Astronomers using the James Webb Space Telescope have confirmed that planet K2-18b has traces of dimethyl sulfide, a potential biosignature of marine microorganisms, in its atmosphere.
Astronomers using the James Webb Space Telescope have confirmed that the planet K2-18b has traces of dimethyl sulfide, a potential biosignature of marine microorganisms.
K2-18b is a super-Earth exoplanet orbiting the small, cool star K2-18.
Located about 111 light-years from Earth in the constellation Leo, this planet was discovered in 2015 using NASA's Kepler space telescope.
K2-18b has a radius 1.6 times that of our own Earth and orbits within its star's habitable zone, where liquid water could exist on its surface.
Astronomers have detected water vapor in the atmosphere of K2-18b, making it one of the most promising exoplanets for searching signs of life beyond our solar system.
The detection of these compounds in the atmosphere of K2-18b is significant because they are produced by microbial life on Earth, such as phytoplankton. The presence of these substances on an exoplanet would be strong evidence for the possibility of extraterrestrial life.
Extraterrestrial life refers to the existence of living organisms outside Earth's atmosphere.
The possibility of life on other planets has been a topic of interest and debate among scientists and philosophers for centuries.
To date, there is no definitive evidence of extraterrestrial life, but ongoing research and exploration continue to shed light on this intriguing question.
According to NASA, over 4,000 exoplanets have been discovered, with some potentially hosting conditions suitable for life.
The discovery of exoplanet Kepler-452b in 2015, which orbits a G-type star similar to the Sun, has sparked renewed interest in the search for extraterrestrial life.
Theoretical Background and Previous Discoveries
K2-18b is a Hycean planet, characterized by having vast liquid oceans and a hydrogen-rich atmosphere. According to astrobiologists, discovering a Hycean planet would represent one of the best opportunities to find extraterrestrial life. In 2023, the same team of scientists found methane and carbon dioxide in its atmosphere, which was the first time carbon-based molecules were discovered on a planet within a habitable region of space.
A hycean planet is a type of exoplanet characterized by its thick atmosphere and oceanic composition.
These planets are thought to be composed primarily of water, with some containing up to 80% water by mass.
Hycean planets are often found in the habitable zones of their respective stars, making them potential candidates for hosting life.
Research suggests that these planets may have unique properties, such as being able to support liquid 'water' on their surfaces despite being tidally locked.
The Detection Method and Implications
The researchers used the James Webb Space Telescope to detect dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) in K2-18b’s atmosphere. While there is a possibility that these substances have been produced on the planet by an unknown chemical process unrelated to microorganisms, the data represent the strongest evidence to date for possible life on a planet other than our own.
The Planet and Its Conditions
K2-18b is 8.6 times the mass of Earth and nearly three times its size. It orbits a small, low-temperature type of star called a red dwarf, which allows liquid water to exist on its surface. The planet takes only 33 days to complete one orbit around its star.
Conclusion
The detection of dimethyl sulfide and dimethyl disulfide in K2-18b’s atmosphere is a significant finding that has the potential to revolutionize our understanding of extraterrestrial life. While there are still uncertainties surrounding this discovery, it represents a promising indication of the possibility of life beyond Earth.
