Final answer:
The Kepler telescope's sensitive detector measured the light intensity from other stars, which allowed for the detection of exoplanets based on the transit method.
Step-by-step explanation:
The Kepler telescope had a highly sensitive detector designed specifically for measuring the light intensity from other stars. As it observed a fixed area of space, it could detect the small fluctuations in brightness caused by a planet passing in front of a star from our point of view, a phenomenon known as a transit. By accurately monitoring these changes in light intensity, Kepler could infer the presence of exoplanets orbiting distant stars, thus achieving its primary goal of identifying transiting exoplanets.