By that definition, correct. There will always be things that defy explanation. The universe does contain something on the order of 10^22 stars, however, by latest estimates. Certainly countless numbers of them must also conain life. But the distance to even the nearest star is incredible. It’s hard to believe they would cross hundreds of trillions of miles of cold, empty space just to fly around frightening people, mutilate cows, and make pretty pictures in wheat fields. Still, it can’t be ruled out completely.
and a companion site:
HTTP://WWW.ALIENRESISTANCE.ORG
have the best analysis of their motives . . . and . . . nature, . . . origins etc.