New observations by the Webb Space Telescope have reignited the debate about possible life on K2-18b, a potentially habitable exoplanet 124 light-years away.
The post Life on K2-18b? Exciting new results met with skepticism first appeared on EarthSky.
Science matters. Wonder matters. You matter. Join our 2025 Donation Campaign today. K2-18b is an exoplanet 124 light-years away and is larger and more massive than Earth. Scientists said it might have a deep global ocean under a hydrogen atmosphere. Could it support life? Scientists said it might have a deep global ocean under a hydrogen atmosphere. Could it support life? New observations from the Webb Space Telescope show there is a molecule called dimethyl sulfide in its atmosphere, a possible signature of life. Webb had previously tentatively detected it before, but the new observations show a stronger signal. show there is a molecule called dimethyl sulfide in its atmosphere, a possible signature of life. Webb had previously tentatively detected it before, but the new observations show a stronger signal. The results don't prove there is life on K2-18b, but they are tantalizing. Other scientists are quite skeptical, however. Life on exoplanet K2-18b? In 2023, scientists announced they had tentatively identified the gas dimethyl sulfide – a possible biosignature of life – in the atmosphere of K2-18b, an exoplanet 124 light-years away. On April 17, 2025, scientists at the University of Cambridge in the U.K. said they found the gas again with the Webb Space Telescope, but this time with a stronger signal. They said the dimethyl sulfide appears to be thousands of times more abundant on K2-18b than on Earth. However, more data are needed to fully confirm its presence and whether it is connected to life … or not. And many scientists are still skeptical. The New York Times first broke the news on April 16, 2025. The researchers published their peer-reviewed results in The Astrophysical Journal Letters on April 17, 2025. A hint of dimethyl sulfide K2-18b is a super-Earth or sub-Neptune world, orbiting in the habitable zone – where liquid water could exist – of its star. Its exact classification is also still a matter of debate among scientists, which has a lot…