Willard stopped. A happy dreamy smile touched his lips. "When will we go to Earth?" he asked. The Captain did not answer. Willard waited and a strange memory tugged at him. "You don't know," the Captain said. It was not a question or a statement. The Captain found it hard to say it. His lips moved slowly. Willard stepped back and before the Captain told him, _he knew_. "Matter is relative," he said, "the existent under one condition is non-existent under another. The real here is the non-real there. All things that wander alone in space are gradually drained of their mass and energy until nothing is left but mere shells. That is what happened to the _Mary Lou_. Your ship was real when we passed by twenty years ago. It is now like ours, a vague outline in space. We cannot feel the change ourselves, for change is relative. That is why we became more and more solid to you, as you became more and more faint to any Earth-ship that might have passed. We are real--to ourselves. But to some ship from Earth which has not been in space for more than fifteen years--to that ship, to all intents and purposes, we do not exist. "Then this ship," Willard said, stunned, "you and I and everything on it..." "... are doomed," the Captain said. "We cannot go to Earth for the simple reason that we would go _through_ it!" The vision of Earth and green trees faded. He would never see Earth again. He would never feel the crunch of ground under feet as he walked. Never would listen to the voices of friends and the songs of birds. Never. Never. Never.... "Then this is the Ghost Ship and we are the Ghosts!" "Yes." End of the Project Gutenberg EBook of Galactic Ghost, by Walter Kubilius