A recent study by researchers from Penn State and NASA’s Jet Propulsion Laboratory offers fresh insight into how and where alien civilizations might detect signals from Earth, according to IFL Science. Published in Astrophysical Journal Letters and presented at the 2025 Penn State SETI Symposium, the research maps the patterns of Earth’s most powerful deep-space transmissions—potentially guiding future efforts in the search for extraterrestrial intelligence (SETI).
Lead author Pinchen Fan explains that radio signals sent from Earth to interplanetary spacecraft, such as those orbiting Mars, could be detectable by distant observers—if they exist. When Earth aligns with other planets, these transmissions can leak or “spill over” into deep space, increasing the chances they might be picked up beyond our solar system. The same principle, Fan suggests, could help SETI scientists decide when and where to search for alien signals by focusing on similar alignments around distant stars.
To conduct the study, the team analyzed 20 years of data from NASA’s Deep Space Network (DSN), the primary system used to communicate with interplanetary missions. Although other countries have their own deep space networks, NASA’s DSN is considered a good proxy for most Earth-based deep space transmissions due to its wide-ranging use.
Project scientist Joseph Lazio highlights that the DSN emits some of Earth’s strongest and most consistent signals, making it a key focus for this research. The team specifically looked at transmissions aimed beyond low Earth orbit—excluding weaker signals to nearby satellites, which are unlikely to travel far enough to be detected.
By mapping the frequency and direction of these deep space signals, the researchers hope to better pinpoint the most promising times and places to listen for signs of alien technology.