The European Space Agency will launch an observatory into space designed to seek out potentially habitable planets outside of our solar system. The PLATO (Planetary Transits and Oscillations of stars) mission will search for planets by monitoring the brightness of up to a million nearby stars. The space-based observatory will use 34 separate small telescopes and cameras to watch for tiny, regular drops in their targets’ brightness: a sign that a planet is passing in front of the star.