On 2002-11-20 11:59, JS Princeton wrote:
Unfortunately (for those opposed for some unknown reason to the big bang), I have yet to see an alternative model that explains the observational evidence as well as the standard picture Big Bang. Of course, Olber's paradox does not exist in the Big Bang model. I'm apt to simply say, fuggetaboutit.
Here's why I believe in the Big Bang:
1) Ockhams' Razor for a redshift distance relation. You've seen the argument before. If you don't think that the redshifts are due to a difference in velocities then you need to provide an alternative CONSISTENT theory that explains the universe JUST AS WELL as the Hubble Flow. I have not seen one. We know that the Hubble Flow is consistent with GR, we know that it gives us a look into different epics in the history of the Universe that we can probe with other means.
2) Nucleon abundances. Four basic nuclear matter: hydrogen, deuterium, helium, and lithium are found cosmically. If we look at their relative ratios, we find that the Big Bang model can give us an excellent first-principles explanation for the reason the ratios are the way they are. You can derive the abundances using particle physics cross-sections and knowledge of thermodynamics. Theory matches data well. It could just be a coincidence, but I'm of the opinion that any alternative theory should be able to explain why we got it right.
3) The CMB. This is the most damning evidence of all. There are those on this board that don't believe that it is a real signal or believe that they can explain it using other models. None of them have provided a rigorous analysis of this. That is to say, the standard model explains the CMB to a precision of better than one part in 10^6 or so. This includes the fact that the CMB is a beautiful planck spectrum to the first four orders of magnitude and its deviations from that can be characterized on an angular scale as coinciding with the formation of large scale structure in the universe. This would be a RIDICULOUS coincidence if the CMB were due to some other homogeneous mechanism that was spread throughout the universe. I'm not inclined to say that the Big Bang is wrong because independent analysis of epics and scales is just massively coincidental. That would be like saying quantum mechanics is just coincidental: that the fact we can measure states of the hydrogen atom snd their interactions is just a coincidence. I don't buy it.
There are plenty of other incidental evidences that allow us to fit the Big Bang model in. There are all kinds of distance measurements and lensing analyses and large scale structure correlation functions and hot x-ray emmission gases in intercluster space and metalicity evolution in redshift space and temperature evolution in redshift space.... I could go on, but what's the point.
I will take a Big Bang denier seriously when they start out their post with: "I am aware of the overwhelming evidence for the Big Bang. I am aware it explains quite a bit and understand that's why it has been successful. But I think I can explain everything that it explains better." Then I'll be interested. Right now, everybody who is a denier is more interested in weak ontological and even anthropological arguments against the theory. They give away their own ignorance with regards to the topic.