Ok here's one that I often spend long amounts of time letting screw up my poor little mind... Is the universe infinite? Personally, the limitations of my mind don't really let me accept either answer.
By it's very definition, everything that exists has to be within the universe, which means there can be nothing outside of it. Not only that, but there can be no outside of it... There would have to be... nothing. Surely there would just be more empty space and then that would be more universe. So surely the universe isn't finite.
You see... I'm already confusing myself. My mind can't handle this!
If the big bang theory is true then it all started from one little bit which exploded and started travelling outwards. If this is true then what the chuff was there beforehand? No universe? Surely not. Even if it is true then if the universe is expanding it must have limitations and therefore can't be infinite.
Anyway, this isn't going anywhere in particular. I think people have written whole books about this... sometimes involving many universes... and these people don't even have the answer I don't think.
So if anyone knows what's really going on please let me know.
'Space, the final frontier'..... Or is it? Maybe after space there's then another frontier.... Milk maybe... Then it'd be 'Milk, the final frontier'. That wouldn't sound half so cool though, huh?