A team of Spanish astronomers is leading the investigation into one of stargazing’s most perplexing mysteries.
Three bright stars photographed in the night sky above southern California in 1952 vanished just an hour later.
Generations of scientists have sought to explain the rare phenomenon over the past half-century, but nothing has yet convinced the community.
Researchers at the Centre for Astrobiology (CAB) in Madrid tried to solve the riddle of the “triple transient” that has “remained absent from telescope exposures for 71 years” in a new paper published online.
While they believe to have whittled down the possible explanations to a plausible few, only the capturing of a similar event with modern telescopes could confirm the hypotheses once and for all.
The Palomar Observatory in San Diego County, California, is legendary in astrological circles. Its 200-inch Hale telescope was the largest in the world when it first saw light in 1949, under the direction of astronomy doyen Edwin Powell Hubble.
After just a few years of operation, during a routine photographic study of the night sky – which involved a number of pictures of the same region at different times to identify passing comets or asteroids – it recorded an observation that would stump the field to this day.
At 8.52pm on July 19, 1952, the plate registered a compact group of three perfectly visible stars very close to one another.
At 9.45pm, less than an hour later, they were absent from a photograph of the very same spot. They had disappeared without a trace.
More than highly unusual, this was scientifically improbable. Stars can explode, or even change in brightness suddenly if objects pass in front of them, but not cease to exist entirely.
Over the years since, scientists suggested that perhaps they had simply dimmed at the same time. This was soon dismissed, for the probability of the brightness of all three dropping by a factor of 10,000 simultaneously was just too infinitesimally small.
Next came the idea of a “gravitational lens” – what if the initial observation was in fact just one star, normally very faint but briefly luminous, whose profile was distorted by a passing black hole that acted like a cosmic magnifying glass and triplicated the image for a short time?
According to astrophysicist Enrique Solano’s Spanish team, while such an explanation is “plausible”, it comes with a number of caveats.
In an article recently published on the open-source science server arXiv, they said: “But if so, it would take a significant population of massive objects with a structure that serves as lenses, to produce three images and explain the hundreds of transients of less than an hour.”
Their work went on to explore other possibilities, including the notion that they were not stars at all but other types of objects. The initially captured bright spots were calculated to be just six Astronomical Units (AU) – or six times the distance between the Earth and the Sun – away, meaning they weren’t considered to be at “stellar distance”.
Rather, they were possibly on the fringe of our own solar system, objects in the Oort Cloud simply passing through on their orbits.
But perhaps the most likely account suggests that the specs weren’t picked up from space at all. Frequent nuclear weapons tests were being carried out in the nearby deserts of New Mexico at the time, and radioactive dust kicked up could have contaminated the photographic plates.
Despite Solano and his team’s best efforts, however, they could only conclude that the truth is “still unclear.” All that remains is to wait for history to repeat itself within the sights of the latest in telescope tech, and use that as a key to decipher this 70-year-old enigma.
