OCS 1005 Lecture : Lecture 4
15 Mar 2019
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Document Summary
The big bang is the term used to describe the beginning of the universe, probably about 14 billion years ago. Most of the substance of earth its ocean and all living things was. Most of the substance of earth, its ocean, and all living things, was formed by stars. Every chemical element heavier than hydrogen was manufactured and released into space by stars. A spinning flattened disk of dust and gas. Hydrogen and helium remain gaseous, but other materials can condense into solid. Our sun, like all normal stars, is powered by nuclear fusion. Formation of the planets of the solar system. Density is a key concept for understanding the structure of earth. Density measures the mass per unit volume of a substance. Something that is small but heavy has a high density; Something that is light for its size has low density. Things that have high density sink, while things with low density float.
