Detecting exoplanets with transits

Transiting exoplanets are detected as they pass in front of – transit – their host star, causing a dip in the starlight as seen from the observer’s viewpoint. The transit repeats, with the time interval depending on the time it takes the exoplanet to orbit its star. For example, an observer of our own Solar System would have to wait a year to see a repeat of Earth transiting the Sun.