets -- numerology, UFOs, "alternative medicine," reflexology, and a host of others.

Gardner's prose is light, lucid, and often funny, but he skewers charlatans with the sharpness of a rapier.  His book is a must-read for anyone who wants to work toward a cure for gullibility -- a cure that is desperately needed these days.

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

Blowing the dogwhistle

It's no secret that I'm a privileged white guy.  I've never had to deal with -- hell, I've never had to think about -- being on the receiving end of discrimination based on my gender or the color of my skin.  I'm not saying my life has been without any impediments, but inequities of race and gender have not been amongst them.

So when people who have experienced this kind of prejudice and bigotry tell me about their experience, I listen to them.  Simple as that.

Which is why the nasty rebranding of COVID-19 as "the Chinese virus" is, in fact, racism.

The racist part isn't from the first time the term was used.  Being a privileged white guy, I've probably said things that have been insensitive -- not from any malice, but simply from ignorance of the implications.  But if someone points it out, what you do then is you stop fucking doing it.  If you call COVID-19 "the Chinese virus" and someone says, "you really shouldn't call it that, there are Asians who are being targeted for harassment because they're being blamed for the virus's spread," you say, "Good heavens, I didn't realize that, I'm so sorry, that was so thoughtless of me," then you don't say it again.

You don't say, "here's why your perspective is wrong, I know so much better, so I'm gonna damn well call it Chinese virus if I want."

That is racist.

Of course, Donald Trump, whose attitude is that anything that comes out of his mouth is perfect, is where this started.  And of course, when called on it, he didn't back down.  "It’s not racist at all," he told reporters.  "It comes from China, that’s why."

Which is somewhere beyond disingenuous.  No one doubts that the virus originated in China.  But continuing to harp on it as "Chinese virus" even after you know that Asians are being threatened or outright physically harmed because of it -- yeah, that's racist, however you're trying to whitewash it.

Any argument for it being a casual, offhand slip of the tongue went out the window yesterday when a photograph by a reporter for the Washington Post showed that Trump had actually crossed out the word "corona" and handwritten in "Chinese" (in black Sharpie, if I even needed to add that).  So make no mistake; this is absolutely deliberate.

And of course, as soon as Trump labeled it that way, his various bootlickers were quick to follow suit:

• Meghan McCain: "I agree with you that I think if the left wants to focus on P.C. labeling this virus, it is a great way to get Trump re-elected.  I don’t have a problem with people calling it whatever they want.  It’s a deadly virus that did originate in Wuhan."
• John Cornyn: "[Chinese] people eat bats and snakes and dogs and things like that.  These viruses are transmitted from the animal to the people, and that’s why China has been the source of a lot of these viruses...  China has been the source of a lot of these viruses like SARS, like MERS and swine flu and now the coronavirus.  So I think they have a fundamental problem, and I don’t object to geographically identifying where it's coming from."
• Marsha Blackburn: "This outlandish claim is crucial to Communist China's propaganda machine.  It is a bold-faced lie and a corrupt attempt to shift the blame and origins of the Chinese novel coronavirus."
• Tucker Carlson: "Today, NBC News sent a tweet suggesting the president's use of the phrase 'Chinese virus' was 'both inaccurate and harmful, in tying racist associations between the virus and those from China...'  Another statement written by morons in our news media.  How is it inaccurate to call a virus from China 'Chinese?'...  That was Trump at his very best."
• Lindsey Graham: "I think it is fair, because China is accusing American soldiers of causing this problem, so yes, we're gonna fight that.  I'm not blaming the Chinese government.  It did come from China...  This problem came out of China.  You guys [reporters asking whether the term is racist] are nuts."
• Brian Kilmeade: "While some here say that’s a racist term, it’s actually just an accurate term of where it started and them not being transparent about how it started really hurt literally the rest of the planet."

Let me put this succinctly: if your words are inciting others to harass, demean, threaten, or harm someone based on their race, and even after finding this out you continue to use those words, your actions are racist.

Of course, I'm not naïve enough not to know why they're doing it; these kinds of racist dogwhistles play well with their base, who just love the ultranationalist, 'Murica-first attitude that Trump and his cronies excel at.  This kind of language has been used against Hispanics, Muslims, and a number of other ethnic groups (remember the "shithole countries" comment directed against people from subsaharan Africa?), to cheering crowds.  And whenever this is flagged as racism, immediately the "political correctness" epithet comes out, as if treating people with consideration, and recognizing that people from other demographics have a different perspective than you do, is somehow a character flaw.

As journalist David Plotz put it: "Changing the way we talk is not political correctness run amok.  It reflects an admirable willingness to acknowledge others who were once barely visible to the dominant culture, and to recognize that something that may seem to be innocent to you may be painful to others."

[Image licensed under GNU Free Documentation License version 1.2]

For me, it boils down to one of the guiding principles of my life, which is "don't be a dick."  I'm not saying I don't make mistakes or that I've never offended anyone.  Being privileged means that's probably inevitable.  But when I do, I try like hell not to do the same thing again.  Maybe sometimes this will mean I'll change my language because someone's being hypersensitive, but what harm has come to me because of that?

Given the choice between hurting someone and making a small amendment to the way I talk, I know which one I'd choose.  And seeing it that way makes the fact that this isn't just random thoughtless talk, but a deliberate dogwhistle, abundantly clear.

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This week's Skeptophilia book recommendation of the week is a classic -- Martin Gardner's wonderful Did Adam and Eve Have Navels?

Gardner was a polymath of stupendous proportions, a mathematician, skeptic, and long-time writer of Scientific American's monthly feature "Mathematical Games."  He gained a wonderful reputation not only as a puzzle-maker but as a debunker of pseudoscience, and in this week's book he takes on some deserving targets -- numerology, UFOs, "alternative medicine," reflexology, and a host of others.

Gardner's prose is light, lucid, and often funny, but he skewers charlatans with the sharpness of a rapier.  His book is a must-read for anyone who wants to work toward a cure for gullibility -- a cure that is desperately needed these days.

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

Animal magnetism

In my introductory neuroscience class, I always began the unit on our sensory systems by asking students how many senses they think we have.

The standard answer, of course, is "five."  There were always a few wishful thinkers who like the idea of psychic abilities and answered six.  They were uniformly blown away when I told them that depending on how you count them, it's at least twenty.

Don't believe me?  There are three in the ears (hearing, proprioception/balance, and pressure equalization).  The tongue has separate, distinct chemoreceptors for at least five different taste categories -- sour, sweet, salty, bitter, and savory.  For convenience we'll call the sense of smell one, because we don't even know how many different kinds of olfactory receptors we have.  The eyes are not only responsible for image reception, but also perception of depth and adjustments for light intensity.  You've got six in your skin -- touch, pain, pressure, heat, cold, and stretch.  Your brain has chemical sensors that keep track of your blood pH and stimulate your breathing rate to speed up or slow down to accommodate (in general, breathing faster dumps carbon dioxide and makes your blood pH rise; slower breathing makes you retain carbon dioxide and drops your blood pH).  The kidneys have sensors not only for blood pH but for the salt/water balance, concentrating or diluting your urine to keep your blood's osmotic balance correct.

And those are just the most obvious ones.

In reality, your body is a finely-tuned environmental sensor, constantly detecting and making adjustments to your internal state to accommodate for the external conditions.  It works admirably well most of the time, even though there are some stimuli out there detectible by other animal species that we are completely unaware of.

The one that jumps to mind first is the range of light frequencies the eyes can detect.  We can only pick up a tiny slice of the entire electromagnetic spectrum, the familiar red-orange-yellow-green-blue-indigo-violet of the rainbow.  Many insects can see in the ultraviolet region, picking up light waves completely invisible to us; this is why a good many flowers that seem to be a single color to us have wild patterns if photographed with a UV-sensitive camera.  Mosquitoes can pick up infrared light, meaning they see the world through heat-sensing goggles -- with the unfortunate result that they can find us with ease in the pitch dark.  (They can also smell us, apparently, possibly explaining why some people are so attractive to the little bastards.)

How a bee sees a flower of Potentilla reptans that looks solid yellow to us [Image licensed under the Creative Commons Wiedehopf20, Flower in UV light Potentilla reptans, CC BY-SA 4.0]

Sharks can pick up shifts in the underwater electric field, one way they find their prey -- muscle contractions run on electrical signals.  So, oddly enough, can platypuses, using electric sensors in their weird rubbery bill.  Many species of migratory birds are sensitive to magnetic fields, using magnetite crystals in their brains as a natural compass -- and, some scientists think, not only using them to figure out which direction is north, but using the declination (angle it tips up or down with respect to horizontal) to figure out the latitude, as the Earth's magnetic field lines become more and more vertical the closer you get to the poles.

This last one is a sense humans might actually share.  There have been anecdotal accounts for years of some people being sensitive to magnetic fields, but there hasn't been any hard evidence of it.  Now, a paper in eNeuro describes an experiment that shows the human brain has sensitivity to magnetic fields -- even if the owner of the brain may not be aware of it on a conscious level.

In "Transduction of the Geomagnetic Field as Evidenced from alpha-Band Activity in the Human Brain," by a team led by Connie Wang of the California Institute of Technology, we read about a clever set-up to see what was going on in people's heads when they were subjected to a fluctuating magnetic field.

The thought was, if there is anything at all to the anecdote, it should be detectible by an electroencephalogram.  "Our approach was to focus on brainwave activity alone," said study co-author Joseph Kirschvink (also of CIT) in an interview with Gizmodo.  "If the brain is not responding to the magnetic field, then there is no way that the magnetic field can influence someone’s behavior.  The brain must first perceive something in order to act on it—there is no such thing as ‘extra-sensory perception.’  What we have shown is this is a proper sensory system in humans, just like it is in many animals."

Test subjects were placed in a Faraday cage, a web of conductive material that blocks electromagnetic fields, to shut out anything coming from the Earth's magnetism.  Then, an array of Merritt coils were activated to alter the magnetic field within the cage.  The subjects were asked if they detected anything -- and at the same time, the EEG machine kept track of what was going on inside their skulls.

The results are fascinating.  The effect of the magnetic field shifts on the alpha waves was dramatic; you don't need a class in reading EEGs to see it.  What was equally interesting is that none of the test subjects reported being aware of any changes.  So even though there's a dramatic change in the brain waves, whatever effect that's having, if any, is happening on a completely subconscious level.

But it does mean the anecdotal stories about people's sensitivity to magnetic fields have at least a possible explanation.  It still doesn't mean those anecdotes are reliable -- that would take test subjects who were able to report a detectible change when the magnetic field shifted the wave pattern in their brains -- but it's a step in the right direction.

"Magnetoreception is a normal sensory system in animals, just like vision, hearing, touch, taste, smell, gravity, temperature, and many others," Kirschvink said.  "All of these systems have specific cells that detect the photon, sound wave, or whatever, and send signals from them to the brain, as does a microphone or video camera connected to a computer.  But without the software in the computer, the microphone or video camera will not work.  We are saying that human neurophysiology evolved with a magnetometer—most likely based on magnetite—and the brain has extensive software to process the signals."

So this might be another one to add to the list of human senses, at least for some of us.  Whatever the results, it's certain that we're more finely-tuned to our environment than we realize -- and sensitive to stimuli to which we've always thought we were wholly insensate.

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

This week's Skeptophilia book recommendation of the week is a classic -- Martin Gardner's wonderful Did Adam and Eve Have Navels?

Gardner was a polymath of stupendous proportions, a mathematician, skeptic, and long-time writer of Scientific American's monthly feature "Mathematical Games."  He gained a wonderful reputation not only as a puzzle-maker but as a debunker of pseudoscience, and in this week's book he takes on some deserving targets -- numerology, UFOs, "alternative medicine," reflexology, and a host of others.

Gardner's prose is light, lucid, and often funny, but he skewers charlatans with the sharpness of a rapier.  His book is a must-read for anyone who wants to work toward a cure for gullibility -- a cure that is desperately needed these days.

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