Scientists using the James Webb Space Telescope have announced a discovery they describe as the strongest signs of potential life beyond our solar system.

By detecting chemical fingerprints of gases produced only by biological processes on Earth in the atmosphere of an alien planet, researchers have made a breakthrough discovery.

Two gases identified in observations of the planet named K2-18 b with the James Webb Space Telescope (Dimethyl sulfide or DMS and dimethyl disulfide or DMDS) are produced by microbial life forms on Earth, especially by live organisms such as marine phytoplankton and algae.

Researchers stated that this indicated the planet could be teeming with microbial life. Yet, they did not announce the discovery of actual live organisms, rather they announced a potential bio-signature (an indicator of a biological process) and emphasized that the findings should be cautiously viewed, further observations were needed. However, they expressed their excitement nonetheless.

FIRST CLUES OF LIFE ON AN ALIEN WORLD

Lead author of the study published in the Astrophysical Journal Letters, astrophysicist Nikku Madhusudhan from the University of Cambridge’s Institute of Astronomy, stated that these were likely the first clues of an alien world that could be inhabited.

Madhusudhan said, “This marks a turning point in the search for life beyond our solar system; we have shown that with current capabilities, it is possible to detect bio-signatures on potentially habitable exoplanets. We are entering an era of observational astrobiology.”

ANOTHER PLANET DISCOVERED

K2-18 b is 8.6 times larger than Earth and has a radius approximately 2.6 times bigger than our planet. Orbiting a smaller and less bright red dwarf star in the “habitable zone,” a distance where liquid water, a vital component for life, could exist, the planet is located around 124 light-years away in the Leo constellation. A light-year is known as the distance light travels in one year, approximately 5.9 trillion miles (9.5 trillion km). Another planet orbiting this star has been discovered.

“AN OCEAN WORLD TEEMING WITH LIFE”

Since the 1990s, approximately 5,800 exoplanets have been discovered beyond our solar system. Scientists speculated that exoplanets covered with habitable liquid water oceans and rich in hydrogen in their atmospheres, named ocean worlds, were existent.

The previous observations by Webb, launched in 2021 and operational by 2022, detected methane and carbon dioxide in the atmosphere of K2-18 b; signaling the first discovery of carbon-based molecules in the atmosphere of an exoplanet in the habitable zone of a star.

Madhusudhan stated, “The only scenario consistent with all JWST-derived data to date, including historical and current observations, is that K2-18 b is an ocean world teeming with life. However, we must remain open and continue exploring other scenarios.”

CORE ASSUMPTION: SIMPLE MICROBIAL LIFE

If ocean worlds exist, Madhusudhan mentioned, “We’re likely talking about microbial life as we see in Earth’s oceans.”

It is assumed that their oceans are hotter than Earth’s. When asked about possible multicellular organisms and even intelligent life, Madhusudhan stated, “We cannot answer that question at this stage. Our core assumption is simple microbial life.”

“ARE WE ALONE?”

It is estimated that both DMS and DMDS, belonging to the same chemical family, are significant exoplanet bio-signatures. Webb discovered that one of them or probably both are present in the planet’s atmosphere with a 99.7% confidence level, meaning there’s still a 0.3% chance that the observation is a statistical fluke.

K2-18 b is part of the “Neptune-under” class of planets, with a radius larger than Earth but smaller than Neptune, the smallest gas giant in our solar system.

Madhusudhan mentioned the “Holy Grail” of exoplanet science is finding evidence of life on a Earth-like planet beyond our solar system. He stated that our species has wondered for millennia whether we are “alone” in the universe and now detecting possible alien life on an ocean world beyond could happen in just a few years.