Know why Jupiter has a hydrogen atmosphere? Because unlike Earth and smaller planets the hydrogen produced during planetary evolution cannot escape its gravity. I bet underneath is ice, frozen hydrocarbon etc.

Odd that stellar evolution/growth/shrinking is readily accepted yet planetary and moon(etary) expansion for which there is visual forensic evidence is not.

BTW I do not KNOW where the hydrogen came from but I can see that its emergence fits the FACTs and I suggest possible mechanisms.

How about those with deep and specialist knowledge test the hydrogen-driven evolution theory? What FACTs (if any) refute it? And how secure is their basis?