The survey, which is based in the European Southern Observatory's Paranal Observatory in Chile, will look for moments when distant stars dim temporarily. Periodic dimming in stars is a sign that there's a planet there that has transited, or passed, between the star and Earth. (You might remember NASA's Kepler Space Telescope also looks for transits.) Bigger planets cause more obvious dimming, but for this survey, astronomers are most interested in planets closer in size to Earth than easier-to-spot gas giants such as Jupiter. Thus, the Next-Generation Transit Survey will seek "super-Earths" about two times to eight times the size of humanity's home world. The survey array measures the brightness of stars more accurately than any other ground-based telescope.