Astronomy: The Original Science

STUDYING SPACE

Modern Calendar

Based on observations of bodies in our solar system

Day

Time required for Earth to rotate once on its axis

Month

Time required for the moon to revolve once around Earth

Year

Time required for Earth to revolve once around the Sun

TWO CAMPS OF THOUGHTPtolemy Copernicus

• Sun is center of universe

• All heavenly bodies revolve around Sun

• Spurred major changes in science & society

• Earth is center of universe

• All heavenly bodies revolve around Earth

TWO CAMPS OF THOUGHTPtolemy Copernicus

Tycho BraheThought the Sun revolved around Earth & other bodies revolved around Sun

Made precise observations

Johannes Kepler

All planets revolve around the Sun

Developed 3 laws of planetary motion

Galileo Galilei

First to use a telescope to observe objects in space

Galileo’s Discoveries

Craters on moon

Mountains on moon

4 moons of Jupiter

Sunspots on the Sun

Sir Isaac Newton

Law of Gravity

Explained why all planets orbit the most massive object in solar system - Sun

Edwin HubbleProved that there are other galaxies in universe.

Confirmed belief that universe is much larger than first thought.