Theories of the Universe Review

• 13.7 billion years ago

• States that the universe began at a singularity (a hot, small, dense force) and started rapidly expanding

• Hubble observed that galaxies are moving further away from one another --> The universe is constantly expanding --> "Hubble's Law"

• Galaxies are constantly moving away (expanding)

• Cosmic Background Radiation, the afterglow of the Big Bang, can be observed

• Dark energy (mass --> gravity --> slows)

Theories of the Universe

Ptolemy was an astronomer and mathematician who further developed the geocentric theory through mathematical detail.

It would later become known as the Ptolemaic Theory.

•  Nicolaus Copernicus was a great polymath or Renaissance man.

• His main idea was that our world is heliocentric (helios = sun).

• His theory was that the sun is in the middle of the solar system, and the planets go around it.

Galileo has been called the founder of modern science. He was one of the first people to examine the heavens with a telescope.

Galileo DID NOT agree with Ptolemy. He felt that Copernicus had a better idea and used his telescope to prove the truth in the Heliocentric Theory.

• The Earth is the center of the solar system.

• The moon, the planets, the sun, and the stars all rotate around the earth in circular orbits.

• The Earth stays still.

• The sun is between Venus and Mars.

• The Sun is the center of the Universe.

• The Earth, planets, and stars revolve around the Sun.

• The earth revolves on its own axis