One summer night in the 1960s in the suburbs south of the Southside of Chicago, I saw a large round object traveling not too fast from the southeast to northwest direction. It was glowing blue and red with no specific lights showing and made absolutely no sound. It was very low in the sky.
The only thing I have ever been able to think of is some sort of high tech weather balloon but I haven’t found weather balloons described that way. Plus it was a LOT bigger than a balloon. It was kind of more the size of a large blimp. But there is a blimp that flies over our area sometimes and its engine noise can clearly be heard. Suggestions anybody?????