• Planet, called K2-18 B, is 8.6 times the mass of the earth.
• It is about 124 light years from Earth.
• Researchers do not advertise the discovery of actual alien life.

In a potential landmark discovery, scientists using the James Webb spaces have achieved what they call the strongest signs of a possible life beyond our solar system, and detects in a foreign planet’s atmosphere the chemical fingerprints of gases produced on earth only by biological processes.

The two gases – dimethylsulfide or DMs and dimethyldisulfide or DMDs – involved in Webb’s observations of the planet named K2-18 B are generated on Earth by living organisms, primarily microbial life, such as marine phytoplankton – algae.

This suggests that the planet can teem with microbial life, the researchers said. However, they emphasized that they do not advertise the discovery of actual living organisms, but rather a possible biosignature – an indicator of a biological process – and that the conclusions should be seen gently with several necessary observations.

Nevertheless, they expressed excitement. These are the first tips of a foreign world possibly inhabited, said astrophysicist Nikku Madhusudhan of the University of Cambridge’s Institute of Astronomy, lead author of the study published in Astrophysical Journal Letters.

“This is a transformational moment in search of life beyond the solar system, where we have demonstrated that it is possible to discover biosignatures in potentially habitable planets with current facilities. We have entered an observation astrebiology,” Madhusudhan said.

Madhusudhan noted that there are different efforts that seek signs of life in our solar system, including various claims of environments that can be conducive to life in places such as Mars, Venus and different icy moons.

K2-18 B is 8.6 times as massive as the Earth and has a diameter approx. 2.6 times as large as our planet.

It orbits into the “habitable zone” – a distance where liquid water, a key ingredient for life, can exist on a planetary surface – around a red dwarf star that is less and less luminous than our sun, which is about 124 light years from Earth in the constellation Leo. A light year is the spacer travel in one year, 5.9 trillion miles (9.5 trillion km). Another planet has also been identified orbiting this star.

A ‘HYCEAN WORLD’

About 5,800 planets in addition to our solar system, called exoplanets, have been discovered since the 1990s. Researchers have assumed the existence of exoplanets called Hycean Worlds covered by a floating water sea residential of microorganisms and with a hydrogen-rich atmosphere.

Previous observations of webb launched in 2021 and operational in 2022 had identified methane and carbon dioxide in K2-18 B’s atmosphere, the first time carbon-based molecules were discovered in the atmosphere of an exoplanet in a star’s habit zone.

“The only scenario that is currently explaining all the data that has been achieved so far from JWST (James Webb-Rum Telescope), including past and current observations, is one where K2-18 B is a Hycean world teeming with life,” Madhusudhan said. “However, we have to be open and continue to explore other scenarios.”

Madhusudhan said that with Hycean Worlds, if they exist, “we are talking about microbial life, possibly like what we see in the ocean of the earth.” Their oceans are assumed to be warmer than the earth’s. On the question of possible multicellular organisms or even intelligent life, Madhusudhan said, “We will not be able to answer this question at this time. The baseline assumption is of simple microbial life.”

DMS and DMDs, both from the same chemical family, have been predicted as important exoplanet -biosignatures. Webb found that one or the other, or possibly both, was present in the planet’s atmosphere at a 99.7% confidence level, which means there is still a 0.3% chance that the observation is a statistical fluke.

The gases were detected at atmospheric concentrations of more than 10 parts per day. Million by volume.

“As a reference, this is thousands of times higher than their concentrations in the Earth’s atmosphere and cannot be explained without biological activity based on existing knowledge,” Madhusudhan said.

Researchers who are not involved in the study advised bypass.

“The rich data from K2-18 B makes it a tempting world,” said Christopher Glein, head scientist at the Space Science Division of the Southwest Research Institute in Texas. “This latest data is a valuable contribution to our understanding. Still, we need to be very careful to test the data as thoroughly as possible. I look forward to seeing further, independent work with the data analysis that starts as soon as next week.”

Transit method

The K2-18 B is part of the “sub-NEEPTUN” class of planets, with a diameter larger than the Earth’s, but smaller than Neptune, the smallest gas planet of our solar system.

In order to ascertain the chemical composition of an exoplan’s atmosphere, astronomers analyze the light from its host star as the planet passes in front of it from the Earth’s perspective, called the transit method. As the planet transites, webb can detect a decrease in the star’s brightness, and a small fraction of Starlight passes through the planetary tate of the planeta before discovering by the telescope. This lets researchers determine the constituent gases of the planet’s atmosphere.

Webb’s previous observations of this planet gave a tentative hint of DMS. Its new observations used another instrument and another wavelength range.

The “sacred grail” from exoplanet Science, Madhusudhan said is finding evidence of life on an earth -like planet beyond our solar system. Madhusudhan said that our species for thousands of years have been wondering “are we alone” in the universe, and now it may be within a few years after discovering a possible foreign life in a Hycean world.

But Madhusudhan still called for caution.

“First, we need to repeat observations two to three times to make sure the signal we see is robust and to increase detection significance” to the level where the odds of a statistical fluke are below about one in a million, Madhusudhan said.

“Secondly, we need more theoretical and experimental studies to ensure if there is another abiotic mechanism (one that does not involve biological processes) to make DMS or DMDs in a planetary atmosphere such as K2-18 b. Although previous studies have hinted at them (as) robust biosignatures, even for K2-18 b, we have to remain open and pursue to others, and we have to open and pursue and pursue to others, Opportunities, ”said Madhus.

So the results represent “a big one if” about observations is due to life and it is in “no interest to claim too early that we have discovered life,” Madhusudhan said.