Two astronomers think they have plucked signals from 234 extraterrestrial civilizations. In 2012, Ermanno Borra of Laval University in Quebec, suggested that lasers might be the method by which we receive first contact from extraterrestrial intelligence.
He hypothesised that we would see periodic bursts of light hidden in the spectrum of the host star of the civilisations, faint and frequent. We'd discover them through mathematical analysis of the spectrum and the signal.
To send this kind of signal would not be beyond our means currently - should we wish to reveal ourselves to the universe, we could do so with the Helios laser at the Lawrence Livermore National Laboratory.
Borra instructed graduate student Eric Trottier to comb through 2.5 million stars in search of such a signal, who found it in 234 of them, most of which are in the same spectral class as the Sun.
Borra said of the results:
We have to follow a scientific approach, not an emotional one, but intuitively – my emotion speaks now – I strongly suspect that it’s an ETI signal.
Other astronomers are less convinced. Andrew Siemion, the director of the SETI Research Centre at the University of California Berkeley, said:
There is perhaps no bolder claim that one could make in observational astrophysics than the discovery of intelligent life beyond the Earth.
It’s an incredibly profound subject—and of course that’s why many of us devote our lives to the field and put so much energy into trying to answer these questions. But you can’t make such definitive statements about detections unless you’ve exhausted every possible means of follow-up.
A Breakthrough Listen Initiative, set up to monitor the stars Borra found emitting these stars, later ranked the detection as a zero to one on the Rio Scale for SETI observations, meaning that it is insignificant. An omni-directional beacon would be ranked a two on the index, whereas an Earth-specific message would be a six.
The scale does give you pause for thought - it's likely our first contact with extraterrestrial life will be a lot more ambiguous than a giant spaceship landing in Manhattan.