Astronomy
Exomoon Detection Through Transit Timing Variations
Quick fact
A single moon can cause a planet's transit to arrive up to a few minutes early or late, and the pattern of those deviations repeats with the moon's orbital period.
Why this is interesting
If a planet like Jupiter orbited a distant star, its giant moons would be almost impossible to see. Yet they might still be detectable—just by looking at when the planet passes in front of its star.