Is someone really out there?

For as long as humans have gazed at the night sky weve asked a question both simple and profound Are we alone in the universe Once the domain of philosophers and science fiction writers that question has become the subject of serious scientific inquiry And now thanks to a faraway planet and the most powerful space telescope ever launched we may be closer than ever to a real answerThe planet in question is K218 b orbiting a red dwarf star roughly 120 lightyears away in the constellation Leo It was discovered in 2015 and at first was just one among thousands of exoplanetsmdashworlds outside our solar systemmdashdiscovered over the past three decades But recent findings using NASArsquos James Webb Space Telescope JWST have thrust this planet into the spotlightWhat makes K218 b so interesting isnrsquot just its sizemdashabout 26 times the diameter of Earth and almost nine times its massmdashbut the fact that it orbits in the socalled ldquohabitable zonerdquo of its star where conditions might allow liquid water to exist More compelling still are the atmospheric chemicals detected by JWST methane carbon dioxide andmdashmost intriguinglymdashdimethyl sulfide or DMS On Earth DMS is a compound produced almost entirely by living organisms particularly marine plankton No known nonbiological process creates DMS in notable amounts on our planet If confirmed the presence of DMS in K218 brsquos atmosphere would represent the first possible biosignaturemdashan actual clue to lifemdashfound beyond our solar system While methane and carbon dioxide can be created through geological processes DMS is different It is not something that volcanoes or chemical reactions typically produce on their own Its presence suggests at the very least that we may be looking at an environment that resembles Earthrsquos oceans in some fundamental wayTo understand how scientists reached this conclusion consider the technique usedmdashtransit spectroscopy When K218 b passes in front of its star a tiny fraction of starlight filters through the planetrsquos atmosphere The molecules in that atmosphere absorb certain wavelengths of light leaving behind a spectral fingerprint By analysing this fingerprint astronomers can determine which gases are present Itrsquos an unbelievable featmdashanalysing the atmosphere of a planet more than a hundred lightyears away based solely on how it bends starlightThe team behind this work was led by Professor Nikku Madhusudhan of the University of Cambridge an Indianorigin astrophysicist who has emerged as a leading voice in exoplanet science While methane and carbon dioxide detections are robust the signal for DMS is still tentative though statistically meaningful Currently the DMS detection stands at a 3sigma confidence levelmdashmeaning therersquos about a 0337 chance the signal is a statistical fluke In scientific terms this constitutes ldquoevidencerdquo but not a discovery The gold standard is 5sigma a 00000637 chance of error which is the threshold that decided the discovery of the Higgs boson at CERN in 2012 This level of rigour isnrsquot bureaucraticmdashitrsquos foundational Science works not just on excitement but on evidence A 3sigma signal invites further scrutiny while a 5sigma signal demands acceptance In acknowledging this limitation the researchers embody an oftenoverlooked virtue in sciencemdashepistemic humility Instead of making bold claims theyrsquove opted for cautious optimism refining their models collecting more data and inviting peer review This is science at its bestmdashselfcorrecting careful and grounded in evidence The DMS signal could eventually reach 5sigma or it could fade with better data Either way itrsquos the process not just the outcome that pushes our understanding forwardOf course in science caution is essential The excitement around DMS must be tempered with the understanding that this is not yet a confirmed discovery The signal is intriguing but not yet strong enough to rule out all other explanations Another team led by Dr Nicholas Wogan at NASA Ames Research Center has proposed an alternative interpretation According to their models K218 b might not be an oceancovered ldquoHyceanrdquo world but rather a miniNeptune with a deep thick atmosphere and no solid surface In such an environment high temperatures and pressures deep inside the planet could drive complex chemical reactions producing gases like methane and carbon dioxide without any biological input These gases would then rise to the upper atmosphere mimicking what we might expect from a lifebearing planetTemperature adds another layer of complexity If K218 b lacks a reflective cloud layer it may absorb too much heat from its star pushing the temperature of its lower atmosphere above 647 degrees Celsiusmdashthe socalled critical point of water At that point water no longer behaves like a liquid or a vapour but instead becomes a supercritical fluid a state of matter that is not known to support life as we understand it Whether K218 b has such cloudsmdashor any water at allmdashis still unknownStill whether or not life exists on K218 b these findings represent a turning point in the way we search for life beyond Earth For the first time we are not just cataloguing distant planets we are analysing their atmospheres searching for the kinds of chemical fingerprints that might indicate biology And we are doing so with a level of detail and sophistication that was unimaginable just a decade agoItrsquos also a moment of quiet pride for Indian science and for scientists of Indian origin working at the frontiers of discovery Professor Madhusudhanrsquos work is a reminder that the exploration of the universe is a global endeavour one that draws on the talents and insights of researchers from every part of the world In a recent interview he remarked ldquoWe are now in an era where we can not only find potentially habitable planets but also explore their atmospheres It is a truly transformative moment for sciencerdquo That transformation is still unfoldingMore observations of K218 b are planned using JWST and other telescopes are on the horizon NASArsquos upcoming Roman Space Telescope and the European Space Agencyrsquos ARIEL mission will add new tools to the astronomerrsquos kit allowing even more detailed studies of exoplanet atmospheres Meanwhile scientists here on Earth are working in laboratories to recreate the conditions found on distant planets testing whether molecules like DMS can be formed in lifeless settingsIf future data confirms the presence of DMS and rules out nonbiological sources K218 b could become the first serious candidate for a lifebearing planet beyond Earth But even if that confirmation never comes this moment matters It marks the beginning of a new eramdashone where our search for life is guided not by speculation but by data precision and evidenceMaybe the universe is finally whispering backNishant Sahdev is a theoretical physicist at the University of North Carolina in Chapel Hill United States He can be contacted at nishantsahdevoncogmailcomatOptionskeyd0ddb8ef8f1a62a8cdd22fac27fc5ea7formatiframeheight90width728params