Astronomers from Trinity College Dublin, the Breakthrough Listen project and Onsala Space Observatory have demonstrated the effectiveness of using multisite simultaneous observations for rejecting anthropogenic signals in the search for technosignatures from extraterrestrial intelligences.
In the last five decades, evidence has steadily mounted that the constituents and conditions necessary for life are common in the Universe.
Predicting specific properties of electromagnetic emissions from extraterrestrial technologies is one of the most challenging aspects of searching for life in the Universe. However, it also represents a high-risk, high-reward endeavor.
If an extraterrestrial civilization were intentionally attempting to indicate its presence through such emissions, it would be advantageous to make the signals easily distinguishable from natural phenomena.
The evidence of such emissions is referred to as technosignatures, and the field dedicated to their detection is known as the Search for Extraterrestrial Intelligence (SETI).
It is commonly assumed that civilizations elsewhere in the Universe may employ similar technologies to those developed on Earth.
Consequently, radio frequencies are considered a logical domain for conducting SETI surveys, due to the widespread use of telecommunications and radar.
Therefore, radio astronomy has played a significant role in the field of SETI since the 1960s.
Numerous previous SETI surveys have utilized large single-dish telescopes operating at frequencies over 1 GHz. However, exploration of the radio window below 1 GHz has been relatively limited.
Technosignature searches commonly seek narrowband (approximately Hz-scale) radio emissions, either transmitted directly or leaking from other civilizations. Nonetheless, there is no inherent preference for any specific segment of the radio spectrum, which necessitates surveys spanning from low frequencies (30 MHz) to high frequencies (100 GHz).
“In the last 50 years…
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