Completing the recipe

Last week, I wrote a piece on the peculiarities of Jupiter's moon Io -- surely one of the most inhospitable places in the Solar System, with hundreds of active volcanoes, lakes of liquid sulfur, and next to no atmosphere.  But there's a place even farther out from the warmth of the Sun that is one of our best candidates for an inhabited world -- and that's Saturn's icy moon Enceladus.

It's the sixth largest of Saturn's eighty-some-odd moons, and was discovered back in 1789 by astronomer William Herschel.  Little was known about it -- it appeared to be a single point of light in telescopes -- until the flybys of Voyager 1 and Voyager 2 in 1980 and 1981, respectively, and even more was learned by the close pass in 2005 by the Cassini spacecraft.  

One of Cassini's spectacular photographs of Enceladus [Image is in the Public Domain courtesy of NASA/JPL]

Enceladus, like Io, is an active world.  It has a thick crust mostly made of water ice, but there are "cryovolcanoes" -- basically enormous geysers -- that jet an estimated two hundred kilograms of water upward per second.  Some of it falls back to the surface as snow, but the rest is the primary contributor to Saturn's E ring, 

Where it gets even more interesting is that beneath the icy crust, there is an ocean of liquid water estimated to be ten kilometers deep (just a little shy of the depth of the Marianas Trench, the deepest spot in Earth's oceans).  Like Io's wild tectonic activity, the geysers of Enceladus are maintained primarily by tidal forces exerted by its host planet and the other moons.  But that's where any resemblance to Io ends.  Chemically, it could hardly be more different.  Analysis of the snow ejected by the cryovolcanoes of Enceladus found that dissolved in the water was ordinary salt (sodium chloride), with smaller amounts of ammonia, carbon dioxide, methane, sulfur dioxide, formaldehyde, and benzene.

What jumped out at scientists about this list is that these compounds contain just about everything you need to build the complex organic chemistry of a cell -- carbon, nitrogen, oxygen, hydrogen, and sulfur.  I say "just about" because one was missing, and it's an important one: phosphorus.  In life on Earth, phosphorus has two critical functions -- it forms the "linkers" that hold together the backbones of DNA and RNA, and it is part of the carrier group for energy transfer in the ubiquitous compound ATP.  (In vertebrates, it's also a vital part of our endoskeletons, but that's a more restricted function in a small subgroup of species.)

But just last month, a paper was presented at the annual meeting of the American Geophysical Union describing the research that finally found the missing ingredient.  There is phosphorus in Enceladus's ocean -- in fact, it seems to have a concentration thousands of times higher than in the oceans of Earth.

This is eye-opening because phosphorus is a nutrient that is rather hard to move around, as vegetable gardeners know.  If you buy commercial fertilizer, you'll find three numbers on the package separated by hyphens, the "N-P-K number" representing the percentage by mass of nitrogen, phosphorus, and potassium, respectively.  These three are often the "limiting nutrients" for plant growth -- the three necessary macronutrients that many soils lack in sufficient quantities to grow healthy crops.  And while the nitrogen and potassium components usually (depending on the formulation) "water in" when it rains and spread around to the roots of your vegetable plants, phosphorus is poorly soluble and tends to stay pretty much where you put it.

The fact that the snow on Enceladus has amounts of phosphorus a thousand times higher than the oceans of Earth must mean there is lots down there underneath the ice sheets.

This strongly boosts the likelihood that there's life down there as well.  Primitive life, undoubtedly; it's unlikely there are Enceladian whales swimming around under the ice.  But given how quickly microbial life evolved on Earth after its surface cooled and the oceans formed, I feel in my bones that there must be living things on Enceladus, given the fact that all the ingredients are there.  (The oceans on Earth formed on the order of 4.5 billion years ago, and the earliest life is likely to have begun on the order of four billion years ago; given a complete recipe of materials and an energy source, complex biochemistry seems to self-assemble with the greatest of ease.)

Maybe I'm being overly optimistic, but the discovery of phosphorus in the snows of Enceladus makes me even more certain that extraterrestrial life exists, and must be common in the universe.  If we can show that there are living things down there, on a mostly frozen moon 1.4 billion kilometers from the Sun, then it will show that life can occur almost anywhere -- as long as you have all the ingredients for the recipe.

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

Replacement coffee

Commercial farmers of perennial crops have an inherent problem.

The cheapest, most efficient, and most cost-effective method of growing something where the roots (or the entire plant) persists from year to year -- which includes fruits, nuts, and tropical products like coffee and cacao -- is to plant a large quantity of a single variety of plant.  The difficulty is that the plants are therefore closely related genetically, if they're not out-and-out clones, and susceptible to the same pests and diseases.  It's what did in the Irish potato farmers during the 1840s and 1850s; late blight (Phytophthora infestans) wiped out the single-variety potato crop five years running, resulting in the Great Famine in which a million people starved to death and another two million left Ireland for good, one of the largest exoduses from a single country in the history of humanity.

This is increasingly the situation being faced by the people who raise bananas.  Virtually all the bananas produced commercially are a single variety -- the Cavendish banana -- all descended from root cuttings of a plant from Mauritius that was in the greenhouse of the Duke of Devonshire.  Those cuttings were sent first to Samoa and other islands in the South Pacific, and thereafter to the Canary Islands, West Africa, and South and Central America, where the variety was found to be resistant to a fungal infection called Panama disease that had wiped out the previous main cultivar ("Gros Michel"). 

The problem is -- as we're seeing from COVID-19 -- pathogens have a way of staying one step ahead of us, and now there's a strain of Panama disease that kills Cavendish bananas.  Unfortunately for those of us who, like myself, love bananas, there is no obvious next strain to turn to.

The other plant in a similarly dire situation is -- and I hate to bring this up -- cacao.  Chocolate producers are fighting an increasingly long list of pests and diseases that target cacao plants, which are notoriously fragile and easy to kill.  As with banana growers, there is no good option for cacao farmers other than to fight the pathogens and insects when they show up and hope for the best.

Hearteningly, the situation is a little better with another of the world's most beloved crops, which is coffee.  

[Image licensed under the Creative Commons Julius Schorzman, A small cup of coffee, CC BY-SA 2.0]

In fact, this is the reason why the topic comes up; an article in Nature a couple of weeks ago looks at a different species of coffee (Coffea liberica) that shows real promise in avoiding some of the difficulties of growing the two main varieties, arabica (Coffea arabica) and robusta (Coffea canephora), which make up (respectively) about 55% and 45% of the commercial coffee in production.  The plants have better heat and humidity tolerance, and good resistance to coffee leaf rust and coffee wilt disease.  Liberica coffee (often called "excelsa" in the trade) was initially discounted because of the quality of coffee it produced, but that seems to be because the larger seeds have to be processed a little differently or they lose a lot of their flavor.  Dealt with correctly, liberica coffee has (according to the writers):

...a mild, smooth, pleasant-flavoured coffee of low to medium acidity and low bitterness, as per historical accounts.  Tasting notes include cocoa nibs, peanut butter, dried fruits, Demerara sugar and maple syrup; and for samples from South Sudan, there are notes of raspberry coulis, figs, plums and milk chocolate.

All of which is awesome but a little mystifying to me.  You probably know that there are people called "supertasters," who have a far greater acuity in their senses of taste than average, and who can pick out all the delicate nuances of taste in things like coffee, chocolate, wine, and so on.  I, on the other hand, am the opposite.  I'm a stuportaster.  I have two taste buds, "thumbs up" and "thumbs down."  Presented with most cups of coffee, my response is "coffee good, want more."  (The rest of the time my response is "coffee bad, no thanks.")  I do the same thing with wine, much to the dismay of the sommeliers when we visit wineries, who love nothing more than blathering on about the wine's nose and flavors and notes and finish, and do not appreciate a dolt like me who pretty much just drinks it and looks around for a refill.  So while I'm glad there's someone around who can pick out notes of Demerara sugar and raspberry coulis in their morning cup of coffee, for me it kind of starts and ends with "me like it lots."

In any case, it's encouraging that the coffee farmers may be able to escape dire situation being faced by owners of banana and cacao farms.  It's bad enough facing the prospects of losing two of them; losing all three would just be catastrophic, even for people like me who only have two taste buds.

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

The empty pews

Today I'd like to look at two articles that are mainly interesting in juxtaposition -- and a third that is as horrifying as it is enlightening.

The first is from Christianity Today and describes a one hundred million dollar ad campaign designed to bring the uncommitted, undecided, and "cultural Christians" -- what the people running the campaign call "the movable middle" -- back into the fold.  The money is being spent for television and online advertisements, billboards, and YouTube videos, all designed to make Christianity look appealing to the dubious.  The program is called "He Gets Us," and focuses on Jesus's warm, human side, his struggles against people who judged him, and his commitment to dedicate himself to God's will even so.

I'm perhaps to be forgiven for immediately thinking of the "Buddy Christ" campaign from the movie Dogma.

The reason for "He Gets Us," of course, is that in the last ten years Christian churches in the United States have been hemorrhaging members, especially in the under-30 demographic.  A 2019 study found that 66% of Americans between 23 and 30 stopped going to church for at least a year after turning 18; most of the ones who left didn't go back.  The main reasons they gave for leaving were church involvement in politics (especially support of Donald Trump), issues of contraception and women's bodily autonomy, and policies and attitudes discriminating against LGBTQ+ individuals.

Haven, the group running the campaign, summed up the problem thusly: "How did the world’s greatest love story in Jesus become known as a hate group?"

The second article is a paper in the Journal of Secularism and Nonreligion, and attempted to quantify the degree of in-group favoritism and out-group dislike amongst various religions in the United States, agnostics, and atheists.  Contrary to the common perception that "atheists hate the religious," the researchers found that the converse was closer to the mark:

Atheists are among the most disliked groups in America, which has been explained in a variety of ways, one of which is that atheists are hostile towards religion and that anti-atheist prejudice is therefore reactive.  We tested this hypothesis by using the 2018 American General Social Survey by investigating attitudes towards atheists, Christians, Buddhists, Hindus, Jews, and Muslims.  We initially used a general sample of Americans, but then identified and isolated individuals who were atheists, theists, nonreligious atheists, religious theists, and/or theistic Christians.  Logically, if atheists were inordinately hostile towards religion, we would expect to see a greater degree of in-group favouritism in the atheist group and a greater degree of out-group dislike.  Results indicated several notable findings: 1). Atheists were significantly more disliked than any other religious group. 2). Atheists rated Christians, Buddhists, Jews, and Hindus as favourably as they rated their own atheist in-group, but rated Muslims less positively (although this effect was small).  3). Christian theists showed pronounced in-group favouritism and a strong dislike towards atheists.  No evidence could be found to support the contention that atheists are hostile towards religious groups in general, and towards Christians specifically.

The fact is, it's not the atheists who have a hate problem to address.  I find Haven's disingenuous question about Christianity and hate groups wryly funny, especially since they have also run ad campaigns for Focus on the Family, one of the most virulently anti-LGBTQ+ groups in existence (they are on record as calling LGBTQ+ marriage and parenting equal rights as "a particularly evil lie of Satan").

Maybe the first thing to do before trying to market a kinder, gentler Jesus is for the Christians themselves, as a group, to confront the Religious Right's ongoing campaign of persecution against queer people.  (And if you think I'm overstating the case by using the word "persecution," allow me to remind you that only six months ago, a pastor in Texas told a cheering congregation that anyone identifying as queer should be stood up against a wall and shot; only two months ago, a right wing nutjob went to a nightclub in Colorado Springs and did exactly as told; and shortly afterward, a different pastor told a different cheering congregation he was glad it had happened.)

And they wonder why people are looking at the church, shaking their heads, and walking away.

The last story I probably wouldn't have bothered commenting on if it hadn't been for the first two; in fact, when I first saw it, I thought it was a joke.  It's about former United States Representative and current complete lunatic Michele Bachmann, who since her failed attempt at re-election has turned herself into a spokesperson for the evangelicals.  She was on the Christian radio program Lions & Generals a couple of days ago, and proudly told the interviewer that she had spent Christmas day warning her grandchildren about the fires of hell.

No, I'm not making this up.  Here's a direct quote:

I was with two of my grandchildren this weekend, a two-year-old and a six-year-old, and I was just compelled to talk to them about, when we die, it’s judgement," she said.  "We talked about what heaven is, and we talked about what hell is.  That hell is just as real as heaven.  And in hell, there’s eternal fires and damnation and it’s a real place, we do not want to go there, that’s where the wicked will go.  And then I explained how they don’t go — that they receive Christ and confess their sins … [Jesus] cleanses them and then because of his righteousness, they go to heaven...  And so my little granddaughter immediately started saying, ‘I don’t want to go to hell, I want to go to heaven.’ I said, ‘Bella, can I pray with you? Let’s pray.  Do you want to pray?’ … And I think, why miss an opportunity?

Or, more accurately, "why miss an opportunity to subject a six-year-old and a two-year-old to religiously-justified emotional abuse?"

And once again, they wonder why people are looking at the church, shaking their heads, and walking away.

Look, I know, "not all Christians."  Not, perhaps, even most Christians.  As I've said many times, I have lots of Christian friends, as well as friends of various other belief systems, and mostly we all get along pretty well.  But unfortunately, in the United States, Christianity has allowed itself to get hijacked by the loudest, ugliest, and most vicious minority, and those are the people who are creating the image American Christianity has.  Until the Christians who really do stand for Jesus's command to "love thy neighbor as thyself" -- and that includes thy brown neighbor, thy immigrant neighbor, thy homeless neighbor, thy queer neighbor, thy Muslim neighbor, and thy atheist neighbor -- stand up and shout down the bigots and extremists, no multi-million-dollar ad campaign is going to do a damn thing to stop the pews from emptying.

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

The disappearing elephant

Ever heard of gomphotheres?

They're a group of prehistoric megafauna related to modern elephants with some pretty wacky-looking dental adornments.  There was Cuvieronius:

[Image licensed under the Creative Commons DiBgd, Cuvieronius hyodon2, CC BY-SA 4.0]

And Stegatetrabelodon:

[Image licensed under the Creative Commons ДиБгд, Stegotetrabelodon11, CC BY-SA 4.0]

And strangest of all, Platybelodon:

[Image licensed under the Creative Commons Tim Bertelink, Platybelodon, CC BY-SA 4.0]

Illustrating that it's a good thing I'm not in charge of assigning scientific names, because I'd'a named this one Derpodon bucktoothii. 

In any case, these behemoths were once widespread across North America and Europe, but gradually died out during the Pliocene Epoch (5.3 to 2.6 million years ago), with the last species persisting a little way into the next epoch, the Pleistocene.  Probably for the best, actually.  I have a hard time keeping rabbits and woodchucks out of my vegetable garden, I'd just give up if I had to fend off these things as well.

Where it gets even more interesting is that these animals, like (literally) millions of others, had coevolved with other life forms.  Coevolution -- when the adaptations of one species effect the adaptations of an unrelated species -- can take two forms.  First, there's an evolutionary arms race, where a predator/prey relationship pushes both species to evolve (such as cheetahs and antelopes, where the fastest cheetahs catch the slowest antelopes, selecting both for greater speed).  The other is mutualism, where each of the two helps the other, like flowers that have adapted to specific pollinators, sometimes resulting in such dependence that neither species can survive without the other.

It's this latter type that happened with the gomphotheres.  They were major seed dispersers -- eating fruits of trees and shrubs, then defecating out the seeds (unscathed) after digesting the pulp.  Many of these plants still exist in North America and Europe, and all are united by having large, tough-skinned fruits, usually with hard or unpalatable seeds, and some sort of thorns or spikes on the branches to deter smaller animals from eating them.

There's only one problem -- as I mentioned earlier, all the gomphotheres have been extinct for millions of years.

So that leaves a bunch of plants without an efficient way of dispersing their seeds.  And we're not talking about exotic and unfamiliar plants, here.  If you look up evolutionary anachronisms, you'll see lots of names you recognize, including:

• Avocado (Persea americana)
• Papaya (Carica papaya)
• Cacao (Theobroma cacao)
• Custard apple (Annona spp.)
• Wild squash (Cucurbita pepo)
• Pawpaw (Asimina triloba)
• Osage orange (Maclura pomifera)
• Kentucky coffee tree (Gymnocladus dioicus)
• Honey locust (Gleditsia triacanthos)
• Devil's walking stick (Aralia spinosa)
• American persimmon (Diospyros virginiana)

Some of these, like cacao, Osage orange, and Kentucky coffee tree, have only prospered and/or expanded their range because humans intervened.  The last-mentioned, for example, was found only in a highly fragmented, restricted range in the south central United States when it was first cultivated by botanists and found to be a decent ornamental tree.  In the wild, the big, leathery pods -- like the fruit of a lot of these species -- simply fall to the ground when ripe and rot, the seeds nearly all failing to germinate.  Now it's planted throughout the eastern half of the United States, although given its poor germination rate even with help, the species will probably never be common.

Unless the elephants come back somehow.

This all illustrates a point I've made before -- the biosphere is a complex interwoven tapestry.  While change is inevitable -- and the extinction of the gomphotheres isn't the fault of humanity but (likely) the changing climate -- it behooves us to keep in mind that nothing on the Earth exists in isolation.  You can't pull out one thread without making the entire thing start to come unraveled.  And too many threads pulled out, the entire tapestry falls apart.

I can only hope we learn from what we've found out about the ebbs and flows of prehistory.  While we can't halt change, we need to do a far better job of protecting what we have.

Lest we go the way of the gomphotheres.

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

The skein of lies

The only thing that is surprising about Representative-elect George Santos's tangled skein of lies is how unsurprising it is.

The list of his falsehoods is extensive, and include:

• He claimed his mother's family is Jewish and fled the Holocaust.  He said her parents' surname was Zabrovsky, and did fundraising for a charity under the name "Anthony Zabrovsky."  In fact, he does not appear to have Jewish ancestry at all, and tried to dodge the lie when confronted about it by a reporter from the New York Post by saying "I didn't say I was Jewish, I said I was Jew-ish."  He'd also said on another occasion that his mother "was born in Belgium and fled socialism in Europe" to come here -- but investigative reporters from CNN found she was actually born in Brazil.
• He stated that "9/11 claimed his mother's life."  She actually died of cancer in 2016.
• He claimed to have gone to a prestigious prep school, but had to leave because his parents had financial problems.  The school has no record of his ever attending.
• He claimed to have graduated from Baruch College.  The school has no record of his ever attending.
• He claimed to have been an associate asset manager at Goldman Sachs.  The company has no record of his ever working there.
• He claimed never to have broken the law anywhere.  There are records of his being charged with fraud in Brazil after writing checks from a stolen checkbook.  Reporters found that he'd been released on his own recognizance and then failed to show up at his court date.
• He claimed to own thirteen properties from which he derived income, and later admitted he didn't own any at all.

And so on and so forth.  Confronted with the list of falsehoods, he called them "embellishments" and "poor choices of words," instead of what they are, which are brazen, bald-faced lies.

All appalling enough.  But what finally pissed me off enough to write about it here was an interview two days ago on Fox News, where Tulsi Gabbard (sitting in for Tucker Carlson) had some sharp words for Santos, calling him out on his lies and saying, "Have you no shame?" and "You don't seem to be taking this seriously."

Okay, whoa now.  Fox News has zero standing to call out Santos for lying.  They stood by and defended Donald Trump for lying pretty much every time he opened his damn mouth, and still largely support him (and attack anyone who opposes him).  They sided with Trump counselor Kellyanne Conway when she defended then-White House spokesperson Sean Spicer's lies about the number of attendees at the Inauguration, calling them "alternative facts."  They've been at the forefront of spreading lies and propaganda about climate change (it's a hoax), COVID-19 (it's no big deal), masks (they don't work), and vaccines (neither do they).

They do not get to stand on the moral high ground now and pretend they care about the truth.

In a very real sense, Fox News created George Santos.  Without the complete disdain they've shown for truth, without their "facts you don't like are lies by the radical left" philosophy, without the constant message of "every media agency in the world is lying to you except us," the network of easily-disproved falsehoods by George Santos wouldn't have lasted five minutes.  Members of his own party would have found out what a fraud he is, and fronted another candidate for the position.

But we're sunk so deep in the attitude that "truth doesn't matter as long as you're in power," he not only ran, but got elected.

It remains to be seen what will happen to him.  A House ethics committee is looking into his background, but whether his past actions crossed the line from "unethical" into "illegal" isn't certain.  It's probable that since in a week the House of Representatives will have a Republican majority, he'll sail into office without a problem.

Honestly, if you think Santos is shocking, you haven't been paying attention.  He's just the end of a long pattern of increasing disdain for inconvenient truths.  We haven't seen the last of his kind, either, especially given the likelihood that he won't face anything worse for his lying than a slap on the wrist.  Until we, as a voting citizenry, demand that our elected officials and the media we consume respect the truth above all, we will continue living out the famous quote by Jean de Maistre, that "A democracy is the form of government in which everyone has a voice, and therefore in which the people get exactly the leadership they deserve."

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

The mystery of the Cagots

It will come as no surprise to long-time fans of Skeptophilia that I love a mystery.  And if that mystery is mixed up with questions of ancestry and human genetics, well... that's going to pique my interest but good.

This topic comes up because a couple of days ago I stumbled upon an interesting ethnic minority I'd never heard of -- the Cagots, a distinct group found in northern Spain and southwestern France (the same region where you find high proportions of Basque ancestry -- although they appear to be unrelated).  Like many minorities, they were persecuted by the majority culture, to the point that a separate Cagot culture has all but disappeared, and today people are reluctant to admit they have Cagot ancestry (if they even realize it).

The "Street of the Cagots' Bridge" (Campan, Hautes-Pyrénées département) [Image licensed under the Creative Commons Sotos, Rue du village de Campan (Hautes-Pyrénées) 3, CC BY-SA 4.0]

Where it gets really interesting is their origin.  To start with, their name varies by region -- Cagot is the most common, but they've also been called Cagous, Cahets, Gahets, Gafets, Agots, Argotes, Capots, Cacons, Cacous, Caquots, and Caqueux, not to mention about a dozen others.  This makes any kind of linguistic analysis of the name difficult, to say the least.  One idea is that the name comes from the Occitan word caas, meaning "dog," and an old version of the word "Goth" -- and comes along with a suggestion that they are the descendants of the remnants of the Visigoths who were defeated by Clovis I at the Battle of Vouillé in 507 C.E.  Illustrating the truth of the adage that "for every claim there's an equal and opposite claim," others have suggested that they're descended from people who called themselves "hunters of the Goths" -- i.e. the Saracens and Moors left behind after the Battle of Tours in 732 C.E.  Yet another claims they're descended from the Erromintxela, a group of Spanish Roma, thus linking them to another tragically marginalized group.

Typical of persecuted minorities, there hasn't been much in the way of study of these people, and by now most of them have long since been subsumed into the dominant French and Spanish cultures.  But it should be possible to figure this out; for centuries there was "forced endogamy," where Cagots could only marry other Cagots, and they were only allowed to live in self-contained communities on the fringes of towns.  (In a scary parallel to other practices of visually identifying minorities, during the seventeenth and eighteenth centuries, Cagots were required to wear a badge with a pattern of a duck's foot and/or a cloak with a yellow trim.  The reason for the association with ducks and the color yellow is unknown.)  The result of these practices of isolation is that there should be enough genetic distinctness to detect, even if the current descendants are of considerably mixed ancestry.

It immediately got me to thinking about other groups I've read about that are of uncertain origins -- three in the United States that come to mind are the Melungeons of eastern Tennessee and Kentucky and southwestern Virginia, the Brass Ankles of South Carolina, and the Redbones of southwestern Louisiana.  What little genetic study has been done -- and members of all three groups have been understandably reluctant to cooperate with scientists they perceive as being part of the prejudiced majority -- suggests that all of them are "tri-racial," with ancestry from Sub-Saharan Africa, Native American tribes, and Europe.  Members of all three groups were classified as "mulattos" or "Indians" on the nineteenth-century censuses, but census takers back then were notoriously bad about accuracy of data collection on minorities.

So like the Cagots, they are still poorly-studied mysteries with little to no certainty about their origins.

Besides the obviously abhorrent treatment members of these groups received, what's appalling and frustrating about all of this is that the truth is, there is no such thing as ethnic or racial purity.  Which, of course, is the basis of most of these discriminatory practices.  I look pretty solidly White Western European, but my DNA test picked up my ancestry from my Ashkenazi great-great grandfather, something I wrote about not long ago -- and my genealogical research has found ancestors who were Basque, Mi'kmaq, and Abenaki, although they're long enough ago that those didn't show up on my genetic analysis.  If you go farther back still, the concept of race gets even more ridiculous (from a genetic perspective; it obviously has extremely important historical and cultural significance).  All people of western European descent, for example, are thought to have common ancestors as little as a thousand years ago; the same is almost certainly true of other clusters of related ethnic groups.  And there's decent evidence of a genetic bottleneck triggered by a volcanic eruption on the Indonesian island of Toba 74,000 years ago, an event that may have reduced the entire human population of the Earth to around seven thousand people -- the size of a single small village.  If this is correct, those seven thousand people are the ancestors of everyone on Earth, over and over and over, and all of our family trees first branch out and then coalesce to a very narrow set of limbs.

What the racists don't get, and don't seem to want to get, is that the science is incontrovertible; we're all cousins, regardless of whether we look different now.

In any case, I thought the presence of a curious ethnic group in an area to which a large chunk of my mom's ancestry traces its origins was pretty fascinating.  I don't know if I have Cagot ancestry, but it wouldn't surprise me; my mom's forebears in western France were largely poor laborers and peasants.  No way to figure out for certain, though, especially given the paucity of studies on the group.

But it does bring home the fact that the ties that unite us are, in reality, far stronger than the features that divide us.  A lesson that many of us, unfortunately, have yet to learn.

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

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.

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