Round white object

About 3:00 pm I noticed what appeared to be a round object very high in the sky, slightly east. The sun was reflecting on it and I could see it with my naked eye from my backyard. It looked like a pale white sphere. The background sky was blue, it was a clear and sunny day today. Through binoculars it looked as though the bottom of the object had a rectangular metal piece or reflective material that was brightly reflecting from the sun. It appeared as though it were barely moving. And I was able to see it for about 10 minutes. Altitude seemed very high. A smaller plane flew over around the same time at a much lower altitude, flying north.