The ability to separate astral from the physical body during trance, is associated with the phenomenon of "excretitive experience"
Signs, the dus is separated from the body and moves on a journey. The spond between a physical and astral body is known as "silverly taken"
Many sorts this trip with lucid dreams, but there is a significant difference. Lucid dreams always happen between 3 and 5 hours in the morning and we enter into it unconsciously.
The astral projection is not spontaneous but intentional. This is to achieve constant meditations, cleaning the body and mind, the power of will. The reason why people suspect an astral journey, because it would be proof of existence beyond the physical body, which is for many unimaginable.