Clusters of stars could yet prove a happy hunting ground in the search for alien life, according to new research.
Tightly packed clumps of stars found at the fringe of the Milky Way were once considered fertile ground in the search for extraterrestrial intelligence, reports the BBC.
However, efforts to find alien life have brought little success, leading many scientists to look further afield.
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Now two astronomers say recent discoveries mean the search should continue as the areas represent a "globular cluster opportunity".
Rosanne Di Stefano, of the Harvard-Smithsonian Center for Astrophysics in the US, and Alak Ray, from the Tata Institute of Fundamental Research in India, pointed to the discovery of PSR B1620-26 b – also known as Methuselah - the only exoplanet so far detected orbiting stars within a globular cluster.
"I think most of us would say that the discovery of that one, bizarre planet indicates that there must be other planets in that cluster," said Dr Di Stefano.
"Now we can use the information that we've gleaned from other planet discoveries – and there are over 2,000 planets known today – to ask: Is it likely that they'd be in globular clusters?"
She added: "A globular cluster might be the first place in which intelligent life is identified in our galaxy."
The scientists have also identified what they call a "sweet spot" where planets could survive the gravitational pull of the packed clusters.
Other experts have cautiously welcomed the suggestion. "The idea gives rise to notions of not just one, but whole networks of interconnected alien civilizations," says EarthSky.
Speaking to the BBC, Alan Penny, an astronomer at the University of St Andrews and co-ordinator of the UK Seti Research Network, said of the discovery: "I think it does lift globular clusters up in the wish list of targets to search."
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