. . . riverrun, an image rooted in the ancient philosophies of Heraclitus, Plato, and Marcus Aurelius who each noted in their own way that we cannot step twice into the same river. The thirteenth-century Buddhist poet/priest Chōmei echoed their insights in the opening line of his classic tale of impermanence: “the flowing river never stops and yet the water never stays the same.”19 When we come to the banks of any river we find ourselves at the very shores of space and time.
Try as we might we cannot dam time; neither the clock nor the calendar slows its flood. “Like as the waves make toward the pebbled shore / so do our minutes hasten to their end.”20 Nothing stands still. Modern physics reveals that the very building blocks of matter are not passive and inert, but constantly dancing with everything else in the universe. Every atom vibrates, pulses with energy, oscillates with the absorption and emission of existence itself. Everything is in the dynamic process of both being and becoming. Change is the eternal constant; life is liquid, riverine. Time can slow to a trickle—or overflow its banks and become a torrent. Regardless of the direction the river flows it branches into tributaries we call the past, the present, and the future—the rivulets Augustine called memory, attention, and expectation—what was, is, and will be.
The Romans saw the Milky Way—the great river of stars above our heads—as the luminous wake of a celestial ship. To the Māori of New Zealand it is a canoe crossing the sea. In Chinese astronomy, it is a celestial river; people of Eastern Asia believed it was the Silvery Stream of Heaven. The Aboriginal People of Australia see the band of stars as a river in the “skyworld,” and in Hindu myth it is Akasaganga, which means “the (Ganges) River of the Sky.”
Something in us has always understood the implications of the stars streaming by above our heads; the flickering, fleeting firelight of life’s timelessness.
In the beginning was flow, flux . . . change.
And ever since: nothing has been the same.
11. Rilke, The Poet’s Guide to Life, 130.
12. Augustine of Hippo, The Confessions, 52.
13. For Taoist, Hindu, and Gnostic references see, for example, Lao Tzu, Tao Te Ching, 51, 201–202; and Hooper, Jesus, Buddha, Krishna, Lao Tzu, 53, 55.
14. Griffith, Hymns of the Rig-Veda, II, 621–22.
15. In Eiseley, The Firmament of Time, 1.
16. Buber, I and Thou, 18.
17. Maclean, A River Runs Through It, 104.
18. In what is the beginning and end—and beginning again—of his literary classic: “A way a lone a last a loved a long the / riverrun.” Joyce, Finnegan’s Wake, 628, 3.
19. Chōmei, Hōjōki, 19.
20. Shakespeare, “Sonnet 60.1–2” in The Complete Works, 1606.
The Time of Our Lives
We say the existence of eternity cannot be proven, that it makes no logical sense. But the same can be said of the measurement of something we’ve agreed to call, for lack of a better word, time. There was a time when we simply looked to the sky to guide us—when the planet spun, tilted on its axis just so, and there was evening and there was day—and that was enough. Or, on a more practical, corporeal level, we looked to our stomachs to tell us, for example, when it was time to eat. We didn’t have a name for it back then, but the suprachiasmatic nucleus and preoptic areas in the part of our brains known as the hypothalamus told us when it was time to sleep or time to rise and shine.
Then we decided those markers needed further delineation and we made up hours.
Then minutes.
Then seconds.
Now we tick time off in fractions thereof: microseconds, and nanoseconds.21 Our digitized, computerized, speed-mad world streams by 24/7 at warp speed—or, at least at information transfer rates of so many kilobits and megabits and gigabits and terabits every second.
The base unit of time in the International System of Units as well as other systems of measurement, we usually think of a second as the simple division of a minute into sixty equal measures; the minute being a previous sexagesimal division of the hour. While seconds have been used to measure and calculate time at least since the time of al-Bīrūnī, the preeminent eleventh-century Persian mathematician and astronomer, it wasn’t until much later that the second was formally defined as 1/86,400th of a day.
That definition of a second didn’t last very long.
Now the scientific standard of time is measured in atomic terms, by the steady frequency of emitted photons: the antiquated second has been updated to “the duration of 9,192,631,770 beats of the radiation corresponding to the transition between two hyperfine levels of the ground state of the cesium 133 atom at rest at a temperature of 0 on the Kelvin thermodynamic scale.”
No wonder we’re out of breath.
Rush Hour
Cesium-beam atomic clocks can measure time accurately to within trillionths of a second. Or, in context, the time needed for a beam of light travelling at 186,000 miles per second to travel less than the distance equivalent to the thickness of a sheet of paper, a page of a book. When it comes to time, accuracy is absolutely important. Think about the air traffic controller and so many planes speeding through space to the same runway . . . or any navigation, be it by air, land, or sea, or even outer space. Timing is everything. A network of atomic timekeepers and other chronographic instruments circles our planet, constantly monitored and synchronized via signals and satellites circling in turn in the space above the planet into near-perfect, super-precise lockstep with each other. All this circling data is continuously collected and analyzed at the International Bureau of Weights and Measures in Sèvres, France day and night, internationally agreed upon as Coordinated Universal Time—as the time—then spun back out into the non-stop spinning world and dials of the watches on our wrists to complete the circle.
Still, the planet spins, tilted on its axis just so, and there is evening and there is day. Twenty-four hours, a pirouette: an arbitrary measure of time we agree to obey.
Except we do not all leap gracefully through space at the same speed: circumference and latitude join us in the dance. Because the earth makes one complete revolution on its axis every twenty-four hours (what we have come to know as a “day”) we can calculate the surface speed of the spinning earth as the division of the planet’s circumference by the same number of hours. We don’t all spin at the same tempo, though, because the circumference of the earth decreases latitude by latitude the closer one gets to either