Scientists Find 'Strongest Proof Yet' Of Life Outside Our Solar System

K2-18 b is 8.6 times as massive as Earth and with a diameter of about 2.6 times as large as our planet. It orbits in the "habitable zone" where liquid water can exist on a planetary surface.

This artist's impression shows the planet K2-18b, its host star and an accompanying planet in this system.

Source : NASA

Scientists have found the strongest signal of life beyond our solar system in the latest discovery. Using the James Webb Space Telescope, they have detected the chemical fingerprints of gases that can only be produced by biological processes on the exoplanet named K2-18 b, about 124 light-years from Earth.

According to a report by Reuters, two gases, dimethyl sulfide, or DMS, and dimethyl disulfide, or DMDS, have been observed on the planet. On Earth, these gases are produced by living organisms, such as microbes and marine phytoplankton or marine algae.

"This is a transformational moment in the search for life beyond the solar system, where we have demonstrated that it is possible to detect biosignatures in potentially habitable planets with current facilities. We have entered the era of observational astrobiology," said astrophysicist Nikku Madhusudhan of the University of Cambridge's Institute of Astronomy, the lead author of the study published in the Astrophysical Journal Letters.

K2-18 b is said to be approximately 8.6 times more massive than Earth and has a diameter about 2.6 times larger. It orbits within the "habitable zone"—the region around a star where liquid water, essential for life, can exist on a planet's surface.

This exoplanet circles a red dwarf star that is smaller and less luminous than our sun, located roughly 124 light-years away. A light-year is the distance light travels in one year, which equals about 5.9 trillion miles (9.5 trillion kilometres). Another planet has also been discovered orbiting the same star.

'Hycean Worlds'

The report says about 5,800 planets beyond our solar system, called exoplanets, have been discovered since the 1990s. Some of the planets are within the habitable zone. Scientists call these hycean worlds – covered by a liquid water ocean, habitable by microorganisms and with a hydrogen-rich atmosphere.

"We are talking about microbial life, possibly like what we see in the Earth's oceans," said Madhusudhan about life in hycean worlds, if they exist.

He added, “Their oceans are hypothesised to be warmer than Earth's. Asked about possible multicellular organisms or even intelligent life. We won't be able to answer this question at this stage. The baseline assumption is of simple microbial life."

The two gases DMS and DMDS, both from the same chemical family, have been predicted as important exoplanet biosignatures.

Madhusudhan said that the scientists will have to repeat “the observations two to three times to make sure the signal” are “robust”. He also added, “we need more theoretical and experimental studies to make sure whether or not there is another abiotic mechanism (one not involving biological processes) to make DMS or DMDS in a planetary atmosphere like that of K2-18 b.”

So the findings still remain “a big if” on whether their observations are due to life.