Can you imagine one day looking up at the sky and seeing that some of the stars you know are no longer there? And no, we’re not talking about them being invisible due to light pollution. We mean stars pulling a space smoke bomb trick and vanishing.
Well, that’s exactly what happened to a group of astronomers who discovered that nearly 100 stars have disappeared as if by magic in the last 70 years. And the most striking part of it all: none of them knows why.
The project closely monitoring the disappearance of these stars/light sources is called VASCO, an acronym in English for “Vanishing & Appearing Sources during a Century of Observations,” led by the Spanish researcher Beatriz Villarroel from the Nordic Institute for Theoretical Physics in Sweden.
The disappearance of these stars was confirmed by comparing sky observation data from 70 years ago with more recent data, using a specialized program to analyze the light sources they expected to see in both sets of data. Out of the anticipated 600 million light sources, 150,000 seemed to have vanished between 1949 and 2014.
They then narrowed down the number to around 24,000 candidates and eventually to about “100 pinpoint sources,” which were “redder and had larger proper motions than typical objects,” apparently having disappeared over the 70-year period.
But what could have caused all these light sources to vanish in less than a century? Based on everything we know about stars, this should be impossible, but Villarroel and her colleagues have some hypotheses.
One of them is that it might be some kind of optical flare produced by gamma-ray bursts or fast radio bursts, which are highly energetic and brief phenomena that can increase a star’s brightness by eight to ten magnitudes but fade away within minutes, and they don’t seem to have any visible counterpart when observed with large telescopes.
Another possibility is that it could be a failed supernova, meaning a massive star that collapses into a black hole so drastically that it leaves no trace behind. However, this possibility is highly unlikely.
There are also more “exotic” explanations, such as the stars being hidden behind interstellar dust clouds, being swallowed by wandering black holes, or even being obscured by alien megastructures (let the imagination roam free).
Whatever the reason, the VASCO project continues to search for answers and hopes to find more vanished stars in the future using data from more powerful and sensitive telescopes. Will they manage to solve this mystery?