Just before eight in the morning on December 1st of last year, Ada Monzón was at the Guaynabo studios of WAPA, a television station in Puerto Rico, preparing to give a weather update, when she got a text from a friend. Jonathan Friedman, an aeronomer who lives near the Arecibo Observatory, about an hour and a half from San Juan, had sent her a photo, taken from his sister-in-law’s back yard, of the brilliant blue Caribbean sky and the green, heavily forested limestone hills. In the picture, a thin cloud of dust hovered just above the tree line; the image was notable not for what it showed but for what was missing. On a normal day—on any day before that one, in fact—a shot from that back yard would have captured Arecibo’s nine-hundred-ton radio-telescope platform, with its massive Gregorian dome, floating improbably over the valley, suspended from cables five hundred feet above the ground. Accompanying the photo was Friedman’s message, which read, simply, “Se cayó ”—“It fell.”
Every year since Arecibo’s completion, in 1963, hundreds of researchers from around the world had taken turns pointing the radio telescope toward the sky to glean the secrets of the universe. It had played a role in the fields of radio astronomy and atmospheric, climate, and planetary science, as well as in the search for exoplanets and the study of near-Earth asteroids that, were they to collide with our planet, could end life as we know it. There were even biologists working at Arecibo, studying how plant life developed in the dim light beneath the telescope’s porous dish.