nopeda, on 15 January 2013 - 07:28 PM, said:
For years I was convinced that xts could not be flying around in our atmosphere or humans would be able to detect them with radar. I was less convinced about whether or not they had been here in the past. Later after seeing the evidence AA presents I re-thought my original belief and realised that if beings could travel from one star to another then they can probably absorb or reflect electromagnetic energy pretty much as they wish meaning we wouldn't be able to detect them with radar unless they allowed it or had a malfunction, which seems less likely from my pov. I had to figure out on my own how it could be possible though, because no one explained it to me or has even seemed to think it's significant since I started mentioning it to people.
I've never made much study of all the UFO reports from the distant past, but have no problem with the idea that some of them have been around for a very long time, and that time probably does not mean the same thing to them that it does to us. We're talking about civilizations that may have qualitatively different ideas from ours when it comes to space, time, science, intelligence, biology and so on, including the existence of intelligent machines.
I don't doubt that they have craft that can be invisible or stealthy, not detectable on radar, at least not unless they want to be detected. They have been known to monitor our communications and sometimes even mimic IFF signals, although generally they do not respond when contacted by radio.