“The kind of energy needed to generate this signal is not crazy,” says Borra. In fact, Borra showed that technology we have on Earth today – specifically the Helios laser at the Lawrence Livermore National Laboratory – could generate that kind of signal, should we want to reveal ourselves to the cosmos.

With this in mind, Borra’s graduate student Eric Trottier combed through 2.5 million stars recorded by the Sloan Digital Sky Survey in search of such a signal. He found it, down to the exact shape, in 234 stars.

The overwhelming majority of those stars are in the same spectral class as the sun, which Borra says supports his hypothesis that this signature must be the result of extraterrestrial intelligent life. And with the data in hand, he thinks that 234 distinct civilisations are beaming pulses of the same periodicity (roughly 1.65 picoseconds) toward the Earth.

Borra and Trottier ruled out other possible explanations for the pattern, like rapid pulsations in the atmospheres of the stars themselves and rotational transitions in molecules. “We have to follow a scientific approach, not an emotional one,” says Borra. “But intuitively – my emotion speaks now – I strongly suspect that it’s an ETI signal.”