On a clear blue afternoon sky, there appeared a slow moving disk-like shiny object that gradually vanished after about 20 secondsI was sitting in our great room facing the backyard through a big glass window. I was eating a snack and my 8 month old son was facing me. As I was talking to him, I slighlty glanced in the cloudless sky and noticed a disk like object that is so shiny. It was moving very slowly towards the west and looked like it was 1 mile away. From my vantage point, the object was the size of a penny. I called my wife and tried to show it to her but then as I kept on pointing to it so that my wife could see it, the object slowly vanished in thin air. It just dissapeared in the sky eventhough there were no clouds that time. I was very sure it was not a bird nor a plane. It was something that I have not seen in my entire life. I trembled a bit when I realized that I had seen an unidentified flying object.