A team of astronomers recently made the bold claim that they had found “the strongest evidence yet” that life exists anywhere else besides Earth – setting off a media frenzy.
By studying data from NASA’s James Webb Space Telescope, the researchers at the University of Cambridge announced April 17 that they had found possible biosignatures hinting at the existence of microbial organisms on a distant exoplanet.
That star-orbiting exoplanet, K2-18b, has long fascinated astronomers who consider it among the best ocean worlds to search for signs of extraterrestrial life.
But one independent researcher is already casting doubt on the recent sensational discovery.
Jake Taylor, an astrophysicist at the University of Oxford, took another look at the Webb telescope data used in the study and came to a much different conclusion: Taylor found no evidence of the atmospheric clues that were so integral in the Cambridge study’s findings.
“I don’t personally think that this is a detection of life on K2-18b,” Taylor said in a skeptical video shared on TikTok. “We need way more observations.”
Does alien life exist on exoplanet K2-18b?
K2-18b, which orbits a red dwarf star more than 120 light-years from Earth, has for years intrigued astronomers who believe it exists in what they refer to as the “habitable zone” – where conditions could be right for water to pool on the surface.
Observations have allowed scientists to conclude that the exoplanet, which is 8.6 times bigger than Earth, could be a Hycean world covered by ocean water underneath a hydrogen-rich atmosphere.
The latest findings on K2-18b came from a team of researchers led by Nikku Madhusudhan, an astrophysicist at the University of Cambridge in England.
The team studied data from Webb’s infrared instrument to study the light from K2-18b’s parent star as the exoplanet passed in front of it from Earth’s vantage. That’s what led Madhusudhan and his team to detect hints of sulfur-based gases dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) in the atmosphere – both molecules from the same chemical family.
On Earth, the gases are only produced by life, primarily microbial life such as marine algae like phytoplankton, according to the researchers.
An illustration shows a hycean world – an exoplanet with a liquid water ocean beneath a hydrogen-rich atmosphere – orbiting a red dwarf star. Based on observations by the James Webb Space Telescope, the exoplanet K2-18 b might fit in this category.
Researcher casts doubt on exoplanet discovery
But according to Taylor, those molecules can also be produced naturally including, for instance, by comets.
Taylor was also critical in the TikTok video of the researchers’ decision to compare the molecules found to nitrogen-rich atmospheres like Earth, as researchers aren’t certain how those molecules would behave on a world with a hydrogen-rich atmosphere.
“The data they use are not appropriate for these type of atmospheres,” Taylor said.
In his own study, published to arXiv, Taylor used a common data model for exoplanet studies and found no conclusive traces of either sulfur-based gases.
“I conclude no strong statistical evidence for spectral features,” Taylor wrote in the study.
Scientists to study K2-18b further
This artist’s concept shows what exoplanet K2-18b could look like based on scientific data. NASA’s James Webb Space Telescope has observed K2-18b, an exoplanet 8.6 times as massive as Earth, revealing conditions that could support life on the exoplanet.
Taylor and Madhusudhan, however, may agree on one point: Additional analysis is needed of K2-18b to determine if anything does indeed live on the planet.
Madhusudhan readily acknowledged that his team’s observations could have occurred by chance or could be the result of previously unknown chemical processes at work on K2-18b.
“It’s important that we’re deeply skeptical of our own results, because it’s only by testing and testing again that we will be able to reach the point where we’re confident in them,” Madhusudhan said in a statement announcing his own findings. “That’s how science has to work.”
Independent scientists are sure to analyze the data soon to see if they come to the same conclusion.
Eric Lagatta is the Space Connect reporter for the USA TODAY Network. Reach him at elagatta@gannett.com.
This article originally appeared on Florida Today: New study refutes claim of possible alien life on exoplanet K2-18b