OK,the negatives first. I am VERY skeptical about UFOs. First, video cameras have been around for a couple of decades now, but for some reason, no one has been able to film a sharp well defined image of a structured craft. Its always fuzzy, or a white dot moving in the dark sky, or something that could easily be an airplane, star, helicopter, balloon, bird or hoax. Lets not forget hoaxes. Remember ET buzzing Haiti a few months back? That one took me hook line and sinker for a day or two. But alas, it was not to be. CGI is getting pretty damn good. Its going to make identifying a video of an actual authentic UFO allot more difficult I fear. And though I am skeptical, its something I would LOVE to be true. I have been keeping an eye out for UFOs for around 4 decades now, scanning the sky since the early '70s when I used to spend most of my evenings in the small rural town on the west coast of Florida I lived in with outside with my telescope, looking at stars and planets. It was pretty much an every evening thing for around 22 years, to the degree I got the nickname "spaceman" and only twice in that period of time did I see anything I could call unusual. The first "sighting" occurred around dusk as I was setting up for an evening of observing. I saw a little tailless "shooting star sort of skipping across the evening sky. Watching it streak south, I suddenly noticed two other shooting stars behind it, forming roughly an equilateral triangle. The whole sighting lasted about 5 seconds. I was speechless. Then after a few minutes of contemplation, I realized that the UFOS were headed in the general direction of Mcdill air force base, to the south. What I had probably seen was a group of F16s at very high altitude. I didn't give it another thought because I knew that was exactly what I had seen. The second sighting occurred many years later, again at dusk. This time, I saw something extremely weird. It was a slowly moving star like object, at obviously great altitude, that was was in a sort of slow pulsation of brightening and dimming, it would get fairly bright, then dim out almost to non visibility. It was like no aircraft I had ever seen, actually unlike anything I had ever seen. This time, my heart pounding in my chest, I was thinking this could be the actual article, an alien spacecraft. Then again, a little bit of reasoning set in, and I started to put it together. Moving slowly from west to east at high altitude, sounds like, a SATELLITE. The light curve was curious, brightening, dimming, brightening, unless, it was, TUMBLING. I went in the house and yahoo ed "tumbling satellite" Sure enough, there was a tumbling satellite mentioned, launched by Japan, that lost control once in orbit and started to cartwheel. A check of its orbital position on another site had positioned it exactly over my location at the time of my observation. So no alien ship, no greys scouting my neighborhood. The two experiences have made me even more skeptical of the sightings of other people. Being an amateur astronomer I had some degree of familiarity with the sky and objects in it. But when people who very infrequently study the sky and look up and see something they don't recognize, they can be easily fooled. I once had to nearly smack a neighbor across the face to convince him that he was looking at the planet Venus , which he was absolutely certain was moving in a little circle in the sky. The mind can play tricks on us. Then there is the whole "alien abduction" thing. I have two basic observations to make about it. One, Why hasn't anyone ever "observed" an abduction from an adjacent house? You would think if a large glowing craft was hovering over the neighborhood in the middle of the night and our buddies the greys were tractor beaming up Mrs Smith in her nightgown, someone, maybe an insomniac or the garbage man making an early run, might have spotted it going down. As far as I know there are no accounts of this. Secondly, accounts of alien abduction and sleep paralysis are just too close in description to be coincidence, and since most of the abductions I have ever read about happen at night, I am willing to bet they are one and the same. Lastly, the shear number of people claiming to have been abducted should mean that you should be able to look out your window any time at night and see saucers whizzing overhead (Carl Sagan pointed this out). Yet this writer hasn't seen this. Yes they may be knocking out the neighbors and using a cloaking device, but I kinda doubt it.
OK, now the positives. Certainly, the universe is teeming with life. We are discovering extra solar planets at the rate of a few a year now, and some systems even have a similar structure to our own. So I don't think its impossible that someone could be visiting us. The universe is very old, and they may have been watching us for a very long time. The best case for the existence of UFOs I think, comes from sightings by experienced professionals who are very familiar with aircraft and astronomical phenomena; pilots. There have been scores of sightings over the years by pilots that are not so easily explained away by other aircraft or tumbling satellites. These guys are familiar with both, so when they see something they care to call a UFO, you can pretty much rest assured its something unidentified. The same thing goes to a lesser degree to law enforcement, they are trained to be good observers so they are also not easily fooled. Lastly, some astronauts are starting to come forward with some amazing accounts of sightings in space. The Apollo 11 astronauts had a sighting between the earth and the moon that has never been explained. Apparently, they HAVE seen things out there. I will close on this note. UFOs are no more improbable than a primate evolving over 3.5 billion years on a rock ball orbiting a little yellow star on the edge of a spiral galaxy. And I cross my fingers that Keanu Reeves gets "The day the Earth stood still" right. Look to the skies.