When it comes to the search for extraterrestrial life, astrophysicist Bradley Hansen says one of the biggest problems is not knowing where to start.

“We don’t have very much data and so the traditional technique is just to do something very general,” Hansen tells Inverse. Hansen is a professor of physics and astronomy at the University of California, Los Angeles.

Hansen spends his time trying to narrow down the search by hunting for alien life within specific star systems. What makes these stars so special is their proximity — extraterrestrials may be traveling to and from each system like cosmic emigrés.

In a recent paper published on the preprint server arXiv, he lists eight stellar pairs that engage in hyperbolic encounters — essentially when their gravitational pull brings them in together as they speed past each other like a comet might do around the Sun. Some of these encounters are close enough for an intelligent civilization to migrate from one star to another.

Targeting these stars could reveal signals from alien technology as they make the leap, Hansen argues — and help us resolve whether or not we are alone in the universe.

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