THE BIG BANG THEORY

STATES THAT THE UNIVERSE BEGAN AS A SINGLE COSMIC EXPANSION ABOUT 15 BILLION YEARS AGO. THE BIG BANG THEORY

Who? In 1964, Penzias and Wilson discovered the remnant heat of the Big Bang. This is called cosmic microwave background radiation. It is all around us. The radiation corresponds to a temperature of 3 degrees above absolute zero (- 454 F).

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.

The COBE Satellite (Cosmic Background explorer)  Before correction of the Earth movement around the Sun  Before correction of the microwave radiation emitted by our own galaxy  The final image of the microwave radiation

And then a better picture! The WMAP satellite gave a better resolution of the small fluctuations of temperature

WMAP Data So, the big-bang must have taken place at the same time everywhere.

But we can also observe small fluctuations of temperature which may have lead to the formation of the galaxies.

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.

The Race is On!! 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.

Distance between Stars Fortunately for us, the average distance between stars is about 3 light years or 20 trillion miles. If stars were 10 times closer (~2 trillion miles), a nearby star could pull the earth into an eccentric orbit and kill life here. If the stars were much farther apart, then there would not be enough heavy elements to make life. Heavy elements (like carbon and oxygen) are the ashes of dead stars and living things (including us) need these elements.

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) Left over 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 total emptiness 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.