huge molten sphere with liquid surface blending colors. Moving approx. 120 mph south to north. maybe 5000 feet. seen by six people

Hello Mr. Davenport,  I would like to let you know of an event that happened approximately 40 years ago in Reading, Pa. From what I can recall of the people present, there were probably five or six of us playing baseball in a large lot between two buildings. Don’t remember who said look at that up in the sky but we all froze when we saw the object. I recently checked out on google-earth the direction the object was traveling and it seems that it was going exactly south to north. The object was a large ball, but not fire. It had molten liquid flowing over its entire surface. The colors were blending and constantly moving. I can still picture it after all this time. The colors were green, purple and red and with other colors. It was moving horizontally with the earth. It also was an overcast day but not raining. The sky gave a good backdrop of the object. It was the size of a hardball if it was at ceiling height. There was no wind that could be felt at the time. As it went past overhead you could hear it make a slight whooshing sound. Its speed was probably about that of a single engine plane, not fast at all. I remember saying to my brother how can it stay up in the air going so slow. I also thought it odd that the liquid stayed on the object and did not drop off of it. I just can’t remember what year it was exactly, probably 1966 or 1967. At the time I was fourteen or fifteen. It has just bothered me all these years as to what it was. I wonder if you have heard of anything like this from other people? It’s just something you can’t forget.
 Thank You For Your Time