He had set up a telescope on a corner of the roof, and we went up to take a look. This is time travel, he said, narrowing an eye to set the lens. Because the light is old. We're seeing back in time. No, we said, wrinkling our noses. We are seeing right now, today. No, he said, the light has to travel to us and it takes millions of years. What you're seeing is time. Excuse me, we said. We were embarrassed to correct him. He seemed so smart. What we're seeing is space. It's space, yes, he said. It's also time. You're seeing what has already happened.