Okay, this might be the closest we’ve ever come to finding signs of life beyond Earth—and it’s blowing some minds in the astrophysics community.
A planet called K2-18 b, located 124 light-years away in the Leo constellation, has just served up the strongest evidence yet that alien life might be out there. Using data from the ultra-powerful James Webb Space Telescope, researchers picked up on chemical signatures that — here on Earth—are only produced by living organisms.
We’re talking about dimethyl sulfide (DMS) and dimethyl disulfide (DMDS)—both compounds largely associated with marine life like phytoplankton. While the presence of these chemicals doesn’t prove aliens exist, it’s a major step forward in answering that age-old question: Are we alone?
“This is the strongest evidence to date for biological activity beyond our solar system,” said Prof. Nikku Madhusudhan, who led the observations at the University of Cambridge. “We’re cautious, of course — but this could be the tipping point.”
K2-18 b isn’t your average rock floating in space. It’s a super-Earth (or mini-Neptune)—about 9 times heavier and 2.6 times larger than Earth — and it orbits in the habitable zone of its star. That’s the sweet spot where conditions could allow for liquid water.
This planet first made headlines in 2019 when Hubble spotted what looked like water vapor in its atmosphere. Later, it turned out to be methane — but that didn’t kill the hype. Madhusudhan’s team doubled down in 2023, suggesting this world might be covered in a deep global ocean. The latest Webb data only adds fuel to the fire.
Here’s the catch: we’re still guessing, and the planet is too far away for us to snap a clear pic or send a probe. Instead, astronomers watch as the planet crosses its star and analyze how the light filters through its atmosphere. In this case, they noticed a drop in light that aligns perfectly with DMS and DMDS, meaning those molecules are very likely there — and in amounts thousands of times higher than what we find on Earth.
Still, not everyone’s ready to toast the aliens just yet.
Some scientists point out that DMS was also found on an icy, lifeless comet. Others suggest weird geological processes like volcanic vents or even lightning storms could be responsible — though those ideas remain speculative. In other words, life is one explanation, but not the only one.
“My skepticism dial for any claim relating to evidence of life is permanently turned up to 11,” said Dr. Jo Barstow from the Open University. “Extraordinary claims need extraordinary proof.”
Fair. But even if it’s not aliens this time, these findings are pushing the limits of what we can do with space science. They’re proof that humanity is starting to sniff out biosignatures on distant worlds — which is pretty wild when you think about it.
As Prof. Madhusudhan put it:
“We’re not trying to go there and swim in the ocean to catch the fish. We’re trying to understand if the laws of biology apply universally.”
TL;DR—We may not have found ET just yet, but we’re getting freakishly close.
