Nasa has provoked excitement across the world with the promise that it will reveal a “new discovery about the Moon” in a major announcement.

The space agency gave no details on what the announcement might be, apart from indicating that it “contributes to NASA’s efforts to learn about the Moon in support of deep space exploration” and had been made with Sofia, a converted Boeing 747 that works as a flying observatory.

But clues have begun to emerge about what the announcement could be about to reveal.