Last year I went to a lecture given by the famous(ly eccentric) John Dobson, inventor of the do-it-yourself "Dobsonian" telescope. Unknowingly he worked on the Manhattan project and became a Buddhist monk after realizing his efforts materialized as the most powerful bomb ever dropped. He's an interesting fellow, and kind of a black sheep of the physics/astronomy community. As such, he holds some interesting views on cosmology.
Cosmology, the study of large scale structure of the universe and its evolution, has been debated for literally thousands of years. A basic function of religion is to give us a sense our origins, and so all major religions assign the universe some set of cosmological attributes. Each having their own philosophical, theological and scientific implications
What Dobson advocates is what is classically referred to as a "steady state" cosmology. That is the universe is eternal and has always been so. Or, more crudely, that the arrow of its lifespan extends infinitely in "both directions". This cosmology has been debated as early 1610 and more recently by Fred Hoyle in the 1940's.
Steady state theories seem somewhat asinine to us in the 21st century because we've been raised with Big Bang cosmology. However, this is a relatively recent scientific discovery, and so steady state theories had been a viable alternative idea. Serious problems with the ramifications of various versions of the steady state theory have caused multiple revisions to be presented. Some of which are detailed below.
Infinite spatial universe: the simplest kind of universe. Infinite in space and infinite in time. However this cosmology is plagued by what is called Olbers' Paradox. Simply stated, the night sky is dark, but, if the universe were infinite then there would be an infinite number of stars, and my line of sight would eventually intersect some part of sky that contains a star, so the night sky would look as bright as a sky full of suns (which, essentially, it would be). You might be thinking, "What about interstellar gas that would obscure the stars?" Well that would work... but only for a brief time. You see the gas would be bombarded by light (radiation) from all sides until it too radiated uniformly (which we don't see, we detect anisotropic microwaves) so that's not a viable solution. Ultimately this cosmology has been abandoned (Although, Wikipedia states that Mandelbrot suggested that a highly ordered fractal distribution of stars could be infinite and still allow a dark sky, although this much order in a "randomly" generated universe would be startling).
Finite spatial, infinitely growing universe: This model is what Hoyle proposed as an alternative to the Big Bang. He speculated that matter was spontaneously generated within the universe causing it to be ever growing, but not infinite in its spatial dimension. However (philosophical/metaphysical problems aside) problems with this theory are that we know that the speed of light is finite and that there exists distant and therefore ancient phenomena that do not occur in our cosmic neighborhood. The distant distribution of these phenomena, quasars for instance, are not explained by steady state theory. Furthermore, the existence of the cosmic microwave background (the anisotropic radiation measured at every point in the sky mentioned earlier) is predicted by the Big Bang and is equally unexplained by steady state. Very few people still cling to this idea any more (Hoyle himself later bacame a Christian and renounced his idea).
Next: A Dobsonian universe with help from quantum mechanics.