In a previous essay I discussed constructive and destructive geologic forces that continue to shape and reshape the earth. Today I would like to concentrate on the planet’s birth and early (prebiotic) conditions. My purpose here is to provide facts where facts are known and discuss various theories (possible explanations).
There have been and still continues to be many theories formed to try to explain the formation of the earth. One popular theory held that all the planets in our solar system were formed from hot gasses thrown off by the sun as it formed. An American geologist, P. C. Chamberlain proposed the Planetisimal hypothesis which says that the earth formed from coalescing solid particles. In 1788, Lord Kelvin (Kelvin temperature scale) proposed that the earth was much older than originally thought and believed the core was a molten liquid but he completely missed the (approximately) true age because he believed there was no source of continuing heat supply. A radioactive core consisting mainly of lead and nickel eventually provided the answer to the heat problem and now the scientific community estimates the earth’s age to be about 4.5 billion years. Robert Holmes in 1911 discovered radioactive dating and subsequent use of uranium (U235) in rocks is the primary basis for this. James Hutton, a Scottish geologist, had already predicted that the earth had a long history with many many gradual changes and based his predictions on fossil rock examination. However, the earth was not yet hospitable for life–not for about another billion years. First the earth’s core had to cool for about 100 million years which allowed the crust of volcanic rock to form. But there was no life supporting atmosphere. The primitive atmosphere probably consisted of water vapor, nitrogen, carbon dioxide, sulfur dioxide, and hydrogen by out gassing over millions of years of volcanic activity. Eventually the atmosphere probably became saturated with water vapor and the continued cooling of the earth would have allowed rain to fall (for millions of years) to form the oceans. By 4.0 billion years ago as much as 40% of the earth’s surface was probably oceans with a CO2 filled atmosphere. Eventually a rock hard enough (granite) formed to become the continents. As noted in an earlier essay, Alfred Wegner, a German meteorologist first proposed the Continental Drift hypothesis in 1912. He noted like fossils on separate continents and assumed they once were much closer together. He also noted, as many of you have, that continents such as South America and Africa seem to fit together like pieces of a jigsaw puzzle. Since then the concept of plate tectonics (with ridges where new lava rises pushing continents apart and seduction zones where volcanic faults occur) has been substantiated.
Credit to: pompeiiplates.weebly.com
The Continents move approximately 1 inch per year. The original source of earth’s water and, therefore, its oceans has been a subject of much debate. Some scientists have proposed comets provided at least some of the water while others believe that water frozen in meteors provided most of it over millions of years. Other scientists favor the idea that some of the coalescing “mini planets” might have collided to form the earth and might have already contained water in them. Perhaps several sources provided the water that was to become necessary for life.
I know there are many gaps and holes here but remember from an earlier essay it was pointed out that this is a part of the nature of science which makes it both challenging and interesting. I know there are skeptics reading this that, no doubt, will reject all of this and simply say that God created it and I firmly agree. But how did God create it? What methods did He use? The Bible doesn’t give many details. God also gave us a mind, the desire to learn about our world and beyond, an imagination to ask the important questions, and the capacity to dream dreams. He also gave us science and the “laws of nature” to study it. I have always said that knowledge of science will help reveal the mind of God. Science tries to answer the question of “how” and religion tries to answer the ultimate question of “why”