I feel pretty

The drive to adorn our bodies is pretty close to universal.

Clothing, for example, serves the triple purpose of protecting our skin, keeping us warm, and making us look good.  Well, some of us.  I'll admit up front that I have a fashion sense that, if you were to rank it on a scale of one to ten, would have to be expressed in imaginary numbers.  But for a lot of people, clothing choice is a means of self-expression, a confident assertion that they care to look their best.  

Then there are tattoos, about which I've written here before because I'm a serious fan (if you want to see photos of my ink, take a look at the link).  Tattooing goes back a long way -- Ötzi the "Ice Man," a five-thousand-year-old body discovered preserved in glacial ice in the Alps, had no fewer than 61 tattoos.  No one knows what Ötzi's ink signifies; my guess is that just like today, the meanings of tattoos back then were probably specific to the culture, perhaps even to the individual.  

Then there's jewelry.  We know from archaeological research that jewelry fashioned from gems and precious metals also has a long history; a 24-karat gold pendant found in Bulgaria is thought to have been made in around 4,300 B.C.E., which means that our distant ancestors used metal casting for more than just weapon-making.  So between decorative clothing, tattoos, and jewelry, we've been spending inordinate amounts of time and effort (and pain, in the case of tattooing, piercing, and scarification) altering our appearances.  

Why?  No way to be sure, but my guess is that there are a variety of reasons.  Enhancing sexual attractiveness certainly played, and plays, a role.  Some adornments were clearly signs of rank, power, or social role.  Others were personal means of self-expression.  Evolutionists talk about "highly conserved features" -- adaptations that are between common and universal within a species or a clade -- and the usual explanation is that anything that is so persistent must be highly selected, and therefore important for survival and reproduction.  It's thin ice to throw learned behaviors in this same category, but I think the same argument at least has some applicability here; given that adornment is common to just about all human groups studied, the likelihood is that it serves a pretty important purpose.  What's undeniable is that we spend a lot of time and resources on it that could be used for more directly beneficial activities.

What's most interesting is that we're the only species we know of that does this.  There are a few weak instances of this sort of behavior -- for example, the bowerbirds of Australia and New Guinea, in which the males collect brightly-colored objects like flower petals, shells, and bits of glass or stone to create a little garden to attract mates.  But we seem to be the only animals that regularly adorn their own bodies.

How far back does this impulse go?  We got at least a tentative answer to this in a paper this week in Science Advances, which was about an archaeological discovery in Morocco of shell beads that were used for jewelry...

... 150,000 years ago.

"They were probably part of the way people expressed their identity with their clothing," said study co-author Steven Kuhn, of the University of Arizona.  "They’re the tip of the iceberg for that kind of human trait.  They show that it was present even hundreds of thousands of years ago, and that humans were interested in communicating to bigger groups of people than their immediate friends and family."

A sampling of the Stone Age shell beads found in Morocco

Like with Ötzi's tattoos, we don't know what exactly the beads were intending to communicate.  Consider how culture-dependent those sorts of signals are; imagine, for example, taking someone from three thousand years ago, and trying to explain what the subtle and often complex significance of appearances and behaviors that we here in the present understand immediately.  "You think about how society works – somebody’s tailgating you in traffic, honking their horn and flashing their lights, and you think, ‘What’s your problem?'" Kuhn said.  "But if you see they’re wearing a blue uniform and a peaked cap, you realize it’s a police officer pulling you over."

Unfortunately, there's probably no way to know whether the shell beads were used purely for personal adornment, or if they had another religious or cultural significance.  "It’s one thing to know that people were capable of making them," Kuhn said, "but then the question becomes, 'OK, what stimulated them to do it?'...  We don’t know what they meant, but they’re clearly symbolic objects that were deployed in a way that other people could see them."

So think about that next time you put on a necklace or bracelet or earrings.  You are participating in a tradition that goes back at least 150,000 years.  Maybe our jewelry-making ability has improved beyond shell beads with a hole drilled through, but the impulse remains the same -- whatever its origins.

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Mathematics tends to sort people into two categories -- those who revel in it and those who detest it.  I lucked out in college to have a phenomenal calculus teacher who instilled in me a love for math that I still have today, and even though I'm far from an expert mathematician, I truly enjoy considering some of the abstruse corners of the theory of numbers.

One of the weirdest of all of the mathematical discoveries is Euler's Equation, which links five of the most important and well-known numbers -- π (the ratio between a circle's circumference and its diameter), e (the root of the natural logarithms), i (the square root of -1, and the foundation of the theory of imaginary and complex numbers), 1, and 0.  

They're related as follows:

Figuring this out took a genius like Leonhard Euler to figure out, and its implications are profound.  Nobel-Prize-winning physicist Richard Feynman called it "the most remarkable formula in mathematics;" nineteenth-century Harvard University professor of mathematics Benjamin Peirce said about Euler's Equation, "it is absolutely paradoxical; we cannot understand it, and we don't know what it means, but we have proved it, and therefore we know it must be the truth."

Since Peirce's time mathematicians have gone a long way into probing the depths of this bizarre equation, and that voyage is the subject of David Stipp's wonderful book A Most Elegant Equation: Euler's Formula and the Beauty of Mathematics.  It's fascinating reading for anyone who, like me, is intrigued by the odd properties of numbers, and Stipp has made the intricacies of Euler's Equation accessible to the layperson.  When I first learned about this strange relationship between five well-known numbers when I was in calculus class, my first reaction was, "How the hell can that be true?"  If you'd like the answer to that question -- and a lot of others along the way -- you'll love Stipp's book.

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

The hills are shadows

One of the reasons I became a speculative fiction novelist is because I love to think about how the world would be if the rules were different.  What if we could pick up from inanimate objects the emotional impressions of the last person who held them?  What if time travel into the past were possible?  What if the force of people's belief caused mythological creatures to come to life?

The difficulty is that this dreaminess about altering the laws of the universe runs headlong into my desire to understand what the actual rules are, and which ultimately led me to dedicate my life to science.  After an unfortunate time in my teenage years when I worked really, really hard to convince myself that all the weird paranormal shit I'd immersed myself in was the truth, I was forced by the modicum of intellectual honesty I had back then to admit that the evidence for all of it was nil, and to give the whole thing up as a bad job.

So I ended up teaching science and critical thinking, and simultaneously writing paranormal fiction.  Seemed like a good compromise.

But this push to explore the fringes still shows up.  I'm most attracted to the areas of science that are strange and counterintuitive.  Regular readers of Skeptophilia will attest to this, given my near obsession with things like quantum physics and the behavior of black holes.  And there's one other realm of science that allows me to do what journalist Kathryn Schulz calls "seeing the world as it isn't" -- and that's paleontology.

Because after all, things in the distant past were very, very different than they are now.  We're so used to looking around us and seeing The World As It Is that we don't often consider that this brief point in time is part of a continuum of geological and biological change, and is framed on both sides -- past and future -- by worlds that were and will be wildly different from the one we live in.

As an example, consider the paper published last week in the journal ZooKeys, which is about the fauna of the Sahara.  Immediately I said that name, I'm guessing you pictured sand dunes, perfectly clear blue skies, no plant life (maybe a palm tree or two, if there was an oasis in your imagination), and perhaps a camel or a white-robed Bedouin.

Turn the chronometer back a hundred million years, though, and you wouldn't even know it was the same place.

At that point, the Sahara was a tropical forest, with a huge bay of the Tethys Ocean (the remnant of which we now call the Indian Ocean) right in the middle.  The Atlantic Ocean had only recently opened up, and western Africa was separated from South America by a narrow strait.  What is now an unbroken swath of desert was a large island in the west, a smaller island in the middle of the central bay, and a big chunk of land to the east that is now the remainder of the continent of Africa.

A map of the continents during the late Cretaceous Period [Image licensed under the Creative Commons Mannion, P. D. (2013). "The latitudinal biodiversity gradient through deep time". Trends in Ecology and Evolution 29 (1). DOI:10.1016/j.tree.2013.09.012., LateCretaceousMap, CC BY-SA 3.0]

But that just scratches the surface.  The paper I referenced above, "Geology and Paleontology of the Upper Cretaceous Kem Kem Group of Eastern Morocco," by a team led by Nizar Ibrahim of the University of Detroit, describes the fossil finds in the Kem Kem Group, a dazzlingly rich fossil bed that is only now beginning to be investigated thoroughly.

What this fossil bed shows us is a world that's not only drastically different from how we picture the Sahara today, it's drastically different from anything currently on Earth.  "This was arguably the most dangerous place in the history of planet Earth," Ibrahim said in an interview in Science Daily, "a place where a human time-traveller would not last very long."

Such a time-traveller, in their short remaining life expectancy, would meet up with such beasts as Carcharodontosaurus -- the name means "jagged-toothed lizard" -- which averaged eight meters from tip to tail, just shy of the length of an average school bus.  Its signature teeth were twenty centimeters long and serrated like steak knives.  There were twenty-meter-long crocodilians such as Aegisuchus, which were big enough to turn your average modern saltwater crocodile into saltwater taffy.  There was the fifteen-meter-long, twenty-ton Spinosaurus, another carnivore.  The skies were no safer -- there was a variety of pterodactyloids, including the flying hunter Apatorhamphus, which had a long, needle-toothed snout and a wingspan of five meters.

And that's just a sampler.

"Many of the predators were relying on an abundant supply of fish," said study co-author Professor David Martill from the University of Portsmouth.  "This place was filled with absolutely enormous fish, including giant coelacanths and lungfish.  The coelacanth, for example, is probably four or even five times larger than today's coelacanth [which averages two meters in length].  There is an enormous freshwater saw shark called Onchopristis with the most fearsome of rostral teeth, they are like barbed daggers, but beautifully shiny."

So if you went for a swim, at least you'd have something pretty to look at while you were being messily devoured.

But the vagaries of plate tectonics and climate eventually widened the Atlantic and closed off the bay in the mid-Sahara, and the place started to dry out.  It was green for a lot longer than you'd think, however.  There's evidence that as little as seven thousand years ago, the Sahara got a great deal more rain and was much more verdant than it is today, but a shift in the path of the African monsoon turned off the tap and converted the whole area into a vast, mostly-uninhabitable desert.

I'd like to close with the beautiful and poignant words Alfred, Lord Tennyson wrote in his poem "In Memoriam."  I've quoted them here before, but they are so apposite there's really no fitter way to end.  Read this, and think about the Sahara -- and what your own homeland might look like in a hundred million years' time.

There rolls the deep where grew the tree.
O Earth, what changes hast thou seen?
There where the long road roars has been
The stillness of the central sea.
The hills are shadows, and they flow
From form to form, and nothing stands,
They melt like mists, the solid lands,
Like clouds, they shape themselves, and go.

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This week's Skeptophilia book recommendation is an important read for any of you who, like me, (1) like running, cycling, and weight lifting, and (2) have had repeated injuries.

Christie Aschwanden's new book Good to Go: What the Athlete in All of Us Can Learn from the Strange Science of Recovery goes through all the recommendations -- good and bad, sensible and bizarre -- that world-class athletes have made to help us less-elite types recover from the injuries we incur.  As you might expect, some of them work, and some of them are worse than useless -- and Aschwanden will help you to sort the wheat from the chaff.

The fun part of this is that Aschwanden not only looked at the serious scientific research, she tried some of these "cures" on herself.  You'll find out the results, described in detail brought to life by her lucid writing, and maybe it'll help you find some good ways of handling your own aches and pains -- and avoid the ones that are worthless.

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