Our Universe The Only One?

Our Universe The Only One? 

I imagined to have reached the outer most part of our universe and I surmise that outside this ball there could be many more universes and that the, our universe is not just the only one. 

Could that “outside” of our universe not exist? Our most brilliant human brains couldn’t discover, prove that. Does it mean that that  “outside” doesn’t exist? 

But for beings on other solar systems with a higher intelligence equipped far superior to those of us,  isn’t it impossible for them to discover  many more universes? 

Is it impossible that life and beings exist on other solar systems on planets very similar to ours? Is life and human beings only possible to exist on our planet and in our solar system?