The remake of Cosmos began airing last night. Featured a presentation of the time since the Big Bang scaled as a year-long calendar starting January 1 at 13.8 billion years ago (bya) and ending in the last few seconds of December 31 corresponding to the entire time of human recorded history. Been thinking about this immensity of time focusing on recent news of the earliest piece found of the earth’s crust and of the earliest signs of life.
The earth was formed some 4.5 bya. The moon was formed in a colossal collision between earth and a Mars-sized planet some 4.45 bya. That oldest piece of crust – a zircon – has been dated to 4.4 bya. It took some 50 million years after the collision for the earth to cool down enough to have a solid surface. But the earth was still in for further impacts during the Late Heavy Bombardment that lasted until around 3.9 bya. The first signs of life – monocellular bacteria and archaea – appear around 3.5 bya. But it takes almost another two billion years for complex single cell life – the first eukaryotes, cells with nuclei and DNA – to appear. Sexual reproduction follows at about 1.2 bya and the first multicellular life at 1.0 bya. The first fossils of multicellular animals date to around 550 million years ago (mya), fish to 500 mya, land plants to 475 mya, insects to 400 mya, reptiles to 300 mya, mammals to 200 mya and primates to 60 million. Humans are some 2 million years old.
Life was quick to emerge once the earth had a solid surface. It took only 400 million years for inert chemicals interacting somewhere on that surface to become life. To us, that is a long time. But given the leap from non-living to living, maybe not so much. During those 400 million years, the laws of physics and chemistry plus the raw conditions of earth and water somehow gradually led to small clumps of matter coming and staying together and reproducing themselves. The first such clumps that successfully kept out the environment, organized themselves internally and made copies of themselves may have been something like viruses. At what point they crossed from non-living examples of complex chemistry to living things is unknown. But it took another two billion years for those clumps to become the most simple form of single cell life we know and then another billion years years or so to become the simplest form of multicellular life.
Four hundred million years for life to get started, two thousand million to reach the level of bacteria, another one thousand million to reach jellyfish and then fish in 50 million years, plants on land in 25 million, 75 million more for land animals (insects). Some 170 million after the first land animals takes us to dinosaurs and then — clearing the board — their extinction 65 mya. In a blink of an eye, at 60 mya, the first primates appear and then in the past 200,000 years homo sapiens.
Life started quickly but took a long time to build the tool box for evolution by sexual reproduction. It then took off leading to complex life within a comparatively short time and exploded in the last 500 million years. What about the universe might account for the easy start to life, the steady progress of evolution and the relatively fast emergence of higher forms of life and ultimately human awareness?
With the confirmation of the Higgs field, it now seems that the universe beginning with the Big Bang had its properties imprinted from the start. The laws and constants of physics and chemistry seem to conspire to produce the material universe of which we find ourselves part. Atoms emerge from a primordial soup of particles, combine in stellar processes to form elements and eventually become planets. Stars themselves combine the simplest elements in such a way as to provide copious amounts of free energy. The Kepler program has confirmed that planets are common and most stars have them. Put together a planet like the early earth – and there probably are millions of them in our galaxy alone – and wait 400 million years or so and life may emerge. Given a degree of long term stability, it may become self-aware.
I've speculated here that consciousness is itself a property of the universe and may well be prior to it. But how might it be connected to life? What is “life” and how did it emerge from chemistry and physics? Suppose that consciousness pervades matter and the universe and drives – through the laws of physics – increasing levels of complexity beginning with atoms toward sufficiently elaborated organizations of matter to enable mind and thereby self-awareness. Life becomes a form of striving, a movement of consciousness toward a clumping of matter sufficiently complex to provide it with the biological substrate for perception and thought. Life is the process of individual striving within and against its environment. At various levels, we call this process physics, chemistry or biology. Within biology, it manifests as evolution. But it might be seen as “God thinking.” Hegel anyone?