We were at work saying goodbye to a customer. It had the appearance of an object falling from the sky with a contrail. It first looked like some type of aircraft. The object was determined to be at an extreme altitude due to the fact that a large aircraft passed below at approximately 10,000 feet. It appeared to be teardrop shaped with lead gray color with a mist aura and a contrail which remained the same size throughout the event. It was approximately 45 degrees above the Southeast horizon traveling from West to East and did not seem to be traveling at great speed. We were wondering at first if we were being attacked by a missile, due to the fact that it is September 11th. Afterwards we felt that it was some type of unexplained object that we had never seen before. We watched the object till it disappeared over the horizon, which took about 15 minutes.