Scientists discover strongest evidence of life beyond Earth - but how hopeful should we be?

Scientists have discovered what they are calling the strongest sign yet of possible life outside of our solar system.

In the atmosphere of K2-18b, a planet 124 light-years from Earth, scientists have detected traces of gases that, on our planet, are primarily produced by living organisms, according to a team of researchers at Cambridge University.

Using the James Webb Space Telescope (JWST), scientists detected traces of dimethyl sulphide (DMS) and dimethyl disulphide (DMDS). On Earth, these gases are produced by marine phytoplankton and bacteria. JWST is powerful enough to analyse the chemical composition of the K2-18b’s atmosphere from the light that passes through from the sun it orbits.

However, before you get too excited about the possibility of aliens existing on a faraway planet, researchers have stressed that the findings are not an announcement of the discovery of living organisms. Instead, they are announcing the discovery of gas traces that could be an indicator of a biological process occurring on K2-18b.

K2-18b orbits the red dwarf star K2-18commons.wikimedia.org

The exoplanet at the centre of the fascinating discovery is in the constellation Leo and has 8.6 times more mass than Earth. There's evidence suggesting K2-18b could have a surface ocean because it orbits its star within the habitable zone. This indicates that the planet could potentially host microbial life.

Earlier observations of the planet identified methane and carbon dioxide in the atmosphere of K2-18b, this marked the first time that carbon-based molecules were identified in the atmosphere of an exoplanet within a star’s habitable zone.

Prof Nikku Madhusudhan from the Institute of Astronomy at the University of Cambridge said the discovery was a “transformational moment in the search for life beyond our solar system”.

More data is needed to confirm the results, however Madhusudhan told the BBC all signs are hopeful: “This is the strongest evidence yet there is possibly life out there. I can realistically say that we can confirm this signal within one to two years.”

You should also read:

• Scientists now say finding alien life in the universe is 'only a matter of time'
• This massive new telescope could find alien life in hours

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