Models of the Universe

Front

Ptolemaic System/Model of the Universe

Back

Earth at the center

Front

Copernicus' Model of the Universe

Back

Heliocentric Model

Front

Aristotle's Model of the Universe

Back

Geocentric; planets revolve around Earth

Front

Geocentric Model

Back

Earth is the center; sun rotates around Earth

Front

Irregular Galaxy

Back

No regular shape; young stars

Front

Galaxies without gravity

Back

Would fall apart

Front

Spiral Galaxy

Back

Bulge in middle; arms spiral outward; middle-aged stars

Front

Elliptical Galaxy

Back

Oval-shaped; old stars

Front

Galileo Galilei

Back

Italian astronomer; first to use telescope

Front

Age of the Universe

Back

14 billion years old