She Rewrote the Moon’s Origin Story

Fifty years ago, in the Oval Office, Richard Nixon made what he called the “most historic phone call ever.” Houston had put him through to the men on the moon. “It’s a great honor and privilege for us to be here,” Neil Armstrong said, “representing not only the United States but men of peace of all nations, and with interest and a curiosity and a vision for the future.” The Apollo missions—a daring feat of passion and reason—weren’t just for show. In reaching the moon in 1969, fulfilling John F. Kennedy’s promise seven years earlier to go there not because it would be easy, but hard, humanity tested its limits—as well as the lunar soil. 

The samples the astronauts brought back to Earth have revolutionized our understanding of the moon’s origins, leading scientists to imagine new models of how our planet, and its companion, emerged. One of those scientists is Sarah T. Stewart, a planetary physicist at the University of California, Davis. Last year she won a MacArthur Foundation Fellowship, unofficially known as the “genius grant,” for her work on the origin of Earth’s moon. Her theory upends one held for decades.