New Delhi: Scientists searching for extraterrestrial life are increasingly turning their attention to some of the most theoretically inhospitable environments in the universe, from oceans hidden beneath frozen moons to the acidic clouds of Venus. Some researchers are even investigating whether advanced alien civilisations could exist around black holes, leaving traces of their technology in astronomical observations.
These investigations are part of a broader effort to understand whether life can exist under conditions very different from Earth’s, and whether extraterrestrial intelligence might be detectable without them reaching out to humanity first.
A review published in October this year by philosopher Clément Vidal and 18 other researchers examines how the search for alien intelligence is expanding beyond radio signals to include evidence of advanced technology, known as technosignatures.
Life beneath ice and inside rocks
Among the more promising locations for extraterrestrial life are Europa, a moon of Jupiter, and Enceladus, a moon of Saturn. Both are believed to contain oceans beneath their icy surfaces, where internal heating could sustain liquid water despite extremely low surface temperatures.
NASA’s Europa Clipper mission, launched in October 2024, will reach Jupiter in 2030 to investigate whether Europa has conditions suitable for life. Meanwhile, NASA’s Cassini spacecraft previously detected organic compounds and other ingredients associated with habitability in material erupting from Enceladus.
“On Europa, we’re not looking for life itself, we’re just looking for an environment in which life could thrive,” said Bonnie Buratti, Europa Clipper deputy project scientist, in a NASA video.
Mars presents another possibility. NASA’s Perseverance rover has been examining ancient lakebeds and river deposits for evidence of microbial life. In September 2025, NASA reported that a rock sample collected from Jezero Crater contained potential biosignatures, although non-biological explanations remain possible.
“Astrobiological claims, particularly those related to the potential discovery of past extraterrestrial life, require extraordinary evidence,” said Katie Stack Morgan, Perseverance’s project scientist at NASA’s Jet Propulsion Laboratory in the September report.
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Could life survive in the clouds of Venus?
Venus presents a more extreme challenge. Its surface temperatures reach approximately 465°C, while its clouds contain concentrated sulfuric acid.
However, a 2023 study by William Bains, Janusz Petkowski and Sara Seager suggests that unusual forms of life might survive in its atmosphere, potentially using alternate biochemical processes completely unlike those found on Earth.
The proposed Rocket Lab mission to Venus aims to investigate cloud particles for organic compounds and unusual physical properties. NASA’s planned DAVINCI mission will also examine the atmosphere’s composition and the planet’s geological history.
Searching for alien technology
Other researchers are considering whether highly advanced civilisations could leave detectable evidence through their high energy consumption.
A paper published in 2026 discusses hypothetical artificial intelligences called “Dyson Minds”, which could harvest energy from matter falling towards supermassive black holes. Such systems might produce unusual infrared emissions or other astronomical signals detectable through existing telescopes.
Another study proposes that sufficiently advanced civilisations might manipulate entire stellar systems using theoretical structures called stellar engines, potentially allowing stars to be moved through the galaxy.
Scientists are still conducting more conventional searches. The Breakthrough Listen initiative was established to survey one million nearby stars and 100 neighbouring galaxies for possible artificial radio and optical signals.
“Right now there could be messages from the stars flying right through the room, through us all,” said astronomer Frank Drake during the initiative’s announcement in 2015.
Although these approaches differ considerably in scientific feasibility, they share the objective of identifying evidence of life without assuming that extraterrestrial organisms or civilisations must resemble those on Earth.
So far, no confirmed evidence of extraterrestrial life has been discovered. But improvements in spacecraft instruments, astronomical observations and data analysis are allowing scientists to investigate environments and possibilities that were previously beyond their reach.
(Edited by Janaki Pande)