spaceSpace and Physics

Sorry Everyone, That Alien Signal Was Probably Just A "Terrestrial Disturbance"


Jonathan O'Callaghan

Senior Staff Writer

There's probably something out there somewhere, though. rangizzz/Shutterstock

For most people, it is a question of when, not if, we discover life elsewhere in the universe, be it intelligent or otherwise. So it’s no surprise, then, that even the faintest of hopes – such as an anomalous signal from another star – can send the world into a frenzy.

But for those holding out hope from a recently announced signal, we’re afraid we’ve got bad news.


Earlier this week, it was reported that the RATAN-600 radio telescope in Zelenchukskaya, Russia, had detected a promising signal in May 2015 that seemed to be coming from the Sun-like star HD 164595, about 94 light-years away from Earth. The high-powered radio signal was similar to what one might expect an advanced alien race to beam in our direction, if they were trying to make contact.

Sadly, though, it seems like the detection was false. As reported by the Russian news agency TASS, the signal has now been attributed to a disturbance from Earth, perhaps a defunct satellite in orbit. Yulia Sotnikova from the Special Astrophysical Observatory in Russia told TASS it was “most likely a terrestrial disturbance,” and her team was preparing to release an official report to that effect. Indeed, follow-up observations from other organizations had revealed no additional signal from the star.

Had the signal truly been of extraterrestrial origin, it would have been powered by something beyond our comprehension. According to Seth Shostak, Director of the SETI Institute, writing in a blog post, it would have needed “the total energy consumption of all humankind” had it been directed solely at us. If it was sent in all directions, it would have needed “hundreds of times more energy than all the sunlight falling on Earth.”

Another immediate red flag had been the timing. Being 94 light-years away, this alien race would have been sending the signal in 1921, as they saw Earth in 1827 – before we’d even begun broadcasting our presence into the cosmos with radio waves.


This isn’t the first false alarm. There was another erroneous signal from a satellite in 1997, and of course the infamous Wow! Signal in 1977, the latter of which still remains unexplained.

But it’s not all doom and gloom – just look at how popular this story was around the world. People, you and us included, are clearly excited about the prospect of finding alien life, which seems closer than ever at the moment thanks to initiatives like the $100 million Breakthrough Listen project. There must be something out there. Right?

“At a minimum, the HD 164595 episode reminds us of the need to prepare all the more carefully for the day we may actually detect a signal from another civilization,” Douglas Vakoch, President of METI (Messaging Extraterrestrial Intelligence) in California, told IFLScience.


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