Is there a heaven and a hell?
As stated above, there are thirty one planes or states of existence (loka) in the universe, including that of humans. Beings are born into a particular plane depending of their accumulated kamma.
Below the human plane are four planes (asura,peta,thiracchana and niraya) which are described as unhappy states of existence. Beings are born into these states as a result of their unwholesome kamma. Excessive greed and attachment to worldly belongings may cause re-birth in the peta plane and be drawn to the place of attachment.
Above the human plane are the deva and brahma planes. As the level of plane becomes higher, more subtle is the state of existence and longer is the life span.
The devas have physical forms which are composed of more subtle material than that in the human plane. They possess five physical senses and mind as in humans and enjoy a life of great pleasure. They may also possess supernormal powers.
The brahma planes are described as form and formless states (rupa and arupa loka). The brahmas in the rupa loka have material forms even more subtle than that of devas. They have only three sense faculties; sight, hearing and the mind. In the formless states (arupa loka), the beings are devoid of any material bodies. They transcends all physical sensations and exist in a state of equanimity.
In general, the beings in the higher planes are invisible to the beings in the lower planes of existence. The humans cannot see devas or brahmas unless they have developed special powers called abhinna, through the practice of certain meditations.
Beings in these higher planes are described as celestial beings and their life span is said to last billions of years relative to earthly life.
Even though the life-spans in these higher planes of existence last millions of years relative to earth, they eventually come to an end, since the existence in all these planes are conditioned: that is, the laws of cause and effect operate, and all conditioned things are impermanent.
This is what is meant by the terms ‘heaven' and 'hell' in Buddhist teachings: there are no permanent heavens or hells as taught in other religions.