Search for radio signals finds no hint of alien civilisation on K2-18b
New Scientist
February 20, 2026
AI-Generated Deep Dive Summary
Scientists have conducted a thorough search for radio signals from K2-18b, a distant exoplanet often speculated to be a water world and a potential candidate for hosting alien life. Despite extensive observations using powerful telescopes like the Very Large Array and MeerKAT, no detectable radio transmissions were found. This comprehensive study aimed to identify any signals similar to those humans have emitted since the 1960s, particularly focusing on frequencies that could indicate advanced technological civilizations.
Previous speculation about K2-18b centered on the detection of dimethyl sulfide (DMS) in its atmosphere, a molecule associated with life on Earth. While this discovery generated excitement, further analysis revealed that DMS could also originate from non-biological processes. As a result, scientists concluded that while the planet likely contains abundant water, either in an ocean or atmospheric form, there is no concrete evidence of advanced intelligent life.
The search for radio signals involved monitoring the planet during multiple orbits around its star, ensuring coverage over different periods and angles. The study specifically looked for persistent, narrow-band radio emissions akin to those from Earth's largest telescopes, such as Arecibo. However, after carefully filtering out terrestrial interference, no signal was detected. Researchers emphasized that this non-detection does not necessarily rule out the existence of alien life but significantly narrows the scope of potential technological signatures.
Michael Garrett of the University of Manchester noted that civilizations might not utilize radio communication in the way we do, or they could transmit intermittently, directionally, or at lower power levels. Additionally, the planet's water-rich environment may pose challenges for developing complex technology, as it lacks exposed landmasses typically associated with infrastructure development on Earth.
This study highlights the complexity of searching for extraterrestrial intelligence and underscores the need for diverse approaches in the quest to understand alien life. While K2-18b remains an intriguing target for future research, particularly in the search for biosignatures, the absence of radio signals suggests that advanced civilizations may be rare or may not communicate in ways we currently comprehend.
Verticals
science
Originally published on New Scientist on 2/20/2026