This evening I had an extremely odd experience. I am a very rational 37 yo. never having really believed in UFO's too much. I am currently on holiday in Portugal, tonight is extremely clear with a crescent moon. I was sat on my hotel balcony watching a high speed bright light that I took to be a satellite or aircraft crossing the moons axis. The problem was though that when it hit the dark side of the the crescent moon it didn't emerge on the other side, not at all. I sat staring at an extremely clear sky and I didn't see the object reappear after whiting out against the crescent part of the moon. Can anyone offer a rational explanation that I may be missing?