The Far Star emerged from Daneel's sublunar base and began its ascent away from the surface of the Moon. Pelorat, sitting in the pilot-room with Trevize and Bliss, gazed longingly at the Earth showing in the viewscreen. The sunlit side didn't look quite like any other world he had seen. With no plants and animals to keep the atmosphere in balance, the oxygen was being chemically bonded with the ground (so Daneel had explained). By now, there was scarcely any free oxygen left. The same was happening more slowly to the atmospheric nitrogen. Eventually, Earth would have only a thin trace of atmosphere, just like the Spacer world of Melpomenia.
"Why so sad, Pel?"
Pelorat sighed. "Because, my dear, in a sense my goal in life has proved a failure."
Bliss was puzzled. "But your goal in life was to locate the original homeworld of humanity, and you've succeeded. There it is."
"I didn't just want to locate it. I wished to study it. I wished to walk upon its surface and search for clues of what life was like there back in the days before interstellar travel was discovered."
Trevize said, "Surely Daneel was able to give you all the information you needed about that. You just got done saying that his records of the origins of humanity were unique and comprehensive, and that you could happily remain here the rest of your life."
"True, they are unique and comprehensive, as far as they go. Unfortunately, for my purposes, they don't go far enough. As old as Daneel is, he still can't tell me everything I want to know about Earth.
"You must understand that Daneel himself is far from well-informed about the details of Earth's history. He was, so he tells me, built by Spacers from Aurora, that world we visited with the feral dogs. As long ago as that was, it was still over a thousand years after the discovery of interstellar travel. Also, the Spacers were contemptuous of Earth, and deliberately eliminated most of their information about their world of origin. Daneel himself was built in a Spacer enclave on Earth that had as little contact with the rest of the planet as possible, and he was brought to Aurora within months. He only made two brief trips to Earth before it became radioactive, and he had little time to learn details of its ancient history."
Pelorat sighed again. "All my life, I've dreamed of locating the Earth, and beginning the work of unearthing and preserving its past. Now that I've finally found it, I know that will never happen. With Earth as radioactive as it is, archeological fieldwork is impossible. Apart from the bare outlines preserved by Daneel, and the stories I got from Monomee on Alpha, nothing from Earth's past has survived to the present. It's all gone, and there is no way to retrieve it."
The pilot-room was uncharacteristically silent after Pelorat finished. Finally, Bliss stood, and led Pelorat by the hand back to their room. There was nothing else she or Trevize could do.