There are unidentified flying objects. That is, there are a...

There are unidentified flying objects. That is, there are a hard core of cases-perhaps 20 to 30 percent in different studies-for which there is no explanation. We can only imagine what purpose lies behind the activities of these quiet, harmlessly cruising objects that time and again approach the Earth. The most likely explanation, it seems to me, is that they are simply watching what we are up to