Origins — Module 1

The Origin of the Earth

Introduction

This module is about the origin of the Earth, and is in three parts. The first part is about how we think the Universe formed, and the evidence for the Big Bang hypothesis for the origin of the Universe. The second part of the module is about galaxies and stars — how they form and how they are able to generate the chemical elements. In the third part of the module we consider the origin of planets and how we think our own planetary system formed.

Many of the processes we are considering took place a very long time ago. In the text that follows time is referred to in millions of years (Ma -106 yrs) or billions of years (Ga — 109 yrs).

Printable versions of this module

Table of Contents

1. The Origin of the Universe and the Big Bang
2. An Expanding Universe
3. The Cosmic Microwave Background
4. The Early History of the Universe
5. Appendices:
6. The Cosmological Redshift
7. The Age of the Universe
8. Competing Big Bang Hypotheses
9. Star Formation
10. 'Lumpiness' of the Universe
11. Gravitational Collapse and the Formation of Galaxies
12. The Evolutionary Cycle of Stars
13. Origin of the Chemical Elements
14. Appendix:
15. Types of Galaxy
16. Planetary Formation and the Origin of the Earth
17. The Planets of the Solar System
18. The Stages of Planetary Formation
19. The Search for Planets in other Solar Systems
20. And Finally...
21. Module 2: The Origin of Life
22. About the Author