I've read that a gas giant, like Jupiter, doesn't have a rocky surface. But planets must start as a rocky conglomerate of flotsam. Is the interior so hot that all the material is molten and there ...
Since Neptune/Uranus have high percentages of methane, wouldn't it be highly likely that there will be combustion (triggered by the lightning storms or any other factor) if oxygen was abundant? And ...
Most of the known gas planets (Jupiter, Saturn, etc.) are huge. They are even called "gas giants". is it possible to exist a gas planet around the size of Earth? If yes, why; if no, why?