I witnessed a very bright light in the sky last night moving east than slowing down and dimming out.

My wife and I were enjoying a nice evening on our back porch When I witnessed a bright object high in the sky moving south east from a north west direction. It was a very bright white light and at first glance I thought it might be the international space station because of the brightness and the fact it had no flashing aircraft beacon lights. But I considered it to be moving much slower than the space station or any other satellite I’ve observed in the past.
 I pointed to it and told my wife to look up, she observed it with me until it started getting closer to being obstructed by the top of our porch. That’s when I got up to continue looking it the light when It started to slow down and it’s light began to fade out like someone turning down a dimmer light.
 The sighting only lasted for 20 to 30 seconds. It was like nothing I’ve seen in the sky’s before. Wish I knew what the hell it was.