A night test of a small-scale starshade model in the darkness of the desert, which mimics the conditions of starlight in space. Another light, which is 10-8  less bright than the light source standing in for the star, represents the light of a planet. Telescopes searching for the relatively dim light of an exoplanet next to its much brighter star are faced with a challenge. It's as difficult as standing in Los Angeles and searching for a firefly next to a lighthouse in New York. These tests determined that a starshade, or external occulter, is capable of blocking starlight to a degree that reveals the light of a planet.