The Big Bang
THE UNIVERSE IS EVERYTHING. IT INCLUDES ALL GALAXIES, ALL STARS, PLANETS, MOONS, COMETS, ALL MATTER, AND EVERYTHING THAT EXISTS.
The visible universe is about 14 billion light years across.
Astronomers believe it may be much larger, but we can only confirm what we can see so far.
The Big Bang Hypothesis
The Big Bang Hypothesis is the currently accepted explanation for how the Universe formed. It's basic premises are:
- About 14 billion years ago all matter in the universe was condensed to about the size of an atom.
- This singularity exploded sending matter, energy, and the forces that govern our universe in an outward expanding cloud
- As it expanded the cloud cooled, and matter began to condense
- Gravity started pulling matter together to make larger objects including galaxies, stars, planets, etc.
Evidence 1: red shift of distant stars
The Doppler Effect is a phenomenon that occurs when objects that emitting waves of sound or light move.
When the object is MOVING TOWARDS you it causes the waves to reach you with HIGHER FREQUENCY.
- WITH SOUND
- objects moving towards you have a higher pitch
- objects moving away from you have a lower pitch
- WITH LIGHT
- objects MOVING TOWARDS you give off BLUE SHIFTED LIGHT
- objects MOVING AWAY from you give off RED SHIFTED LIGHT
If the Big Bang Hypothesis is correct then everything in the Universe should be expanding, getting farther and farther apart, and distant stars should be red shifted.
THIS IS IN FACT WHAT WE OBSERVE HAPPENING IN THE UNIVERSE
EVIDENCE #2: COSMIC BACKGROUND RADIATION
When the first radio-telescopes were invented and used, astronomers noticed that the apparently empty space between stars was emitting a very faint glow with no observable source. Later with microwave telescopes we were able to visualize this field of mysterious energy that fills space called COSMIC BACKGROUND RADIATION.
We now believe that cosmic background radiation is energy left over from the Big Bang, and its existence is evidence supporting the hypothesis.