Astronomers have discovered 234 mysterious signals from stars that could be different alien species trying to talk to us, according to a new study from E.F. Borra and E. Trottier, two researchers at Laval University in Canada.
The authors used data from the Sloan Digital Sky Survey to analyze the spectra of 2.5 million stars and identified 234 which are producing strange 'strobe-like' signals: pulses of light separated by a constant time interval. Borra had hypothesised back in 2012 that if an extraterrestrial civilisation wanted to contact us, it would make sense to beam laser pulses at us that look unnatural enough to warrant investigation.
According to the abstract, the 234 stars are "overwhelmingly in the F2 to K1 spectral range". That's significant because this is a small range centred around the spectrum of our own Sun. And our own Sun is the only one we know of that has an intelligent species living near it. If ours does, maybe others do too?
Even though the signals “have exactly the shape of an ETI [Extraterrestrial Intelligence] signal”, there are several other possible explanation, like effects caused by the instruments or the data analysis. Or maybe there is a tiny subset of stars with chemical peculiarities that make them act in this way. As the researchers say: ”This hypothesis needs to be confirmed with further work.”
That further work is already being planned by the SETI Research Centre and the Breakthrough Listen Initiative, a project that searches for intelligent life in the cosmos. They plan to use the Automated Planet Finder telescope at the Lick Observatory to further observe some of Borra's 234 stars.
In a statement on Borra's paper, the Breakthrough team annonced that "The Berkeley SETI Research Centre team has added several stars from the Borra and Trottier sample to the Breakthrough Listen observing queue on the 2.4-metre Automated Planet Finder (APF) optical telescope. The capabilities of the APF spectrograph are well matched to those of the original detection, and these independent follow-up observations will enable us to verify or refute the reported detections."
They don't seem that excited about Borra's findings though, and have already poured cold water on it, trotting out the old axiom that "Extraordinary claims require extraordinary evidence". They also give Borra's findings a score of 0 to 1 on the Rio Scale. The Rio Scale is something used by the international SETI community to rank detections of phenomena that could indicate advanced life beyond Earth. A rating of 0 to 1 means its insignificant.
Astronomers have believed that stellar oddities were caused by aliens before, when in reality it was simply an unknown, new phenomenon. A couple of months ago, sky-watchers around the world got pretty excited when news broke about a mysterious radio signal that seemed to be emanating from a star called HD 164595.
HD 164595 is located some 94 light-years away from Earth, and that epic distance – together with the unexplained nature of the transmission – had people thinking: if this were contact from an alien civilisation, they'd need to have some pretty powerful technology to send a signal all that way. However, the anomaly was later explained as a terrestrial disturbance caused by a Soviet satellite.
We'll have to wait and see what's going to be found. But it's possible that in the not too distant future, all the various evidence collected will make the conclusion inevitable that in this Universe, we are not alone.
Image: Radio Telescope in Ondrejov, Czech Republic 2014 - Martin Vorel