Star clusters may be the one of the best places to look for advanced alien life, a new study suggests. Star clusters are classified as groups of gravitationally bound stars with areas of just a few hundred light-years across, typically consisting of hundreds of thousands of stars.
“If they house planets, globular clusters provide ideal environments for advanced civilizations that can survive over long times,” said Roassane Di Stefano who participated in the study.
Star clusters could provide a stable home for an advanced alien civilization. Within a cluster, stars are close enough together that colonization of planets around other stars would be within reason for a technologically advanced civilization. In the case of a catastrophic event on one planet, the civilization could survive on another.
“The very old, stable populations, coupled with the very small distances between stars might make it possible for civilizations in globular clusters to travel and possibly to develop outposts in relatively short times,” says Di Stefano.
The problem with searching for extraterrestrial civilizations in star clusters is the potential lack of planets. Currently, only one exoplanet has been found around a star contained in a star cluster. Many of the stars in star clusters are very old and may lack the material needed to form planets. Because of this, the search for life in star clusters has been criticised by some scientists. However, other scientists are defending the search for life in clusters.
“It’s premature to say there are no planets in globular clusters,” says Alak Ray of the Talak Institute of Fundamental Research.
The interactions between the stars in a cluster may also cause trouble for extraterrestrial life. Heavier stars can pull planets away from lighter ones taking them out of a stable orbit. According to the study though, stars near the outside of clusters will likely provide a stable orbit for their planets but will still be close enough to neighbouring star systems to allow for interstellar travel.
Since many of the stars in the stable zones of star clusters are very old, there would have been more than enough time for the emergence of life and the evolution of technologically advanced civilizations if suitable planets are present.
Neighboring stars in clusters are generally less than a light-year apart. This would allow for fairly effective communication between civilizations.
In the future, SETI (the Search for Extraterrestrial Intelligence) may point their telescopes towards some of the 150 star clusters contained within the Milky Way galaxy