Out of This World

Scientific American's Steve Mirsky shows a sense of humor in his story about the drop-off in UFO reports, giving several flippant explanations for the lack of sightings. Some claim that the aliens have completed their survey of Earth, but Mirsky believes the idea that they could complete their survey of Earth in a mere 50 years is both ludicrous and insulting and reasons that they must have run out of their alien government funding. My favourite explanation:
The aliens have finally perfected their cloaking technology. After all, evidence of absence is not absence of evidence (which is, of course, not evidence of absence). Just because we no longer see the aliens doesn't mean they're not there. Actually, they are there; the skies are lousy with them, they're coco-butting one another's bald, veined, throbbing, giant heads over the best orbits. But until they drop the cloak because they've got some beaming to do, we won't see them.
I love the description "bald, veined, throbbing, giant heads". [via Follow Me Here]