The Sparrow By Mary Doria Russell

In 2019, humanity finally finds proof of extraterrestrial life when a listening post in Puerto Rico picks up exquisite singing from a planet that will come to be known as Rakhat. While United Nations diplomats endlessly debate a possible first contact mission, the Society of Jesus quietly organizes an eight-person scientific expedition of its own. What the Jesuits find is a world so beyond comprehension that it will lead them to question what it means to be "human".