Scientists are in the business of solving mysteries—or trying to, anyway. That’s true across all disciplines, but astronomers and physicists are the only ones who get to think about questions that are literally cosmic.

And even in that rarefied category, in which the subject matter ranges from black holes to neutron stars to the search for Earth-like planets across interstellar space, it doesn’t get any more esoteric than the ongoing quest to uncover the secrets of dark matter and dark energy. Together, they make up a whopping 96 percent of the cosmos—but to this day, nobody can say with any confidence what either one of them actually is.