Is there alien life on exoplanet K2-18b? Scientists are doubtful

In April, the presence of potential biomolecules on the distant exoplanet K2-18b raised hopes about the possibility of life beyond Earth — yet scientists are divided.

K2-18b is 2.5 times bigger than Earth and is located 700 trillion miles away. Scientists first spotted the presence of dimethyl sulfide (DMS) and dimethyl disulfide (DMDS), which are only produced by living organisms on Earth.

At the time, it was a promising discovery — and a glimmer of hope that life might exist beyond our planet. And yet, researchers were already sceptical.

“It was exciting, but it immediately raised several red flags because that claim of a potential biosignature would be historic, but also the significance or the strength of the statistical evidence seemed to be too high for the data,” said Dr. Luis Welbanks, a postdoctoral research scholar at Arizona State University’s School of Earth and Space Exploration, according to CNN.

The detected molecules are associated with microbial organisms on our planet, but, according to scientists, they can also form in the absence of life.

Three separate teams of astronomers have now assessed the models and data used in the original discovery and have gotten different results. They suggest that the evidence falls far short of signifying life.

Two scientists at the University of Chicago — Dr. Rafael Luque, a postdoctoral scholar in the university’s department of astronomy and astrophysics, and Michael Zhang, a 51 Pegasi b / Burbidge postdoctoral fellow — found “insufficient evidence” of dimethyl sulfide in the planet’s atmosphere.

Luque and Zhang spotted other molecules that could fit the same profile instead, like ethane, but it doesn’t indicate signs of life.

Meanwhile, in April, additional research by lead researcher Prof. Nikku Madhusudhan reinforced his previous findings about the planet, calling it the most compelling evidence yet that there could be life on K2-18b.

All of this highlights the complexity of the scientific process in searching for life on other planets, and researchers are largely in disagreement about the conclusions.

Earlier, the James Webb Space Telescope (JWST) broke its own record by spotting the earliest known galaxy to date, known as MoM-z14. The galaxy existed just 280 million years after the Big Bang.