doi.org/10.48550/arXiv.2505.13407
Credibility: 888
#K218b
Scientists recently found a molecule on a distant planet that they thought might indicate alien life
But new research suggests that the molecule is probably just an ordinary gas, and the evidence isn’t as strong as it first seemed.
In April, a group of scientists at the University of Cambridge caused a stir when they announced that the James Webb Space Telescope had detected a molecule in the atmosphere of a planet called K2-18b, 124 light-years from Earth.
They believed the molecule might be dimethyl sulfide or dimethyl disulfide, substances that are produced only by living things on Earth.
The news made headlines around the world.
But a team at the University of Chicago decided to investigate further, knowing that such extraordinary claims require very solid evidence.
A Molecular Puzzle
The new research, led by Rafael Luque and published in the journal Astronomy and Astrophysics Letters, concluded that the available data is too uncertain to confirm the presence of life.
“The data we have so far is too confusing to make such a big claim,” Luque said.
“There’s not enough certainty to say one way or the other.”
Observing planets like K2-18b is difficult because they’re too far away and too faint to see directly.
Scientists use clever techniques to analyze starlight passing through the planet’s atmosphere.
As light passes through the atmosphere, different molecules block different parts of the light, creating a pattern that can indicate what substances are present.
But Michael Zhang, a co-author of the study, explains that identifying a specific molecule based on such weak data is very tricky.
“Any molecule with a carbon atom bonded to three hydrogens shows up at a certain wavelength,” he said.
“Dimethyl sulfide has this characteristic, but so do many other molecules, and they can produce similar patterns in the telescope data.
Even with better data, it would be hard to be sure that it is really dimethyl sulfide.”
Ethane, Not Aliens
The team’s analysis showed that other molecules could explain what the telescope detected.
One of them is ethane, a common gas found on planets like Neptune that has no association with life.
Caroline Piaulet-Ghorayeb, another co-author, explained that scientists prefer the simplest explanation: “We should only consider exotic molecules after ruling out the ones we expect to find in the atmosphere.”
If the signal could be both dimethyl sulfide and ethane-a gas common on planets in our solar system-then the most likely explanation is the more common one, not the more exciting one.
Missing Data and Exaggeration
Another problem is that the April announcement was based on just one observation of the planet.
Both the James Webb Telescope and Hubble have made multiple observations of K2-18b.
When all of this data is taken together, the evidence for dimethyl sulfide becomes much weaker.
The study authors want to provide a more complete and cautious view of the results.
Beware the Search for Life
“Finding out if there is life outside the solar system is the most important question in our field.
That’s why we study these planets,” Luque said.
“We are making great progress, and we don’t want that to be overshadowed by hasty announcements.”
This research shows that, for now, we need to be careful before claiming that we have found signs of life on other planets.
What seemed like an exciting discovery may just be a common gas, such as ethane, and more studies are needed to shed light on the mystery.
Published in 05/27/2025 16h20
Text adapted by AI (Grok) and translated via Google API in the English version. Images from public image libraries or credits in the caption. Information about DOI, author and institution can be found in the body of the article.
Reference article:
Original study:
| Geoprocessing Drone Systems HPC |
| ERP and CRM Systems Mobile Systems AI |