I believe that this Universe is part of an infinite multiverse or it has no start nor any end. I don't know whether Science has anything to disprove or prove it but I believe this Universe we are in, did have a beginning and there were infinite Universes unlike (you will understand why I said unlike if you read forward) this one before. Each Universe started with different Physical Laws and then collapsed back because they were not suitable (maybe, this one will also be like that). We can say that during the time of the big bang, the Universe was kind of a Blackhole or something like that, which burst open due to the right Laws of Quantum Physics and is still going on expanding and I think it will expand forever. This proves that there is no need of a Creator to make a Universe. And, maybe, this universe will again go back to its initial stage because of the Big Crunch or maybe this Universe will be divided into infinite Universes due to the Big Rip. I don't think there will be a Heat Death or a Big Chill.