The exoplanet K2-18b presents compelling evidence that suggests it may be habitable

The exoplanet K2-18 b appears to harbor life! Initial indications of life on this distant planet emerged in 2019 when NASA laboratories detected potential signs of water vapor in K2-18 b’s atmosphere.

Since then, the study has become a top priority for astronomers.

The recent discovery of methane and carbon dioxide molecules reinforces the belief that the distant planet, which orbits a red dwarf star 120 light-years from Earth, may host some form of life and is potentially habitable.

Astrology enthusiasts may find it interesting that K2-18 b is located in the constellation of Leo. This planet is 8.6 times the volume of Earth and orbits at a distance from its sun that allows for the possibility of hosting life forms.

The presence of dimethyl sulfide (DMS) molecules, also found in Earth’s atmosphere and produced by oceanic phytoplankton, suggests a similarity with our planet’s atmosphere.

K2-18 b is classified as a sub-Neptune, a type of planet smaller than Neptune but larger than Earth, which is not found in our solar system.

Their characteristics are diverse and not well understood; they could be super-Earths, mini-Neptunes with hydrogen atmospheres and ice mantles, or even more exotic types like Oceanians with vast oceans, habitable surfaces, and extensive hydrogen atmospheres.

These planets are intriguing to scientists because their exact nature is unknown, and some, such as ocean planets, might even support life.

The role of DMS as a potential indicator of oceanic life on Earth necessitates further investigation on K2-18 b to confirm its origins and implications for life.

The James Webb Space Telescope is expected to shed light on many of these mysteries, including the confirmation of DMS and its association with life. If there is life in K2-18 b, it is expected that it will most likely be microbial.

Research on K2-18 b

The head of research on K2-18 b is astrophysicist at the University of Cambridge, Dr. Nikku Madhusudhan. He has called the planet the “globe world,” which is a relatively new term he coined for a rocky planet with an atmosphere rich in hydrogen and oceans of water.

“If we detect DMS in K2-18 b, that basically puts it on top of possible signs of habitability,” Dr. Madhusudhan told the Times.

In 2023, the James Webb Space Telescope detected carbon dioxide and methane in its atmosphere, as well as ammonia deficiency.

Dr. Madhusudhan called this moment “very important” because it supports the theory that there is an ocean of water beneath an atmosphere rich in hydrogen.

Webb’s initial observations provided a possible detection of a molecule called dimethyl sulfide (DMS), which on Earth is “produced only by life.”

Most of the DMS in Earth’s atmosphere is emitted by phytoplankton in marine environments – suggesting a similar life form on the distant planet.

In fact, scientists have been unable to think of any physical geological or chemical process that could create DMS without living organisms.

Dr. Madhusudhan said the finding came as a shock to them, but because these were initial observations, he could only say with 50% certainty that there is DMS in K2-18 b.

“It was a real shock, I had sleepless nights for a week. That week, I didn’t even find the courage to announce it to my own team.”

James Webb’s new observations

The new observations from James Webb are expected to provide a definitive answer – although the expert will have to spend months studying the data to get it.

NASA’s $10 billion (£7.4 billion) space telescope is able to analyse the chemical composition of a distant planet by recording light from its host star after passing through the planet’s atmosphere on its way to Earth.

The atmosphere’s gases absorb some of the stellar light, but each leaves telltale signatures in the light spectrum, which astronomers can then unravel.

Although the “water worlds” are predicted to be covered in water, the researchers say it’s also possible that K2-18 b’s supposed ocean is too hot to be habitable or humid.

In fact, a study published earlier this year suggested that the ocean may be lava.

K2-18 b is known as “super Earth” because it is larger than our planet but smaller than Neptune.

The large size of K2-18 b – with a radius 2.6 times that of Earth, meaning the planet’s interior likely contains a large high-pressure ice mantle, like Neptune, but with a thinner atmosphere rich in hydrogen and an ocean surface.

“Although this kind of planet does not exist in our solar system, ‘sub-Neptunes’ is the most common type of planet known so far in the galaxy,” said researcher Subhajit Sarkar of Cardiff University. “We have obtained the most detailed spectrum of a sub-Neptune habitable zone to date, and this has allowed us to calculate the molecules present in its atmosphere.”