A whole bunch of BABloggees have sent me email about a video floating around purportedly showing a UFO flying over the Moon:
OK, let's assume the video is legitimate. It shows the Moon through a telescope, and a small black dot moving across it. The object is resolved; that is, it's not a tiny point. I can see smaller features on the Moon, so we can assume this object really is roughly circular in shape.
If we assume the object is just over the surface of the Moon, it would be kilometers in diameter. That seems unlikely! Remember, too, that just because we see it silhouetted against the Moon doesn't mean it's on the Moon. It could be just a few hundred meters over the Earth.
So from the shape we know it's not an airplane or a bird. It's not a satellite; satellites move more quickly across the sky, and besides, we see it change direction.
So what can it be?
I would bet 83.7 bazillion dollars ($5.95 Canadian) that it's a balloon. Why? First, the shape. It's round, and balloons are round. Second, the motion. It tracks relatively straight, then sorta languidly moves off in another direction, just like a balloon wafting on the breeze. Third, I have seen many, many balloons floating in the sky, and this looks just like one. Fourth, the video caption says it was taken in the town of Busto Arsizio, which has over 80,000 people. If this were a very rural location a balloon would be less likely, but that's a bustling town. The video was shot at 11:00 at night, which is rather late, but a balloon can stay aloft for many hours.
So I'm giving this one a 3 on the "what the heck is it?" scale, where a 1 = something as familiar as seeing your face in a mirror, and a 10 is whatever Britney Spears is wearing.