Big bang? Then how's this?, page 2

About the big bang theory

First, we must make very clear what a theory actually describes. The big bang theory does not describe the formation of the earth, the formation of the moon, the formation of the solar system, the beginning of life. It describes the changes the universe on a large scale went through from its very hot, high density start to it's current state. It says nothing about how the actual universe started, just like evolution says nothing about how the first organism was formed.

If we extrapolate the expansion backwards using general relativity, we do get a singularity and a real start. But you're already far in GUT energy scales there, so what scientists do is the following: they go back as far as currently proven theory and current evidence allows us to and simply say that we don't know what happened before that 10^-43 s (or something) after the hypothetical singularity. If we irresponsibly extrapolate with theories that aren't made for such energies, we get a singularity, but we don't really know.

There are theories that do describe the start of the big bang, like Ekpyrotic theory. These require some to be present before the big bang and therefore don't solve the problems of the start of the universe either. You can also make theories that describe cyclic or infinitely much Big Bang events and prevent the start of the universe that way. Most people don't find the very satisfactory though. Others think that the arrow of time is not something that is part of the real laws of nature, but just something that shows up on macroscales (Sean Carroll on this theory).

The reality is that we probably will never find out. There is nothing or not much information left from before or the moment of the big bang. We can construct metaphysical theories by extrapolating current theories, but I don't like that. Maybe new technology will allow us to test those theories, but they are currently unfalsifiable (although some theories do give testable predictions, like cosmic natural selection).

The big bang theory is not unfalsifiable and is not metaphysical, as I have explained above. There is evidence supporting it and there are observations imaginable that falsify the theory. The supporting evidence is quite large and includes the higher redshift for galaxies further away, CMBR and the amounts of elements in the universe at different times (big bang nucleosynthesis). There are people that think there are other explanations, like intrinsic redshift or a redshifting by the interstellar medium instead of doppler shift. We don't know if these other explanations and current evidence still favours big bang theory.

About design in the universe

Some of you are saying that the universe is designed. How do you know? We only have one example of a universe. We can't compare our universe with a designed and a non-designed one to see which universe ours resembles most.

Galvatron and others are right about the moon and earth design argument. Even if our solar system is special, there is reason to assume design. There is a very large number of solar systems in the universe. Chance can bring forth a seemingly special solar system, just like a random number generator can generate by coincidence the first 100 decimals of pi. If such a solar system favours life, it is only logical that we were formed there.

We don't really understand the formation of solar systems that well. Our system seems special compared to the solar systems we have detected, but our equipment is not very sensitive. Earth itself would not be noticed by the equipment.

In the end, there is no reason to assume design. The laws of nature can form this solar system and us. There are enough solar system to make even the very rare events possible. Arguments from design about nature have been proven in the past, with evolution, and are generally not testable or falsifiable. They are usualyl arguments from ignorance: "If we don't know how this formed naturally, it must have been designed." Not in science, in science the argument goes like this: "If we don't know how this formed naturally, we don't know how this formed naturally." A design required more evidence than ignorance.

The evidence for design in the universe is especially crappy: we only have one example of a universe, the universe is very large so rare random events can occur, we wouldn't be here if the parameters weren't right for life (so bad parameters can't be observed) and in general the universe is very hostile to life.

About belief

I respect your belief in a higher force, although I don't share your belief. However, you must understand that the evidence does not require a higher force to be explained.

I recommend a more agnostic stand towards a higher force than the one most of you seem to have. I think you're trying to fit the evidence to the theory, instead the theory to the evidence. Sometimes a simple 'we don't know' is better.

[edit on 30-10-2004 by amantine]