Hubble Expansion

Re: Hubble Expansion

Most of the big bands existed and were popular in the 1930s and 40s, and are pretty well out of the picture now. I am not aware of any particular theoretical work about them, except J. Thomas Miner's "The Big Band Era - A Theoretical Framework."

From observations the universe appears to be expanding, and if you follow the time line in the reverse way to zero, the universe must have been a point at time zero.

That can't be the only proof though, it's quite obvious that growing or shrinking values neither need to increase to infinity nor decrease to 0.

Let me expand on what satt said...

Hubble was interested in the relative motion of Galaxies. Astronomers figured out a couple of ways to tell how far a galaxy was from us, and a good way to find out how fast it was moving.

Hubble noted something very strange. First... all of the Galaxies seemed to be moving away. Second, the Galaxies that were moving away from us the fastest were the ones that were farther away.

He then did the math, and the data suggested that all of the galaxies were at the same point at the same time.

This observation by Hubble was the beginning of the Big Bang theory. But, ss Vengo suggested, there is quite a bit more evidence that the Big Bang really happened.

Physicists started thinking about what a Big Bang would mean, and what evidence they should be able to find had it really happened. So far, scientists have found pretty much what they expected based on an assumption of the Big Bang, there is nothing to refute it and no other explanation for the data collected.

One area of evidence that is both interesting and important is the Background Radiation left over from such a huge Univeral explosion. The story (I think it is true) is that this radiation was predicted by physicists, but discovered by accident by people working on Radar after WWII. NASA now has an important satellite called COBE to research this radiation.

Another interesting area is being done by particle physicists. The idea is that if all the subatomic particles in the Universe were created by the Big Bang, you can see evidence about the Big Bang, and learn more about it... by seeing the particles that resulted. There are some very interesting models that have been made and confirmed. Again there is nothing that refutes the Big Bang theory and no other good explanation for the data.

THANK YOU!