A new study of human deep space communications identifies the regions of space where signals from extraterrestrial intelligence are most likely to be detected.
If an extraterrestrial civilization were trying to detect human signals, where and when would they be most likely to find them? They found patterns that could not only reveal how outsiders might detect us but also help refine our own strategies in the search for extraterrestrial intelligence (SETI).
“Humans are predominantly communicating with the spacecraft and probes we have sent to study other planets like Mars,” said Pinchen Fan, graduate student in astronomy and astrophysics in the Penn State Eberly College of Science, science principal investigator of the NASA grant supporting this research and first author of the paper. “But a planet like Mars does not block the entire transmission, so a distant spacecraft or planet positioned along the path of these interplanetary communications could potentially detect the spillover; that would occur when Earth and another solar system planet align from their perspective. This suggests that we should look for alignment of planets outside of our solar system when searching for extraterrestrial communications.”
Likelihood of alien detection
“Based on data from the last 20 years, we found that if an extraterrestrial intelligence were in a location that could observe the alignment of Earth and Mars, there’s a 77% chance that they would be in the path of one of our transmissions — orders of magnitude more likely than being in a random position at a random time, Fan said. “If they could view an alignment with another solar-system planet, there is a 12% chance they would be in the path of our transmissions. When not observing a planet alignment, however, these chances are minuscule.”
