The collapse

A couple of weeks ago, I wrote about the spike in atmospheric oxygen concentration -- by some estimates, rising to 35% -- during the Carboniferous Period, triggered by explosive growth of forests, and allowing arthropods like insects, arachnids, and millipedes to grow to enormous sixes.

The good times, though (for them at least), were not to last.  Around three hundred million years ago, there was a sudden drop in oxygen and rise in carbon dioxide.  This triggered rapid climatic shifts that resulted in the Late Carboniferous Rain Forest Collapse, which saw a major alteration from the swamp-dwelling plants and animals at the height of the period to species that could tolerate the dry heat that was to persist throughout the next period, the Permian.  (This set up the rise of reptiles, which would see their peak in the dinosaurs of the Mesozoic.)

Artist's depiction of the mid-Carboniferous swamps (ca. 1887) [Image is in the Public Domain]

The source of the excess carbon dioxide was very likely volcanic.  Besides the fact that lava can contain dissolved gases (mostly carbon and sulfur dioxide), the heat of the eruptions may have caused the oxidation of the plentiful limestone and coal deposits formed during the earlier lush, wet part of the period -- a precursor of the much bigger disaster that was in store fifty million years later, when at the end of the Permian, the Siberian Traps erupted and tore through a huge amount of the sequestered carbon, causing widespread global anoxia and climate change, and the largest mass extinction ever.

By some estimates, ninety percent of life on Earth died.

But the rain forest collapse at the end of the Carboniferous was bad enough.  A study that came out this week in Proceedings of the National Academy of Sciences found the anoxia/hypoxia hit the oceans the hardest, where the oxygen levels rapidly dropped by between four and twelve percent, with a commensurate rise in dissolved carbon dioxide.  When carbon dioxide dissolves in water, it produces a weak acid -- carbonic acid -- lowering the pH.  Organisms that make their shells out of calcium carbonate, like mollusks, brachiopods, and corals, literally dissolved.

You ready for the kicker?

The study's estimate of the rate of carbon dioxide release during the Late Carboniferous Rain Forest Collapse is a hundred times smaller than the rate we're putting carbon dioxide into the atmosphere today through burning fossil fuels.

"This is a huge discovery, because how do you take an ocean sitting under an atmosphere with much more oxygen than today and permit this?" said Isabel Montañez of the University of California - Davis, senior author of the study.  "The message for us is, 'Don't be so sure that we can't do this again with our current human-driven release of carbon dioxide.'"

The problem is, the current administration is in the pockets of the fossil fuel industry, and is doing their level best to pretend this isn't happening, and to discredit anyone who says it is.  Worse, actually; they've cancelled funding for any scientific research about climate.

Because apparently "la la la la la la not listening" is now considered wise political policy.  This, despite warning signals like the eastern half of the United States sweltering this past week under the most extreme heat wave we've had in over fifty years.

So I'm expecting studies like the one released this week by Montañez et al. to receive exactly zero attention from the people who actually could work toward addressing this situation.  It brings to mind a quote from Upton Sinclair, uttered almost a century ago: "It is difficult to get a man to understand something when his salary depends on his not understanding it."

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A Jurassic wake-up call

About 183 million years ago -- during the Toarcian Age, one of the subdivisions of the early Jurassic Period -- there was a sudden and puzzling extinction.

Things had been recovering nicely after the End-Triassic Mass Extinction, eighteen million years earlier.  While dinosaurs were not yet at the peak they would hit in the later Jurassic, they were well on their way to taking over the place.  The temperatures were cool -- there's evidence of widespread glaciation during the ten million years prior -- but by and large, everything seemed to be coping just fine.

Then, suddenly, wipeout.

It wasn't as big as some of the truly dramatic mass extinctions the Earth has experienced, but that doesn't mean it was insignificant.  Marine invertebrates got clobbered, dropping both in diversity and in overall numbers.  Over ninety percent of coral species went extinct.  Two entire orders of brachiopods died; bivalves, ostracods, and ammonoids survived, but with greatly reduced populations.  Coelophysid and dilophosaurid dinosaurs got wiped out completely.  Seed ferns and lycophytes declined sharply, to be replaced by cycads and conifers.

Fossil seed fern [Image is in the Public Domain]

All of it occurred rapidly -- the current estimates are less than five hundred thousand years, which is a snap of the fingers geologically.

So what happened?

The culprit seems to have been the Karoo-Ferrar Large Igneous Province, an enormous volcanic formation (estimated at about three million square kilometers) now underlying much of southern Africa, eastern Antarctica, and southwestern South America.  At this point, Gondwana -- the southern half of the supercontinent of Pangaea -- had just begun to break up, and this massive series of eruptions was part of the process of rifting.  But what caused the extinction was not the eruption itself -- it was the sudden spike of atmospheric carbon dioxide, which swung the climate from a glacial period to a hothouse.  A study released last week by a team at Duke University found evidence of a twenty thousand gigaton carbon dioxide pulse, triggering not only a drastic temperature increase, but widespread ocean acidification and anoxia.

According to the study, during the event, eight percent of the global seafloor -- an area three times that of the United States -- became completely anoxic.  The pH dropped so much that animals with calcium carbonate exoskeletons literally dissolved.  Rainfall patterns shifted dramatically, impacting terrestrial biomes as well.  By the time things began to recover, it was a changed world, all in a matter of a half of a million years.

Ready for the punchline? 

Today's rate of carbon dioxide increase in the atmosphere is over two hundred times what it was during the Toarcian Extinction Event.

Twenty thousand gigatons in five hundred thousand years is a lot, and had a devastating effect on the world's ecosystems; we've put two thousand gigatons into the atmosphere in the past two hundred years.  

Is it any surprise why the scientists have been trying like hell to get everyone's attention?

"We just don't have anything this severe [in the geological record]," said paleoclimatologist Michael Kipp, who co-authored the study.  "We go to the most rapid CO2-emitting events we can in history, and they're still not rapid enough to be a perfect comparison to what we're going through today. We're perturbing the system faster than ever before.  We have at least quantified the marine oxygen loss during this event, which will help constrain our predictions of what will happen in the future."

None of this is meant to stun people into giving up.  We have got to get a handle on this.  Yes, we've crossed several benchmarks the climate scientists have warned us about.  But every tenth of a degree's further increase we can prevent will mitigate the effects of what we're doing.  We have got to stop electing politicians who shrug their shoulders about anthropogenic climate change, most strikingly Florida's belligerent and willfully stupid Governor Ron DeSantis, who recently signed a law striking any mention of climate change in state statutes, banning offshore wind turbines, and deregulating natural gas production, transport, and use.  

In one of the lowest-lying, most hurricane-prone states in the country.

Maybe it will take our getting slapped hard to wake us up; we don't have a good record of addressing problems that aren't right in front of our faces.  Events like the massive heat dome that just cooked the southern, central, and northeastern states are just the beginning, and are easily forgotten once they pass.  They're predicting a vicious hurricane season, fueled by a central Atlantic with a surface the temperature of bath water, but we've seen dire predictions before and gone on our way as if nothing was amiss.

So how many lives will it cost before that wake-up call is finally listened to?

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Fingerprint of a catastrophe

Ever heard of the Bruneau-Jarbridge event?

If not, it's unsurprising; neither had I.  Plus, it happened twelve million years ago, during the mid-Miocene Epoch.  It's a supervolcano eruption of the Yellowstone Hotspot, which was at the time under what is now southwestern Idaho.  Between then and now, the hotspot has stayed pretty much where it was, but the North American Plate has moved, resulting in its current location underneath northwestern Wyoming,

The Bruneau-Jarbridge event was enormous.  It created monstrous pyroclastic flows that traveled 150 kilometers from the caldera, incinerating everything in their path.  The winds at the time of the eruption were from the west; we know this because the ash produced by the eruption traveled at least 1,600 kilometers to the east, creating meters-thick layers including the ones at the amazing Ashfall Fossil Beds in northeastern Nebraska.

In fact, it's the Ashfall Fossil Beds -- now an official National Natural Landmark and State Historical Park -- that's why the topic comes up.  A friend and frequent contributor of topics for Skeptophilia sent me a photograph of the site, and asked me if I'd heard of it:

[Image licensed under the Creative Commons Carl Malamud, Ashfall fossil beds - Baby rhino "T. L.", CC BY 2.0]

I hadn't, so naturally I had to look into it.

The whole thing is staggering, if grim.  Ashfall contains the skeletons of thousands of animals killed, more or less simultaneously, by the Bruneau-Jarbridge ash cloud.  The remains of the rhinoceros species Teloceras are so common there that one part of the fossil bed has been nicknamed "the Rhino Barn."  But there are lots of other species represented as well; five different kinds of prehistoric horses, including both three-toed and one-toed; three species of camels; two canids, the fox-sized Leptocyon and the wolf-sized Cynarctus; a saber-toothed (!) deer species, Longirostromeryx; three species of turtles; and three species of birds -- a crane, a hawk, and a vulture.

Despite the size of the eruption and resulting ash cloud, everything in the area didn't die during the ashfall.  Some of the bones show signs of scavenging, and some have breaks and tooth marks consistent with the dentition of the hyena-like canid Aelurodon.  So even a horrific catastrophe like Bruneau-Jarbridge didn't extinguish life completely; there were still scavengers around to chow down on the victims.

When looking at this sort of event, the question inevitably comes up of whether it could happen again.  The facile answer is: of course it could.  The Earth is still very much tectonically active, and more specifically, the Yellowstone Hotspot is a live volcano, as the frequent earthquakes and boiling-hot geysers and lakes should indicate.  It's likely to erupt again -- whether a monumental cataclysm like Bruneau-Jarbridge, or something smaller, isn't certain.

But despite the prevalence of clickbait-y YouTube videos about how "Yellowstone is about to erupt!" and "Scientists fear the Earth will crack wide open!" (both direct quotes from video titles), there is no imminent danger from the Yellowstone Hotspot.  What the geologists are actually saying is that a major eruption is likely some time in the next hundred thousand years, which puts it well outside the realm of what most of us should be worried about.

However, there's no doubt the the Ashfall Fossil Beds are a sobering reminder of what the Earth is capable of.  They're the fingerprint of a twelve-million-year-old catastrophe that makes any recent eruption look like a wet firecracker.  But as horrible as it was for the Miocene animals in the path of the ash cloud, it's provided us with a snapshot of what life was like back then, when Nebraska had a climate more like modern Kenya -- and the Great Plains was home to rhinos, camels, horses, and wild dogs.

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Violent moon

If I had to vote for the single weirdest place in the Solar System, my choice would be Jupiter's moon Io.

Io is the innermost and third-largest of the "Galilean moons" of Jupiter, the ones that caused so much trouble for poor Galileo Galilei when he observed them in 1610 and informed the Catholic Church powers-that-be that we aren't the center of the universe.  It wasn't until the Voyager flybys in the late 1970s that we could see it as anything more than a fuzzy dot, even in the largest telescopes; the first close-up photographs invited comparisons to a moldy pizza,  Detailed photos from the Galileo probe in 1999 confirmed the original assessment: Io is one bizarre place.

1999 photograph of Io from the Galileo probe [Image is in the Public Domain courtesy of NASA/JPL]

The first weird thing about it is that it is the most tectonically active place in the Solar System.  Those pock-marks on the surface aren't impact craters, they're volcanoes.  In general, the smaller a body is, the less tectonically-active you might expect it to be.  Tectonic activity is (usually) triggered by convective fluid motion in a molten mantle or core, which requires a very hot interior to keep it going.  The heat comes from two sources; the energy released by its coalescence during its formation, and the decay of radioactive elements in its interior.  If that heat radiates away faster than it's being released, eventually the body cools off and freezes, and (most) tectonic activity stops.  Heat dissipates more rapidly from a small object, so they tend to shut down much sooner.  (That's what happened to the Moon, for example.)

But despite Io's small size, something is keeping it hot enough to create hundreds of active volcanoes.  But what?

It turns out it's the proximity to Jupiter.  The giant planet's gravitational pull creates significant tidal forces, and the stretching and compressing Io experiences generates enough friction in the moon's interior to keep the insides molten.  The result: violent volcanic activity that spews liquid sulfur jets into the sky, creating plumes as much as five hundred kilometers in height.  (It's the sulfur that's responsible for Io's bright colors.)

In fact, Io actually ejects so much material from its volcanoes that it has created a plasma torus around Jupiter in its wake -- a donut-shaped ring of charged particles tracing out its orbit.

Another cool thing about Io is that it's in orbital resonance with two of the other Galilean moons, Europa and Ganymede.  Io is the innermost, and has an orbital period exactly twice as fast as Europa and four times as fast as Ganymede -- a stable configuration that has since been found in other systems with multiple moons.  So every fourth revolution of Io, all three line up perfectly!

The reason this comes up is a new study out of Caltech that has found data suggesting an enormous underground magma ocean inside Io -- planetary scientists David Stevenson and Yoshinori Miyazaki believe the presence of a hundred-kilometer-thick liquid mantle explains the extremely active surface and its anomalous magnetic field, another feature Io shares with few other small bodies in the Solar System.

What lies deeper than the mantle is unknown.  Some astrophysicists believe it has a metallic core, but that question is far from settled.

What's certain is that Io is a peculiar place -- sulfur volcanoes, seething lava lakes on the surface, continuous "moonquakes" caused by the tidal forces exerted by the enormous planet Jupiter looming overhead.  And like anything odd and unexpected, it will continue to attract the attention of scientists, and we will continue to be astonished at what we learn about one of the weirdest places in our neighborhood.

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The dunes of Io

By anyone's standards, Jupiter's moon Io is a strange place.  It is by far the most geologically-active body in the Solar System, which is extremely unusual for an object its size.  Since tectonic forces are created by heat generated in the core, and smaller objects radiate away heat faster, it was thought that most planetary moons should be tectonically dead -- essentially, frozen in place.

What keeps the fires in Io going are the tidal forces between Jupiter and the other three "Galilean" moons (so called because they were first spotted by Galileo Galilei in January of 1610, and were instrumental in his championing of the heliocentric model of the Solar System).  But from earthbound telescopes all four just looked like points of light, despite the fact that as moons go, they're pretty big.  In fact, the largest of them -- Ganymede -- is bigger than Mercury, with a radius of 2,634 kilometers (as compared to Mercury's 2,440).  The four, the two aforementioned plus Europa and Callisto, were all named for various of Zeus's lovers, which meant astronomers had an extensive list of names to choose from, given that 95% of Greek mythology was driven by Zeus's inability to keep his toga on.

In any case, the push-and-pull of the gravitational forces from Jupiter and its moons stretches Io, and the friction thus created generates enough heat to keep its core (thought to be made mostly of iron, like Earth's) molten.  This thermal energy drives tectonic forces that dwarf the most violent volcanoes and earthquakes here on our planet.  Io has extensive lava flows, some over five hundred kilometers across.  Its volcanoes have ejected so much debris that there is a plasma ring surrounding Jupiter, sketching out Io's orbit.

We got our first good images of Io from Voyager 1 and Voyager 2 in 1979, and from its brightly-colored, pockmarked surface astronomers said it "looked like a moldy pizza" -- a vivid image that is certainly apt enough:

An image of Io taken, appropriately enough, by the spacecraft Galileo in 1995 [Image is in the Public Domain courtesy of NASA/JPL]

The bright yellows and oranges come from crystalline sulfur, which is abundant on the moon's surface.  Also common on its surface is sulfur dioxide, which at Earth's surface temperatures is a colorless gas that smells like rotten eggs; at Io's temperatures, averaging at 110 K (about -160 C), it's a crystalline solid.  The rest is mostly made up of silicate rock and sand.

There's still a lot we don't know about this peculiar place.  One of its odd features is that it has dunes, some of them over thirty meters high.  This should be impossible, as dunes are caused by fluid flow -- on Earth, either wind or water -- and Io has essentially no atmosphere and no liquid component of any kind on the surface.  But a recent paper published in Nature Communications explains a way that dunes can form without any wind; once again, it's caused by Io's extreme volcanism.  The study found that if there's at least a ten-centimeter thick layer of sulfur dioxide ice, and it is contacted by the subterranean (well, subionion) lava flows, the ice sublimates rapidly and explosively, blowing plumes of gas and debris at speeds of up to seventy kilometers and hour, reaching as much as two hundred kilometers high.

The force, though, isn't just exerted upwards, it's exerted outward.  This lateral blast moves enough of the sand and rock on the surface to generate Io's extensive dunes.  A combination of two things -- Io's low gravity and lack of an atmosphere -- means that the airborne debris can move a lot farther than a similar flow could do on Earth.  So while at first glance the processes seem similar to what we know of planetary geology, it's (as far as we know) unique in the Solar System.

"In some sense, these [other worlds] are looking more familiar," says George McDonald, a planetary scientist at Rutgers University, who co-authored the study, in an interview with Science News.  "But the more you think about it, they feel more and more exotic."

If you want to experience mystery and wonder, just look up.  The night sky is filled with a myriad places we are only just beginning to understand.  As French physicist and mathematician Jules Henri Poincaré put it, "Astronomy is useful because it raises us above ourselves; it is useful because it is grand; …  It shows us how small is man's body, how great his mind, since his intelligence can embrace the whole of this dazzling immensity, where his body is only an obscure point, and enjoy its silent harmony."

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Prelude to a detonation

Even though in general I don't think synchronicity Means Anything, there's no doubt that it can be pretty peculiar.

For example, it seems like in the last few days the universe has tried to get me to think about volcanoes.  First, Scientific American recently featured in their "New Books" column Robin George Andrews's Super Volcanoes, and given my fascination with volcanoes in general I had to get it (and it impressed me enough that it's this week's book-of-the-week).  Andrews's book goes a long way toward dispelling a lot of the hype around places like Yellowstone (no, it's not on the verge of an eruption), and has a lot of cool interviews with volcanologists, much in the style of the wonderful essayist John McPhee.  Only a couple of days after I started reading it, a friend sent me a link to the Naked Science YouTube video "Supervolcanoes," which seemed to be the anti-Andrews; if I can sum it up, it would be "WE'RE ALL FUCKED RUN FOR YOUR LIFE."  It isn't terrible, and does include some actual science, but the most striking thing about it is a CGI rendition of Yellowstone blowing sky-high which they use over and over and over and over in the fifty-minute-long video, as if they'd paid somebody a hefty sum to do the rendering, and by god, they were gonna get their money's worth out of it.

Then, just yesterday, a (different) friend sent me a link to a paper in Proceedings of the National Academy of Sciences that kind of splits the difference between Naked Science's screaming alarmism and Andrews's breeziness; it looks at the scarily huge Mount Toba volcano in Indonesia, and comes to the unsettling conclusions that (1) it definitely will erupt again, and (2) we probably won't have much warning when it does.

The last significant eruption of Toba was about 74,000 years ago, and was a VEI8 -- the highest ranking on the Volcanic Explosivity Index -- releasing an estimated three thousand cubic kilometers of ash and lava, and causing a worldwide (if temporary) drop in average temperature by about three degrees Celsius.  (For comparison, this is over seven hundred times the volume ejected by the May 1980 eruption of Mount St. Helens.)  The eruption blew the entire top of the mountain clean off, and the evacuation of the magma chamber beneath it caused the caldera to collapse.  It filled with water, and is now a beautiful -- and seemingly peaceful -- crater lake, Lake Toba.

[Image licensed under the Creative Commons Visions of Domino, Indonesia - Lake Toba (26224127503), CC BY 2.0]

The operative word here is "seemingly."  The processes that caused the original eruption, mostly the subduction of the Indian and Australian Tectonic Plates beneath the Sunda Plate, continue to cause massive earthquakes including the colossal (9.2 on the Richter Scale) Sumatra-Andaman Earthquake of December 2004, which killed over 225,000 people.  In the case of Toba, the magma chamber has been steadily refilling, and now contains an estimated 50,000 cubic kilometers of magma -- four times the volume of Lake Superior.  This refilling has pushed the entire caldera upward, lifting Samosir Island and the Uluan Peninsula an estimated 450 meters.

It's hard to talk about this without lapsing into superlatives.  The scariest thing about it, though, is that the recent study indicates that such volcanoes can seem quiescent until -- well, until they aren't any more.  "[W]ith few super-eruptions in the last two million years, it is not possible for us to obtain statistically significant values for the frequency of these catastrophic events at a global scale," said study co-author Ping-Ping Liu of Peking University, in a press release from the Université de Genève.  "Our study also shows that no extreme events occur before a super-eruption.  This suggests that signs of an impending super-eruption, such as a significant increase in earthquakes or rapid ground uplift, might not be as obvious as pictured in disaster movies by the film industry.  At Toba volcano, everything is happening silently underground."

The reassuring part is "not as obvious" doesn't mean "without any warning;" the entire Indonesian archipelago is an area of intense study by volcanologists and seismologists, and it's likely there'd be enough anomalous activity to give us at least a hint that an eruption was impending.  Whether we'd do much about it in the form of evacuations is another matter.  Sumatra (where the volcano is located) and the nearby island of Bali are densely populated, and the idea of getting all those people out (to where?) makes the phrase "mammoth undertaking" a significant understatement.  And for those of you who like certainty, the current study doesn't give us any clear idea of exactly when the next big eruption will occur, just that (1) it's inevitable, (2) when it does, it'll be bad, (3) the filling of the magma chamber is still happening, and (4) there are signs that the volcanic activity at Toba and the surrounding regions is speeding up.

"[There's been a] progressive increase of the temperature of the continental crust in which Toba’s magma reservoir is assembled," Liu said.  "The input of magma has gradually heated the surrounding continental crust, which makes the magma cool slower.  This is a ‘vicious circle’ of eruptions: the more the magma heats the crust, the slower the magma cools and the faster the rate of magma accumulation becomes.  The result is that super-eruptions can become more frequent in time."

So there's your cheerful news of the day.  As far as the synchronicity aspect of this, I'm not gonna make much of it.  The fact that two different friends know enough of my obsession with volcanoes and earthquakes to send me the link to the YouTube video and paper is hardly to be wondered at.  As far as the book review, it's no wonder I noticed it given that the tile of the book is Super Volcanoes.  I don't think this is some kind of cosmic warning that we're about to get blown to smithereens.

So if you were looking for an excuse to stay home from work this week, you'll probably have to come up with a different one.

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If Monday's post, about the apparent unpredictability of the eruption of the Earth's volcanoes, freaked you out, you should read Robin George Andrews's wonderful new book Super Volcanoes: What They Reveal About the Earth and the Worlds Beyond.

Andrews, a science journalist and trained volcanologist, went all over the world interviewing researchers on the cutting edge of the science of volcanoes -- including those that occur not only here on Earth, but on the Moon, Mars, Venus, and elsewhere.  The book is fascinating enough just from the human aspect of the personalities involved in doing primary research, but looks at a topic it's hard to imagine anyone not being curious about; the restless nature of geology that has generated such catastrophic events as the Yellowstone Supereruptions.

Andrews does a great job not only demystifying what's going on inside volcanoes and faults, but informing us how little we know (especially in the sections on the Moon and Mars, which have extinct volcanoes scientists have yet to completely explain).  Along the way we get the message, "Will all you people just calm down a little?", particularly aimed at the purveyors of hype who have for years made wild claims about the likelihood of an eruption at Yellowstone occurring soon (turns out it's very low) and the chances of a supereruption somewhere causing massive climate change and wiping out humanity (not coincidentally, also very low).

Volcanoes, Andrews says, are awesome, powerful, and fascinating, but if you have a modicum of good sense, nothing to fret about.  And his book is a brilliant look at the natural process that created a great deal of the geology of the Earth and our neighbor planets -- plate tectonics.  If you are interested in geology or just like a wonderful and engrossing book, you should put Super Volcanoes on your to-read list.

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

The catastrophe clock

The human brain is a pattern-seeking machine.

We are evolved to look for correlations, probably because those correlations can be awfully useful.  Our habit of noticing patterns and cycles allowed the ancient Egyptians to figure out the timing of the Nile floods, essential for agriculture in a place that was (and is) a desert.  The people of east Africa did the same sort of thing with the monsoons.  In cool climates, knowing when the growing season was likely to start and end was absolutely critical.

The problem is, this same pattern-seeking feature can trick us into seeing illusory patterns in what are, in essence, random data.  Astrology relies on this sort of thing; a particularly common example recently is the freakout people have when Mercury goes into retrograde (an apparent backward motion of Mercury as seen from Earth because of their relative motion; obviously, Mercury doesn't actually start moving backwards).  Supposedly the whole world goes haywire when Mercury starts its retrograde motion, but believing this requires ignoring the fact that (1) Mercury goes into retrograde three or four times a year, for three or four weeks at a stretch, and (2) the world is kind of haywire all the time.  There's no reason to believe that humanity is any loonier during Mercury retrograde than it is at any other time of the year.

Sometimes those illusory patterns can be oddly convincing.  I remember when I was a kid that much was made of the strange coincidence that since William Henry Harrison was elected President of the United States in 1840, every presidential winner in a "zero year" has died in office: Harrison (1840), Lincoln (1860), Garfield (1880), McKinley (1900), Harding (1920), and Kennedy (1960).  Then Reagan (1980) and G. W. Bush (2000) stubbornly refused to die, forcing True Believers to come up with some kind of nonsense about how it was a 120-year curse and expired after JFK's assassination, or something.  Mostly, though, they just retreated in disarray, because it was a peculiar coincidence, not an actual meaningful pattern.

Fortunately, scientists have statistical methods for determining when you're looking at an actual pattern (i.e., whatever is happening occurs with a true cyclicity) and when you're just seeing random fluctuations or scatter in the data.  This can sometimes uncover odd patterns that are clearly real, but result from some as-yet unknown cause -- such as the natural disaster "heartbeat" that was the subject of a paper in Geoscience Frontiers last week.

Geologists Michael Rampino and Yuhong Zhu (of New York University) and Ken Caldeira (of the Carnegie Institution for Science) analyzed the timing of various major geologic events over the past 260 million years -- continental flood basalt eruptions, changes in the direction of plate movement, oceanic anoxia, major glaciations and changes in sea level, and mid-plate volcanism, as well as events like mass extinctions.  And they found that there was a statistically significant cyclicity to those events -- they tend to cluster every 27.5 million years, and have done so for hundreds of millions of years.

Artist's impression of the moment of the Chicxulub Impact 66 million years ago [Image is in the Public Domain courtesy of NASA and artist Donald E. Davis]

But detecting a pattern is not the same as determining what's behind it.  There is no known geological or astronomical event that occurs on a 27.5 million year cycle that might be the underlying cause of the periodic nature of catastrophes.  The authors throw out a few suggestions -- that it could be due to the motion of the Solar System relative to the rest of the Milky Way (oscillating above and below the plane of the galaxy, perhaps?), a thus-far unknown phenomenon originating in the motion of magma in the Earth's mantle, or the gravitational disturbance of the Oort Cloud by a massive, extremely distant planet orbiting the Sun.  (This latter idea has been around for a while; my college astronomy professor, Daniel Whitmire, was one of the first to treat it seriously, and he and his colleague John Matese wrote one of the first scholarly papers about the "Planet X" hypothesis.  But don't even start with me about Nibiru and the Annunaki, because I don't want to hear it.)

The upshot of it is we don't know.  But if you were worried, we're only about 7.5 million years past the last peak, so we have another twenty million or so years to go before the next one.  As optimistic as I am about my longevity, I seriously doubt I'll be around to see it.  The catastrophe clock has a lot of ticks left until the alarm goes off.

Which is a good thing.  As interesting as they are, flood basalt eruptions and oceanic anoxia and the rest are not events that would be fun to witness first-hand.

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Why do we have emotions?

It's a tougher question than it appears at first.  Emotions like joy and camaraderie can certainly act to strengthen social bonds; fear can warn us away from dangerous situations.  But how often do they get in the way?  The gray emotional vacuum of depression, the overwhelming distress of anxiety and panic disorder, and the unreasoning terror of phobias can be debilitating enough to prevent anything like normal day-to-day functioning.

In Projections: A Story of Human Emotions by Stanford University professor of bioengineering and psychiatry Karl Deisseroth, we take a look at case studies of emotions gone awry -- in Deisseroth's words, "using the broken to illuminate the unbroken."  His deeply empathetic and utterly fascinating account takes the reader through what can go wrong in our emotional systems, and the most recent, cutting-edge research in how the neurological underpinnings of our brains create our emotional world.

It is brilliant reading for anyone wanting to know more about where our feelings come from, and who seek to follow the ancient Greek maxim of γνῶθι σεαυτόν -- "know thyself."

Listening to Cassandra

Yesterday's post, in which I skated backward through geologic time into the deep past, alluded to a few really bad times the Earth has been through.  Episodes of trap volcanism, which make the biggest volcanoes you can think of look like wet firecrackers.  Mass extinctions.  Asteroid collisions.

Bad as 2020 has been, the planet has seen worse.

A lot worse.

One awful event I didn't mention, however, is the Paleocene-Eocene Thermal Maximum.  It occurred about 56 million years ago.  The gist is that over a period of maybe fifty thousand years, there was a spike of carbon dioxide injected into the atmosphere -- over 44,000 gigatons (that's 44 trillion tons) of excess carbon dioxide.  The result was a greenhouse-effect temperature surge that was on the order of five to eight degrees Celsius, on average, worldwide.

The results were catastrophic, starting with the extinction of close to half of the species of foraminifera, single-celled organisms that form the basis of the oceanic food chain and whose calcareous shells were literally dissolved away by increasingly acidic water.  Life eventually bounced back -- it always seems to -- leading to diversification amongst a number of mammalian lineages, including ungulates and carnivores.

But for a while, things were pretty unpleasant.  Unbearably hot, a choking, acrid atmosphere laden with carbon dioxide and methane, and oceans like a sweltering vinegar bath.

Scientists at Columbia University's Lamont-Doherty Earth Observatory just published a paper this week in the Proceedings of the National Academy of Sciences that looks at why this sudden and catastrophic event occurred.  What they found out has two conclusions, one of interest only to folks who like geology, and the other which should terrify the absolute shit out of every human being on Earth.

Let's deal with the tame one first.

In "The Seawater Carbon Inventory at the Paleocene-Eocene Thermal Maximum," the researchers, Laura Haynes and Bärbel Hönisch, found that the cause of all this global havoc was a series of volcanic eruptions in what is now the North Atlantic.  The Mid-Atlantic Ridge had only recently formed, and North America was still in the process of separating from Europe.  Today the processes at the Ridge are relatively slow and steady -- London is moving away from New York City at about 2.5 centimeters a year -- because the area at the junction is made up of thin, fragile oceanic crust that is easy to tear apart.

But back in the Paleocene Epoch, the rift was forming underneath, old, cold, thick continental crust, and when that opened up, it was sudden and catastrophic.  Upwelling lava burned through deep layers of sedimentary rocks, not only coal seams but limestone.  Carbon dioxide was pumped into the atmosphere at a phenomenal rate.  If that wasn't bad enough, disturbance of sea floor sediments caused a massive ejection of methane, which is not only toxic but is a powerful greenhouse gas in its own right.

The result: a huge ecological shift causing a mass extinction.  "If you add carbon slowly, living things can adapt," said study co-author Bärbel Hönisch, in an interview with Science Daily.  "If you do it very fast, that's a really big problem."

[Image is in the Public Domain]

Which brings us to the second conclusion.  This is the part you should really pay attention to.

The estimated rate of carbon injection that caused all this havoc was on the order of one gigaton per year.  (Estimates from the available evidence are between 0.3 and 1.7 Gt/year, so somewhere in the vicinity of one Gt/year is a ballpark average.)  The current measurements of the rate of carbon injection into today's atmosphere are around 10 Gt/year.

Ten times higher than during the catastrophic Paleocene-Eocene Thermal Maximum event.

I don't like to keep ringing the changes on the same topic, but dammit, we need someone in power to take charge of this situation and at least make a passing attempt to do something about it.  This "Meh, we've always used fossil fuels and it's been fine" attitude is seriously imperiling the long-term habitability of the Earth.  The data from today's atmospheric scientists and climatologists are unequivocal; analogous events in the past (the colossal Permian-Triassic Extinction has also been linked to a massive carbon spike) should be an indicator of where all this could lead.

People cite "economic catastrophe" as a potential result of unhooking ourselves from fossil fuels, and use that as a justification for jamming the brakes on any move toward renewable energy.  My response is, if you want to see a fucking economic catastrophe, just keep doing what you're doing.

Economic catastrophe will be the least of our worries.

More and more, people who are warning about the ultimate outcome of climate change -- both actual scientists, and also concerned laypeople like myself -- are seeming like Cassandra, the woman in Greek mythology who was given the power of perfect foresight, but simultaneously cursed to have no one believe her.  I don't know what it will take for elected officials to start listening to today's Cassandras.  Increasingly it's seeming like the only option is voting out damn near every politician currently in office.

The problem is that the political system is propped up by corporate money, with the result that rich donors and lobbyists have a stranglehold on the country.  How to solve that piece of the problem is beyond my ability to parse.

All I can do is keep sounding the alarm, and hope that someone --anyone -- influential is finally listening.

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Author Mary Roach has a knack for picking intriguing topics.  She's written books on death (Stiff), the afterlife (Spook), sex (Bonk), and war (Grunt), each one brimming with well-researched facts, interviews with experts, and her signature sparkling humor.

In this week's Skeptophilia book-of-the-week, Packing for Mars: The Curious Science of Life in Space, Roach takes us away from the sleek, idealized world of Star Trek and Star Wars, and looks at what it would really be like to take a long voyage from our own planet.  Along the way she looks at the psychological effects of being in a small spacecraft with a few other people for months or years, not to mention such practical concerns as zero-g toilets, how to keep your muscles from atrophying, and whether it would actually be fun to engage in weightless sex.

Roach's books are all wonderful, and Packing for Mars is no exception.  If, like me, you've always had a secret desire to be an astronaut, this book will give you an idea of what you'd be in for on a long interplanetary voyage.

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

Explaining an explosion

One of the most puzzling and fascinating questions in evolutionary biology is what kicked off the Cambrian Explosion.

One striking thing about this event is that it points out how many laypeople have the wrong idea about the progression of evolutionary change.  This view -- perpetuated (unfortunately) by a lot of children's books on prehistoric life -- is that we started out with single-celled organisms, then something like a jellyfish, to something like a worm, to something like a crustacean, and so on and so forth -- until we finally get to humans, who are (of course) the pinnacle and end goal of the whole process.

This is wrong on several counts.

First, evolution is not goal-driven.  It's the law of "whatever works now."  There's no support for the Lamarckian idea of reptiles somehow figuring out that it'd be nice if they could fly, and gradually developing wings.  The evolutionary model shows that when changes occur, they're selected for (or against) by whatever the conditions are at the time.  If those conditions change and what once was an advantage now is a disadvantage, well... sucks to be you.  If the population you belong to has the genetic variation to adapt to the new situation, you might make it as a species.  If not, you'll join the 99% of species on Earth that have vanished entirely.

The second problem that it implies a different length of evolutionary history for each sort of organism -- thus you'll see, sometimes even in otherwise excellent books, sea anemones called "primitive" and octopuses called "advanced."  In fact, sea anemones and octopuses -- and humans -- have precisely the same span of ancestral lineage.  Yes, it's true that in that time, the lineage that led to humans has changed a good bit more; it's also true that we've evolved to be a lot more complex than sea anemones have.  So the words "primitive" and "advanced" have to be used with caution -- because we all trace our ancestry back exactly the same number of years, to a common ancestor some three billion years ago.

Last, and most pertinent to this post, the Cambrian Explosion shows us that the"ladder of creation" view of evolutionary history isn't correct.  The Explosion itself occurred on the order of 541 million years ago, and marks the evolution of most of the major body plans of animals we see today.  So nearly simultaneously, and quite rapidly, the fossil record goes from soft-bodied simple forms to a huge diversity of forms -- early arthropods, proto-vertebrates, mollusks, worms, and echinoderms all appear in a relative flash.

It also generated a few animals we don't see around today -- lineages that left no descendants.  These include Anomalocaris...

[Image licensed under the Creative Commons https://commons.wikimedia.org/wiki/File:Anomalocaris_NT_small.jpg]

... Opabinia...

[Image licensed under the Creative Commons Nobu Tamura (http://spinops.blogspot.com), Opabinia BW2, CC BY 3.0]

... and the aptly-named Hallucigenia.

[Image licensed under the Creative Commons Jose manuel canete, H. sparsa, CC BY-SA 4.0]

The conventional wisdom for years has been that the development of fossilizable parts -- teeth, spikes, armor plates -- came about because of the evolution of carnivory.  Once carnivores are around, there's a significant pressure to evolve structures either for defense or to become a carnivore yourself.

But a paper released last week, from research done at the University of Exeter, has suggested a different cause -- that the roots of the Cambrian Explosion, and thus the biodiversity we see around us today, happened because of plate tectonics.  Plate movements in the early Cambrian resulted in the formation of island arcs, similar to what we see today in Japan and Indonesia, and the resultant volcanic activity dumped so much carbon dioxide into the air that it warmed the planet and boosted phytoplankton growth -- leading to a spike in oxygen and rapid cycling of nutrients that fueled an explosion of animal diversity.

"Many studies have suggested this was linked to a rise in oxygen levels – but without a clear cause for such a rise, or any attempt to quantify it," said Josh Williams, now a Ph.D. candidate at the University of Edinburgh, who was the lead author of the paper.  "What is particularly compelling about this research is that not only does the model predict a rise in oxygen to levels estimated to be necessary to support the large, mobile, predatory animal life of the Cambrian, but the model predictions also show strong agreement with existing geochemical evidence."

Of course, such a complex event is very unlikely to have only a single cause, but the Williams et al. research may have found the initial trigger for the rapid diversification.  It's fascinating to think that a little over half a billion years ago, an episode of volcanism might have been the impetus to generating the animal body plans we still see around us today.  As science has shown us so many times, the key to understanding the present lies in the past.

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Richard Dawkins is a name that often sets people's teeth on edge.  However, the combative evolutionary biologist, whose no-holds-barred approach to young-Earth creationists has given him a well-deserved reputation for being unequivocally devoted to evidence-based science and an almost-as-well-deserved reputation for being hostile to religion in general, has written a number of books that are must-reads for anyone interested in the history of life on Earth -- The Blind Watchmaker, Unweaving the Rainbow, Climbing Mount Improbable, and (most of all) The Ancestor's Tale.

I recently read a series of essays by Dawkins, collectively called A Devil's Chaplain, and it's well worth checking out, whatever you think of the author's forthrightness.  From the title, I expected a bunch of anti-religious screeds, and I was pleased to see that they were more about science and education, and written in Dawkins's signature lucid, readable style.  They're all good, but a few are sheer brilliance -- his piece, "The Joy of Living Dangerously," about the right way to approach teaching, should be required reading in every teacher-education program in the world, and "The Information Challenge" is an eloquent answer to one of the most persistent claims of creationists and intelligent-design advocates -- that there's no way to "generate new information" in a genome, and thus no way organisms can evolve from less complex forms.

It's an engaging read, and I recommend it even if you don't necessarily agree with Dawkins all the time.  He'll challenge your notions of how science works, and best of all -- he'll make you think.

[If you purchase this book using the image/link below, part of the proceeds will go to support Skeptophilia!]

Hell's gate

As a diversion from less cheerful subjects like what is currently happening in Washington, D. C., today we will consider: the Gates of Hell.

The interesting thing about the whole concept of hell is that it's connected to Christianity, and yet there's not much of a mention of it in the bible.  The Old Testament version, Sheol, was not really the traditional flaming inferno; it was more of a gray, dreary place cut off from hope and light, sort of like Newark but with less traffic.  The concept of a fire-and-brimstone version of hell doesn't seem to come up until the New Testament, for example Matthew 10:28 and Mark 9:43, where we are introduced to such fun notions as "the fiery furnace" and "unquenchable fire" into which you get pitched if you break the Ten Commandments and commit the Seven Deadly Sins, unless you're also a billionaire fast-talking con man, in which case you get elected president of the United States instead.

Wait, I said I was going to keep this post apolitical.  My bad.

Because of the mention of fire, there's been a picture developed that hell is a hot place underground, which has of course connected it in some people's mind with volcanoes and other subterranean phenomena.  There are a variety of places on Earth that have been considered possible candidates for gates to hell, three of which I describe below.

First, we have the Batagaika Crater in Siberia, which locals have nickname the "Hellmouth."  It's a pretty impressive feature, to be sure:

At its widest, it's a kilometer across and 87 meters deep, and is getting bigger.  The crater has nothing to do with hell, though, unless you're talking about the manmade hell we're creating by ignoring the human causes of climate change; it's something geologists call a megaslump, when removal of groundwater and thawing of permafrost cause massive subsidence.  So it's pretty awful, but doesn't have much to do with the punishment of the damned.

A second candidate is the Necromanteion of Baiae, a tunnel system near the city of Naples which apparently hosted a magical oracle who was supposed to be able to communicate with the spirits of the dead.  She would enter the tunnel, breath the magical vapors, and come back and tell the locals what the dead had to say for themselves, which mostly was confusing, garbled nonsense, that the oracle's handlers then got to interpret whatever way they wanted.

What the dead probably should have told the oracle was "it's a stupid idea to breathe magical vapors in an area of high volcanic activity," because the gases coming out of the tunnel were high in sulfur dioxide and hydrogen sulfide, both of which are quite toxic, and explain her confusion without any magical explanation needed.  Baiae is near the Campi Flegrei, or burning fields, an area of fumaroles and boiling mud pits that illustrate that Mount Vesuvius didn't exhaust its capacity for violence when it destroyed Pompeii in 79 C. E.

Last, we have Darvaza, in the Karakum Desert of Turkmenistan.  Like Batagaika, Darvaza is due to the actions of people -- in this case, a natural gas drilling facility that went very, very wrong.  At some time in the 1960s -- given that we're talking about the Soviets, here, there's no certain information about precisely what happened when -- the ground collapsed underneath a gas-drilling rig, and during the collapse the methane seeping from the walls of the crater ignited.  People expected that it'd burn itself out quickly.

It didn't.

Darvaza is still burning today, and has become a tourist attraction for travelers who don't mind the fact that (1) it reeks of sulfur, (2) if you stay there long enough, the fumes will make you violently ill,  and (3) there are no amenities for miles around.  But if you're an adventurous sort, it's certainly something you won't see anywhere else on Earth.

So that's a trio of candidates for being the doorway to hell.  If none of these float your boat, however, there are actually dozens of others.

And that's not even counting Newark.