I did not know that there were scientific teams dedicated to seeking out intelligent life forms trying to communicate with us on earth, let alone that there were methods of scanning the universe for their signals! Jill Tarter explains in this video that the Drake Equation estimates the amount of civilizations that may be trying to communicate with us. She also explains they are able to scan for certain radio frequencies as a way of seeking out advanced technological use coming from other places in the universe. Specifically time compression and frequency compression are the most promising indicators.
https://www.labxchange.org/library/items/lb:HarvardX:68789c56:lx_simulation:1?fullscreen=true