|I'll accept that, since it's closest to what I meant. |
As far as what the "UFO" could have been, it should be fairly obvious to anyone except those who especially want aliens around that the alien theory is perhaps the last among plausible explanations. First among explanations is that my senses somehow failed me and I am inaccurately describing something I saw. I don't consider this likely, but to someone who wasn't there this is a distinct possibility and the first thing that any sane skeptic would likely consider.
The next most likely thing it could have been is a traditional sattelite configured to do precisely what I said was nearly impossible. As a matter of fact, it is not impossible, just implausibly hard given the prodigious amounts of fuel that would be necessary and the nonexistant margin of error involved in a manuver of this type performed with traditional reactant rocket engines. But we (the public) know so very little about the capabilities of our spy satellites and this capability could well have been built into some of the larger, more expensive spacecraft. The costs would have been enormous, and the satellites larger still, but this kind of capability would, in fact, be extremely useful. Even so, I honestly find it hard to comprehend how this could have been done.
Less plausible and further down the list would be some sort of military spacecraft that was being tested that relied upon an understanding, complete or not, of how gravity is generated or repelled (essentially, an anti-grav drive), which could easily explain the motion of the vehicle. This anti-grav is something of the Holy Grail for sci-fi fanatics, so some adherants might welcome this explanation. If it exists, however, the probability that we may well have developed it without extraterrestrial assistance would dissapoint many. As far as I'm concerned, the only thing this theory has going for it is it neatly explains how the vehicle moved. (I realize, it is something of a non-sequitur to call the object a vehicle, but let's go with that definition for now). As theories go, that's not saying very much. Jean Baptiste Lamarke would probably agree with me.
Last and quite least is the explanation that "aliens" built and/or drove the thing. I would not offer this theory unless all preceding theories could be shown to be so unlikely as to render this one the last sane alternative. Just as Holmes suggests, when all other possibilities are shown to not be correct, the last remaining explanation, however remote or inplausible, must be the truth. We're nowhere near that point now.
At this point, all we can do is guess since all of these theories are untestable.