Time Travel

Time Machine

The dream of time machines, in their many forms, have usually aimed to take us back or forward in time—to slide along the trajectory of human existence, either to visit a long past event or leap to the future. We want to spy how it was, or how it will be, for us and our fellows. Our most urgent concerns are, naturally, with ourselves and this desire animates our quest to unbind the fetters of time. In this quest, we move along a “horizontal” temporal axis, maintaining our experience within a constant human “temporal envelop”.

Our “temporal envelop” is dictated by our biology: life span, adaptive functioning, and evolutionary niche. Our beating heart, breathing lungs, marching steps, habitual movements, and suite of neural and perceptual-motor reflexes are metronomes that establish our time signature.

What would await us if we traveled along the vertical axis? If we to spin the dial to the shortest intervals possible, then to the longest?

Shorter Intervals

Consider if we were to nudge the time dial to a slightly quicker ‘time zone’ within a different biological metronome: hummingbirds.  The life span of hummingbirds is a short 3-5 years, but much intense life is packed into this brief time. The heart of hummingbirds’ pulse at 1000 beats per minute, wings snap at 50 beats per second, lungs breathing 250 times a minute, flying up-down-backward-forward-hovering all in an eye blink, yet migrating for 1000 mile journeys and, at night, entering a hibernating torpor.¹ The contrapuntal rhythms of hummingbird heart, wings and voice, the staccato, stabbing movements of flight and fight, and the allegro molto pace and multi measure rests makes for incomprehensibly complex jazz riffs.

Things get weirder still if we were to spin the dial toward the smallest time intervals. Events in this briefest of temporal neighborhoods occur in the domain of subatomic particles that inhabit near infinitesimal space and throb to very different beats than living organisms. The swarm of subatomic particles, governed by quantum mechanics, has been called a ‘particle zoo’  and the shortest enduring fundamental particle is the Z boson, which exists for a duration of about 10^-25 seconds.² A cloud chamber is one of the first methods used to capture the presence of subatomic particles, which leave vapor trails that allow for observing their fleetingly brief interactions ³.

Perhaps the most bizarre members of this ‘zoo’ are virtual particles, whose liminal existence is both substantive and unmeasurable. Heisenberg’s Uncertainty Principle sets a time-energy/mass limit, or barrier, beyond which we cannot detect the particles themselves. But we know they exist by their effects on particles that endure on the detectable side of the barrier. The Uncertainty Principle, then, both establishes the lower limit of measurable time and also reveals that time, in the quantum zone, is tethered to mass/energy.

Longer Intervals

On the other hand, what if we nudge the time dial to a slightly longer interval, one attuned to a very different biological metronome: trees? Trees, whose upturned arms passionately reach toward the sky and whose roots tenaciously grasp the earth. Who have memory, send alarms to friends, offer aid to neighbors in crisis, nurse the young, nourish the aged and fallen, tell time, create and capture water, create and enrich their home/soil, wave welcome to birds, plants and critters of all kinds—all this we overlook, if not disbelieve, because our temporal beat allows us to see only a snapshot of the life and time of these living, breathing creatures ⁴.

The Big Bang occurred about 13.7 billion years or 10¹⁷ seconds ago,⁵which marks the age of the universe and the longest time interval on our time dial. When we spin the dial toward this limit we lose our moorings. Time, itself, is revealed to be not a simple slide along a single dimension but a thread in a space-time fabric. Incomprehensibly large cosmic distances are measured in light years; the time it would take for light to travel from one point to another. So, the starlight we see convey the happenings that occurred long ago. This measurement of space via time hints at a more fundamental entanglement of the two. Time’s messages travel at a finite speed; the speed of light. Cosmic simultaneity does not exist—it is not the same time everywhere. This realization leads to a host of head-spinning conclusions: The basic coordinates for mapping events must be space-time coordinates. Clocks tic at different speeds, and lengths and distances shrink or expand—depending on the frame of reference. And, the space-time fabric itself is curved, twisted and, in some places, torn, where time-events fall into bottomless black holes. The contours of this fabric are determined by the mass of the matter in its vicinity; more mass, more distortions, and holes where stars have collapsed. Much of what seems bedrock-stable in our narrow time zone is an anomaly from a cosmic time perspective; Alice-in-Wonderland is the cosmic norm.

Time began with the Big Bang. Was there a ‘before’? The ‘before’ might well have been nothing, the void. However, the void— space with no energy, charge or matter— is not empty. It is pregnant with possibility; a churning, bubbling, boiling stew of virtual particles that flicker in-and-out of existence, ever so briefly. It is surmised that the Big Bang was a cataclysmic leap from possibility-to-actuality in this frothing quantum foam. Furthermore, our universe, and its Big Bang, may, perhaps, be a small region of a larger cosmos that has existed prior to this event. Our universe may be but a local time zone amidst an infinite space-time landscape.

Quick Decaying Particles

A being who exists near the largest cosmic space-time interval may likely have a similar perspective toward us as we have toward  subatomic particles— our little, obscure, ephemeral neighborhood of space-time would be its particle zoo. Consciousness, which influences the actions of these tiny, scurrying, quick decaying particles—us— would be a kind of virtual particle in this physics, and our architecture, art, texts, broadcasts and space probes would be our vapor trails. The vertical traverse of time rockets us through  dizzying loops, wrinkles, twists, spins, tumbles and holes. It does not offer visions of our human past or future. Rather, spinning this dial rips us from our comfortable temporal-spatial moorings, offering a wild ride through time itself and a kaleidoscopic glimpse of our place within the roiling cosmic order.

1. There is considerable variation in these values among the hundreds of species; these are rough averages.
2. 10^-25  is scientific notation for a number that begins with a decimal point followed by 24 zeros and then a 1.
3. See image above.
4. See “The Hidden Life of Trees” by Peter Wohlleben
5. Scientific notation for a digit followed by 17 zeros then a decimal point