While astronomers have found thousands of exoplanets over the last few decades, the true prize continues to elude them—they have yet to find an Earth-mass, rocky planet orbiting in the habitable zone of a sun-like star. That's partially due to cosmic geography—around half of all sun-like stars near us aren't alone. They have one or more companion stars that complicate their orbital dynamics, as well as those of any planets they might host.