Slow-moving light with smoky trail lasting about 15-20 minutesAt approximately 1800, looking south about 25-30º above the horizon, I observed what looked like a plane coming through the clouds or fog, heading in a north-westerly direction. As planes do use that corridor fairly regularly, I paused to watch as it was very bright. There were no flashing lights or sounds of an aircraft. It appeared that there were two white lights in close proximity to each other, such as would be found on an airliner. The object moved somewhat slowly and I guessed it was about 4-6 miles away. After about 20 seconds, what looked like a spotlight from the object aimed at an approx. 200º down and to my left. I then thought that it must be SJPD’s helicopter. The “spotlight” continued for about 30 seconds and I wonder why it remained in the clouds/fog instead of dropping to get a clearer view of the subject. It was not a helicopter as far as I could tell. I then looked around the sky and realized there were no other clouds or any fog.! The “spotlight” was in fact a trail of smoke/vapor, etc., and it was about 20º long and continued into a much larger marshmallow-shaped cloud. I could still see the light as it continued on and seemed to curve slightly upward to the west and away from me before disappearing. The event lasted about 2 minutes. The “spotlight” part of the cloud remained for about 15 minutes, glowing bluish-white. The moving light itself faded after about 7 minutes. The cloud formation stretched about 60º across the sky.((NUFORC Note: US Navy missile launch. PD))