On July 16, 1945, at 5:29 a.m., the world changed forever. The Trinity Test (aka the world’s first nuclear explosion), carried out in secret on a plot of empty land smack dab in the middle of New Mexico and overseen by Julius Robert Oppenheimer, proved the atomic bomb was a viable weapon of mass destruction. You can draw a direct line from that moment to the bombs dropped in Hiroshima and Nagasaki, the nuclear arms race that defined the Cold War, and the looming threat of self-assured nuclear annihilation that persists even today.

So you might naturally think that the Trinity Test would be the most important scene in Oppenheimer, Christopher Nolan’s new movie about the so-called father of the atomic bomb. And in a way, it is. The explosion serves as the film’s climax, a visual gut punch that releases two hours of tension and kicks off Oppenheimer’s unexpected third act. But in another sense, that fateful test is the least important part of the movie: a brief detour into blockbuster spectacle in what’s otherwise Nolan’s most grounded, contemplative, and beautiful film to date.

Until recently, Caltech postdoctoral astronomy researcher Ilaria Caiazzo was merely hunting the skies for the bodies of dead stars. She never expected to discover an exotic, two-faced white dwarf.

”It was quite a serendipitous discovery,” Caiazzo tells Inverse. “We did not expect to find something like this. It was not predicted. It's a new class of [stellar] object.”

White dwarf stars are stellar remnants, the glowing hot remains of a star that has exhausted its thermonuclear fuel supply and blown most of the rest of its mass out into space, leaving the compact former core of the old star. Instead, they glow faintly with residual heat and slowly cool down over time, usually showing compositions of either hydrogen or helium.

Except for the white dwarf ZTF J203349.8+322901.1. While Caiazzo was searching for signs of white dwarfs that may have recently merged together (dim stars that rotated, were magnetized, and varied in brightness), she found ZTF J203349.8+322901.1 — and noticed something weird. It appeared to have one side with a surface consisting of hydrogen, while the other side’s surface consisted of helium.