what is nirvana really , what happens to the buddha after death is he annihilated or is it a form of eternal existence
what reborn of us if we have no soul
Thank you for asking me.
Unless a person has attained enlightenment, nirvana can only be a conjecture.
However, we can postulate what nirvana is not. Nirvana is not birth and death. It is not suffering. It is not temporary. It is not changing. It is not of this world. It is beyond our human intelligence to know exactly what it is. If it can be understood easily by mere mortals, then the Buddha did not have to spend countless life-time to attain it. Buddhism will be of little value if it is so simple. That is why it takes only the Buddha to discover the real truths.
To understand rebirth, we must first understand the Buddhist concept of mind and matter, which constitute this life. The body we can see and feel. The other aspect which is very important is "mind"; the essence of this mind is "consciousness". The body without this consciousness will be a dead body. It is this consciousness that gives life to the physical body.
The law of kamma operates throughout our existence. This consciousness is the storehouse of all our kammic actions....good and bad. When this body expires, it is this storehouse of consciousness that passes on and takes rebirth in another existence. However this storehouse of consciousness is not static but changes from moment to moment depending on our kammic energy. It is in a state of flux.
Imagine the electric current flowing through a wire. When a bulb is attached it lights up. After a period the bulb will become weak and will be blown out. When we replace it with another new bulb the light will be on again. These bulbs are like our bodies. The electrical current is like our consciousness. Although the new bulb is a different one, there is this continuation of the electrical current. They are neither exactly the same nor completely different, there is a continuity of personality or character.
The Buddha described this process in Pali as "Na ca so, na ca anno" ("ca" pronounce as "cha"; "anno"= pronounce as "un-your"), which means "neither the same nor different"! This is what the Buddha referred to as "no permanent soul".