I have a few problems with the thought UFO's come from other worlds. Probes launched from Earth to planets/moons within our solar system have so far failed to yield any signs of extra terrestrial life on them. So we are left to consider whether they might be coming from globes further away. If these objects have any mass they are confined to the speed of light, about 300,000km/sec. A snail's pace when dealing with astronomical distances measured in light years. To overcome this confinement they would have to have no mass such as would a Spirit, as does Consciousness. Now they are inter dimensional. Many people who have had near death experiences describe in their stories how they flew past stars and galaxies without any spaceship and fully conscious. In the same way as certain people are able to see ghosts of departed relatives or friends might the same also be able to see touring extra terrestrials?