[bojan]

Theory is a model, mathematical construct that tries to explain the existing data. Moreover, this mathematical model (or just one formula, it could be very simple thing and we can still call it a theory) can be used to predict the outcome of yet unobserved phenomenons. As long as it can do both, it can be considered plausible, even correct.
The good and simple example is the famous relativistic relation describing mass and velocity and how they are related. It describes how mass of the moving object increases with speed, reflecting the fact that if we want to increase the velocity of an object, we must add the energy to this system and that energy has its own mass... And if we want that object to move at the speed of light, according to this formula we have to add infinite amount of energy to this moving system, which will result in infinite mass. Ergo, the speed of light can not be reached or surpassed by any material object with resting mass other than zero.
Now, how about velocities higher than speed of light?
Nope. Or, not quite. If we enter into the formula the speed value greater that light we will end up with an imaginary number for mass.
Mathematically, all is OK again.
But to accept this result, we have to redefine our understanding of mass.
Could it have imaginary or complex value?
So far we have not find anything moving faster than light, and if this remains true, then mass is always real number, never complex.
The thinking in other direction is also valid, of course.
This just illustrates the way of scientific thinking in very simple terms....
Back to the Big Bang now....
Apart from Dr. Halton Arp and conclusions from his observations (many of them proved to be wrong and/or just the result of wishful thinking), what other observational data in particular we can say it does not fit the BB theory?
As a support, I would like to mention Olbers paradox... then background radiation, predicted by G Gamow long time before it was first detected and measured, then the distribution of it etc etc..... Distribution of quasars (which seem to be active supermassive black holes in centres of galaxies).
There is a vast number of observations that supports the idea.
The observations that do not support BB theory are very few. Rather, those observations just point to the need of fine tuning the basic model, but they do not disprove the basic idea.