The two gases involved in Weber’s observation of Weber’s planet called K2-18b – dimethyl sulfide, DMS and dimethyl disulfide or DMD – are produced on Earth by living organisms, mainly microbial life such as plankton in marine plant plants, such as algae.
This suggests that the planet may be filled with life with microbial organisms, the researchers said. However, they stress that they are not announcing the discovery of actual organisms, but a possible biosignature (an indicator of biological processes), and that they need to be carefully observed and require more observations.
Despite this, they expressed excitement. This is the initial hint of a foreign world, said Nikku Madhusudhan, an astrophysicist at the Institute of Astronomy at the University of Cambridge, whose lead authors published in the Journal of Astrophysics letter.
“This is a moment of change in searching for life outside the solar system, and we have proven that it is possible to detect biosignatures in potential habitable planets with current facilities. We have entered the age of observing astrobiology,” Madhusudhan said.
Madhusudhan notes that various efforts are being made to find signs of life in our solar system, including various environmental claims that may be conducive to living in places like Mars, Venus and various icy moons.
Its orbit in the “habitable zone” – a distance from which liquid water (a key component of life) can exist on the planet’s surface – is smaller, smaller stars around the red dwarf stars than our sun, and smaller than our sun (located about 124 light-years from Earth). Light years are 5.9 trillion miles (9.5 trillion kilometers) of light within one year. Another planet was also identified orbiting the star.
A “Hycean World”
Since the 1990s, about 5,800 planets outside our solar system, called exoplanets, have been discovered. Scientists assume that there is an exoplanet called Hycean Worlds – a livable ocean of water covered by microorganisms and a hydrogen-rich atmosphere.
Webb’s early observations, initiated in 2021 and started operations in 2022, identified methane and carbon dioxide in the atmosphere of K2-18 B, the first time that carbon-based molecules were found in the atmosphere of external stars in the habitable zone of a star.
“The only explanation of all the data from JWST (James Webb Space Telescope) to include past and present observations, which is K2-18 B is Hycean World with the craze of life,” Madhusudhan said. “But we need to be open and continue to explore other situations.”
If Hycean Worlds exist, Madhusudhan said, “we are talking about the lives of microorganisms, probably like we see in the Earth’s oceans.” Their oceans are considered warmer than Earth. Asked about possible multicellular organisms and even clever life, Madhusudhan said: “We will not be able to answer this question at this stage. The baseline hypothesis is simple microbial life.”
DMS and DMD from the same chemist family have been predicted as important exoplanetary biosignatures. Webber found that one or the other or possibly both exist in the Earth’s atmosphere with a confidence of 99.7%, meaning that the observation still has a 0.3% chance of statistical fluorine.
Gas was detected at an atmospheric concentration of more than 10 parts per million portion.
“Reference, this is thousands of times higher than their concentrations in the Earth’s atmosphere and cannot be explained without biological activities based on existing knowledge,” Madhusudhan said.
Scientists who do not participate in the research shall make careful provisions.
“The rich data from K2-18 B makes it an attractive world,” said Christopher Glein, chief scientist at the Space Science Department of Southwestern Institute in Texas. “These latest data are a valuable contribution to our understanding. However, we have to test the data in as much detail as possible. I look forward to starting to see other independent work on data analytics next week.”
Transit method
K2-18 B is part of planets like the “subarctic line” with a diameter larger than the Earth but smaller than Neptune, which is the smallest gas planet in our solar system.
To determine the chemical composition of the exoplanet’s atmosphere, astronomers analyzed the light of the host star from the Earth’s perspective (called the Transit method). As the planet transitions, Weber can detect the decrease in star brightness, and a small portion of starlight passes through the planet’s atmosphere before telescope detection. This allowed scientists to identify the composition of the Earth’s atmosphere.
Weber’s previous observations of the planet provided a tentative tip for DMS. Its new observations use different instruments and different wavelength ranges.
Madudan said the “holy grail” of exoplanetary science is to find evidence of life on Earth-like planets outside our solar system. Madhusudhan said that for thousands of years our species has been in the universe “only us” and now it may only take a few years to discover possible alien life in the world of maritime science.
But Madhusudhan still urges caution.
“First, we need to repeat the observations two to three times to ensure the signal we see is robust and improve the detection meaning,” Madhusudhan said.
“Secondly, we need more theoretical and experimental research to ensure there is another abiotic mechanism (a non-biological process involved) to make DMS or DMD in a planetary atmosphere like K2-18 b.
Therefore, these findings represent whether the observations were “a big word” caused by life, “no one claimed in advance that we had discovered the interest in life,” Madhusudhan said.
