I wrote this in a sort of stream-of-consciousness fashion about 9 years ago… I may revisit it and rework it, but here is the original…
About 4.6 billion years ago the Earth, the Sun and our entire solar system coalesced from the debris of long dead stars, in a crowded dusty nursery. Over the short period of just a few million years the planets violently came together under a night sky blazing with the light of other sibling suns also being born from the same massive cloud.
At some point during the formation of our solar system one of the Sun’s closer, more massive siblings died an early death and went supernova- leaving its fingerprints in the isotopic composition of the building blocks of the solar system. Its death, in part, shaping the evolution of all that was to follow.
Since that time our solar system has made about 20 orbits of the galaxy, and the Sun has drifted away from its siblings. Sometime around the Sun’s fourth or fifth orbit of the galaxy over 3.6 billion years ago something amazing happened on the barely cooled third planet. Simple molecules guided only by the laws that govern the universe came together in a way that allowed them to create copies of themselves. By about 3.4 billion years ago life had reached the point where it was actively remaking the earth, stromatolites were engaging in photosynthesis and remaking the atmosphere.
After the Sun’s eleventh orbit of the galaxy the primordial seas were teeming with complex single cell life. Roughly around the time of the Sun’s sixteenth orbit, or 1 billion years ago, multi-cellular life had evolved, life’s diversity and complexity began to skyrocket. In just 500 million years, about two orbits of the sun around the galaxy, multi-cellular life had evolved into the complex and truly alien creatures that we find preserved in the Burgess Shale fossil beds. Most of these bizarre creatures were evolutionary dead ends, but one of them was the first vertebrate- Myllokunmingia- the common ancestor you, your dog, and your pet goldfish.
About half of one galactic orbit later, or 375 million years ago the first vertebrate stepped onto land. You, me, and the squirrels playing outside my window are all directly descended from that creature. It stepped onto land that had been dominated by invertebrates for nearly 100 million years. From that creature evolved both mammals and dinosaurs. The first true mammal evolved after the dinosaurs about 170 million years ago, but it was the dinosaurs that would end up dominating the land for over 150 million years, or two-thirds of a galactic orbit.
Born from the same accretion disk that created the earth was a large asteroid- for about 4.535 billion years it had quietly orbited the sun as the sun made its nearly 20 orbits of the galaxy. Finally, about 65 million years ago, the chaotic nature of orbital dynamics brought it into collision with the Earth. This brought an end to the age of dinosaurs and allowed mammals to dominate. It was just 5 million years after this event that our first primate ancestors evolved.
At first small, and squirrel-like, the primates were successful and diversified over the next 60 million years. 60 million years, or about one quarter of a galactic orbit. Intelligence proved to be a survival trait, and the primate brain evolved in it’s capability.
57-58 million years later (2-3 million years ago) descendants of those early primates (probably Australopithecus garhi ) started using stone tools somewhere in Africa. Anatomically modern humans date back to about 200,000 years ago (a little under one one-thousandth of a galactic orbit). Just 10,000 generations separate us, and those first humans. Ten thousand human lives between struggling for survival on the plains of Africa to you sitting at your computer comfortably reading this. Each of those ten thousand lives filled with countless human sorrows and joys great and small all leading up to this moment in time… to us. Each generation driven by the evolutionary pressure to ensure that the next generation could survive and hopefully thrive.
All this and more is our inheritance, our backstory, and nearly all of this we have come to learn through science within the span of one human lifetime. In 100 years- less than one two-millionth of a galactic orbit- we have learned so much of our history, our understanding of the magnificence of the universe has been revolutionized many times over. We have gone from discovering atoms to taking them apart and studying their building blocks, we have built instruments to image light that was emitted billions of years before the stars from whose ashes we are made were even born.
Some of us sit down at a computer and post messages on an internet bulletin board complaining that science takes the mystery out of the world. Countless people are killed because they violently argue over which Iron Age religion, based on Bronze age mythology, founded in stone age thinking is the ‘CORRECT’ one. People deny the Scientific Fact of global warming and slander the scientists that dare point out the truth. People celebrate and take pride in their ignorance and help ensure that the next generation will have ever more challenges to its survival.
Humanity- as we know it- will not be around for another one one-thousandth of a galactic orbit, that much is certain. The decisions we make as a race today will determine if we will become something more glorious, or just another dead end. We are the first organism in the 4.6 billion year history of this planet to understand all this, and it appears that most of us are perfectly happy to throw it all away.
The Earth will continue to orbit the sun as it circles the galaxy, will humanity come to an end on this planet, having learned only enough to appreciate how much it has squandered? Or will we overcome ourselves to explore the universe we have only begun to truly appreciate? It is a terrifying prospect- made all the more so by the fact that we will irreversibly put ourselves on either the road to glory, or extinction in the next generation or two.