Here's a description of the orb from the Canary Island case link above:
"As he watched the enigmatic sphere, it began to grow larger and larger as it began to move away from the island toward the town of Tenerfie. After reaching its ultimate size, it then dissolved into a small size before disappearing."
Ah, does this sound like a "spaceship". What space ship can grow in size, then dissolve? If you look at this report from a scientific point of view and follow the evidence, the evidence shows that the UFO phenomenom is a real event and that it's not caused by "spaceships". What's left?
The best guy I've read on this is Jacques Vallee, who's been advocating for a true scientific investigation of UFOs for 40 years. This is by far not the only case of UFO's not acting as physical craft, but as something else. Vallee throws out the idea that this type of UFO case could be some kind of holographic projection/transmission of mass. From where? That's a good question. Inter-dimensional?
Vallee warned that Science is setting itself up for its own rejection and loss of credibility. This astronomer is right, UFOs aren't spacecraft from another planet, but he can't take the next step and say UFO therefore don't exist. Vallee says, all it will take, is one undeniable, very public case of an UFO incident.