Dr Ragbir Bhathal, a scientist at the University of Western Sydney, picked up the odd signal in December 2008, long before it was announced that the star Gliese 581 has habitable planets in orbit around it.
A member of the Australian chapter of SETI, the organisation that looks for communication from distant planets, Dr Bhathal had been sweeping the skies when he discovered a ‘suspicious’ signal from an area of the galaxy that holds the newly-discovered Gliese 581g.
The remarkable coincidence adds another layer of mystery to the announcement last night that scientists had discovered another planet in the system: Gliese 581g – the most Earth-like planet ever found.
Dr Bhathal’s discovery had come just months before astronomers announced that they had found a similar, slightly less habitable planet around the same star 20 light years away. This planet was called Gliese 581e.
When asked about his discovery at the time Dr Bhathal admitted he had been really excited about what he had possibly stumbled across.
He told VICE Media: ‘Whenever there’s a clear night, I go up to the observatory and do a run on some of the celestial objects. Looking at one of these objects, we found this signal.
‘And you know, I got really excited with it. So next I had to analyse it. We have special software to analyse these signals, because when you look at celestial objects through the equipment we have, you also pick up a lot of noise.’
He went on: ‘We found this very sharp signal, sort of a laser lookalike thing which is the sort of thing we’re looking for – a very sharp spike. And that is what we found. So that was the excitement about the whole thing.’
For months after his discovery Dr Bhathal scanned the skies for a second signal to see whether it was just a glitch in his instrumentation but his search came to nothing.
But the discovery of Earth-like planets around Gliese 581 – both 581e and 581d, which was in the habitable zone – has also caught the public imagination.
Documentary-maker RDF and social-networking site Bebo used a radio telescope in Ukraine to send a powerful focused beam of information – 500 messages from the public in the form of radiowaves – to Gliese 581.
And the Australian science minister at the time organised 20,000 users of Twitter to send messages towards the distant solar system in the wake of the discoveries.