Technically, heaven or "the heavens" as the ancients called it, is everything that is above the clouds, so basically, space and all the planets outside of ours. Hell is another word for the Underworld, which the ancients believed contained an entire civilisation much like our own and was the final destination of deceased souls. Many of the ancient gods were supposed to originate from other planets.
For instance, the Hindu god Vishnu is supposed to reside on the "heaven" Vaikuntha, which could easily be intrepreted as another planet. It is described as a wondrous paradise, populated by humanoid beings with blue skin and four arms.
In the Mahabharata, when Arjuna visits his father's home, the realm of the gods, he is taken there in a flying chariot and it is clearly described as the planets and stars zoom by. On this planet, people get around in vimanas, flying machines. There is even an entire flying city made of metal, which Arjuna destroys in an epic battle.
The Sumerian gods are also described as having arrived here from another planet. This is a very common theme in ancient myth.