Breakthrough Discovery: New Webb Telescope Findings Provide Compelling Evidence of Alien Life on Distant Planet

Researchers utilizing the James Webb Space Telescope have reported what they describe as the most compelling evidence to date of potential life outside our solar system.

They have identified the chemical signatures of gases in an alien planet’s atmosphere that, on Earth, are produced exclusively through biological processes.

The two gases – dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) – observed by Webb on the planet K2-18 b are primarily produced on Earth by living organisms, mainly microbial entities such as marine phytoplankton and algae.

This finding implies that the planet could be abundant in microbial life, according to the researchers.

Nonetheless, these represent the first signs indicating that an alien world could possibly harbor life, said astrophysicist Nikku Madhusudhan of the University of Cambridge’s Institute of Astronomy, who is the lead author of the study published in the Astrophysical Journal Letters.

Since the 1990s, approximately 5,800 exoplanets beyond our solar system have been discovered.

“This marks a transformative moment in the quest for extraterrestrial life, proving that we can detect biosignatures on potentially habitable planets with current technology. We have entered a new age of observational astrobiology,” stated Mr. Madhusudhan.

He mentioned that various initiatives are underway to search for signs of life within our solar system, including investigations into environments that could be suitable for life on Mars, Venus, and several icy moons.

K2-18 b is 8.6 times larger than Earth, with a diameter approximately 2.6 times greater.

It orbits within the “habitable zone” – a region where liquid water, essential for life, could exist on a planet’s surface – around a red dwarf star that is smaller and less luminous than our sun.

A light-year represents the distance light can travel in a year, equivalent to 9.5 trillion kilometers.

Another planet has also been detected orbiting this star.

Since the 1990s, around 5,800 exoplanets have been identified beyond our solar system.

Scientists have theorized the existence of exoplanets known as hycean worlds, which are enveloped by an ocean of liquid water that could support microorganisms and possess a hydrogen-rich atmosphere.

Earlier observations by Webb, launched in 2021 and operational since 2022, had detected methane and carbon dioxide in the atmosphere of K2-18 b, marking the first time carbon-based molecules were found in the atmosphere of an exoplanet within a star’s habitable zone.

When asked about the possibility of multicellular organisms or even intelligent life, Mr. Madhusudhan stated: “We cannot answer this question at this point.”

“The baseline assumption is that of simple microbial life.”

DMS and DMDS, both belonging to the same chemical family, have been predicted as significant biosignatures for exoplanets.

Webb discovered that either one or potentially both gases were present in the planet’s atmosphere with a 99.7% confidence level, indicating a 0.3% chance that the observation is a statistical anomaly.

The gases were identified at concentrations exceeding ten parts per million by volume.

“For context, these levels are thousands of times higher than their concentrations in Earth’s atmosphere, and existing knowledge suggests they cannot be produced without biological activity,” explained Mr. Madhusudhan.

Scientists not involved in the study have advised caution.

K2-18 b belongs to the sub-Neptune category of planets, characterized by a diameter greater than Earth’s, but smaller than Neptune, the smallest gas giant in our solar system.

To analyze the chemical composition of an exoplanet’s atmosphere, astronomers employ the transit method, analyzing the light from a star as the planet passes in front of it from Earth’s viewpoint.

As the planet transits, Webb can detect a reduction in stellar brightness, allowing a small fraction of starlight to pass through the planetary atmosphere before reaching the telescope.

This enables scientists to determine the atmospheric gases of the planet.

Webb’s prior observations of this planet offered an initial indication of DMS.

The recent observations utilized a different instrument and a different spectrum of light.

The “Holy Grail” of exoplanet science, according to Mr. Madhusudhan, is to find definitive evidence of life on an Earth-like planet beyond our solar system.

Mr. Madhusudhan noted that humanity has pondered for millennia whether “we are alone” in the universe and may be only a few years away from discovering potential alien life on a hycean world.

However, he emphasized the necessity of caution.

“First, we need to replicate the observations two to three times to ensure the signal we are observing is robust, increasing the significance of the detection” to a level where the probability of a statistical anomaly is less than approximately one in a million, he stated.

“Second, further theoretical and experimental research is required to determine whether alternative abiotic processes (those not involving biological mechanisms) can produce DMS or DMDS in an atmosphere akin to that of K2-18 b.”

While prior studies have suggested robust biosignatures for K2-18 b, we must remain open to and investigate other possibilities,” Mr. Madhusudhan remarked.

Thus, these findings represent “a significant if” regarding whether the observations are indicative of life, and it is “not in anyone’s interest to prematurely claim that we have detected life,” he concluded.