Originally Posted by
cuthere
A weather balloon would be substantially larger than “a small car” at 40,000ft (I’ve launched a few in my time - they were nearly the size of a small car at sea level). Also, it would continue to climb until the balloon expanded to such a point as to go pop.
An actual weather balloon (radiosonde) was very conveniently launched from Will Rogers Field at 00Z. It achieved at least FL650 before popping.
As to what the object in question was - no idea.
Yes, I was being sarcastic. It was actually “swamp gas”.