Scientists at the University of Cambridge have made a new discovery that could point to life on a distant world. Using the powerful James Webb Space Telescope, they found signs of gases in the atmosphere of planet K2-18b. These gases, on Earth, are made only by living microbes. While the evidence is not final, the findings are stronger than ever before. Researchers say this may be our clearest sign yet that we are not alone in the universe.
Strange Gases Hint at Possible Life
K2-18b is about 2.5 times the size of Earth and orbits a star 700 trillion miles away. It lies in what scientists call the “habitable zone,” where temperatures might allow liquid water to exist.
The Cambridge team looked at light filtering through the planet’s atmosphere as it passed in front of its star. They believe they spotted signs of two rare gases: dimethyl sulphide (DMS) and dimethyl disulphide (DMDS). On Earth, these gases are created only by oceanic plankton and bacteria.
Lead researcher Professor Nikku Madhusudhan said the amount of gas detected was surprising. “It’s thousands of times more than what we see on Earth,” he explained. If these gases really mean life is present, then K2-18b could be packed with living microbes.
“This is the clearest sign so far that extraterrestrial life might be real,” said Prof Madhusudhan. “We may be able to confirm it within two years.”
Exciting Progress, But Caution Still Needed
While the data is thrilling, scientists are careful not to jump to conclusions. Right now, the evidence is at what is called a “three sigma” level. That means a 99.7% chance the signal is real. However, science requires even higher certainty—five sigma, or 99.99999%—to confirm a true discovery.
Eighteen months ago, an earlier study showed a weaker signal at the one sigma level. That was only a 68% chance. This latest data is far better, but still not final. Prof Catherine Heymans, Scotland’s Astronomer Royal, noted that even if we reach five sigma, the gas might not come from life. “The universe can surprise us. Many processes could create these gases,” she warned.
Could It Be Something Else?
The Cambridge team is open to other ideas. They are working with other scientists to test if these gases could be made without life. Maybe heat and chemicals deep in the planet could form DMS and DMDS.
There are also debates about the planet itself. Some scientists believe K2-18b has a massive ocean. They say the lack of ammonia in its air suggests it’s dissolving in water. Others disagree, saying it might be a sea of molten rock—far too hot for life.
One theory from Dr. Nicolas Wogan at NASA suggests the planet might be a small gas giant with no solid surface. That would make life less likely. But other researchers say that idea doesn’t match the telescope’s data.
Prof Oliver Shorttle from Cambridge stressed how tricky the research is. “We are studying faint light from a planet billions of miles away. That light tells us everything, but it’s so easy to misread,” he said.
A Future Full of Promise
Despite the questions, the discovery has sparked new energy in the search for life. The James Webb Space Telescope continues to collect more data. With each observation, the picture becomes clearer.
Prof Madhusudhan believes we are getting close to answers. “Years from now, people might remember this moment. It could be the start of a new chapter—when we first truly reached out and saw signs of life beyond Earth,” he said.
The idea that microbes might exist on K2-18b is already changing how scientists think about life in the universe. If one planet shows signs of life, maybe many others do, too.
We May Be Closer Than Ever to Finding Life
This research doesn’t give us final proof of life—but it gives us strong clues. As more data comes in, we may soon learn whether tiny life forms float in K2-18b’s alien seas.
If life exists there, it will change everything we know about the cosmos. We’ll learn that Earth is not alone, and that life might be a natural part of the universe.