According to BBC, astronomers at the University of Cambridge have found intriguing evidence suggesting a distant planet may harbour life.
K2-18b, located 700 trillion miles away, is under scrutiny thanks to NASA’s James Webb Space Telescope (JWST), which has revealed unprecedented details.
Led by Nikku Madhusudhan, the team identified atmospheric chemicals on K2-18b that, on Earth, are linked to simple organisms like bacteria and plankton. Their findings appeared in The Astrophysical Journal Letters.
Potential Life Indicators
Using JWST’s ability to analyze starlight passing through a planet’s atmosphere, researchers detected possible traces of dimethyl sulphide (DMS) and dimethyl disulphide (DMDS). On Earth, these compounds are exclusively produced by marine microbes.
“The concentration of this gas we estimate is thousands of times higher than Earth’s,” Madhusudhan noted. “If tied to life, this planet could be brimming with it.”
He added, “Confirming life on K2-18b would suggest life is likely abundant in our galaxy.”
Confidence Level
The signal has a “three sigma” confidence—99.7% likelihood of being genuine. A true discovery requires “five sigma” (99.99994% certainty), a step up from the team’s prior one-sigma result 18 months ago.
Madhusudhan is hopeful: “This is the best evidence yet for extraterrestrial life. We could verify this within one to two years.”
About K2-18b
K2-18b, 2.5 times Earth’s size, orbits a cool red star. Some experts propose it hosts a vast liquid ocean beneath a dense atmosphere, potentially perfect for life.
Others disagree. The study notes low ammonia levels might indicate absorption by an ocean, but molten rock could also explain it, suggesting a lifeless planet. NASA’s Nicolas Wogan posits K2-18b might be a gas-rich mini giant with no solid surface—hostile to life.
‘Extraterrestrial Puzzle’
To bolster their findings, Madhusudhan’s team collaborates to explore if DMS and DMDS could arise from non-biological processes. “Earth’s ocean microbes make these, but we can’t confirm a biological source on an alien planet—odd things happen out there,” said Catherine Heymans, Scotland’s Astronomer Royal.