Please explain on your note card how this picture explains the Doppler Effect and how it relates to “Shifts in light”.

THE BIG BANG THEORY

States that the universe began as a single cosmic explosion about 15 billion years ago.

Background Radiation

• Energy left over from the Big Bang that is evenly spread out throughout the universe.

• This background radiation is one observation that supports the Big Bang Theory.

After the Big Bang

• Gravity began to affect matter racing in every direction.

• The clumps formed into huge clusters of matter.

• These clumps became the galaxies of the universe.

HUBBLES LAW

The farther away the galaxy, the faster it is receding

(moving away) from the earth.

Galaxies seem to be racing away from the center of the Universe.

• Every galaxy seems to be moving away from Earth.

• After examining the Red Shift that appears from distant galaxies astronomers conclude the universe is expanding at tremendous speeds.

Expanding Universe• If the universe is expanding, then

the objects near the very edge of the universe are the oldest objects in the universe.

• The most distant known objects in the universe are over 12 billion light years from the Earth

Three Pieces of Evidence Supporting the Big Bang

• The presence of Background Radiation

• The observation of the galaxies spreading away from the center of the universe (Red Shift)

• Heat in space 3°K

What Happens Next?

• Astronomers feel that the Big Bang theory leads to two possible futures for the Universe.

Open Universe

• Galaxies will continue racing outward (continue to expand). All of the stars will die off as the last of their energy is released. There will be nothing left, total emptiness.

Closed Universe

• Gravitational attraction between the galaxies will cause the movement away from each other to slow and, eventually come to a halt. The gravitational pull will begin to pull the galaxies back to the center of the universe.

Closed Universe cont.

• All of the matter and energy will again come close together and end in a central area (possibly no larger than a dime). Then another Big Bang will occur and the formation of the universe will begin all over again.

Um… I think we may have been here before.

• This restructuring may occur once every 80 to 100 billion years.

Quasar