• Illustration of the exoplanet K2-18bNASA Illustration of the exoplanet K2-18b NASA The planet K2-18b, which drewintense speculationlast year due to apparent signs of life, shows no signs of advanced civilisation after a comprehensive search for radio signals from it. • In 2025,Nikku Madhusudhanat the University of Cambridge and his colleagues sensationally claimed that K2-18b, an apparent water world 124 light years away, showed hints in its atmosphere of the molecule dimethyl sulphide (DMS). • Significant quantities of this molecule on Earth are produced only by life, so Madhusudhan and his team argued that the signals suggest we may be seeing signs of life from K2-18b, too. • Read moreThis mind-blowing map shows Earth’s position within the vast universe Read more This mind-blowing map shows Earth’s position within the vast universe However,subsequent observationsand more rigorous analyses showed that the evidence for DMS could instead have come from other molecules not associated with life. • Scientists concluded that the most we could say about the planet is that it isrich in water, either in the form of an ocean or a water-rich atmosphere. • Now, Madhusudhan and other researchers have looked for whether K2-18b might show signs of intelligent life in the form of radio signals blasted out to space, like the signals humans have been transmitting since the 1960s.

Article Summaries:

  • A recent study found no evidence of advanced extraterrestrial technology on the exoplanet K2‑18b. After earlier claims that the planet’s atmosphere contained dimethyl sulphide-a molecule linked to life on Earth-were refuted, scientists turned to radio searches for signals similar to those humans have broadcast since the 1960s. Using the Very Large Array in New Mexico and the MeerKAT telescope in South Africa, they monitored K2‑18b for several orbits, looking for persistent, narrow‑band transmissions comparable to the Arecibo radar. No such signals were detected, ruling out a continuously transmitting, Arecibo‑class beacon aimed at Earth. The authors note that this non‑detection only limits one specific type of signal; it does not exclude the possibility of life or intermittent, low‑power, or directional broadcasts.

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