A scientific Johnny One-Note

In science, there's sometimes a fine line between looking for data to support your model, and shoehorning every bit of data you can find into your model whether it belongs there or not.

Someone who has stepped over that line -- hell, he left the line behind decades ago, and probably doesn't even know where it is any more -- is British astronomer Chandra Wickramasinghe.  Wickramasinghe is best known for his research into panspermia, the idea that living things, and perhaps the ancestors of all living things on Earth, arrived here on meteorites and in interstellar dust.  He did his Ph.D. dissertation under the supervision of Fred Hoyle, whose views were also a little on the unorthodox side.  (Hoyle, for example, rejected the Big Bang in favor of the Steady-State model, which he steadfastly clung to his entire life despite there being zilch in the way of evidence in its favor.)

So Wickramasinghe was kind of set up from the beginning to be a maverick.  He and Hoyle wrote paper after paper on panspermia, ultimately ascribing an extraterrestrial origin for the pathogens responsible for the 1918-1919 "Spanish" flu, mad cow disease, polio, and SARS.  He has been involved in studies of dust collected from the upper stratosphere that tested positive for microorganisms, which he claimed was extraterrestrial in origin (of course) and turned out almost certainly not to be (of course).  A meteorite strike in Sri Lanka in 2012 was analyzed by Wickramasinghe, and he stated that the rock fragments contained "extraterrestrial diatoms" -- which were ultimately shown to be fossils of entirely terrestrial species that were contained in the sedimentary rocks where the meteorite hit.

Oh, and in the 1981 creationism/evolution "debate" in the courts of the state of Arkansas, Wickramasinghe was the only scientist to testify on the behalf of the creationists.  "Once again," he said, "the Universe gives the appearance of being biologically constructed, and on this occasion on a truly vast scale."

And, he added, the famous Archaeopteryx fossil, showing the clear link between birds and dinosaurs, is a fake.

[Image licensed under the Creative Commons Davidnoy, Chandra-Wickramasinghe, CC BY-SA 3.0]

So here we have a guy who is bound and determined to bang away at the same idea forever, in spite of (or maybe because of) the complete lack of scientifically credible evidence for it.  The more embattled he becomes, the more certain he becomes.

You almost have to admire his determination.

I say "almost," because I have to admit to saying, "are you fucking kidding me?" when I ran into an article over at Mysterious Universe describing a paper Wickramasinghe submitted to the journal The Lancet a couple of weeks ago.  And in it -- which you're probably already anticipating...

... he claims that the Wuhan coronavirus came from outer space.

Wickramasinghe writes:

In the case of the current Coronavirus pandemic in China it is interesting to note that an exceptionally bright fireball event was seen on October 11 2019 over Sonjyan City in the Jilin Province of NE China.  It is tempting to speculate that this event had a crucial role to play in what is now unfolding in throughout China.  If a fragment of a loosely held carbonaceous meteorite carrying a cargo of viruses/bacteria entered the mesosphere and stratosphere at high speed ~30km/s, its inner core which survived incandescence would have got dispersed in the stratosphere and troposphere... 

Following the initial deposition of infective particles in a small localized region (e.g. Wuhan, Hubei province, China) particles that have already become dispersed through over a wider area in the troposphere will fall to ground in a higgledy-piggledy manner, and this process could be extended over a typical timescale of 1-2 years until an initial inoculant of the infective agent would be drained.  This accords well with many new strains of viruses including influenza that have appeared in recent years.

Which, I have to admit, is the first time I've ever seen "higgledy-piggledy" used in a scholarly paper.

Be that as it may, the main problem I see about all this -- besides the fact that (1) meteorites hit the Earth all the time, so finding one in the vicinity of a disease outbreak isn't remarkable, and (2) there is no evidence for what he's saying other than "hey, it could be, y'know?" -- is that all of Wickramasinghe's alleged extraterrestrial microbes are closely related to bacteria and viruses that were already here, and in fact have been here for a long, long time.  Yes, the 1918-1919 flu epidemic was horrifying in its contagion rate and mortality, but the causative virus is not really all that different from other flu viruses seen before and since.  Polio has been around since ancient Egyptian times -- and even if you don't buy that the quick mentions in ancient writings were actually polio, it was unequivocally described in an autobiographical account by Sir Walter Scott of events he endured in 1773.  Mad cow disease, and its human analog Creutzfeld-Jakob Syndrome, are caused by misfolding of a protein called PrP, which (in its properly-folded state) is present the brains of every mammalian species tested, including ones that have never been hit on the head with a meteorite.

And COVID-19, as the epidemiologists have named the Wuhan coronavirus, is one of a large family of viruses that have been troubling humanity for millennia.  In fact, a good many of the cases of the common cold are due to members of the coronavirus family, so it'd be a little odd if there was an epidemic caused by a coronavirus, and that one (and its cousin SARS) turned out to be from outer space while the rest of them were here all along.

Wickramasinghe's response to all this is that since all life on Earth originated in space, it stands to reason that you'll find similarities between the ones that come crashing to Earth and the ones that were already here.  We're all aliens, he says, it's just that some of us are more recent arrivals.

Which to me is stretching credulity to the snapping point.  Ockham's Razor kicks in, here -- in the absence of any positive evidence, the (vastly) simpler theory is that all the life forms on Earth go back to a common (terrestrial) ancestor.  Yes, it's possible that the progenitor of all life forms landed here four-billion-odd years ago from an extraterrestrial source -- but that's all we can say.  It's possible.  There's no independent evidence that this happened, so at the moment, it's just a hand-waving guess, not a valid scientific theory.

But that's not going to stop Wickramasinghe, who is bound and determined to take every new development in microbiology and attribute it to an alien incursion.  I keep hoping the guy will give it a rest eventually, but he's 81 years old and showing no signs of it.  Like I said, have to kind of appreciate his tenacity, but it'd be nice if he'd turn that onto some other lines of scientific inquiry, because it gets a little tiresome to keep listening to the astronomical version of Johnny One-Note.

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One of my favorite people is the indefatigable British science historian James Burke.  First gaining fame from his immensely entertaining book and television series Connections, in which he showed the links between various historical events that (seen as a whole) play out like a centuries-long game of telephone, he went on to wow his fans with The Day the Universe Changed and a terrifyingly prescient analysis of where global climate change was headed, filmed in 1989, called After the Warming.

One of my favorites of his is the brilliant book The Pinball Effect.  It's dedicated to the role of chaos in scientific discovery, and shows the interconnections between twenty different threads of inquiry.  He's posted page-number links at various points in his book that you can jump to, where the different threads cross -- so if you like, you can read this as a scientific Choose Your Own Adventure, leaping from one point in the web to another, in the process truly gaining a sense of how interconnected and complex the history of science has been.

However you choose to approach it -- in a straight line, or following a pinball course through the book -- it's a fantastic read.  So pick up a copy of this week's Skeptophilia book of the week.  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!]

Widening the Goldilocks Zone

The oft-quoted line from Jurassic Park, "Life finds a way," got interesting support from an (unrelated) pair of studies that came out this week, which show that life is a great deal more resilient than we realized.

The first, by a team led by Maxwell Lechte of McGill University, resulted in a paper that appeared in Proceedings of the National Academy of Sciences.  Entitled, "Subglacial Meltwater Supported Aerobic Marine Habitats During Snowball Earth," and looked at a curious (and to us, completely inhospitable) time in Earth's history.  Current models support the conclusion that for a significant chunk of time in the Precambrian Period, between 720 and 635 million years ago, the entire surface of the Earth was covered with ice.  Called the "Snowball Earth" period, it's long been a question in evolutionary biology how any living thing could survive this -- the entire land area of the Earth under a sheet of ice, and the ocean cut off from the atmosphere because its surface is frozen solid.

The authors think they've found the answer.  According to their models, subglacial meltwater streaming through stress cracks in the ice would have been sufficient to generate oxygen-rich "oases" in which life could have survive the deep freeze.  The authors write:

The Earth’s most severe ice ages interrupted a crucial interval in eukaryotic evolution with widespread ice coverage during the Cryogenian Period (720 to 635 Ma).  Aerobic eukaryotes must have survived the “Snowball Earth” glaciations, requiring the persistence of oxygenated marine habitats, yet evidence for these environments is lacking.  We examine iron formations within globally distributed Cryogenian glacial successions to reconstruct the redox state of the synglacial oceans. Iron isotope ratios and cerium anomalies from a range of glaciomarine environments reveal pervasive anoxia in the ice-covered oceans but increasing oxidation with proximity to the ice shelf grounding line.  We propose that the outwash of subglacial meltwater supplied oxygen to the synglacial oceans, creating glaciomarine oxygen oases.  The confluence of oxygen-rich meltwater and iron-rich seawater may have provided sufficient energy to sustain chemosynthetic communities.  These processes could have supplied the requisite oxygen and organic carbon source for the survival of early animals and other eukaryotic heterotrophs through these extreme glaciations.

"The evidence suggests that although much of the oceans during the deep freeze would have been uninhabitable due to a lack of oxygen, in areas where the grounded ice sheet begins to float there was a critical supply of oxygenated meltwater," said study lead author Maxwell Lechte in a press release.  "This trend can be explained by what we call a ‘glacial oxygen pump’; air bubbles trapped in the glacial ice are released into the water as it melts, enriching it with oxygen...  The fact that the global freeze occurred before the evolution of complex animals suggests a link between Snowball Earth and animal evolution.  These harsh conditions could have stimulated their diversification into more complex forms."

The second study is of a very peculiar species of bacteria, Metallosphaera sedula, which is from a curious group of microbes called chemolithotrophs -- they "eat rocks" as part of their required metabolism.  Some chemolithotrophs break down minerals like pyrite (iron sulfide), but Metallosphaera is even weirder than that.  It requires minerals -- more specifically, the elements in those minerals -- found in significant quantities only in meteorites.

Metallosphaera sedula  [Image by T. Milojevic et al.]

In "Exploring the Microbial Biotransformation of Extraterrestrial Material on Nanometer Scale," by a team led by Tetyana Milojevic of the University of Vienna, we find out that this bizarre bacteria thrives only with provided with minerals rich with nickel and copper, and in fact was discovered on a stony meteorite called Northwest Africa 1172.

"Meteorite-fitness seems to be more beneficial for this ancient microorganism than a diet on terrestrial mineral sources," said lead author Milojevic in a press release in Science Alert.  "Our investigations validate the ability of M. sedula to perform the biotransformation of meteorite minerals, unravel microbial fingerprints left on meteorite material, and provide the next step towards an understanding of meteorite biogeochemistry."

Besides that, it also brings up a couple of interesting questions -- first, it immediately made me wonder about the largely-ignored idea of panspermia -- that the earliest life on Earth came here from elsewhere in the universe.  The objection has always been that it'd have to be a pretty hardy life form to survive both both the vacuum of interstellar space and the fiery descent and collision of the meteorite with Earth's surface.  The Milojevic et al. study suggests that the first part might be entirely possible -- if the earliest life forms were chemolithotrophs, there's no reason they couldn't have been out there on a piece of space rock, nestled in a crack and chowing down on the minerals.

The other question, though, it the extent to which we're doing the reverse -- bringing terrestrial microbes out into space, contaminating every world we visit.  The conventional wisdom always was that the trip through space would effectively destroy any microorganisms riding on the outside of the spacecraft, but Metallosphaera sedula shows that might be more of an issue than we thought.

In any case, it does show that life is a great deal more resilient than we ever dreamed, further bolstering my contention that it's common out there in the universe.  The so-called "Goldilocks Zone," in which there are Earth-like conditions that foster the generation of life, might be a great deal larger than we ever dreamed.

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Long-time readers of Skeptophilia have probably read enough of my rants about creationism and the other flavors of evolution-denial that they're sick unto death of the subject, but if you're up for one more excursion into this, I have a book that is a must-read.

British evolutionary biologist Richard Dawkins has made a name for himself both as an outspoken atheist and as a champion for the evolutionary model, and it is in this latter capacity that he wrote the brilliant The Greatest Show on Earth.  Here, he presents the evidence for evolution in lucid prose easily accessible to the layperson, and one by one demolishes the "arguments" (if you can dignify them by that name) that you find in places like the infamous Answers in Genesis.

If you're someone who wants more ammunition for your own defense of the topic, or you want to find out why the scientists believe all that stuff about natural selection, or you're a creationist yourself and (to your credit) want to find out what the other side is saying, this book is about the best introduction to the logic of the evolutionary model I've ever read.  My focus in biology was evolution and population genetics, so you'd think all this stuff would be old hat to me, but I found something new to savor on virtually every page.  I cannot recommend this book highly enough!

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

Life out of catastrophe

After yesterday's post about mysterious explosions in distant galaxies, today I want to look at a colossal explosion that happened much, much closer to home -- and may have jump-started life on Earth.

In a paper by Steven Benner of the Foundation for Applied Molecular Evolution in Alachua, Florida, presented at a conference last fall in Atlanta, we find out that there's geological evidence that early in Earth's history, there may have been a collision with an enormous object -- by some estimates, the size of the Moon -- that drastically altered the atmosphere.  4.47 billion years ago, only sixty million years after the Earth coalesced from the ring of planetary debris where it originated, it was struck so hard by planetoid that water molecules were ripped apart into oxygen and hydrogen, and superheated metallic debris was flung into the air and generated a torrential rain of molten iron.

Artist's conception of what the collision might have looked like from space

As the atmosphere (and everything else) cooled, the highly reactive oxygen bound to the iron, forming a thick layer of iron (and other metal) oxides that explains their prevalence in the Earth's crust today.  More interesting still is that the collision left behind the hydrogen in the atmosphere.  This created what is called a reducing atmosphere -- a collection of gases with an abundance of free electrons, essentially the opposite of what we have today (an oxidizing atmosphere, where oxygen and other electronegative elements mop up any available electrons, making organic matter and other reduced compounds fall apart).

The reducing atmosphere, Benner says, stuck around for two hundred million years, and it was during this time that the first organic compounds were formed.  This lines up neatly with the famous Miller-Urey experiment, where biochemists Stanley Miller and Harold Urey of the University of Chicago showed back in 1952 that in the presence of reducing gases and a source of energy, organic compounds formed readily, including DNA and RNA nitrogenous bases, amino acids, and simple sugars.

Benner believes that the critical one was RNA.  RNA is (as far as we know) unique in that it can not only replicate itself, it's autocatalytic -- it can catalyze its own reactions.  This pull-yourself-up-by-your-shoelaces ability is why a lot of scientists believe that the first genetic material was RNA, not the (currently) more ubiquitous DNA.  And Benner's theory about how the reducing atmosphere was generated explains not only how the building blocks of RNA could have formed, but why the Earth's atmosphere was reducing in the first place.

Benner believes the key is a set of biochemical reactions that involves repeated wetting and drying, along with interaction of the oxygen-free atmosphere with sulfur-containing gases released from volcanic eruptions.  He has demonstrated that in these conditions, formaldehyde -- CH₂O, one of the simplest organic compounds, would form "by the metric ton."  From there, reactions with the sulfur-bearing gases produced hydroxymethanesulfonate, which reacts readily to form glyceraldehyde (a simple sugar) and the four bases of RNA, adenine, cytosine, guanine, and uracil.

Once that happens, the autocatalytic ability of RNA means you're off to the races.  As Richard Dawkins pointed out in his tour-de-force The Blind Watchmaker, if you have two things -- an imperfect replicator, and a selecting mechanism -- you can generate order from disorder in the blink of an eye.  "[M]any experiments have confirmed that once RNA chains begin to grow, they can swap RNA letters and even whole sections with other strands, building complexity, variation, and new chemical functions," said science journalist Robert F. Service, writing for Science magazine.  "[T]he impact scenario implies organic molecules, and possibly RNA and life, could have originated several hundred million years earlier than thought.  That would allow plenty of time for complex cellular life to evolve by the time it shows up in the fossil record at 3.43 billion years ago."

This research not only confirms what Miller and Urey showed in their landmark experiment 67 years ago, but lines up beautifully with what is known from studies by geologists of the earliest rocks.  As for Benner, he's ready to put aside any doubt.  When Ramon Brasser, paleogeologist at the Tokyo Institute of Technology, laid out a timeline of the early Earth in his talk at the Atlanta conference, Benner asked him when the atmosphere would have likely dropped below a temperature of 100 C, the boiling point of water.  Brasser indicated a point about fifty million years after the impact with the planetoid.

"That's it, then!" Benner said excitedly, pointing to a spot at about 4.35 billion years ago on the timeline.  "Now we know exactly when RNA emerged. It's there—give or take a few million years."

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This week's Skeptophilia book recommendation is a little on the dark side.

The Radium Girls, by Kate Moore, tells the story of how the element radium -- discovered in 1898 by Pierre and Marie Curie -- went from being the early 20th century's miracle cure, put in everything from jockstraps to toothpaste, to being recognized as a deadly poison and carcinogen.  At first, it was innocent enough, if scarily unscientific.  The stuff gives off a beautiful greenish glow in the dark; how could that be dangerous?  But then the girls who worked in the factories of Radium Luminous Materials Corporation, which processed most of the radium-laced paints and dyes that were used not only in the crazy commodities I mentioned but in glow-in-the-dark clock and watch dials, started falling ill.  Their hair fell out, their bones ached... and they died.

But capitalism being what it is, the owners of the company couldn't, or wouldn't, consider the possibility that their precious element was what was causing the problem.  It didn't help that the girls themselves were mostly poor, not to mention the fact that back then, women's voices were routinely ignored in just about every realm.  Eventually it was stopped, and radium only processed by people using significant protective equipment,  but only after the deaths of hundreds of young women.

The story is fascinating and horrifying.  Moore's prose is captivating -- and if you don't feel enraged while you're reading it, you have a heart of stone.

[If you purchase the book from Amazon using the image/link below, part of the proceeds goes to supporting Skeptophilia!]

Parsing the Drake Equation

The Drake Equation is one of those curiosities that is looked upon as valid science by some and as pointless speculation by others.  Here's what it looks like:

Math-phobes, fear not; it's not as hard as it looks.  The idea, which was dreamed up by cosmologist Frank Drake back in 1961, is that you can estimate the number of civilizations in the universe with whom communication might be possible (Nb) by multiplying the probabilities of seven other independent variables, to wit:

R* = the average rate of star formation in our galaxy
fp = the fraction of those stars that have planets
ne = the fraction of those stars with planets whose planets are in the habitable zone
fl = the fraction of planets in the habitable zone that develop life
fi = the fraction of those planets which eventually develop intelligent life
fc = the fraction of those planets with intelligent life whose inhabitants develop the capability of communicating over interstellar distances
L = the average lifetime of those civilizations

Some of those (such as R*) are considered to be understood well enough that we can make a fairly sure estimate of its magnitude.  Others -- such as fp and ne -- were complete guesses in Drake's time.  How many stars had planets?  Could be nearly 100%, or it could be the Solar System was some incredibly fortunate fluke, and we're one of the only planetary systems in existence.  But now, with improvements in the techniques for surveying stars, we're finding planets everywhere we look -- most stars seem to have planets, and some research published just last month by a team of astronomers at the University of Witwatersrand (South Africa) has shown that planets could form stable orbits in multiple-star systems, something previously thought extremely unlikely.

That they can do so is fortunate not only for alien intelligence enthusiasts like myself -- as much as half of all stars are thought to be part of multiple-star systems -- but for this guy:

So the estimates keep being revised upward.  The one we still have no real idea about is L -- how long civilizations tend to last.  Carl Sagan, when he described the Drake Equation in his amazing series Cosmos, was pessimistic -- many civilizations, he suggested, lasted long enough to develop weapons of mass destruction, then proceed to blow themselves to smithereens.

But the fact is, we just don't know about L.  But one that was complete speculation -- fl, the fraction of planets in the habitable zone that develop life -- just got a bit of a boost from a study done at the University of Bristol (England).  The researchers, Holly C. Betts, Mark N. Puttick, James W. Clark, Tom A. Williams, Philip C. J. Donoghue, and Davide Pisani, published their results in Nature: Ecology and Evolution last week in a paper titled "Integrated Genomic and Fossil Evidence Illuminates Life's Early Evolution and Eukaryote Origin."  And one of the points the team makes is that once the Earth's surface had cooled sufficiently that water was able to exist in liquid form, life appeared in a relative flash -- while it was still being clobbered every other day by meteorites.

The authors write:

Establishing a unified timescale for the early evolution of Earth and life is challenging and mired in controversy because of the paucity of fossil evidence, the difficulty of interpreting it and dispute over the deepest branching relationships in the tree of life.  Surprisingly, it remains perhaps the only episode in the history of life where literal interpretations of the fossil record hold sway, revised with every new discovery and reinterpretation.  We derive a timescale of life, combining a reappraisal of the fossil material with new molecular clock analyses.  We find the last universal common ancestor of cellular life to have predated the end of late heavy bombardment (>3.9 billion years ago (Ga)).

Besides being of obvious interest to evolutionary geneticists, this should get astronomers' blood pumping; it implies that life originated on Earth when the conditions were still nothing short of hostile, with the corollary that once a planet has conditions that allow liquid water, life probably follows soon thereafter.

The implication being that it's likely that every planet with water that sits in its star's habitable zone has some form of life.

So understandably enough, I think this is way cool.  It doesn't give us any information about the remaining variables we have little information about, especially fi, fc, and L.  There's no particular reason to believe that intelligence is a necessary outcome of evolution; it's tempting to think that the process always drives organisms to be bigger, better, stronger, and smarter, but that's not supported by the evidence.  After all, it bears remembering that by far the dominant life-forms on Earth right now, both in terms of biodiversity and overall numbers, are... insects.

It might be that intelligence sufficient to communicate over interstellar distances is a very uncommon occurrence, which leads to the most likely scenario (in my opinion) being plentiful planets with huge diversity of life, but few that have anything like us.

Still, the galaxy is a big place, with billions of stars, so even if it's unlikely, intelligent life probably exists somewhere.  Which segues into tomorrow's post, which is about the Fermi Paradox.  When told about the Drake Equation, physicist Enrico Fermi famously shrugged his shoulders and said, "Then where is everybody?"

Tomorrow we'll look at a few possible answers -- some of which are considerably more cheerful than others.

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This week's Skeptophilia book recommendation is from one of my favorite thinkers -- Irish science historian James Burke.  Burke has made several documentaries, including Connections, The Day the Universe Changed, and After the Warming -- the last-mentioned an absolutely prescient investigation into climate change that came out in 1991 and predicted damn near everything that would happen, climate-wise, in the twenty-seven years since then.

I'm going to go back to Burke's first really popular book, the one that was the genesis of the TV series of the same name -- Connections.  In this book, he looks at how one invention, one happenstance occurrence, one accidental discovery, leads to another, and finally results in something earthshattering.  (One of my favorites is how the technology of hand-weaving led to the invention of the computer.)  It's simply great fun to watch how Burke's mind works -- each of his little filigrees is only a few pages long, but you'll learn some fascinating ins and outs of history as he takes you on these journeys.  It's an absolutely delightful read.

[If you purchase the book from Amazon using the image/link below, part of the proceeds goes to supporting Skeptophilia!]