Webb Space Telescope Discovers Strongest Evidence Yet Of Extraterrestrial Life
With the aid of NASA's James Webb Space Telescope (JWST), scientists have found compelling evidence that biological life is present and active on a planet called K2-18b, located some 124 light years from Earth. The team was able to determine dimethyl sulfide and dimethyl disulfide—gases normally produced by biological activity on Earth—in the exoplanet's atmosphere as it passed across its parent star. While these gases could come from other sources, scientists are bookmarking K2-18b for closer observations with future tools more sensitive than JWST.
Life beyond Earth. This idea has captured minds for ages, sparking just as many debates as there are searches into space. Practically all of our extraterrestrial missions carry some kind of hope of finding little green men or, at the very least, signs of simple organic life, from Voyager 1 to Mars rover Curiosity. Adding to that mountain of possibility is a new peer-reviewed report (via the Astrophysical Journal Letters) which claims to have found the strongest evidence of biological life on a planet 124 light-years away from us.
According to the author of the report, Nikku Madhusudhan, an astrophysicist at the University of Cambridge, the exoplanet K2-18b contains extremely strong traces of sulfur-bearing gases in the atmosphere. The gases, specifically dimethyl sulfide and dimethyl disulfide, were able to be detected by astronomers as K2-18b glided across its red dwarf star. As the light spectrum from the star filtered through K2-18b's hazy atmosphere, researches used JWST to "read" what wavelengths were absorbed.
The big deal here is that these sulfur gases, at least in Earth context, are produced by marine phytoplankton. The report also states that the concentration of sulfur gas levels on K2-18b are thousands of times higher than on Earth: ten parts per million versus one part per billion. Madhusudhan pronounces the finding as "potentially one of the biggest landmarks in the history of science," adding that "this is the first time humanity has ever seen biosignature molecules — potential biosignature molecules, which are biosignatures on Earth — in the atmosphere of a habitable-zone planet."
Of course, further observation will be required to confirm or deny the research team's declaration. There's much we do not know of chemistry beyond our solar system whereby yet undiscovered photochemistry and geological reactions could technically produce these same sulfur-bearing gases. Future projects, such as the European Extremely Large Telescope and Habitable Worlds Telescope, can be used to better sniff out the truth behind K2-18b.
