This article was automatically translated from the original Turkish version.
K2-18 b is an exoplanet orbiting a red dwarf star. It completes one orbit around its star in 32.9 days and is located at a distance of 0.1429 AU from the star, which is approximately seven hundred trillion miles from Earth. Its discovery was announced in 2015. While some technical details about this planet have been established, the accuracy of certain data remains unconfirmed.
Position of the K2-18b planet relative to Earth and the Sun (Ibtest)
According to a peer-reviewed scientific article published on April 17 in The Astrophysical Journal Letters, K2-18b, located 124 light years from Earth and situated within its star’s habitable zone—the region where conditions are suitable for liquid water to exist on the planet’s surface—has been found to contain dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) in its atmosphere. On Earth, these molecules are produced exclusively by marine algae and other microscopic organisms. This raises the possibility that similar life forms may be responsible for the presence of these molecules on K2-18b.
To date, DMS and DMDS have never been definitively detected in the atmosphere of any other planet or natural satellite. In their paper, researchers stated, "Our findings provide new independent evidence for the presence of a biosphere on K2-18 b and represent a significant step forward in the search for biosignatures on exoplanets."
The researchers noted that the levels of DMS and DMDS in the atmosphere could reach up to 10 parts per million, which is significantly higher than their concentrations on Earth.
The researchers have assigned a significance level of "three sigma" to their observations of K2-18b. This means there is a 0.3 percent probability that these chemicals could have arisen by chance without biological activity. However, current scientific standards require a higher threshold to confirm a discovery. Scientists typically demand a "five sigma" level to rule out random occurrence, which corresponds to a probability of less than 0.00006 percent that the molecules appeared by chance. This level has not yet been reached.
Generated by artificial intelligence
Schwieterman stated, "In an ideal scenario, researchers could send a spacecraft or astronauts to the surface of this exoplanet and directly detect molecules that can only be produced by life." In comments to Space.com, Schwieterman added, "Researchers could deploy a probe to search for RNA, DNA, and other biomolecules we know are associated with life, and use their findings as evidence of extraterrestrial activity."
However, scientists consider this approach currently unfeasible. Since the exoplanet lies outside the Solar System, sending a spacecraft to reach it is generally a project requiring decades of planning.
Therefore, scientists rely on analyzing the light spectra that telescopes can observe to search for signs of life beyond Earth. Astronomers gather information about the wavelengths of light that pass through a planet’s atmosphere and are absorbed by its gases. Based on the characteristics of these wavelengths, they can infer the composition of the atmosphere.
Debate on Potential Biosignatures on the Exoplanet
Human Accessibility to the Exoplanet
