As we look up at the starry sky, countless celestial bodies silently peer down upon us. Most of these have been there for billions of years as stellar processes slowly unfold, starting from their birth until their final demise. Light from other celestial objects, though long vanished, has only recently reached us. In other instances, swift changes in the sky occur at timescales as short as seconds or minutes, like when a dwarf star momentarily flares up or when a human satellite crosses the field of view.
My team has been searching for objects that may have vanished. As an unexpected result of our searches, we found cases where multiple star-like objects (transients) appeared and vanished in a small image within an hour, and even more peculiarly, two of our brightest cases happened in July 1952, coinciding in time with the 1952 Washington D.C. UFO flyovers. But what have we actually found, and how do these two events potentially link to one another?
In the Vanishing & Appearing Sources during a Century of Observations (VASCO) project, our team has been dedicated to the search for celestial objects that vanished over the span of 70 years. In the grand scheme of cosmic time and the billions of years needed for a low-mass star to turn into a white dwarf, seventy years is only a fleeting moment in cosmic time. But 70 years is also much longer than the time needed for a satellite to pass through the telescope’s field of view. Our original objective was to search for a star that had vanished, with the hope of detecting instances where a star directly collapses into a black hole (failed supernova), an event predicted by supernova theoreticians. Alternatively, we were intrigued by the prospect of finding a star that vanishes entirely without a trace or explanation; a signature of a highly advanced civilization.
However, this task was far from straightforward. My colleague spent two years developing powerful methods  for sifting through…