The young man was very interested in my work. I described how the tunable laser worked, how we were able to measure carbon dioxide and why it mattered. He was genuinely interested lasers and asked about other uses. I explained that laser can be used for cutting steel, measuring how fast cars are traveling, and as guide stars for observatories. I mentioned that scientists are able to accurately measure the distance to the moon by bouncing the lasers off or reflector arrays placed there by the Apollo astronauts. As I talked about the astronauts on the moon, I watched this guy’s face change. He thought for a minute and asked something like: You think we landed on the moon?