My wife and I were on our way to a doctors appointment. While driving North by North East on mitchell Blvd, I looked out of my driverside window and saw an object that did not automatically fit the description of anything I had ever seen before. It was highly reflective and round. It was smaller than a blimp and moving pretty quickly. It was appoximately 2500 ft in elevation and moving to the South at approximately 400 mph. I started to point it out to my wife and it dissappeared instantly. I am unsure of the size of the object If I had to take a guess I would say it was the same size as a VW minibus. Another side note; It made no sound and left no contrails. (there were several contrails still hanging in the air from normal air traffic.) It made me feel curious at first and then when it dissappeared I felt a little dissappointed becuase I could not figure out what it was.