Earth - from Apollo 17
Earth – from Apollo 17

Earth was formed approximately 4.5 Billion  years ago….. 4,500 million years ago.  It consisted entirely of  molten rock with a hot dry gaseous atmosphere.  A significant portion of uranium was present and the heat from its decay contributed to the molten environment.   100 million years later enough cooling had occurred that water vapor condensed, forming free water.  Water vapor is thought to have initially arrived with meteorites and accumulated over millions of years.  During this period earth was bombarded with countless meteorites.   Oxygen and CO2 formed thick clouds and heavy rain continued for millions of years.

After 400 million years of water accumulation, over 90% of the earth was ocean and it remained this way for 500 million years. The atmosphere was dense and surface temperature was just below the boiling point of water…around 200F. The ocean and the sky were a dirty, dark color.  It was a very inhospitable place.

At 3.4 Billion years ago…3,400 million years….volcanoes appeared and brought with them granite which was lighter than the mantel material and therefore floated on the mantel and began to form the continents. (…….to be completed)