There are three ways to look for evidence of alien technological civilizations. One is to look out for deliberate attempts by them to communicate their existence, for example, through radio broadcasts. Another is to look for evidence of them visiting the solar system. And a third option is to look for signs of large-scale engineering projects in space.
A team of astronomers have taken the third approach by searching through recent astronomical survey data to identify seven candidates for alien megastructures, known as Dyson spheres, “deserving of further analysis.”
This is a detailed study looking for “oddballs” among stars—objects that might be alien megastructures. However, the authors are careful not to make any overblown claims. The seven objects, all located within 1,000 light-years of Earth, are “M-dwarfs”—a class of stars that are smaller and less bright than the sun.