The Origin

[Izzy]

It's something about the light waves getting shorter or longer that shows that the star is getting farther and closer. Why that automatically means the universe is expanding I'm not sure. Which is what i was saying earlier about how it could be evidence for something else and we just aren't looking for it.

[Xx{Midday}xX]

The Doppler Effect is the phenomenon used to explain the expansion and acceleration of the expansion of the universe today. The substances of various stars in their various stages are discreet. The substances radiate what is known as an emission spectrum. Every element has its own spectrum, and this spectrum under normal circumstances are always the same (the spectrum is caused by the discharge of energy of electrons as they go from excited to ground state. Planck's constant is a constant, so the amount of energy released based on the type of element is always the same).

An exception to this spectrum would be the Doppler's Effect, which is caused by relative motion between the source and the observant. If we take a daily example, when firetrucks pass us at relatively fast speeds, we can notice a difference in the pitch of the siren as it was coming towards, and as it was moving away from us. This is caused because the frequency of sonar radiation stays the same, but the apparent frequency is changed by the motion of the source. As the firetruck moves closer to us, the sound waves are compressed, and the pitch is higher. As the firetruck moves away, the sound waves are expanded, and the pitch is lower.

If we observe the Doppler Effect on light, it would look something like this. The numbers represent the visible spectrum's frequency. Bold represents the recognized frequency emitted from Element X.

Normal emission spectrum: 6 5 4 3 2 1

If Element X is constantly moving away from us, the emission spectrum experiences a red shift.

Red shifted emission spectrum: 6 5 4 3 2 1

If Element X is constantly moving towards us, the emission spectrum experiences a blue shift: 6 5 4 3 2 1

Blue has a larger frequency than red. Red has a larger wavelength than blue. As the wavelength increases, the spectrum becomes "redder" and vice versa.

As stars move away from us, the entire emission spectrum of the substances radiating energy from the star "shifts red" which means the wavelength increases. Scientists observed this red shift and recognized that the stars were moving away from us. This is a definite fact. Every year, the red shift becomes more and more severe, which means the velocity at which the stars are moving away from us is increasing, hence the universe is expanding its acceleration even further.

That is the modern proof of the expansion of the universe. =) Accurate and definite evidence.

[Izzy]

You explained all that stuff to come to same conclusion that since the stars are moving away from us it automatically means the universe is expanding.

[Reach]

Originally Posted by Izzy

I am interested to know what other evidence of the big bang theory there are other then the patterns of heat left over and how stars are moving away from us showing that the universe is expanding. Someone probably knows here.

http://map.gsfc.nasa.gov/universe/bb_tests.html

You can find some good information here. In 2006 the results of WMAP left little to doubt with regards to whether or not the Big Bang happened, but it is still an incomplete theory.

[Xx{Midday}xX]

Originally Posted by Izzy

You explained all that stuff to come to same conclusion that since the stars are moving away from us it automatically means the universe is expanding.

The Cosmic Background Radiation, also known as the boundary between space and void (the edge of the universe), also shows red-shifting under the Doppler Effect. =)

[ballaw hare]

Originally Posted by Xx{Midday}xX

The Cosmic Background Radiation, also known as the boundary between space and void (the edge of the universe), also shows red-shifting under the Doppler Effect. =)

Well for one I always thought the background radiation was uniform throughout the universe (at like something like 1.2 degrees above absolute zero), and hence why it was discovered. Not just at the edge of the universe.

Second off it's kinda assumed that the universe is expanding because matter can't just start expanding (that we know of) just out of our universe and into somewhere else, and the reason why it's expanding is the initial thrust of the big bang. Now, the universe could be A LOT bigger than we think it is (which is pretty damn big), and that matter is still condensed toward the center and just expanding into a vacuum.

If I'm wrong in any of that feel free to correct me.

[Xx{Midday}xX]

Originally Posted by ballaw hare

Well for one I always thought the background radiation was uniform throughout the universe (at like something like 1.2 degrees above absolute zero), and hence why it was discovered. Not just at the edge of the universe.

Note: the reason why it's called background radiation is because nothing can be detected behind it. As in nothing that's not antimatter in origin. Therefore, it is assumed that this is the edge of the universe.

Originally Posted by ballaw hare

Second off it's kinda assumed that the universe is expanding because matter can't just start expanding (that we know of) just out of our universe and into somewhere else, and the reason why it's expanding is the initial thrust of the big bang. Now, the universe could be A LOT bigger than we think it is (which is pretty damn big), and that matter is still condensed toward the center and just expanding into a vacuum.

The Big Bang explains the initial expansion, but it fails to explain the current acceleration of the expansion. The Big Bang was an instantaneous process. The Big Bang does not provide evidence for the acceleration of the expansion that is happening now. If the universe's expansion was decelrating (as in slowing down), then there would be no controversy, but it's not. Gravity should be pulling all of the space in the universe together to cause one of the theorized ends of the universe, the Big Crunch. However, this won't happen because the expansion of the universe is getting faster. Recent physcists say that dark energy, named alpha, produced by dark exotic matter, causes this acceleration. It is now inferred that the universe will cease to be active when the last star burns out.

The red-shift of the cosmic background radiation provides the evidence of this current acceleration. As explained below. =/

Searching for the cause of the Big Bang will only result in a moebius ring. It's basically impossible to do anything but guess. If something caused the Big Bang, then something must've caused that something. Which means something must have caused that something too, and so on. It's impossible to reach a conclusion.