Just for clarification, I wasn't suggesting that there's only two competing theories, I just added the two that I thought were most relevant. The first was referenced because it's the more likely scenario, i.e., if the current data about the size and shape of our universe is correct, it's very likely that our universe will continue to expand indefinitely because the density of the universe is less than or equal to the critical density, hence no 'Big Crunch' or cosmic contraction. The second I offered as evidence in opposition in an attempt to be fair, evidence which may (if the data and observations check out) actually support a continually expanding and contracting model of the universe, which seems to be more in line with how Buddhist cosmology is often presented (i.e., expanding and contracting world-systems).
Just as thought-input. I don't consider that the world being talked about in the Agganna Sutta is "the universe". In fact I don't see why anyone would have this notion after considering the context. I also don't think that those words should be translated as "expansion" and "contraction", in a controversy I think that those words are being supposed into this context to support the idea that the Buddha was talking about this big universe that we study "expanding" and "contracting" according to present scientific theory. The translation of those words is more like "this world dies" or you might even say "dissolves", but "contraction" is just uncalled for.
These people did not know what the solar-system looked like. They didn't know that there we galactic structures, or that these were clustered together. They didn't know about the universe that we scientifically study today. In the Agganna Sutta the Buddha clearly describes a world forming, with the sun and the moon and firmament and a body of water. It would not make any sense at all to apply this to scientific understand, by saying that he was talking about all planets in the universe forming simultaneously and yet describing it as one planet? He didn't say they were on a sphere, and that their world was the system of a star.
However it is said that above the first-jhanic planes, the three planes of Radiance are above the "system-of-a-thousand-worlds". And the third-jhanic planes are above the "system-of-a-thousand [of those]", and the fourth jhanic planes (including Suddhavasa planes) are above the "system-of-a-thousand-[of those]". So there is talked about a thousand-world system, a million-world system, and a billion-world system, and above that are planes of formlessness in which there is infinite space and no relative location.
I think that if one is going to consider the Agganna Sutta in regards to science (which is in itself a strange thing to do), then they should consider what "a world" is according to the Pali Canon and not just say "oh, he was referring to this big universe that all these people knew nothing about," and calling it "contraction" and "expansion". That theory would have made no sense to them, and neither would a round world.