You sure can speculate, and yours would be no less (well, perhaps not much less) valid than anyone elses ideas about what if anything is beyond the universe we're able to observe.

You might enjoy this:

http://space.mit.edu/home/tegmark/multiverse.html

The good professor is a bone fide physicst and cosmologist with some interesting ideas - these 'multiverse' ones are also speculation; whether it will help you gain a deeper understanding of the universe is debatable.

Tegmark has a lot of other stuff on his website which is genuine (mainstream?) science. As far as I can tell anyway.

Personally I've come to accept that the universe almost certainly carries on for a fair bit beyond what we can see, and quite probably is very similar to what we already see, somewhat like Tegmark's 'level one' multiverse, except I'll pass on infinity. Beyond that is anyone's guess.

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If something is in me which can be called religious then it is the unbounded admiration for the structure of the world so far as our science can reveal it... of the manifestations of the profoundest reason and the most radiant beauty, which are only accessible to our reason in their most elementary forms...
Albert Einstein