Science Musings Blog

There is a concept in physics called angle of repose. Set an object, a book say, on a plank. Now slowly tip up one end of the plank until the moment when the book just starts to slide. The angle between the plank and the horizontal is the angle of repose, where the component of the gravitational force down the plank becomes greater than the maximum friction force holding the book at rest.

Or, in more evocative terms -- As I write I am lying on the couch with the laptop in my lap, in perfect repose. If you started tipping up the couch, at some point I'd go sliding into a heap at the bottom. That's the angle of repose, or perhaps it would be more accurate to call it the angle of the end of repose.

This comes to mind because I just spent fifteen minutes on my knees in the yard watching ants excavate a nest in the ground. One by one they scurry out of the hole carrying a tiny grain of sand, which they dump in a ring around the hole. A circular pile. Now if the ants just dumped their burdens at the mouth of the hole, pretty soon the pile would get so steep that the sand grains would slide back into the hole. Instead, the circular ring gets higher and wider, with a slope that never exceeds the angle at which the grains will slip -- the angle of repose.

Now here's the thing: the ants almost invariably carry their grain to just beyond the top of the pile. If the grain slips, it will slide away from the hole. These tiny ants, hardly bigger than sand grains themselves, understand a little physics in their mysterious instinctive way.

Wallace Stegner has a novel titled "Angle of Repose." It is indeed an evocative phrase. In a job, in a relationship, in life itself, many of us instinctively seek that maximum degree of individual gratification that will satisfy emotional needs without doing violence to our essential repose, and that of those around us -- the art of walking close to the edge, the thrill without the spill. Every day in the news we hear of folks -- politicians or celebrities -- who tipped the plank too far, whose lives went sliding into self-destruction, who failed to grasp, metaphorically speaking, something that a tiny ant instinctively understands.

We have lots of beautiful fish on our reefs, but here is one of the gaudiest -- a lionfish, a native of the Southeast Pacific, popular with folks who keep aquaria. Somehow, a few individuals were released or escaped into the waters near Florida, and, according to reports, they are spreading throughout the Bahamas like weeds. My son-in-law spotted one on the reef in front of the house, and with my granddaughter saw another on a reef just to the north of here. The lionfish have arrived.

They have no natural predators in the Atlantic. They have voracious appetites for other reef denizens, and for the young of local food fish. An adult grouper (an island staple) will apparently gobble a lionfish, but lionfish go about hoovering up grouper young. So far the lionfish appears to be winning that particular battle. And, to top it off, the spines of lionfish are venomous to humans.

It's all one big world now. Viruses and tropical birds wing around the globe at nearly the speed of sound. The lionfish may have made it to the Atlantic on a jet liner from Auckland, via a aquarium in Boca Raton. Oh, it's pretty, all right. I'd love to see one on the reef. But beauty is not always benevolent. "Beauty is the beginning of terror," wrote the poet Rainer Maria Rilke. I'm not quite sure what he had in mind, but the lionfish fits the bill.

Herewith, a simplified history of the first three billion years of life on Earth:

The first living organisms got their energy by fermentation. They took
sugar molecules from their environment -- brewed up by plain old non-biological chemistry -- and broke them apart, rearranging the atoms into smaller molecules of carbon dioxide and alcohol, releasing some of the energy stored in the sugar.

Two problems: The earliest organisms were essentially hunter-gatherers, living off the land (or rather sea), and life was increasing faster than the abiotic production of sugar. The food supply was running out. Moreover, alcohol is a poison: The first toxic waste crisis.

Necessity is the mother of invention. Just in the nick, so to speak, life "invented" photosynthesis, a kind of primitive agriculture -- using sunlight to synthesize carbon dioxide and water into sugar, thus securing the food supply.

More problems. To photosynthesize you had to be in the sun, which meant exposure to ultraviolet light, which can kill. And a byproduct of photosynthesis is oxygen, the second toxic waste crisis; life was in danger of burning up by spontaneous combustion.

However, as the level of oxygen in the atmosphere rose, an ozone umbrella formed in the upper atmosphere, which helped with the UV problem. And -- necessity again -- life learned to use oxygen to burn sugar -- respiration -- breaking it down more completely and releasing far more energy than fermentation. Respiration solved the alcohol problem, and kept oxygen in the atmosphere at a safe level.

And with all that extra energy, it wasn't long before life invented sex.

There, now that was simple, wasn't it?

Not much has changed. It's spring break here in the Bahamas, and thousands of American college students are pretty much recapitulating three billion years of life history. Alcohol, sun and sex. Hangovers, sunburn, and broken hearts.

Look who's on the cover of Science, Drosophila melanogaster, the "black-bellied dew lover," better known as the fruit fly that swarms annoyingly about our food trash. Shoo! Shoo! We brush them away with our hand, and still they swarm, a cloud of living confetti.

And here he is, in all his ugly glory, up close and in your face, every bristle, every crease, every facet of its compound eyes. An 8-by-10 glossy ready for the Hollywood casting agent -- "The Creature from the Black Banana," Gozilla's tiny cousin. A splendid portrait this, made with a scanning electron microscope (the eyes artificially colored).

The fruit fly was adopted as a research animal by T. H. Morgan in his important studies in genetics that began at Columbia University in the early years of the last century. These studies led to the classic textbook of Morgan, Sturtevant, Muller, and Bridges, "Mechanisms of Genetic Inheritance," which in 1915 established the link between genes and chromosomes. Since that time, much of what we know about mutation, speciation, and other genetic phenomena has been discovered with populations of fruit flies. Drosophila is an ideal research animal. It is small enough to breed in the lab in large numbers, but large enough to examine with only modest magnification. And it has a short life cycle, which means it can be bred through many generations during a typical graduate student's time of study.

The Science cover introduces work by a group of California researchers who identify proteins that inhibit age-related pathologies in fruit flies -- muscle degeneration and cardiac malfunction, among others. Does Drosophila hold the key to eternal youth? Who knows. Humans are more complex than fruit flies -- more genes, more chromosomes -- but many of our proteins and their way of functioning are virtually the same. Much of the basic biochemical machinery of human life evolved before the ancestors of fruit flies and humans diverged a half-billion years ago.

I've had the pleasure of examining mutant fruit flies, jiggered by geneticists to study the relationship between genes and their expression. The mutants have Seven Dwarfish sorts of names -- Dumpy, Curly, Stubble, Spineless, Wrinkled, Bristle, and Scarlet -- every aberrant feature determined by a sequence of four paired chemical units called nucleotides, A-T, T-A, G-C and C-G. Somehow it's all there in the four-letter code, the plan for making a fruit fly maggot, then for rearranging the maggot to make a fly, the alarm clock that causes the fly to emerge from its pupa in the dewy morning, the courtship love song, and all the rest.

Take another long look at the microphotograph above, and next time you swat, think of all the wonderful living detail that you squash between your hands.

(Image by T. Deerinck and M. Ellisman of the National Center for Microscopy and Imaging Research, University of California, San Diego.)

As I wrote Monday's post on the avian poetry anthology Bright Wings, I had just finished reading a cover review in the NYT Book Review of Danielle Trussoni's novel Angelology. I had two kinds of winged creatures in mind: natural and supernatural.

The review observed that books about angels are wildly popular, something I made note of in a Boston Globe column twenty years ago. I suggested then that the 90s promised to be the decade of angels, and polls confirmed that a healthy majority of Americans believed in the literal existence of heavenly spirits. Well, if anything, angels have grown in popularity, Apparently you can now better your life with angelic alliances. The self-help literature includes How to Hear Your Angels, Working With Angels, In the Arms of Angels, and so on.

Now, I'm as fond of fairy tales as the next person. Humanoid celestial creatures have been a part of our culture since Genesis. By Milton's time, the lore of the angelic armies had reached epic proportions. Lord knows I learned enough of it in parochial school. Angels have even danced through these posts on occasion. But literal? Anyone who in 2010 takes angels literally suffers a severe detachment from empirical reality.

Meanwhile, the real wonders get lost in the din of fluttering wings.

If a medieval philosopher were confronted, on the one hand, with the lore of angels, and, on the other, with the idea of the air resonant with a hundred species of unheard music (Bach, Beethoven, and Mozart, to say nothing of the Grateful Dead and Norah Jones) made actually audible by a small box called a radio, he would surely call the latter more wondrous. And what of that continuous wind of invisible neutrinos that pours through our bodies from the animating furnace of the Sun? Closer to home, the idea of humanness revealed by molecular biology and neurobiology is a far more stunning conception than the medieval philosopher's "little world made cunningly of elements and an angelic sprite."

There's no point decrying our culture's preoccupation with the mystical and paranormal, at least not until scientists and naturalists are better able to show that a scientific world-view can satisfy the human need for meaning. Scientists and naturalists may feel plugged into something larger and more wonderful than themselves, but so far they have failed to convince the public that science is anything more than a practical tool for wringing material benefits from nature. Until they do, aerodynamically impossible spirits will continue to haunt the bookstores. And Danielle Trussoni's biologically implausible angel-human hybrids have surely already been optioned for the movies.

Meanwhile, I have my own little angels at the hummingbird feeder, stoking their racing metabolism with my wife's own mix of celestial ambrosia.

As I wrote those words in yesterday's post I was watching an osprey cruise the shore in front of the house. Fish hawk, they call it here. It dipped and soared, hardly moving its wings, its keen eye fixed on the turquoise water below, waiting for a glint of sunlight from the scales of a silver fish. Flow. Flow. The bird, the air, the sea, the fish. Different at every moment. Always the same.

And somehow my thoughts drifted back more than half-a-century to...

Somewhere about the second or third week of every university calculus course, the student is introduced to the concept of the limiting value of a ratio both terms of which approach zero -- a concept crucial to all that follows. The definition was the most incomprehensible thing I had encountered in my life, a mess of mathematical gobbledegook. It was appended to the statement "These preliminary remarks should now enable us to understand..."

But, of course, I did not understand. I doubt if any first-year calculus student reaches this point in the course with understanding. Still, I was smart enough to know that if I sidestepped this initial hurdle I would never grasp what followed. So I beat my head against it for a week until the light bulb finally went on. I had figured out the concept of a limit.

The rest, as they say, was a piece of cake. The study of calculus became pure bliss, the neatest thing I encountered in college.

I took my final degree in physics, and physicists use calculus to express the laws of nature. But it was a funny sort of nature we studied in physics -- without ospreys, wind, sea, or fish. As the years passed I drifted into writing, and more or less forgot about calculus. But something ineradicable had been planted in my mind. Something about flow. About transformation. About continuous change.

Something about ospreys riding gifts of air.

The poet Marianne Moore wrote: "The power of the visible is the invisible." Calculus is about invisibles -- the infinite and the infinitesimal. That's what the cryptic definition of a limit is all about. A way to talk meaningfully about the unobservable instant. The thing we call a derivative in calculus is the calculable ratio of two numbers that separately vanish into nothingness, leaving behind something spooky but palpably real, like the grin of the Cheshire cat -- a rate of change, a measure of continuous flow. Calculus clicked when I made the connection between the grin and the cat.

Which brings me back to the osprey. As I watched that splendid bird riding gifts of air it occurred to me that I was observing the physical embodiment of those abstract differential equations I studied long ago. Calculus was invented as a language for describing continuous change in nature -- the glide, the dive, the soar, the flow. Watching the osprey I was an eavesdropper, listening in on nature's conversation with itself.

House guests brought me as a gift Billy Collins' spanking new anthology of poems about birds, Bright Wings, splendidly illustrated with paintings by David Allen Sibley, who you may know from his Sibley Guide To Birds. Collins is himself a poet of considerable renown, twice Poet Laureate of the United States. The book is beautifully produced by Columbia University Press, and I have been curled up all morning enjoying the feathered flights of many of my favorite poets: Marianne Moore, Mary Oliver, Amy Clampitt, Elizabeth Bishop, Howard Nemerov, Wallace Stevens, and more.

Who, watching birds, hasn't wished to be a poet? The hummingbird, there! at the slipper-flower blossom, a blur of wings, stealing fuel with his soda-straw beak -- it's not science he evokes but breathless excitement. And the mischievous bananaquit, hopping from branch to branch in the white torch tree, waiting for her turn at the feeder -- one wishes then for a gift of rare words, not some dry and abstract ornithological treatise, but a song of praise, an Ode To Joy, a Hallelujah Chorus.

Oh! how one wishes to rise into their element, to loose the hawsers that anchor us to earth, to dive, to dart, to dance at the tips of twigs in the buttonwood tree, to cruise out there along the shore like the osprey, riding gifts of air. But even poets must rue the way their words stay pasted on the page. Howard Nemerov's Blue Swallows ends:

Swallows, swallows, poems are not
the point. Finding again the world,
That is the point, where loveliness
Adorns intelligible things
Because the mind's eye lit the sun.

Click Anne's image to enlarge, then again if you wish.

I've been reading Stephen Baxter's Ages In Chaos, the story of James Hutton and the discovery of geologic time. As someone who has studied and taught this stuff for half a century, there is not much in the book that I don't already know. It strikes me, however, that the book is not so much an account of the discovery of geologic time as it is the story of how Europeans escaped from the intellectual shackles of the Scriptures.

Leonardo, Bacon, Steno, Burnet, Buffon: All grappled with the problem of how to make the evidence of their senses conform to the ancient stories and myths of prescientific peoples -- stories and myths that had been ordained the inerrant word of God by the Christian church. The intellectual acrobatics necessary to stay on the right side of orthodoxy were sometimes ludicrous, but try they did. It wasn't until the time of Hutton, Lyell and Darwin that the senses finally trumped Scriptures as the arbiter of truth.

Today, within the scientific community at least, it seems obvious that what presents itself to the senses -- the fossils, the folded strata, the faults and unconformities -- tell a more reliable story of the Earth than the utterly typical imaginings of peoples who lived in the Middle East thousands of years ago. Indeed, it seems so obvious that one wonders how the ancient books were ever considered to be divine communications. But of course, not a lot has changed. The majority of peoples in the world continue to put their faith in scriptures -- the Bible, the Koran, the Book of Mormon, etc. -- even when it requires rejecting the knowledge so painstakingly wrested from nature by Hutton, Lyell and Darwin.

Why? Is it that we like immutable certainty? Do we prefer the ancient stories because we like to believe that the creator of the universe has me -- yes, me -- constantly in mind? Is it the privilege of belonging to a chosen people -- God's in-crowd? Is it the irresistible attraction of immortality?

Who knows? Perhaps a bit of all. Whatever the reason, those of us who accept with gratitude the liberating efforts of Hutton and company find in the new empirical stories a cosmic vista of unsurpassed grandeur -- even if it means foregoing the notion that we possess the Truth and will live forever.

Nothing we know about in the universe approaches the complexity of the human brain. What is it? A vast spider web of neurons, cells with a thousand octopuslike arms, called dendrites. The dendrites reach out and make contact at their tips with the dendrites of other cells, at junctions called synapses.

A hundred billion neurons in the human brain, with an average of 1,000 dendrites each. A hundred trillion octopus arms touching like fingertips, and each synapse exquisitely controlled by the cells themselves, strengthening or weakening the contact, building webs of interlinked cells that are knowledge, memory, consciousness -- a soul, a self.

A hundred billion neurons. That's more brain cells than there are grains of salt in 1,000 one-pound boxes of salt. A roomful of salt grains, floor to ceiling. Each in contact with hundreds, thousands, or tens of thousands of others. The contacts flickering with variable strength. Continuously. Unconsciously. Never ceasing. Remembering. Forgetting. Feeling joy. Feeling pain. Thinking. Speaking. Lifting a foot, moving it forward, putting it down again. Flickering. A hundred trillion flickering synapses.

Just thinking about it is exhausting.

In recent years, new scanning technologies enable neuroscientists to watch live human brains at work. Active neural regions flicker on the screens of computer monitors as subjects think, speak, recite poems, do math. Thinking -- displayed on the screen of a scanning monitor -- can look like a grass fire exploding across a prairie.

Perhaps the most exciting research is that of the scientists who study the biochemistry of neurons: How do the cells regulate synaptic connections to build new neural webs? One big surprise is just how much of the "thinking" of neurons is done by the dendrites, those hundreds of spidery arms that connect neurons to one another. DNA in a neuron's nucleus sends messenger RNA down along the dendrites to active synapses, where they are translated into proteins that regulate the strength of synaptic connections. Tiny protein factories in the dendrites are apparently key to learning and memory.

What all this amounts to is awareness of awareness. The biochemical machinery of awareness has been turned upon itself, and we begin to glimpse the astonishing architecture of the human soul.

If love's a sweet passion, why does it torment?
If a bitter, oh! tell me, whence comes my content?
Since I suffer with pleasure, why should I complain,
Or grieve at my fate, when I know 'tis in vain?
Yet so pleasing the pain is, so soft the dart,
That at once it both wounds me and tickles my heart.

A song from Henry Purcell's 1892 opera The Fairy Queen, a musical retelling of Shakespeare's A Midsummer Night's Dream. The song is part of the "Fairy Mask" with which Titania entertains Bottom, who is wearing the donkey's head. According to the program notes that came with my Purcell Quartet CD, the song "became by far the most popular song in the play, was endlessly reprinted and imitated, and was used to great effect by John Gay in The Beggar's Opera." All of which suggests a certain universal resonance of the theme.

Closer to home I think of Lou Rawls' Love Is A Hurtin' Thing:

For every little kiss there's a little teardrop
For every single thrill there's another heartache

There are some things we don't expect science to explain, and romantic love is surely one of them. A hundred billion neurons in the human brain, with an average of 1,000 dendrites each. A hundred trillion tendrils reaching out and touching like lovers' fingertips, each synapse exquisitely controlled by the cells themselves, strengthening or weakening the electrochemical contact in response to internal and external stimuli -- a touch, a blush, a sigh, a pout -- building webs of interlinked cells that are a sweet passion or a bitter, wounding and tickling. Who can map that intricate circuitry? Who can follow that braided Amazon of pleasure and hurt to its source? Lou Rawls again:

When love brings so much joy why must it bring such pain
Guess it's a mystery that nobody can explain

From NASA's Goddard Space Flight Center comes this stunning composite photograph of Earth, the sharpest "blue-dot" picture yet. Here is the planet that two thousand years ago the boldest of thinkers could imagine only in their mind's eye. Here is the watery sphere that Columbus and Magellan kept fixed in their imagination as they launched their tiny craft into the wet unknown. The blue-white planet, dappled with ocher and green, suspended in the vast -- perhaps infinite -- black of space. Almost perfectly round and smooth. If you wrapped a schoolroom terrestrial globe in kitchen wrap, that thin layer of plastic would be thick enough to encompass oceans and atmosphere, the deepest oceanic trench and the highest mountains. And in that gauzy layer too is all of life, teeming, photosynthesizing, respiring, copulating, thinking, dreaming.

What is the season? Note the slight brightening around the tip of the Baja California Peninsula (click to enlarge). Here the Sun is directly overhead, exactly on the Tropic of Cancer, twenty-three-and-one-half degrees north of the equator -- the summer solstice. Here in Exuma we are also exactly on the Tropic of Cancer, a bit more than two hours east of Baja; it is early afternoon on a cloudless summer day. Europe is in twilight.

Nothing in the photograph obviously reveals the presence of the human species (unless it is that perplexing straight line between the southern tips of Greenland and Hudson Bay, which must be an artifact of the photomosaic process). But lord knows we have the power to change the picture dramatically. A nuclear war could shroud the planet in obscuring smoke and dust. Global warming might change the coastlines and the amount of cloud cover. Already, it seems, we have diminished the amount of summer sea ice at the top of the globe.

As I was growing up, in every one of my parochial school classrooms, high on the wall at the front of the room, was the image of a suffering man nailed to a cross. It was there to remind us that the creator of the universe had come to Earth and died to redeem us from the sin of having been born human in a fallen world. What it more graphically instructed me is how "inhumanely" humans can behave toward each other, even to the point of hammering nails through palms. Better, I think, to have had this image of Earth hanging there at the front of the room, to remind us of the gossamer insubstantiality of life in a universe complex and wonderful beyond our knowing, and of the moral imperative of being the only creatures in the universe (that we know about) who can say "It is beautiful" and resolve to make it more so.

Last fall, I wrote here about Jan Vermeer's The Milkmaid, which at the time was enjoying a bit of limelight as the centerpiece of a show at New York's Metropolitan Museum of Art. Since then, the painting has been the desktop for one of my laptops. Here is a detail: this stocky, sensible young woman, who has been studiously ignoring me every day as I write. (Click the image to enlarge.)

Who was she? How long was she required to pose, holding the heavy pitcher, the muscles of her arms straining with fatigue. Did Vermeer pay her, this maid of Delft, or did she volunteer her service for the artist? Could she have guessed that 350 years later we would celebrate her beauty through the illuminating power of art?

The painting is very much a homage to materiality: the flesh of the girl's bared forearms, the rough cloth of her dress, the ceramics, wicker, brass and bread, the dribble of milk. It is, in one specific sense, a very Catholic painting, sacramental in its "faith in the power of the image to incorporate a mysterious presence that is both living and indefinable" (I quote the scholar Daniel Arasse). If there is a defining difference between traditional religions and religious naturalism it is in the notion of revelation. In traditional religions, revelation comes as direct communication from an extranatural divinity through holy books or prophets -- that is, through human imagination and the received stock of stories and metaphors. Traditional revelation is generally expressed in anthropomorphic forms and quickly becomes dogma. For the religious naturalist, revelation is encountered anywhere and everywhere, in the isness of what is, as a vague perception of "a mysterious presence that is both living and indefinable."

With The Milkmaid, Jan Vermeer is our prophet. He sees into the isness of this simple domestic scene -- sees it charged with mystery, that sense, so amply confirmed by science, that there is always more to the world than meets the eye, not something supernatural, but metanatural, the rich and extravagant isness of things that overflows our knowing. And here, this thoughtful young woman from the household or neighborhood has become the instrument of revelation, the channel by which something ineluctable leaps out of the isness of matter and transfixes us. How else to explain the power of pigments on canvas to hold our rapt attention across the ages?

As I mentioned before, during February I presided over a creative writing seminar with a dozen island residents, ten adults and two high school students. Some terrific writing but let me quote here a single sentence from Tamika's final essay:

The wind on my face was a sweet relief for the fire I felt on my skin.

I suggested at our last gathering that this is what it's all about. At first glance there is nothing complex or "writerly" about the sentence. No five-dollar words or big ideas. Just words of one syllable, except for "relief," and honest emotion.

But read the sentence aloud. Catch the rhythm. Hear the way "wind" plays off "sweet," and "sweet" eases up to "relief." Hear the five "fs" beat out their neat tattoo. And note the way "wind" and "skin" bracket the sentence.

Behind the apparent simplicity there is a carefully constructed loveliness, a writer at work, perhaps on autopilot, but with an unerring sense of sound and syntax.

Good writing is not pompous or pretentious. It does not preach or prattle. It can be as effortless as breathing, or, rather, it should appear as effortless as breathing.

Go, Tamika. Fill your life with such sentences.