Time and place seem like obvious things, the anchors of our lives. But when examined closely, they are almost beyond comprehension. For example, we have trouble grasping that at one time in the past, we didn’t exist. We look at photographs of ourselves when we were children and faintly remember. Then we look at photographs of our parents before they were married, and the thought strikes us that we were not yet born. Then we look at photographs of our grandparents and wonder what the world was like in that era. Then our great-grandparents, and on, back and back through the corridors of time, before our conception, before any inkling of us. Yet our sense of being alive in the world is so vivid and strong, it seems impossible that for centuries and millennia, cities rose and fell, winds blew across the land, smells of salt water and honeysuckle drifted through air without a speck of us. How could that be?
Likewise the land. The ground we walk on, our lovely coves and our bays, seem to have been here forever. But not so. Over time, our geography has shifted, tilted, compressed and congealed — for most of the eons beyond recognition.
Twelve thousand years ago, at the end of the last ice age, the entire state of Maine was covered by an ice sheet 2 miles thick. Try to imagine that. As the ice melted, it carved out the major land masses of Harpswell: Orr’s Island, Bailey Island, Great Island, and the Neck. The glaciers slid and eroded along zones of weaker bedrock — the faults, joints and softer formations. That bedrock, in turn, had been folded and fractured earlier in a northeast-to-southwest alignment, giving the land masses that same orientation. Look at a map of Harpswell and you can see that axis of formation. The rocks themselves — originally shale, sandstone, limestone and others — had been buried deep in the Earth, where extreme temperatures and pressures converted them to the quartzite, schist, gneiss, slate and volcanic basalt of today.
About 175 million years ago, the supercontinent called Pangaea began to break apart into the continents we see today, including North America. That fracturing was caused by the shifting of great slabs of rock called tectonic plates beneath the Earth’s surface, their movement driven by heat and convection rising up from the hotter interior of the Earth.
Pangaea formed about 350 million years ago. In that supercontinent, all the land masses of Earth were joined together, a continuous stretch of land bordered by a single global ocean called Panthalassa, whose vast waters wrapped around the land like an endless blue ring. If you were alive at that time, here is what you would see: The interior of Pangaea would look harsh and dry. Because the land mass was so large, moist ocean air could not easily reach its center. Instead, a gigantic desert — larger than any on Earth today — would dominate the continental heart. This region would be characterized by vast dune fields, scorching temperatures during the day, and dramatic swings to cold nights. Far from the coasts, vegetation would be sparse, struggling in the arid climate. Closer to the coast, however, thick forests would create green belts along rivers and shorelines. Swamps and wetlands would form in low-lying areas, nurturing giant insects, early reptiles and amphibians.
Earlier in time, about 400 million years ago, a volcanic island arc known as the Avalon terrane, again moving on tectonic plates, collided with the land that became eastern North America. This collision created the mountain ranges of New England. All of Harpswell’s bedrock was produced in this cataclysmic event.
A billion years ago, the region that would become the state of Maine, including Harpswell, looked nothing like the rocky, pine- and spruce-forested landscape we know today. Instead, the land of future Maine was either submerged beneath ancient oceans or existed as fragments of proto-continental crust, far from its eventual position on the east margins of North America. The future Appalachian Mountains consisted of bare, eroding highlands and volcanic island arcs scattered across warm, shallow seas. These seas were rich in dissolved iron but hosted only simple microbial life. The atmosphere contained far less oxygen than today, perhaps only 10% as much, allowing more of the sun’s UV light to reach Earth, in turn triggering organic haze and making the sky more pale and washed-out than it is today.
Let us hike up our courage and travel even further back in time and in space. Several billion years ago, the primitive Earth was still cooling and being heavily bombarded by comets and asteroids from outer space. Scientists believe the Earth and other planets condensed out of a rotating mass of gas and liquids, which collapsed into spheres because of gravitational attraction. Although most of this material was revolving around the infant sun in the same direction, some of it did not follow the overall pattern, resulting in collisions that released an enormous amount of energy. (Imagine two moon-sized objects colliding at speeds of 40,000 miles per hour.) This energy, plus radioactivity from such elements as uranium and thorium, heated the material that formed the core of the Earth, eventually powering volcanoes and driving the tectonic plates.
And where did the matter of Earth come from — the iron and oxygen and silicon and magnesium and carbon and potassium and calcium that make up soil and rocks and human beings? From massive stars, which produced these large atoms by fusing together smaller atoms in their extremely hot centers (several million degrees), then exploding and spewing the forged elements into outer space, where they were later to become part of the rotating mass of gas and liquids that formed planetary systems.
And where did the stars come from? From the gravitational collapse of dense pockets of gas in the early history of the universe. A great deal of scientific evidence suggests that the universe began about 14 billion years ago, in an extremely hot and energetic event called the big bang. That energy then condensed into subatomic particles whizzing about at great speed.
And where did the big bang come from — the grandmother of all matter, the matriarch of stars and planets, soil and trees, oceans, and us? At last, we don’t know. Theoretical physicists conjecture that before the big bang, baby universes were constantly popping into existence out of a fluctuating sea of energy governed by quantum processes, and then disappearing back into nothingness. According to the theory, a small fraction of those fleeting universes had the right properties to begin expanding, and a small fraction of that fraction had the right conditions to form stars and planets and life. But it is impossible to prove such a theory.
What we do know is that the land, and the world, have been constantly in flux. What we see now, in time and in space, hasn’t always been what it is. Our individual lives are momentary jots in the vast unfolding of time. And the ground that we walk on, the land that feels solid under our feet, has also shifted and changed in the history of Earth. Perhaps such knowledge makes our moment all the more precious, like the night-blooming cereus. The cereus looks like a leathery weed most of the year, but for one night each summer its flower opens to reveal silky white petals encircling lace-like threads. One night of the year.
