The Canon (15 page)

Looked at from this perspective, it wasn't just Rome that was built in a day, but all of human history.

As ancient as Earth may be, the universe, of course, is more ancient
still. But it is not outrageously more ancient. It is not an order of magnitude, or ten times, more ancient than is Earth. Instead, it is only some three times older: 13.7 billion years have passed since the Big Bang gave leave for all being to begin. Personally, I've never been impressed with the age of the universe. To the contrary, its youthfulness makes me uncomfortable, the way I feel when I see the captain entering the cockpit of the plane I'm boarding, and he looks just old enough to no longer need a car seat. Only 13.7 billion years have passed since the beginning of everything—all time, all laws, all complaints? Yet when I've asked astronomers whether they agreed that the universe is remarkably underage for something so universal, they've stared at me as though it were a trick question, or a tedious exercise in metaphysics, before answering, Well, no, now that you mention it, it doesn't seem especially young to me at all. And the reason they see 1.37 × 10
¹⁰
as being a perfectly reasonable vintage is that when it comes to cosmology, if it's about time, it's about space, and the spaces that the stuff of the universe has managed to cast itself across in these peri–14 billion years are so very, very great.

For astronomers, it is difficult to do justice to the scales of cosmic distances. Nearly everything is far away, farther away than you think no matter how innate your anomie. The one exception to this fearful farness is the moon. Our moon is only 240,000 miles away, or ten times the circumference of Earth; if you could fly there by ordinary jet, it would take twenty days. But that's it for the whimsical honeymoon options, practically speaking. A journey by jet to the sun would last twenty-one years, at which point passengers should be advised that contents in the overhead compartment, and the compartment itself, may have melted.

To gain a richer sense of cosmic proportions, we can paraphrase William Blake, and see the Earth as a fine grain of sand. The sun, then, would be an orange-sized object twenty feet away, while Jupiter, the biggest planet of the solar system, would be a pebble eighty-four feet in the other direction—almost the length of a basketball court—and the outermost orbs of the solar system, Neptune and Pluto, would be larger and smaller grains, respectively, found at a distance of two and a quarter blocks from Granule Earth. Beyond that, the gaps between scenic vistas become absurd, and it's best to settle in for a nice, comfy coma. Assuming our little orrery of a solar system is tucked into a quiet neighborhood in Newark, New Jersey, you won't reach the next stars—the Alpha Centauri triple star system—until somewhere just west of Omaha, or the star after that until the foothills of the Rockies. And in between astronomical objects is lots and lots of space, silky, sullen,
inky-dinky space, plenty of nothing, nulls within voids. Just as the dominion of the very small, the interior of the atom, is composed almost entirely of empty space, so, too, is the kingdom of the heavens. Nature, it seems, adores a vacuum.

"The universe is a pretty empty place, and that's something most people don't get," said Michael Brown of Caltech. "You go watch
Star Wars,
and you see the heroes flying through an asteroid belt, and they're twisting and turning nonstop to avoid colliding with asteroids." In reality, he said, when the
Galileo
spacecraft flew through our solar system's asteroid belt in the early 1990s, NASA spent millions of dollars in a manic effort to steer the ship close enough to one of the rubble rocks to take photos and maybe sample a bit of its dust. "And when they got lucky and the spacecraft actually passed by
two
asteroids, it was considered truly amazing," said Brown. "For most of
Galileo
's journey, there was nothing. Nothing to see, nothing to take pretty pictures of. And we're talking about the solar system, which is a fairly dense region of the universe."

Don't be fooled by the gorgeous pictures of dazzling pinwheel galaxies with sunnyside bulges in their midsections, either. They, too, are mostly ghostly: the average separation between stars is about 100,000 times greater than the distance between us and the sun. Yes, our Milky Way has about 300 billion stars to its credit, but those stars are dispersed across a chasmic piece of property 100,000 light-years in diameter. That's roughly 6 trillion miles (the distance light travels in a year) multiplied by 100,000, or 6 × 10
¹⁷
, miles wide. Even using the shrunken scale of a citrus sun lying just twenty feet away from our sand-grain Earth, crossing the galaxy would require a trip of more than 24 million miles.

Interestingly, the distances between galaxies are relatively manageable compared to the gulfs between stars within a galaxy. That is, the average distance from one galaxy to the next is only a few tens of times larger than is the size of either galaxy, while the separation between stars is hundreds of thousands or millions of times greater than any single stellar diameter. "This is why stars don't run into each other, but galaxies do," said Robert Mathieu, a professor of astronomy at the University of Wisconsin. Our own Milky Way is expected to collide someday with its nearest neighbor, M31—more familiarly known as the Andromeda galaxy—but we're talking about an awfully delayed train wreck, maybe 4 billion years in the future. Moreover, given their individual porousness, the fact that there are such wide breaches between each galaxy's solar wares, it will not be a particularly violent event, either.

In large part, cosmological metrics remain tragic, pious, almost impossible to forgive. With an estimated 100 billion galaxies in the universe, each outfitted with some 100 billion to 200 billion stars, we have a stellar inventory of 10
²²
far-flung suns: so many stars to yearn toward, so many ways to get lost in the dark. The distances from one to the next are so forbidding that, even if the universe teems with intelligent life, we are less likely to hear from an alien civilization than parents are from their college-age children. Yet before we curl into a Beckettian state of amniotic gloom, we might consider the perspective of Maarten Schmidt, one of the grandmasters of astrophysics. Schmidt has argued that, far from being a vast moor of anesthetizing proportions, the universe is unexpectedly compact, even homey. Schmidt, a courtly Dutchman in his seventies, has white hair and smock-blue eyes, and as he sat and talked in a calm, quietly animated voice, he kept his long arms folded neatly over his long, crossed legs. If you go outside at night, he said, and the sky is clear and you're far from a city, you can see Andromeda, that next-door galaxy we're expected to bump into someday.

"To get from Andromeda to what we would call the edge of the observable universe, you need only go out by a factor of three thousand," he explained. "The edge of the known universe, then, the most distant point from which light has been able to reach us, is only three thousand times as far from us as is our closest galaxy.

"Now suppose you look at the house nearest yours, and suppose it's a hundred yards away. If you were to go out three thousand times that distance, you'd have traveled only three hundred thousand yards, or about two hundred miles. So if you drew a circle around your entire community, your entire world, and that circle had a diameter of two hundred miles, wouldn't you think your community quite manageably proportioned? Wouldn't you be surprised at how close the edge of your world turned out to be? This is why I've argued that our universe, at least what we can see of it, is small.

"Of course, I realize that my position is totally indefensible," he said, before promptly defending it with a small, courtly smile.

Appealing though Schmidt's case may be in comparing the cosmos to a kind of picket-fenced pueblo, when it comes to professional-grade smallness, the bona fide articles are molecules and particles. You think
you're living a normal, life-sized life, on human terms, driving to the supermarket and foraging for nuts, tubers, and pork chops; but in fact "life-sized" has nothing to do with you, the contents of your shopping cart, or Charlemagne's feet. The real merchants of life, the objects that keep life alive and qualify as life-sized, are all invisible. They are too tiny to be viewed with the naked eye, are instead microscopic, which means, of course, you need a microscope to see them. Unfortunately, for most of us, invisible often translates into insignificant—or, as my grandmother so musically put it, "Feh." Thus we are left with scant sense of just how invisible the components of which we are constructed really are. How big is a cell, or a protein sticking out of the fatty surface of said cell, or the DNA molecule at the center of the cell? When you look at the tip of your finger, roughly how many skin cells are you seeing? How about a bacterium—bigger or smaller than one of those rough skin cells? The water molecules that bond, de-bond, and re-bond so rapidly: Where do they fit on the mise en scène of the unseen?

To orient ourselves in the prefecture of feh, let's exploit the old theological dance floor, the head of a pin. A pinhead is two millimeters, or two-thousandths of a meter, across. By comparison, the average human hair is one hundred microns wide (a micron, you'll recall, being one-millionth of a meter). You could, then, drape twenty hairs over a pinhead if you pack them close together. Half the diameter of a human hair, or fifty microns, represents pretty much the lower limit of even the sharpest human eye's natural resolving power; anything smaller, and, well, there's a reason why "the width of a human hair" is so often used to mean "extremely narrow by naked-eye standards." In other words, you can't see an individual speck of ragweed pollen, which is twenty microns wide, without some sort of magnifying device. But among the allergy-prone, you needn't be seeing to be sneezing, and the 10,000 or so pollen grains that might cling to your pinhead are quite enough for "Gesundheit."

A human white blood cell is twelve microns wide. If the surface of your pinhead were wallpapered with white blood cells, you would be looking at about 28,000 of them. The wiener-shaped
E. coli
bacterial cell is two microns long by half a micron across, allowing 3 million of them to colonize your sewing notion; and, given
E. coli
's pervasiveness, they've probably done exactly that. Bacteria as a rule are much bigger than the other microscopic characters that we designate as "germs"—the viruses. Unlike a bacterium, a virus is not a cell. It lacks nearly all the ingredients of a cell, most notably any means of autonomous replication, and instead must infiltrate the cells of other organisms and hijack the resident reproductive machinery for the sake of personal perpetuity. Shiftiness demands thriftiness: even a large virus like the Ebola pathogen has just one-tenth the footprint of
E. coli.
A tiny virus like the rhinovirus that causes the uncommonly contagious common cold is only three-hundredths of a micron, or thirty nanometers across, and tens of millions of them can sail through the air on a droplet sneezed forth by your ruby-nosed coworker.

Cracking open a human cell, you'll find the labor force of life, the heroic biomolecules that do all the work of keeping you alive for the 3 billion seconds of your life, give or take a few 10
²⁵
attoseconds. Hemoglobin, the blood-borne protein that captures oxygen molecules from the lungs and delivers them throughout the body, measures about five nanometers in diameter, a sixth the size of a cold virus. Collagen, the connective protein that gives both skin and Jell-O their bounce, is long, thin, and tough, like a piece of superfloss a few nanometers across and hundreds of nanometers long.

Deep within the belly of virtually every cell is our DNA—the celebrated, if symbolically overperfumed, corkscrew of a molecule that holds all our genes. This double helix is squeezed into a knobbly bundle that, depending on what the cell is doing, may measure anywhere from 100 to 1,000 nanometers in diameter. Even toward the upper range of DNA packaging, maybe 5 million of these little human genomes—5 million Holy Grails, 5 million Books of Life, 5 million blueprints for a baby—could perch on a pinhead.

Proteins and DNA are blubbering baleens compared to other molecules of the cell. A glucose molecule, the simple sugar that fuels activity within your ever busy body cells, is only one-sixth the size of a hemoglobin protein, and the oxygen molecule that hemoglobin carries is one-third the size of that sugar.

Oxygen molecules are our clearest, shortest links to life. Deprive any part of our bodies of oxygen, and the asphyxiated tissue will start to die within minutes. What are these indispensable links but cufflinks, each molecule a dapper doublet of oxygen atoms, of O2s, linking us to life, and linking us, on our scalar sally, downward to atoms. Sirs and madams, we're all made of atoms, and atoms are
tiny.
But how silly to try conveying information by choosing the smallest and most illegible typeface possible, and me not even a writer of pharmaceutical inserts. Atoms are way beyond the font. There are more than one hundred different types of atoms, from lightweights like hydrogen and helium through welterweights like tin and iodine and out to such mumbling mooseheads as ununpentium and ununquadium, but they're all pretty
much the same nearly nil size. You can fit more than three atoms in a nanometer, meaning it would take 10
¹³
, or 10 trillion of them, to coat the disk of our pinhead. And the funny thing about an atom is that its outlandish smallness is still too big for it: almost all of its subnanometer span is taken up by empty space. The real meat of an atom is its core, its nucleus, which accounts for better than 99.9 percent of an atom's matter. When you step on your bathroom scale, you are essentially weighing the sum of your atomic nuclei. If you could strip them all from your body, go on a total denuclear diet, you'd be down to about 20 grams, the weight of four nickels. Or roughly the weight of the doornail that you would be as dead as.

Those remaining twenty grams belong to your electrons, the fundamental particles that orbit an atom's nucleus. An electron has less than
¹
/
_1,800
the mass of a simple atomic nucleus. Yet the cloud of one or more of these fairy-Ariel electrons that surrounds the atomic core defines the edge of the atom and hence its size. And, oh, how vast is the gulf between chunky core and orbiting cloud. The diameter of the atomic nucleus is just
¹
/
_100,000
the size of the entire electron-limned subnanometer atom. Viewed from the more impressive angle of volumetrics, we see that, while the nucleus may make up nearly all of an atom's mass, of the meaty matter we weigh and inveigh against, it takes up only a trillionth of its volume.