Possible Signs of Life Found on Distant Planet K2-18b
A team of scientists from Cambridge University has discovered new and intriguing evidence that may suggest the presence of life on a distant planet, K2-18b, located 124 light years from Earth.
Using NASA’s powerful James Webb Space Telescope (JWST), the researchers detected molecules in the atmosphere of K2-18b—specifically dimethyl sulphide (DMS) and dimethyl disulphide (DMDS). On Earth, these gases are mostly produced by simple marine organisms like phytoplankton and bacteria.
Although the discovery is exciting, scientists stress that more data is needed before confirming life exists. As lead researcher Professor Nikku Madhusudhan puts it, “This is the strongest evidence yet that life might be out there. But we still need to be sure.”
What Makes K2-18b So Special?
K2-18b is around 2.5 times larger than Earth, and orbits a small red dwarf star. It sits in the so-called “habitable zone”, where conditions may allow liquid water to exist — a key ingredient for life.
The James Webb Telescope captured light passing through the planet’s atmosphere, allowing scientists to analyse its chemical makeup. What they found surprised them.
Professor Madhusudhan explained that the amount of DMS detected is thousands of times higher than what's found on Earth, suggesting a potentially life-rich environment—if the source is indeed biological.
More Research Still Needed
While the signals are promising, the findings aren’t yet strong enough to be called a discovery. The team currently has a three-sigma result, meaning there's a 99.7% chance the findings are correct. But scientists need a five-sigma level (99.99999%) to confirm it as a scientific discovery.
Even if future observations confirm the presence of DMS and DMDS, it doesn’t guarantee these molecules were produced by life. Other natural processes, like geological activity or chemical reactions, might also produce similar signals.
Independent experts, such as Professor Catherine Heymans, caution that more tests are necessary. “We don’t yet know if the source is life or something else happening on this alien world,” she said.
Could K2-18b Have Oceans?
Some scientists believe K2-18b could have vast oceans, mainly because its atmosphere lacks ammonia—often absorbed by water. But others argue the planet might have an ocean of molten rock, which would not support life as we know it.
NASA’s Dr. Nicolas Wogan even proposed that K2-18b might be a mini gas giant with no surface—another reason why experts urge caution before jumping to conclusions.
A Turning Point in Space Science?
Despite the debates, many in the science community believe we’re entering a new era in the search for life.
“This might be the tipping point,” said Prof. Madhusudhan. “In the future, we could look back at this moment as the time when the living universe came within reach.”
While certainty may still be a year or two away, the team is confident that with more observations, they’ll either confirm or rule out life on this distant world.
“Keep watching this space,” said Dr. Subir Sarkar, part of the Cambridge team. “We’re just getting started.”