Green square in sky moving at high speed.

Driving along I-64 N, 9:15pm. Some sort of strange light catches the corner of my eye. I turn my head to see a green square moving very fast through the sky in what is either a manner that is directly down or away from me. The object is seen for what felt like a fraction of a second but not quiet as fast as a shooting star. Shape of the phenomenon is square and color is lighter than an emerald green. No smoke/chem trail. No sound. Just the object in the sky. Object did not emit light at very high lumens. The object disappeared quickly, either down into the city below the skyline or behind the city over a mountain, tracking the object with the human eye was difficult.