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?
