Folks, there are no aliens. *Nobody* saw any aliens before the 1930's. I believe Guy Ballard on Mount Shasta was the first. Why the 1930's? Why in the United States? Because of SCYFY PULP MAGAZINES, that's why. Sure, people have seen strange stuff since time immemorial, but nobody specifically saw "aliens" until the 1930's.
Why don't the aliens tell us anything terribly important which we don't already know? When people were afraid of a thermonuclear war, the aliens warned us about...surprise...the perils of the A-bomb. Thank you. When people began to worry about environmental destruction, the aliens started to sound like Al Gore. When Barack Obama was president, a particular alien faction revealed that *he* (Obama) was an alien. Yet, during the primary elections, when Obama was just one of several candidates, the aliens were silent...
And, good people, if the aliens are so damn sophisticated, WHY DO THEIR SAUCERS ALWAYS CRASH? HA HA HA.
But OK, I admit that none of the above definitely *disproves* the existence of 57 breeds of aliens, visiting Terra for no better reason than mutilate some cows, drop a Bigfoot off in Pennsylvania, or make a fool out of Jimmy Carter. Planet Earth *could* be the fun house of the Galaxy.
I mean, it certainly LOOKS like it! :-D