Protected by the most delicate film of atmosphere, our planet spins alone in a near vacuum of chilling darkness for an eternity of spacetime in all directions, where, apparently, nothing lives and no consciousness wonders. In all the universe, no other planet has been located that is anything like ours—that has even a remote possibility of sustaining what we know as complex life. At least we can be sure of this within 100,000 light-years of Earth. And that's a long way. Yet life has found myriad ways to flourish, no matter what happened, since it mysteriously made its start, here on Earth.
Pursuing my wildlife artist’s lifestyle, I was always roaming the wilderness. The interior plateau rolled northward like waves upon a great sea and there the sky opened wide. At night I would lie half dreaming, glued flat on my back to the surface of our beloved planet, too awed to sleep. Gazing away into the diamond galaxy, as it swept through the black satin background, I felt right at the centre of a universe of wonders. What could be happening at this moment out there, what unimaginable event? When one looks out in this way, human life’s concerns grow dim; it is obvious that in general, up and down has no meaning. Reality consists instead of radiating, gravitating centres, whirling for eternity along invisible paths. There are more stars than grains of sand upon the earth, in galaxies without number, some with gigantic black holes at their centres. There are quasars whose cores are black holes of the mass of many billions of our sun, in a single point 10-43 cm across. There are young stars, old stars, red giants, white dwarfs, and exploding stars.
And you know that what is out there is something terrific, whether or not one of us humble creatures can understand it. As some mystics are wont to say, “Behold the true dragon!”
We are flying at a speed of thirty kilometres per second around the sun, which is moving around our galaxy, the Milky Way, at several hundred kilometres per second. The Milky Way moves against the background radiation at a speed of 600 kilometres per second, or one fifth of a percent of the speed of light. Yet I feel perfectly still, without even a breath of wind to suggest movement—so much of what we perceive is only an apparancy. In fact, there is no such thing as absolute stillness; all movement is relative.
To look out through the universe is to look into the past, since the light revealing it took time to reach us. Therefore, space is measured by the distance light travels in a year, called a light-year; it is impossible to separate space and time. Scientists believe, through many meticulous measurements and calculations, that the universe banged into being 13.7 billion years ago—plus or minus 200 million years—and flew outwards at a rate that had nothing to do with the usual speed limit. The rule that nothing can travel faster than light does not apply to the expansion of spacetime. The observable universe (the part from which light has had time to reach us), is about 28 billion light years across.
Using modern telescopes, scientists can see back in time almost to the big bang, though that mysterious beginning is veiled in the fog that existed before atoms formed and the universe became transparent. However, astronomers have found very old galaxies that formed soon after, from irregularities in spacetime. Those first stars grew old and when they exploded, they scattered the heavier elements we know as matter across the expanding universe. Another unimaginable abyss of time passed as the action of gravitational forces caused this material to cluster, and form a second generation of stars, many with revolving discs around them, as rock, dust, ices, and gases drew together in an ever-turning aggregate. Thus our our planetary system eventually formed—about five billion years ago.
We live in a changing, evolving universe.
Earth formed about four and a half billion years ago as the third of the nine planets in the disc orbiting our newborn sun. The new planet was in wild turmoil due to gravitational forces acting on the different densities of matter tumbling inwards. While debris rained from the skies and lakes of lava exploded, blocks of rock were thrust to the surface, ices melted and boiled, and heavier material sank. For a long period it was a hot, explosive place, littered with active volcanoes, and running with lava.
Slowly Earth cooled and its geological features became more settled. After a billion years, it was cool enough that the steamy atmosphere had mostly condensed and rained into a planetwide ocean. Carbon dioxide precipitated out of the atmosphere, leaving it mostly nitrogen. The sky was cloudy. Earth was still hot inside and volcanoes continued to pour lava to the surface, some forming islands in the ocean. The crust of the planet contracted as it cooled, and the powerful and turbulent forces of the molten rock within forced some regions up to form mountain ranges, and caused others to crack or sink. With the passage of time, chains of islands were pushed together and continents began to take shape.
How life got started is not yet understood, for only life grows more, and not less, orderly. (The tendency for things to fall apart is self-evident and completely irreversible in all but living things.)
Once life was here, it began to change its environment. The fossil record reveals that single-celled cyanobacteria were the first life forms, 3.7 billion years ago. They floated in the hot and shallow ocean—doing nothing much—but they produced oxygen, and claimed this spinning aggregate of rock, fire, water, and gases for life. After two billion years, enough oxygen had collected to turn the sky blue, and there was a breathable atmosphere that could support complex life forms. Our life-supporting atmosphere was created by life itself.
In all that time there had been life, but death waited. For those first aeons, life consisted of single-celled forms that reproduced by cell division—a continuous existence with no death and no change. Until, deep in this interminable peace, somehow two cells merged before dividing, sexual reproduction began, and, 1.7 billion years ago, death appeared.
It was death, with his side-kick, sex, that launched evolution's race. Now, each new individual was endowed with his or her very own combination of genes to play in the chances of life, and only the excellent won the right to reproduce.
Suddenly, life diversified dramatically. Death cleared away all who could not keep up, which was nearly everyone. Molluscs, seaweeds, sponges, coral, starfish, sea-lilies, plankton, algae, shrimps, crabs—a whole array of invertebrate life—sprang into being. Some life forms developed photosynthesis, which continued the production of oxygen, and half a billion years ago, plants appeared and covered the land, while the first vertebrates emerged. Able to support themselves against the pull of gravity, animals could finally leave the waters.
Ninety percent of the
entire history of Earth was required to set the scene—to prepare a
stable, compatible place for complex life to flower. Another eternity passed while a variety of life forms evolved
and vanished, before dinosaurs
dominated the Earth
260 million years ago.
Though they were a victim of a mass extinction 65 million years ago, some are still with us in the form of birds, having evolved considerably in the meantime.
All of us living today descended from the best, the smartest and the strongest individuals from each generation, for all of that time. Many more died than lived to reproduce, but every single one of our ancestors managed to make it to adulthood, AND have kids! What a test. If only we knew of all of their stories, their strife, and their lucky breaks. . .
The latest counts tell us that about nine hundred million species of higher life forms share the planet with us, networking in an intricately inter-tangled play of individuals, large and tiny, which form life’s endless community. From frozen poles, to tropical jungles, to the oceanic abyss, each creature is at the centre of its own world view of events, each challenged by survival. Green plants link the earth to the sun’s energy. Using photosynthesis, they mix sunlight with water and Earth to grow leaves, flowers, and fruit. Physically and chemically intertwined with the air, they recycle water to fall as rain and stream from the forest fringes, back to the sea. The oceans circulate in a cycle taking a thousand years, keeping our climate stable, while, through evaporation, water puffs back into the atmosphere and blows in the winds, forming clouds to rain again upon the land. And forces beyond the power of our imaginations have permitted this spinning globe to rest stably so that we have all had the chance to pursue our lives.
The numbers of life forms who have played out their existences on Earth is unimaginable, as the sun rose and set, and things happened, for them as for us. Did all of these creatures not understand, however simply, the world in which they found themselves? Can consciousness only have existed since our own species emerged? When did life on Earth begin to feel and wonder?
We live in a universe that remains mysterious, after all!
Author of Birds are Impossible: The Supernatural Ways of the Fliers, Outwitted by Chickens: The Bird Who Killed the Tiger and The Spirit of Wild Ducks
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