Views & Theories of the Universe

Ptolemy’s Theory Proposed around 127-145 AD Earth was the center of the universe The sun, moon, stars, and planets all orbited in a circle around the earth

Ptolemy’s Theory

Copernicus’ Theory Proposed in 1543 The Sun was the center of the universe The earth and planets all orbited in a circle around the sun; The moon orbited around the earth The stars did not move

Copernicus’ Theory

Kepler’s Theory Proposed in 1609 Planets move around the sun in an elliptical motion, not a circular motion Planets speed up as they approach the sun and slow down as they move away

Kepler’s Theory

Big Bang Theory Proposed in 1927 Universe was smaller than a pinhead, then it exploded and expanded As the universe cooled, hydrogen and helium atoms began to form The universe is slowly expanding to this day

Big Bang Theory

Steady State Theory Developed in 1948 The universe has no beginning and no end The universe is in perfect balance (when stars die, new ones are created – like when a faucet is running and fills up a sink and the sink stays full)

Steady State Theory

Inflation Theory Proposed around 1980 The universe rapidly (and exponentially) expanded in its first few moments. Extension of the Big Bang theory

Inflation Theory