Awaiting angelic intervention

As I write this, I'm waiting for the Rapture (it was supposed to happen on Tuesday, but evidently got postponed a few days), so I figured to while away the time until the holy are bodily assumed into heaven and the rest of us slobs get visited by the Four Apocalyptic Horsepersons and the Scarlet Whore of Babylon and the Beast and various other special offers, I'd consider the question of how this stuff got included in the Bible in the first place.

The Book of Revelation is one of the parts of the Bible that some True Believers embrace enthusiastically, while if you ask others, they'll shift in their seats and laugh uncomfortably and mumble something about "symbolic... metaphors... not meant to be taken literally..." and then change the subject.  What's interesting, though, is that this is far from the weirdest piece of writing that was considered to be part of scripture.  Back in the fourth century, there were so many gospels and epistles and books and letters and assorted miscellany that church leaders finally had to hold a series of meetings to try to figure out what was canonical and what wasn't.

So they got together at the Council of Rome (382 C.E.), the Synod of Hippo (393 C.E.), and the Synod of Carthage (397 C.E.), and after that the Bible had something close to its current form.  (Interestingly, the idea that canon was established at the Council of Nicaea in 325 is a misconception; Nicaea had nothing to do with decisions about what was scripture and what wasn't, but was about the nature of the Trinity and how to determine the date for Easter.)  In any case, what's fascinating here is that the church fathers had their work cut out for them, because there were tons of manuscripts to sift through.

And when you start looking through the ones that didn't make the cut -- the ones now labeled "apocrypha" -- you find out that by comparison to some of them, the Book of Revelation comes across as blander than Fun With Dick and Jane.

First, let's consider the Books of Enoch, of which there are three.  1 Enoch especially is a trip, and is also interesting because a lot of what angel enthusiasts chatter on about comes right from there.  You might not know that there are only five angels mentioned by name in the standard Bible -- three good guys, Michael, Gabriel, and Raphael, and two fallen angels, Lucifer and Abbadon.  That's it.  All the rest come from the apocrypha, or from People Making Shit Up, which even many religious people agree pretty much amounts to the same thing.

Another thing about 1 Enoch you might find entertaining is that this is also where most of the nonsense about the Nephilim comes from.  The Nephilim were created when angels came down to Earth and had lots of sex with human women, and the result was the women giving birth to babies who grew up into giant "men of renown."  The Nephilim get a passing, and rather vague, mention in Genesis 6 and Numbers 13, but 1 Enoch really gives details.  They were "three hundred ells tall" -- that'd be something on the order of two hundred meters -- and given to doing some seriously bad shit:

And they became pregnant, and they bare great giants, whose height was three hundred ells, [and] who consumed all the acquisitions of men.  And when men could no longer sustain them, the giants turned against them and devoured mankind.  And they began to sin against birds, and beasts, and reptiles, and fish, and to devour one another's flesh, and drink the blood.

So that's kind of nasty.  Fortunately, God commanded the unfallen angels -- the ones who hadn't been canoodling with human women -- to do battle with the Nephilim, and the Nephilim lost big time.  They were all cast into the fiery abyss, where they dwelleth lo unto this very day.

Then there's a weird passage about farm animals doing stuff:

And that sheep whose eyes were opened saw that ram, which was amongst the sheep, till it forsook its glory and began to butt those sheep, and trampled upon them, and behaved itself unseemly.  And the Lord of the sheep sent the lamb to another lamb and raised it to being a ram and leader of the sheep instead of that ram which had forsaken its glory...  And I saw that a great sword was given to the sheep, and the sheep proceeded against all the beasts of the field to slay them, and all the beasts and the birds of the heaven fled before their face.

Ha-ha, yeah... *shifts uncomfortably*  Metaphor... um... symbols...

But if you think that's weird, what's even wilder is what ultimately happens to Enoch.  A passage in 3 Enoch tells us that he's brought up to heaven, and transformed into the angel Metatron, in a process that sounds really fucking uncomfortable:

At once my flesh turned to flame, my sinews to blazing fire, my bones to juniper coals, my eyelashes to lightning flashes, my eyeballs to fiery torches, the hairs of my head to hot flames, all my limbs to wings of burning fire, and the substance of my body to blazing fire. On my right— those who cleave flames of fire—on my left—burning brands—round about me swept wind, tempest, and storm; and the roar of earthquake upon earthquake was before and behind me.

So when you think of Metatron, if you picture the kind, avuncular Derek Jacobi in Good Omens or the snide, wry, world-weary Alan Rickman in Dogma, you might want to revise that image.

And this is just the Books of Enoch.  If you want some even wackier stuff, check out the Gospel of Thomas, which recounts the childhood of Jesus and depicts him as some sort of super-powerful spoiled brat.  (Reading it made me wonder if this is where the expression "holy terror" comes from.)  Amongst many other atrocities, at age one Baby Jesus curses another kid and makes him "wither into a corpse." Later he kills a neighbor kid for spilling water he'd drawn up from a well, and offs a different kid for bumping into him.

When the neighbors complain, he strikes them blind.

The general impression is more gangsta rap than it is "holy infant, so tender and mild."

Then there's the Apocalypse of Ezra, in which God has an argument with the prophet Ezra wherein Ezra says that since God created the Apple and the Serpent, he's responsible for humanity becoming sinful, so he can't rightfully punish people for doing bad shit.  Which seems like a legit objection to me.  But God shows Ezra the fiery tortures of hell, and says, basically, "What now, Ezra?  Any other questions?" and Ezra says, "Oh, okay, I see your point" and the book ends with a score of God 1, Ezra 0.

In any case, what strikes me about all this is that when it came time to sift through all the hundreds of manuscripts and decide what was canonical and what wasn't, the decision wasn't made by any kind of holy agency.  It was just a bunch of guys arguing about it and finally whittling the list down by about half to what we have today.  (And there are still disagreements -- that's why the various Orthodox sects, Catholicism, and Protestant denominations all have a slightly different set of books in their bibles.)

Of course, the apologists say the decision was made by people who were divinely motivated.  As the Christian site Got Questions puts it, "There are no 'lost books' of the Bible, or books that were taken out of the Bible, or books missing from the Bible.  Every book that God intended to be in the Bible is in the Bible.  There are many legends and rumors of lost books of the Bible, but the books were not, in fact, lost.  Rather, they were rejected...  These books were not inspired by God."

So that's convenient.  Me, I find the whole thing bizarre and a little mystifying, which I suppose is unsurprising.

Anyhow, here I sit, drinking my coffee and waiting for the Rapture.  By the time y'all read this, it'll either have happened or it won't, so if I get Raptured I won't be around to read your comments.  (Admittedly, this is unlikely given my history, and if there was any doubt in the minds of the Heavenly Judges, the fact that I just wrote this post probably sealed the deal.)  If I'm still here, we'll see what's going on in the world.  My guess is that regardless, there won't be any angelic intervention by Enoch-Metatron or Gangsta Baby Jesus or anyone else, and we'll all just have to keep plodding forward as usual.

But if sheep start running around swinging swords, or whatnot, I'll happily eat my words.

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In the pink

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

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

All of that's just background, though.  Remember how a few days ago, I mentioned how much I'm fascinated with things that are big and powerful and scary and can kill you?  Well, part of the cachet of diamonds is the fact that the way they form is all of the above.

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

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

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

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

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

Why this all comes up, though, is that not all diamonds are the colorless transparent crystals that usually come to mind in association with the word.  Diamonds actually come in a variety of colors.  Now, on the surface, this isn't that unusual; pure corundum (crystalline aluminum oxide) is colorless, but if it has chromium impurities, it's red (those are called rubies), and if it has traces of iron and titanium, it turns blue (and are called sapphires).  The same is true with beryl (colored varieties include emeralds, heliodor, and aquamarine), spinel, and quartz.

Some diamond colors -- the yellows, blues, and greens -- are due to impurities as well.

The exception is pink.

[Image is in the Public Domain courtesy of photographer Roy Fuchs]

Pink diamonds are really rare, and although they're colored, it's not because they have impurities.  They're pure carbon, just like the colorless ones.  So how do they end up pink?

The clue came from where they're found.  Analysis of pink diamonds showed that they occur in places where kimberlite pipes get caught up in the rupture of tectonic plates.  So it's not just a colossal megaexplosion that's necessary to form them, they then need to get subjected to enormous pressures as supercontinents break up.  Those pressures cause the molecular bonds between the carbon atoms to bend, and that deformation is sufficient to change how the lattice interacts with light, and results in the crystal having a pink color.

Ninety percent of the known pink diamonds come from one place; the Argyle Formation in western Australia.  This area was right on the fault margin during the breakup of the Nuna Supercontinent 1.3 billion years ago.  And the paper that appeared in Nature this week showed that's no coincidence.  Take a colorless diamond, put it in the gigantic vise of a fault during a continental rupture, and it turns pink.

The whole thing is fascinating, not least because producing them requires being in the middle of two of the most violent processes on Earth.  Just goes to show that catastrophic events can result in beauty -- even if you wouldn't want to be in the middle of them as they occur.

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Rose-colored glass

My wife, Carol Bloomgarden, is an amazing artist, and participates in art shows all over the northeastern United States.  (Her work is called micrography -- it's drawings made from patterns of tiny handwritten text.  You can, and should, check it out at her website.)  Because showing framed art work requires moving lots of stuff around -- not only the work itself, but the canopies, frames, and stands on which to display it -- I frequently accompany her to her shows.

My usefulness is best summed up in a line from a t-shirt a student of mine used to wear: "I May Not Be Very Smart, But I Can Lift Heavy Objects."

In any case, in between setup and breakdown, I usually have lots of time to wander around the show and see what the other artists are selling.  Last year, one of the booths belonged to a very talented jeweler who made jewelry out of (amongst other things) fragments of Roman glass.

Carol hinted at me that she loved this jeweler's work, so for her birthday I got her a necklace and matching set of earrings made from chunks of turquoise-colored glass dating to about 300 C.E.

The Romans were outstanding glassmakers, and a lot of their work survives (unfortunately, much of it in fragmentary form).  And one curious thing about a lot of Roman glass is that it has a patina -- an iridescent sheen on the surface, sometimes refracting light and creating a metallic or rainbow appearance.  There is nothing in the existing writing from that era indicating that those effects were created deliberately; it seemed to be some sort of byproduct of the aging of the piece.

Fourth century C.E. Roman glass from a glassworks in Syria, showing the gold patina over pale green glass [Image is in the Public Domain courtesy of its creator, Marie-Lan Nguyen]

Researchers in materials science at Tufts University became curious about how these coatings were produced, and did microscopic analysis of the surfaces of pieces of Roman glass.  They came to a surprising conclusion; the gold, silver, or rainbow-colored coatings were (1) naturally produced after the pieces were buried, and (2) were photonic crystals -- regular, periodic microlayers of precisely-arranged molecules, of the same sort used in semiconductors and solar cells, which have the effect of generating light interference and an opalescent or iridescent appearance.

It turns out that the interaction between the glass surface, rainwater, and the minerals in the soil results in a very slow, orderly deposition of thin films on the artifact's surface, and in two thousand or so years, you have something truly spectacular.  "It's really remarkable that you have glass that is sitting in the mud for two millennia and you end up with something that is a textbook example of a nanophotonic component," said Fiorenzo Omenetto, who co-authored the study.  "While the age of the glass may be part of its charm, in this case if we could significantly accelerate the process in the laboratory we might find a way to grow optic materials rather than manufacture them."

"This is likely a process of corrosion and reconstruction," said Giulia Guidetti, also a co-author.  "The surrounding clay and rain determined the diffusion of minerals and a cyclical corrosion of the silica in the glass.  At the same time, assembly of 100 nanometer-thick layers combining the silica and minerals also occurred in cycles.  The result is an incredibly ordered arrangement of hundreds of layers of crystalline material... [so] the crystals grown on the surface of the glass are also a reflection of the changes in conditions that occurred in the ground as the city evolved -- a record of its environmental history."

So here we have another example of the kind of fascinating crossover you see in the very best science -- in this case, between materials science and archaeology.  With possible applications to engineering.  

I know I'll think about this study every time Carol wears her Roman glass jewelry.  

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Faces in the woods

One of the first things I ever wrote about in this blog was the phenomenon of pareidolia -- because the human brain is wired to recognize faces, we sometimes see faces where there are only random patterns of lights and shadows that resemble a face.  This is why, as children, we all saw faces in clouds and on the Moon; and it also explains the Face on Mars, most "ghost photographs," and the countless instances of seeing the face of Jesus on grilled cheese sandwiches, tortillas, and concrete walls.

When I first mentioned pareidolia, almost thirteen years ago, it seemed like most people hadn't heard of it.  Recently, however, the idea has gained wider currency, and now when some facelike thing is spotted, and makes it into the mainstream press, the word seems to come up with fair regularity.  Which is all to the good.

But it does leave the woo-woos in a bit of a quandary, doesn't it?  If all of their ghost photographs and Faces on Mars and grilled cheese Jesuses (Jesi?) are just random patterns, perceived as faces because that's how the human brain works, what's a woo-woo to do?

Well, a post at the website Crystal Life gives us the answer.

Entitled "A Visit With the Nature Spirits," the author admits that pareidolia does occur:

How do you see nature spirits in trees?  You use pareidolia, a faculty of the mind that enables you to see patterns in objects where none supposedly exist.  It’s how we see faces and shapes and animals in water, rocks, and tree trunks.  Conventional psychology regards this faculty as pure imagination, but if it is used in a certain way, it can open you up to subtler realities of which conventional psychology is unaware.

Okay, so far so good.  So how do we tell the difference between imagining a face (which surely we all do from time to time), and seeing a face because there's a "nature spirit" present?  We can't, the writer says, because even if it is pareidolia, the spirits are still there.  She gives an example:

“Trees like to express their environment,” she [a like-minded person she was talking with] observes, and so create forms, such as burls, in their bark to reflect what they experience.  I could see the figures she described, although my immediate impression had been that of an energy like that of an octopus.  Atala explained that various people will see different images and aspects of the trees’ energy.  Overall her experiences of the nature spirit were more visual (she took many photographs), while mine were more kinesthetic.  It’s possible that with the pine tree, I was simply picking up certain tendrils of energy that it was extending toward me.

So, in other words -- if I'm understanding her correctly -- even if analysis of the photograph showed that the image we thought was a Nature Spirit turned out to be a happenstance arrangement of leaves and branches, it's still a Nature Spirit -- it's just that the Spirit used the leaves and branches to create his face?  (At this point, you should go back and click the link, if you haven't already done so, it includes some photographs of "Woodland Spirits" that she took, and that are at least mildly entertaining, including one of a guy "coming into rapport" with a tree.)

[Image licensed under the Creative Commons Lauren raine, Greenman mask with eyes, CC BY-SA 3.0]

Well, to a skeptic's ear, all of this sounds mighty convenient.  It's akin to a ghost hunter saying, "No -- the ghostly image wasn't just a smudge on the camera lens; the ghost created a smudge on your camera lens in order to leave his image on the photograph."  What this does, of course, is to remove photographic evidence from the realm of the even potentially falsifiable -- any alternate explanations simply show that the denizens of the Spirit World can manipulate their surroundings, your mind, and the camera or recording equipment.

The whole thing puts me in mind of China Miéville's amazing (and terrifying) short story "Details," in which a woman admits that cracks in sidewalks and stains on walls and patterns in carpet that happen to resemble faces are just random and meaningless -- but at the same time, they are monsters.  Here's how the main character, the enigmatic Mrs. Miller, describes it:

"For most people, it's just chance, isn't it?" Mrs Miller said.  "What shapes they see in a tangle of wire.  There's a thousand pictures there, and when you look, some of them just appear.  But now... the thing in the lines chooses the pictures for me.  It can thrust itself forward.  It makes me see it.  It's found its way through."

It does bear keeping in mind, though, that however wonderful Miéville's story is, you will find it on the "Fiction" aisle in the bookstore.  For a reason.

Of course, it's not like any hardcore skeptic considers photographic evidence all that reliable in the first place.  Besides pareidolia and simple camera malfunctions, programs like Photoshop have made convincing fakes too easy to produce.  This is why scientists demand hard evidence when people make outlandish claims -- show me, in a controlled setting, that what you are saying is true.  If you think there's a troll in the woods, let's see him show up in front of reliable witnesses.  Let's have a sample of troll hair on which to perform DNA analysis, or a troll bone to study in the lab.  If you say a house is haunted by a "spirit," design me a Spirit-o-Meter that can detect the "energy field" that you people always blather on about -- don't just tell me that you sensed a Great Disturbance in the Force, and if I didn't, it's just too bad that I don't have your level of psychic sensitivity.  Also, for cryin' in the sink, don't tell me that my "disbelief is getting in the way," which is another accusation I've had leveled at me.  Honestly, you'd think that, far from being discouraged by my disbelief, a ghost would want to appear in front of skeptics like myself, just for the fun of watching us piss our pants in abject terror.  ("I do believe in spooks, I do believe in spooks, I do believe, I do believe...")

In any case, the article on Crystal Life gives us yet another example of how the worlds of science and the paranormal define the word "evidence" rather differently.  The two views, I think, are probably irreconcilable.  So I'll end here, on that rather pessimistic note, not only because I've reached the end of my post for the day, but also because I just spilled a little bit of coffee on my desk, and I want to wipe it up before the Coffee Fairy fashions it into a scary-looking face.

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The legacy of the seafarers

One of the (many) things I find fascinating about science is how often research involves crossing the boundaries between disciplines.  Ideas from one realm cross-fertilize with ideas from somewhere else, and the result is often unexpected and eye-opening.

Of course, to be honest, a lot of those boundaries are artificial constructs in the first place.  I run into this all the time as a book sorter for our local Friends of the Library used book sale.  Is a donated book anthropology?  Or sociology?  Or gender studies?  You can probably think of examples of books that could plausibly go in any of the three.  The same is true for a lot of books and scholarly papers.  Many of them -- often some of the best ones -- represent a drawing together of ideas from disparate sources, and blending them together to get something fresh and new.

The reason this comes up is because of a study sent to me by a friend and frequent contributor of topics for Skeptophilia, that combines genetics, linguistics, and archaeology.  Led by Andrés Moreno-Estrada of the National Laboratory of Genomics for Biodiversity in Guanajuato, Mexico, the team used genomic studies, patterns of languages, stone building techniques, and even such things as the distribution of certain food crops (like sweet potatoes) across the Pacific to reconstruct the movements of the extraordinary explorers who settled those islands centuries ago.

I mean the "extraordinary" part quite literally.  What these people did is almost unimaginable.  The Pacific is enormous.  The islands of Polynesia are widely-spaced specks of land, some only a few square kilometers in area, separated by hundreds or thousands of kilometers of open ocean.  In nothing more than hand-built wooden canoes, these people launched out into the sea, somehow using natural phenomena (like patterns of clouds and the movements of seabirds) to find their way from one island to the next.  How many of them died trying is unknown and unknowable; but that any succeeded is astonishing.  And enough did succeed that one at a time, they settled all the habitable islands between Samoa and Rapa Nui (Easter Island) -- a distance of 6,600 kilometers.

I don't know about you, but I can't even begin to imagine what kind of incentive it would take for me to jump into an open canoe, leave behind home and family, and try to paddle my way to a hoped-for speck of land five hundred kilometers away.  I've done a lot of traveling, including to some pretty exotic places, but that'd be a big old nope for me.

[Image licensed under the Creative Commons David Eccles (Gringer, Polynesian Migration, CC BY 4.0]

The team used not only genetic evidence from current residents of the islands, but archaeological evidence -- especially the habit of the Polynesians of building stone monoliths.  The most famous ones are the giant stone heads on Rapa Nui, but the Polynesian culture took this art form wherever they went.  Monolithic human statues are found all across the Pacific, and even in the ones on the distant Marquesas Islands, you can see the connection with the iconic moai.

What's coolest is that the pattern of the linguistic evolution and the map of the genetic relatedness between the people on the islands of Polynesia line up pretty much perfectly.  Put more simply, more closely-related people speak more closely-related languages, and therefore both the languages and the people who speak them diverged from a more recent common ancestor.  The alignment of the genetic and linguistic studies supports the usefulness of both for determining patterns of migration -- and clearly could be applied to studying the history of other cultural groups.

Anyhow, the whole thing is pretty amazing, and a great example of what happens when you have creative hybridization between research in different fields.  A fascinating study of the legacy of the fearless seafarers of Polynesia who set off into an uncharted ocean -- and ended up colonizing islands all the way across the Pacific.

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A whole lot of nothing

Anybody have any ideas about what this is?

I've shown a bunch of people, and I've gotten answers from an electron micrograph of a sponge to a close-up of a block of ramen to the electric circuit diagram of the Borg Cube.  But the truth is almost as astonishing:

It's a map of the fine structure of the entire known universe.

Most everyone knows that the stars are clustered into galaxies, and that there are huge spaces in between one star and the next, but far bigger ones between one galaxy and the next.  Even the original Star Trek got that right, despite their playing fast and loose with physics every episode.  (Notwithstanding Scotty's continual insistence that you canna change the laws thereof.)  There was an episode called "By Any Other Name" in which some evil aliens hijack the Enterprise so it will bring them back to their home in the Andromeda Galaxy, a trip that will take three hundred years at Warp Factor 10.  (And it's mentioned that even that is way faster than a Federation starship could ordinarily go.)

So the intergalactic spaces are so huge that they're a bit beyond our imagining.  But if you really want to have your mind blown, consider that the filaments of the above diagram are not streamers of stars but streamers of galaxies.  Billions of them.  On the scale shown above, the Milky Way and the Andromeda Galaxy are so close as to be right on top of each other.

What is kind of fascinating about this diagram -- which, by the way, is courtesy of NASA/JPL -- is not the filaments, but the spaces in between them.  These "voids" are ridiculously huge.  The best-studied is the Boötes Void, which is centered seven hundred million light years away from us.  It is so big that if the Earth were at the center of it, we wouldn't have had telescopes powerful enough to see the next nearest stars until the 1960s, and the skies every night would be a uniform pitch black.

That, my friends, is a whole lot of nothing.

What I find most mind-bending about the whole thing, and in fact what sent me down this particular (extremely deep) rabbit hole this morning, is that the location of the filaments is thought to reflect quantum fluctuations in the matter immediately after the Big Bang, when the whole universe was only a fraction of a centimeter across.  As inflation took over and the universe expanded, those tiny anisotropies -- unevenness in the composition of space -- were magnified until you have filaments which are densely filled and gaps where there is almost nothing at all, and the universe resembles a Swiss cheese made of stars.

Of course, I'm using "densely filled" in a comparative sense.  The cold vacuum of space between the Sun and Proxima Centauri, the nearest star, really doesn't have much in it.  Dust, comets, possibly a rogue planet or two.  But even this is jam-packed by comparison to the Boötes Void and the others like it, wherein it is thought there are light-years of space without so much as a single hydrogen atom.

All of which makes me feel awfully small.  Our determination to act as if what happens down here is of cosmic import is shaken substantially by looking up into the night sky.  It's smashed to smithereens by considering the scale of the largest structures in the universe, which are threads of billions of stars making up a latticework -- and between which there is nothing but eternal silence and such profound darkness that it contains not even a single star close enough to see.

I don't know about you, but that makes me want to climb back under the covers and hug my teddy bear for a while.

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Room for exploration

As a followup to yesterday's post, about my generally dubious take on the claim of a Mexican scientist that he'd discovered fossilized alien bodies, today we're going to look at why we haven't run across aliens yet.  As big as the universe is, it seems like we should have heard from someone by now.  What are we, a bad neighborhood, or something?  Do the aliens go zooming by the Earth, making sure their windows are rolled up and their doors are locked?

I mean, Elon Musk alone would be justification for their doing so, but it's still kind of disappointing.

I've discussed the Fermi Paradox here at Skeptophilia before -- and the cheerful idea of the Great Filter as the reason why we haven't heard from alien life.  As I explained in a post a while back, the explanation boils down to three possibilities, nicknamed the "Three Fs."

We're first, we're fortunate, or we're fucked.

Being an aficionado of all things extraterrestrial, that has never sat well with me.  The idea that we might be all alone in the universe -- for any of the three Fs -- is just not a happy answer.  

Yes, I know, I always say that the universe is under no obligation to act in such a way as to make me happy.  But still.  C'mon... Vulcans?  Time Lords?  Ewoks?  G'gugvuntts and Vl'hurgs?  There's got to be something cool out there.  With luck, lots of cool things.  The Dentrassi, the Ood, Quantum Weather Butterflies, the Skithra, Andorians, the Vashta Nerada...

Okay, maybe not the Vashta Nerada.  But my point stands.

The Andromeda Galaxy [Image licensed under the Creative Commons Adam Evans, Andromeda Galaxy (with h-alpha), CC BY 2.0]

So I was considerably cheered yesterday when I ran into a study out of Pennsylvania State University that attempted to estimate what fraction of the universe we actually have surveyed in any kind of thorough fashion.  The authors, Jason Wright, Shubham Kanodia, and Emily G. Lubar, write:

Many articulations of the Fermi Paradox have as a premise, implicitly or explicitly, that humanity has searched for signs of extraterrestrial radio transmissions and concluded that there are few or no obvious ones to be found.  Tarter et al. (2010) and others have argued strongly to the contrary: bright and obvious radio beacons might be quite common in the sky, but we would not know it yet because our search completeness to date is so low, akin to having searched a drinking glass's worth of seawater for evidence of fish in all of Earth's oceans.  Here, we develop the metaphor of the multidimensional "Cosmic Haystack" through which SETI hunts for alien "needles" into a quantitative, eight-dimensional model and perform an analytic integral to compute the fraction of this haystack that several large radio SETI programs have collectively examined.  Although this model haystack has many qualitative differences from the Tarter et al. (2010) haystack, we conclude that the fraction of it searched to date is also very small: similar to the ratio of the volume of a large hot tub or small swimming pool to that of the Earth's oceans.  With this article we provide a Python script to calculate haystack volumes for future searches and for similar haystacks with different boundaries.  We hope this formalism will aid in the development of a common parameter space for the computation of upper limits and completeness fractions of search programs for radio and other technosignatures.

The actual analogy Wright and his colleagues used is that saying our current surveys show there's no intelligent life in the universe (except for here, which itself seems debatable some days) is comparable to surveying 7,700 liters of seawater out of the total 1.335 billion trillion liters in the world's oceans.

So basing a firm conclusion on this amount of data is kind of ridiculous.  There could be intelligent alien species out there yelling, "Hey! Earthlings!  Over here!  We're over here!", and all we would have to do is have our radio telescopes pointed a couple of degrees off, or tuned to a different wavelength, and we'd never know it.

Which is pretty cool.  Given the fact that my all-time favorite movie is Contact, I'm hoping like hell that people don't read Wright et al.'s paper and conclude we should give up SETI because it's hopeless to make a thorough survey.  When I think about what poor Ellie Arroway went through trying to convince her fellow scientists that her research was valid and deserved funding... yecch.  And if anything, the current attitudes of the government toward pure research are, if anything, worse than those depicted in the movie.

But despite all that, it's awe-inspiring to know we've got so much room to explore.  Basically... the entire universe.  So my dream when I was a kid, sitting out in my parents' yard with my little telescope, that as I looked at the stars there was some little alien boy in his parents' yard looking back at me through his telescope, may one day prove to be within hailing distance of reality.

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