Earth and Life Science Lecture Notes

Introduction

Definition: The universe is the whole cosmic system of matter and energy, including Earth and all human beings.
Structure:
- Earth is a rocky planet in the solar system.
- Solar system includes 8 planets (from Latin "Sol" meaning sun).
- Part of the Milky Way galaxy, which has around 200 billion stars.
- Milky Way is one of 125 billion galaxies in the observable universe.

Concept: A symbolic narrative that explains the origins of the universe as understood by various cultures.
Characteristics of Creation Myths:
1. Ideological: Reflect beliefs and values of a culture.
2. Etiological: Provide explanations for causation or origination (causes of universe creation).
3. Philosophical/Theological: Involves existential philosophy; ties to the study of God and spiritual matters.
Example: The Genesis account describes God creating the universe in six days.

Proposed by Alexander Friedman.
Concept:
- Initially, there was nothing and nowhere.
- Random fluctuations led to a great expansion (not an explosion).
- Universe is expanding into something (the "vacant space").
- After millions of years, hydrogen gas clumped under gravity’s pressure, forming stars and galaxies.

Suggests the Big Bang is the end of a previous universe phase.
Involves ideas of destruction and creation, leading to repopulating the universe cyclically.

Proposed by Fred Hoyle, Thomas Gold, and Hermann Bondi in the 20th century.
Concept: The universe is unchanging in time and uniform in space.
- Universe is homogeneous and isotropic (looks the same on large scale).
- Continual creation of matter maintains the universe’s density as it expands, contradicting observable evidence.

Developed in the 1980s by Andreas Albrecht, Allan Guth, Paul Steinhardt, and Andre Linde.
Concept: Exponential expansion occurred before the gradual Big Bang.
- Solves limitations of Big Bang theory by addressing flatness and uniformity issues of the universe.

Proposed in the 1960s by John Schwartz.
Concept: All particles can be described as one-dimensional strings.
- Strings vibrate in different ways and interact with one another.
- Potential breakthrough for unifying general relativity with quantum mechanics, studying both large (universe) and small (subatomic) worlds.

Summary of discussed theories: creation myths and scientific theories explaining the universe’s origin.
Emphasized the philosophical implications of these discussions.
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