Trevize looked up， stared at Pelorat for a moment， turned away，and then said， "We"re zeroing in on the planet."
"But since there"s no atmosphere "
"The computer says there"s no atmosphere. Till now，it"s always told me what I"ve wanted to hear and I"ve accepted it. Now it has told me something I don"t want to hear， and I"m going to check it. If the computer is ever going to be wrong， this is the time I want it to be wrong."
"Do you think it"s wrong？"
"No； I don"t."
"Can you think of any reason that might make it wrong？"
"No， I can"t."
"Then why are you bothering， Golan？"
And Trevize finally wheeled in his seat to face Pelorat， his face twisted in near-despair， and said， "Don"t you see， Janov， that I can"t think of anything else to do？ We drew blanks on the first two worlds as far as Earth"s location is concerned， and now this world is a blank. What do I do now？ Wander from world to world， and peer about and say， `Pardon me. Where"s Earth？" Earth has covered its tracks too well. Nowhere has it left any hint. I"m beginning to think that it will see to it that we"re incapable of picking up a hint even if one exists."
Pelorat nodded， and said， "I"ve been thinking along those lines myself. Do you mind if we discuss it？ I know you"re unhappy， old chap，and don"t want to talk， so if you want me to leave you alone， I will."
"Go ahead， discuss it，" said Trevize， with something that was remarkably like a groan. "What have I got better to do than listen？"
Pelorat said， "That doesn"t sound as though you really want me to talk，but perhaps it will do us good. Please stop me at any time if you decide you can stand it no longer. It seems to me， Golan， that Earth need not take only passive and negative measures to hide itself. It need not merely wipe out references to itself. Might it not plant false evidence and work actively for obscurity in that fashion？"
"How do you mean？"
"Well， we"ve heard of Earth"s radioactivity in several places，and that sort of thing would be designed to make anyone break off any attempt to locate it. If it were truly radioactive， it would be totally unapproachable. In all likelihood， we would not even be able to set foot on it. Even robot explorers， if we had any， might not survive the radiation. So why look？ And if it is not radioactive， it remains inviolate， except for accidental approach， and even then it might have other means of masking itself."
Trevize managed a smile. "Oddly enough， Janov， that thought has occurred to me. It has even occurred to me that that improbable giant satellite has been invented and planted in the world"s legends. As for the gas giant with the monstrous ring system， that is equally improbable and may be equally planted. It is all designed， perhaps， to have us look for something that doesn"t exist， so that we go right through the correct planetary system， staring at Earth and dismissing it because，in actual fact， it lacks a large satellite or a triple-ringed cousin or a radioactive crust. We don"t recognize it， therefore， and don"t dream we are looking at it. I imagine worse， too."
Pelorat looked downcast. "How can there be worse？"
"Easily when your mind gets sick in the middle of the night and begins searching the vast realm of fantasy for anything that can deepen despair. What if Earth"s ability to hide is ultimate？