The Expanding Universe Expanding Universe Theory States that

The Expanding Universe

Expanding Universe Theory • States that: – The universe is constantly increasing in size – All galaxies are moving further and further apart

Raisin Bread Analogy • Dough Represents the Universe • Raisins Represent Galaxies • As the dough expands, raisins got further apart. As the universe expands, the galaxies get further apart!

The Big Bang Theory • The universe began as very hot, dense, small particle. • Suddenly, it began to expand cool rapidly!

The Big Bang Theory • Today, even though the Big Bang happened billions of years ago, the universe continues to expand! • No one knows why the Big Bang happened, but we do have evidence that it occurred. • We’ll talk about this evidence tomorrow!

Just for Fun! • http: //www. youtube. com/watch? v=lh. TSf. OZUNLo

The Doppler Effect

The Doppler Effect • The distortion of frequency of light or sound produced by a moving object as observed by a non-moving person. – When the object moves toward you, the frequency appears higher. – When the object moves away from you, the frequency appears lower.

The Doppler Effect • Sound: – When object moves toward you, the sound seems higher pitched. – When the object moves away from, the sound seems lower pitched.

The Doppler Effect • Light – Objects moving towards you appear more blue. This is called a blue-shift. – Objects moving away from you appear more red. This is called a red-shift.

The Expanding Universe • All galaxies we can observe exhibit a redshift • This means that the galaxies are moving away from us, just like the Expanding Universe Theory Predicted!

Extra Help! • http: //www. youtube. com/watch? v=Fhfnqboac. V 0