How do we know???

The sky is so blue,
when you look up,
thats all you see.
but past the blue,
and past space,
and the undiscovered,
is there something more?
Is there a heaven with puffy clouds and angels?
and is there a golden gate that lets us in?
or a big handle to pull to perish us into hell?
Do you really have the chance to visit loved ones that once died?
is this all true,
or does it all just become dark?
When the lights in your brain go to sleep for the rest of all time,
does it all just end?
Since no one can come back to life,
how do we know what is true?
How do we know that the scenarios that tv and movies give us,
are true?
How do we know what to expect?