object heading towards earth causing a large vapor trail. I was heading due east on I-80 at eastfork road and I could see what looked like a very large vapor trail descending back to earth. It had a tear drop shape with a black center extending up half way thru the vapor trail. It appeared to be above the thunder head cloud that was approximately 20,000-30000 feet high and the object descended behind the thunder head. I can't be totally sure about it's dimensions but the size and altitude of the object would have made it larger than most airliners that I have observed in similar altitudes. It's speed was slower and more of a free fall maybe terminal velocity descent. I believe the thing that stood out most was it's relative size. It appeared to be a very large object. I lost sight of the object as it dissappeared behind the thunder head clouds.You can contact me by email and I will be willing to give further info face to face if need be.