Alien signals may be hiding where we rarely listen

Astronomers may have been listening for alien civilizations in only a small slice of the radio spectrum while overlooking a largely unexplored range of higher frequencies. Using archived data from the ALMA telescope in Chile, researchers conducted the observatory’s first SETI survey, searching for narrow signals that could indicate advanced technology. No possible alien transmissions were found, but the study revealed that even a handful of telescope observations may quietly include millions of stars.