A new signal has been found deep in space that could come from alien life.

The community of astronomers and scientists who scan the skies with telescopes in an attempt to find extraterrestrial life is abuzz with excitement over a “strong signal” detected deep in space that could come from an alien civilisation.

Scientists are cautioning people not to get quite too excited – at least not yet. The evidence remains preliminary and more work will need to be done to establish if it is not just a mistake, let alone whether it’s actually an extraterrestrial communication.

The message appears to have come from a nearby star, HD164595, in the constellation Hercules. That star is 95 light years away – relatively close at the scale of the universe – and almost exactly the same size as Earth.

What’s more, that same star has at least one planet, HD164595b, which is roughly the size of Neptune and has a 40-day year. It’s this planet that has people excited, since it appears that it could have the right conditions for supporting life.

The signal came to public attention after it had been noted by science fiction author Paul Gilster, who maintains a blog that looks at deep space exploration and alien life. Until then it had gone unremarked – the signal was actually detected in May last year, and was only brought to light after a presentation by the scientists who found it.

Claudio Maccone of Turin University in Italy attended a talk by the two scientists, who work at Russia’s Ratan-600 telescope. He passed that data on to Mr Gilster, who then wrote up his blog describing what had been found.

Possible second Earth discovered

“No one is claiming that this is the work of an extraterrestrial civilisation, but it is certainly worth further study,” wrote Mr Gilster on his site Centauri Dreams.

He wrote that the strength of the signal might suggest that it came from a Kardashev Type II civilisation. The Kardeshev scale indicates how advanced an alien civilisation might be: a Type I civilisation can use and store energy from a nearby star as we can, whereas a Type II civilisation can harness the energy of the entire star and would be far more advanced than mankind.

“Working out the strength of the signal, the researchers say that if it came from an isotropic beacon, it would be of a power possible only for a Kardashev Type II civilisation. If it were a narrow beam signal focused on our solar system, it would be of a power available to a Kardashev Type I civilisation,” Mr Gilster said.

He did acknowledge that the signal might have been noise rather than an actual signal.

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“The possibility of noise of one form or another cannot be ruled out, and researchers in Paris led by Jean Schneider are considering the possible microlensing of a background source by HD164595. But the signal is provocative enough that the RATAN-600 researchers are calling for permanent monitoring of this target.”

The Russian scientists who first found the signal wrote in their presentation that the probability of it being noise was low. As such, it should be permanently monitored by Seti scientists to see whether more can be learned about the star and its planet, they said.

Some at Seti – the search for extraterrestrial intelligence, which is a collective of scientists looking to find transmissions from alien life – have already squashed the possibility of alien communications.

“I was unimpressed,” wrote Eric Korpela, an astronomer who works closely on the Seti project. “Because the receivers used were making broad band measurements, there's really nothing about this 'signal' that would distinguish it from a natural radio transient”, he wrote, pointing to the fact that it could equally have been caused by a stellar flare, active galactic nucleus, microlensing of a background source, or something else entirely.

“There's also nothing that could distinguish it from a satellite passing through the telescope field of view,” he wrote in a post aimed at trying to temper the excitement . “All in all, it's relatively uninteresting from a Seti standpoint.”

Hawking launches alien search

Mr Korpela said that SETI@home – the project that lets people volunteer their computers to search for life elsewhere in the universe – picks up “millions of potential signals with similar characteristics, but it takes more than that to make a good candidate”. The new potential star didn’t even satisfy the minimum criterion – that it should be detected multiple times.

If it isn’t heard again then it might be something like the “WOW” signal, received in 1977. That was a powerful radio signal that came from a group of stars called Chi Sagittarii. The astronomer who discovered it, Jerry Ehman, circled it and wrote WOW next to it to mark it for future study, but the message was never detected again.

Seti scientists hope to hear more from the star by using the Allen Telescope Array, a huge system that can be used to look for messages that indicate alien intelligence. It was pointed towards the star over the weekend but has not as yet found any signal.

“However, we have not yet covered the full range of frequencies in which the signal could be located, if it’s of far narrower bandwidth than the Russian 1 GHz receiver,” Seti wrote. “We intend to completely cover this big swath of the radio dial in the next day or two. A detection, of course, would immediately spur the Seti and radio astronomy communities to do more follow-up observations.”

Seti hopes that those observations can be enough to learn more about the star system that the signal is supposedly coming from.

“So what’s the bottom line?” asked Seth Shostak, senior astronomer at Seti. “Could it be another society sending a signal our way? Of course, that’s possible.