Death is a temporary transition period for all such intelligent material beings such as human beings. While they are dead, their personality essence is preserved and kept in the safe custody of superior beings whose job is just that. They get new morontial bodies in a morontia world some time later and they continue their life further in stage wise progression to ages upon ages ultimately getting spiritual material bodies which are practically indistructible and capable of being in the presence of the ultimate power of God.
Normal material does not offer any resistance to morontia material and hence morontia material can easily pass through normal materials. But they may be made to be like normal materials with some energy adaptations. Similarly they are invisible to the short range vision of human beings. However, by certain energy adaptations they could be made visible to human eyes. However, spiritual materials or bodies are much more difficult to be brought into the vision of humans.
The Urantia Book explains that the resurrected body of Jesus Christ was not his original human body, but a look-alike body made of morontia material. That was the reason why resurrected Jesus was both visible and invisible to humans and also was able to pass through material enclosures and walls while some could actually feel him as a genuine person in fleshy body. Jesus remained in his morontia form for some time on earth and in the morontia worlds later to adopt his original spiritual body.
My dear friend, our universe is a treasure house of wonders for not only we human beings of earth, but also for thousands of other material beings living in many other worlds far away from our earth.
It is not possible for us to ever visit to those far away worlds in our material bodies because of the limitations of time taken for travel. We have to be dematerialised and projected to far away spheres if at all we have to be in such places.
Death is part of such a dematerialization process planned by God, the universal creator. Death also makes it possible for God to test the ability of those who could be passed for the dematerialized projection to other worlds.
Even NASA would not be selecting astronauts with out intensive testing for space travel !
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