Short-lived flashes in the night sky that flicker on and off over several decades are baffling scientists.
No suitable explanations have been presented so far, and academics are not ruling out the possibility they were created by alien lasers used for communication.
Ongoing research is trying to decipher what causes the intermittent lights and researchers say 'interstellar communication lasers' may be as good an answer as any.
However the researchers, from the University of Stockholm, say the most likely sources of the lights are 'natural, if somewhat extreme, astrophysical sources'.
Publicly available data with images of the sky dating as far back as to the 1950s have been used by scientists as part of the the project Vanishing & Appearing Sources during a Century of Observations (VASCO). More than 150,000 of the weird lights have been studied, with at least 100 found to be behaving erratically and rapidly flaring up to become several thousand times brighter.
These so called 'red transients' have not yet received an adequate origin story accepted by scientists. One option is the possibility of an actual vanishing star, which has the potential to rewrite what we know about astrophysics.
'Finding an actually vanishing star - or a star that appears out of nowhere! - would be a precious discovery and certainly would include new astrophysics beyond the one we know of today,' says project leader Beatriz Villarroel, Stockholm University and Instituto de Astrofísica de Canarias, Spain.
The alluded to era of a new astrophysics may well include signals produced by extraterrestrial life.
Researchers write in their paper, recently published in The Astronomical Journal, that traditional searches may have to be expanded to include 'more exotic searches for evidence of technologically advanced civilisations'.
Blinking lights are so unusual because normally a dying star gradually changes into either a white dwarf or goes supernova.
Both eventualities can be monitored and witnessed, but for the light to appear and disappear, indicates there must be something different happening entirely.
A vanishing star, believed to be the most likely option, could be an example of an 'impossible phenomenon', according to researchers. The only explanation for the lights that does not include alien life would be exceedingly rare events called 'failed supernovae'.
A failed supernovae is theoretically predicted to occur when a very massive star collapses into a black hole without any visible explosion.
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