A firey ball of light descending from left to right and high to low in front of us changed colors from white, to yellow to green.My wife and I were traveling in our car in a north by northeast direction on Palmetto Ave. in central Chico at 8:22 PM PST (per the clock in the car). In a very surprising instant we both observed what appeared to be an astrological event in the eastern sky. A large, bright object that seemed to to me to be a fireball was descending rapidly from left to right starting at about "12 o'clock" and disappearing at about "5 o'clock" in our field of vision. The object basically followed a very slightly curved path approximately 30-40 degrees from a perpendicular line drawn from the horizon directly in front of us.The size of the object appeared 1/2-2/3 the size of the full moon overhead. It changed color while in view, from bright white to firey yellow to a brilliant iridescent blue/green. My first thought was that it was a large shooting star or meteor, but then I was shocked to see it change it's size (it become larger) and color. About half way through its descent it begin projecting a tapering trail as its color changed to bright yellow, almost as if there had been an explosion and acceleration in speed. The trail remained yellow as the object then took on a beautiful greenish-blue color just before it disappeared from view. It was not clear whether the object disappeared over the horizon or simply self-extinguished.I estimate the entire elapsed time of viewing was less than five seconds.((NUFORC Note: Other reports from multiple points in the western U. S.. We spoke with this witness, and he sounded to us to be exceptionally sober-minded, sincere, and credible. PD))