Figure 5-6Microlensing Reveals an Exoplanet (a) Gravitational fields cause light to change direction. As a star with a planet passes between Earth and a more distant star (b), the light from the distant star is focused toward us, making the distant star appear brighter. The focusing of the distant star’s light occurs twice, once by the closer star and once by the closer star and its planet (c), making the distant star change brightness. For these simulations, the closer star and planet are 17,000 ly away, while the distant star is 24,000 ly away.