Friday, 15 May 2015

Our precious planet. Part 4. Timing of civilization

1. Introduction

This post tries  to explain how the genesis and evolution of human civilization depended on our planet having first gone through an orchestrated sequence of astronomical, geological and biological processes. This is over and above the cosmic fine tuning needed to allow pre-human life to exist. (Some of Part 4 overlaps with Part 3 but re-presents the material from a different perspective.)

2. Defining civilization

Civilization I am defining as a way of living which, depending on the values and beliefs adopted confers  benefits on its people through improving technology, communications and transport, increasing security against internal or foreign attacks on life and property,  growing agricultural efficiency, development of medicine and continually evolving knowledge of the world and how humanity relates to the Creator.

3. Origin

It appears to have started over 5000 years ago with the Sumerians in the fertile, periodically flooded plains between the Euphrates and the Tigris known as Mesopotamia, roughly coinciding with southern Iraq, Kuwait and parts of western Iran.

4. Cosmic time window

The universe started 13.73 billion years ago, expanding steadily after the first fraction of a second (the Big Bang). After 7 billion years it started to accelerate and appears set to continue this acceleration indefinitely. Before the stars were as far apart as they are now an observer anywhere in the universe would be blinded by a perpetually bright sky, unable to observe or deduce the nature of the cosmos, even if the atmosphere was clear. Only very recently in cosmic terms have the stars been sufficiently far apart to permit peering back to the moment of creation.

Conversely, in future the expansion will be so fast that observers would see only relatively nearby objects, and again would be unable to witness the Big Bang creation event.

Therefore we appear to be in a time window of a few million years when it is possible to deduce the history and nature of our universe.

5. Solar time window

The Sun, a yellow dwarf star with a lifetime of about  10 billion years, emitted radiation at a subdued level as it  entered into a relatively stable period of solar flare activity, beginning 50,000 years ago and likely to continue for another 50,000. This is based on the assumption that it will follow the pattern of similar stars observed at different stages of evolution  over billions of years i.e. by monitoring a given type of star at different distances, you can see what that type of star was doing at different times in the past.

Even with the Sun in a relatively calm phase it still emits lethal streams of particles. At the same time our planet is irradiated with life destroying cosmic rays from supernovae, gamma-ray bursts  and the supermassive black hole at the centre of  our galaxy. Providentially, at this stage of galactic evolution and in our present position in the galaxy, such irradiation is well below normal. Nevertheless  it would still have prevented human life without the magnetic shield which surrounds our planet and which was in place in time to protect humans when they first appeared, as it does now.

UV rays from the  Sun also would have prevented human life had it not been for the ozone layer, around 25 km high, the triatomic oxygen molecules of which absorb much of the incoming ultraviolet, rendering it benevolent, e.g. by stimulating the production of vitamin D, rather than doing harm to the body.

6. Clear skies and celestial order

By the time human beings (homo sapiens sapiens) appeared the Earth’s rotation period had slowed down from just a few hours to the 24 hours we know today. It is still gradually slowing down because of the Moon’s influence and at some time in the far future it will be too slow for habitability because of the effect on climate. Even another half hour or so would cause too much difference between day and night temperature.

Initially the sky was opaque. Then by the time human beings appeared it had cleared over much of the globe to permit a good view of the Sun,  Moon, planets, stars and comets. The Moon and  Sun in particular would have excited the curiosity of early man by their cyclic order, phases and eclipses, as well as by the way their movements are related to tides and seasons.  The stars, Milky Way and planets would also have been sources of wonder. The ordered behaviour of the heavens and the correlation of this to the seasons  would have led many to believe in a hidden order throughout the living world.

7. Preparation for agriculture and its consequences

Cultivation of land for crops was necessary for the generation of food surpluses which allowed  resources to be spent on discovery, music, art, literature, drama, public buildings, a civil service , a judiciary, a religious order and  armies for protection, conquest and subjugation.

The first civilization, the Sumerians in Mesopotamia, was made possible by the large areas of very fertile soil deposited when the Euphrates and Tigris flooded. This soil had been formed over millions of years by the weathering, erosion and crushing of rocks coupled with the action of bacteria. The rocks had a composition beneficial to farming because of the minerals brought to the surface of the earth by tectonic activity, itself a consequence of the heat from radioactive U and Th generated in supernovae and somehow transported into the vicinity of the Earth as it formed, 4.4 billion years ago.

The fertility of soil greatly depends on the fixation of nitrogen from the atmosphere,  a process which depends on  lightning for energy  and on the presence of bacteria or blue green algae.  Again, the possibility of civilization depends on the most unlikely of causes. No lightning and  bacteria would mean no Sistine Chapel.

8. Preparation for construction and technology

Wood, metallic ores and clay were essential to allow the construction of houses, public buildings, bridges, roads, temples, ploughs, carts , ships and, within a short span of  geological time, aircraft, spaceships, engines, computers, communication technology and much  else. The wood obviously came from forests,  the clay was another form of soil (see above) while the metallic ores were made available through plate tectonic activity which prevented heavy metals like iron sinking through the magma towards the centre of the planet. Certain metals, e.g. gold and titanium, were also delivered by meteorites.

Apart from its use in cooking, keeping warm and providing light, fire was essential  for smelting, refining and  materials processing, all necessary for the development of a civilization.  Fire depended very much on the atmosphere having the right amount of oxygen for controllable combustion and appears to have been the result of sophisticated biochemical 1feedback over billions of years.

9. Preparation for water transport and motive power

Apart from the provision of fish etc. for food the rivers, lakes and oceans which cross and connect the continents were and still are  needed  for  the transport of heavy loads up to very long distances, making trade and industrial specialization possible on a global scale
Fast flowing rivers were also used for pumps and mills. Even today they are used for hydroelectric schemes .  All expanses of water were used for recreation right from the earliest civilizations.

10. Animals

Certain domesticated animals were crucial to early societies for motive power, transport, farming, hunting, hygiene by scavenging in human settlements, sport and companionship. These included, and still include: oxen, sheep, goats, horses, donkeys,  elephants, birds of prey and dogs. Such animals had a genetic structure lending itself to varying degrees of selective breeding.  Parts of the world where they had been hunted to extinction (e.g. parts of the Americas)  or were not present initially, were not able to progress beyond the Neolithic stage.

Birds of prey must have inspired the concept of humans being able to fly, a vision which ultimately led to balloons, aircraft and spaceships. In fact without birds it is difficult to imagine how anyone would even have dreamed of flying.

11. A precious planet indeed

 So overall it looks as though civilization was made possible by a unique set of circumstances and that the Earth is indeed a precious planet.

Whether we are the  only conscious beings in the created order and ones having a sense of love, truth, justice and beauty as well as relentless curiosity and the power of reason we are unlikely ever to know. If there were no creator, i.e. if all the above is a product of blind chance, the probability of sentient beings elsewhere is, for all practical and rational purposes, zero.

Conversely, if there is a God (and all rational and reasonable argument points in that direction) no being in his or her mortal state can define God’s ultimate purpose, one which could include sentient beings on another precious planet. Personally, it would not bother me if the humans are the only sentient life in the universe. It need not make us feel lonely- just alone with God.


These posts in the Our Precious Planet series were inspired largely by Hugh Ross’s Why the universe is the way it is. Other sources include  Paul Davies’s The Goldilocks enigma,  Peter Douglas Ward’s Rare earth,  and Rodney Holder’s Big Bang Big God. I also made use of Wikipedia and popular science sources.

John Sears
Author, 2077:Knights of Peace

Links to all 4 parts of Our Precious Planet and some related links are given here.