The switch from one density to another has many nuances, so that objects in 3rd Density can seem to disappear while in the Bermuda Triangle, for instance, and then reappear, all the while being essentially in 3rd Density. Likewise, we can move contactees through walls or window glass by slightly switching their density, but other humans in 3rd Density can observe this occurring. When the physical switch to 4th Density occurs for Earth and its Moon and Sun, the switch will not be gradual, so that no swinging back to 3rd Density will occur. It will be sudden and complete. The variability of density can be seen in the range of vibrational frequency that sub-atomic particles sustain. For instance, the speed of light is not the constant that most of mankind assumes it to be, and the speed of slower moving particles has long been a variable in mankind's equations.