Brilliant white light traveling East to West very fast at a steep angle of descent over Redmond, Washington.2015-02-15 (Sunday 20:00 - 20:30) Clear Sky - No Clouds In passenger vehicle SEA-TAC Air Traffic Visible Overhead and in the Distance.While driving south on 166th AVE NE in Redmond, Washington my passenger and i BOTH saw a brilliant white light traveling EAST to WEST in an what seemed to be a descending flight path.The light was much brighter than the SEA-TAC air traffic.No debris/sparks/trailing fire were visible at or near the object.The object was traveling significantly faster than the commercial SEA-TAC aircraft traffic that were visible.The object was traveling EAST to WEST from approximately 10:00 (EAST) to 3:00 (WEST).SEA-TAC air traffic is a constant presence in the sky over our community. I've seen many different types of aircraft of varying types (private, commercial, and military fixed, rotary, and jets) in the sky over Redmond at different altitudes.Never have I seen any aircraft traveling at this speed. Additionally the apparent angle of descent had me expecting a fireball in the distance. Nothing.