 <unk> had , on the assumption that the planet is similar to Jupiter in composition and that its environment is close to chemical equilibrium , predicted <unk> <unk> b to have reflective clouds of <unk> and iron in its upper atmosphere . The cloud deck instead absorbs the sun 's radiation ; between that and the hot , high pressure gas surrounding the mantle , exists a <unk> of cooler gas . The outer shell of dark , <unk> , hot cloud is assumed to consist of <unk> and <unk> oxides ( " <unk> planets " ) , but other compounds like <unk> cannot be ruled out yet . 
