When, it means time. Empty means space. Shuttle is a jumping movement between time and space. The combination of time and space is called dimension. From the point of view that everything in the world is made up of quantum, if you want to shuttle between time and space, you must first be fast, and how fast this speed is is beyond human estimation at present. If this speed is equal to the speed of light, under the movement of the speed of light, the human body may be scattered because of quantum instability in the body. At this time, the human body is in a quantized state, and the density of the human body may be consistent with the space-time density. In this state, the human body can travel freely in time and space with the help of wormholes or black holes, and after traveling to another dimension, the quantized human body will be reorganized (materialized). It can be reorganized or not. At this time, the human body will live in the dimension it passes through in a quantized (virtual) state, which is also commonly known as suspended animation. In suspended animation, we live in spirit. Among many theories of possibility, it is possible to resurrect those who faked their deaths.