Signals detected from galaxy light years away

Cosmologist Stephen Hawking co-launched the Breakthrough Listen project two years ago. Photo / AP

Astronomers say equipment could detect ET life.

Astronomers hunting for signs of intelligent alien life have recorded 15 mysterious radio signals coming from a dwarf galaxy three billion light years away.

The signals were picked up by the Green Bank Telescope in West Virginia, part of the Breakthrough Listen project co-launched by Professor Stephen Hawking in 2015.

Although the latest fast radio bursts, or FRBs, are unlikely to have come from an alien civilisation, the researchers say it proves their equipment is working and ready to pick up signs of life if they exist.

FRBs are radio signals from somewhere in deep space that last for just milliseconds. The new bursts came from an unknown source, named FRB 121102, discovered in 2012.

At first scientists thought the signals were the fallout from a catastrophic event, such as a supernova, but when they were recorded again in 2015 and 2016 it suggested whatever produced them was still there.

In the new experiment, scientists from the University of California scanned the same galaxy at a higher frequency to detect the original bursts, and found 15 more.

Explanations for the signals range from rotating neutron stars with extremely magnetic fields, to energy sources used by aliens to power spacecraft. Whatever they are, they left their galaxy when our solar system was just two billion years old, and life was just taking hold on Earth.

Dr Vishal Gajjar, at UC Berkeley Research Centre, said: "We really have no idea about where they come from.

"We know of 30 to exist and only one is known to repeat, which means we can look at it again and again.

"If some form of life would like to produce a signal detectable to another civilisation, this could be a way to do it, but I don't think they are coming from intelligent civilisations.

"There are more theories than the number of sources."

Martin Rees, the astronomer royal and chairman of the US$100 million ($139m) global astronomical initiative, said, "Journalists have written that this is evidence for extraterrestrial intelligence. Nobody is claiming this. But it confirms their equipment is working well."