Chapter 1: Introduction to Astronomy
1.1 What is Astronomy?
Astronomy is the branch of science that studies celestial objects, space, and the universe as a
whole.
It includes:
Stars
Planets
Moons
Comets
Galaxies
Black holes
Astronomy is one of the oldest sciences in the world.
1.2 Difference Between Astronomy & Astrology
Astronomy
Astrology
Scientific study of space
Belief system
Based on experiments
Based on zodiac signs
Uses telescopes
Uses horoscopes
Astronomy is science. Astrology is not science.
1.3 History of Astronomy
Ancient Astronomy
Egyptians used stars for calendars.
Indians studied planetary motion.
Babylonians tracked eclipses.
Important Scientists
Galileo Galilei – First used telescope for astronomy
Nicolaus Copernicus – Proposed heliocentric theory
Isaac Newton – Laws of motion & gravity
Albert Einstein – Theory of relativity
Chapter 2: The Universe
2.1 What is the Universe?
The universe includes:
All matter
All energy
All space
All time
It is believed to have started with the Big Bang about 13.8 billion years ago.
2.2 The Big Bang Theory
Main points:
Universe started from a very hot, dense point.
It expanded rapidly.
It is still expanding today.
Evidence:
Cosmic Microwave Background radiation
Redshift of galaxies
2.3 Galaxies
A galaxy is a huge system of stars, gas, and dust.
Types:
Spiral galaxy
Elliptical galaxy
Irregular galaxy
Our galaxy is the Milky Way.
Chapter 3: The Solar System
