"The whole aim of practical politics is to keep the populace alarmed (and hence clamorous to be led to safety) by menacing it with an endless series of hobgoblins, all of them imaginary." ~ H.L. Mencken
What Aliens Know About Earth
One bit of speculation: Maybe our alien observers are hanging around Earth to observe the expected demise of our planet. Reportedly some scientists have observed a planet-dissolving cloud of cosmic dust, with a penchant for devouring tiny planets and all their inhabitants, nine years away and traveling fast. Maybe, just maybe, the aliens are hanging around, reserving grandstand seats, to witness one spectacular light show.
Wouldn't that explain all the human abductions, cattle mutilations, crop circles and increased sightings? With only nine years to go, they have a lot of experiments to finish.