> Also, it would be trivial to avoid detection in our own solar system. Duck behind a moon or planet, or just quietly float in the blackness of space, and no ea

> Also, it would be trivial to avoid detection in our own solar system. Duck behind a moon or planet, or just quietly float in the blackness of space, and no earthling will ever see you. yet we have thousands of reports of UFO sightings (the vast majority seem to be in the US for some reason). So the aliens who can travel here in...assuming they come from a nearby solar system 4 light years away, and they are arriving as a result of observing "pollutants and nuclear detontations", meaning if they started traveling in 1950 (upon receiving the light from the first nuclear detontation in 1945) and UFO sightings picked up by the 1960s they traveled 4 light years in about 10-15 years, and can be "undetectable" except.... for thousands of non-confirmable sightings per year. I think the aliens aren't going to visit us until Zefram Cochrane achieves his first warp flight.