Have signs of life been discovered on a planet 110 light years away by an international team of scientists, led by the University of Cambridge?

The tantalising prospect emerged as data from the James Webb Space Telescope confirmed methane and carbon dioxide had been detected in the atmosphere of K2-18 b, an exoplanet in the ‘Goldilocks zone’ – not too hot and not too cold to support life.

It is the first time carbon-based molecules have been discovered in the atmosphere of an exoplanet in the habitable zone – but there was also another, weaker signal in the K2-18 b spectrum.

The researchers carried out several analyses and believe that signal could only be caused by a molecule called dimethyl sulphide (DMS).

On Earth, this is only produced by life – primarily microbial life like marine phytoplankton – which hints at the possibility of biological activity on K2-18 b.

The researchers are cautious, however, saying these signs are tentative and require further validation.

But what the findings do suggest is that K2-18 b and other such ‘Hycean planets’ could be our best chance to find life outside of our own solar system.

“Our ultimate goal is the identification of life on a habitable exoplanet, which would transform our understanding of our place in the Universe,” said Professor Nikku Madhusudhan, from Cambridge’s Institute of Astronomy. “Our findings are a promising first step in this direction.”

K2-18 b lies 110 light years from Earth in the constellation of Leo and is 8.6 times the size of Earth. It orbits a cool dwarf star, K2-18, in the habitable zone.

The Hubble Space Telescope provided us with the first insight into its atmosphere, but there has been debate over the findings.

The same research team examined it in 2021 and 2021, identifying it as belonging to this new class of habitable exoplanets called ‘Hycean’ worlds, which are hot, water-covered planets with a hydrogen-rich atmosphere.

Those findings prompted them to look again with the power of Hubble’s successor, the James Webb Space Telescope, to understand the constituent gases and physical conditions of its atmosphere.