Astronomers say they have found the strongest indication of life beyond our solar system, on a planet 124 light-years from Earth called ‘K2-18b.’
A group of scientists think they may have found the strongest sign of alien life yet. It’s not in our solar system, but on a planet called K2-18b, which is 120 light-years away from Earth. They found a certain gas in the planet’s atmosphere that, on Earth, only comes from living things—like ocean algae.
One of the scientists, Dr. Nikku Madhusudhan from the University of Cambridge, said they are being careful not to claim they’ve found life too soon. Still, their results suggest that K2-18b might have warm oceans full of life. He called it a “revolutionary moment”—the first possible sign of life on a planet that could support it.
The study was published in the Astrophysical Journal. Other scientists said the findings were exciting, but it’s too early to be sure. One researcher said, “It’s a hint, but not proof.”
Even if life does exist on K2-18b, it may take a long time to confirm it. One scientist joked that unless we see aliens waving at us, we won’t have a clear answer anytime soon.
K2-18b was first discovered in 2017 by Canadian astronomers. It’s a type of planet called a sub-Neptune—bigger than Earth but smaller than Neptune. These planets are hard to study because we don’t have any like them nearby.
In 2021, Dr. Madhusudhan and his team came up with a new idea: some of these planets might be covered in oceans and have thick, hydrogen-rich atmospheres. They called these planets “Hycean”—a mix of “hydrogen” and “ocean.”
The James Webb Space Telescope, launched in late 2021, helped scientists look more closely at planets like K2-18b. When a planet passes in front of its star, the light shines through its atmosphere. Scientists can study the changes in the light to figure out what gases are in the atmosphere.
While studying K2-18b, the scientists found many of the gases they expected to see on a Hycean planet. Then in 2023, they noticed a small amount of a special molecule called dimethyl sulfide (DMS). On Earth, this chemical only comes from living things—especially from ocean algae.
Later, with more data from the telescope, they found a stronger signal of dimethyl sulfide, and also a similar molecule called dimethyl disulfide. Dr. Madhusudhan said this discovery was shocking—they tried many ways to explain it, but the signal didn’t go away. They think the amount of DMS on K2-18b could be thousands of times higher than what we find on Earth.
Still, not all scientists agree with this view. Some think K2-18b might just be a hot, rocky planet with no oceans—definitely not a place where life could survive. Others say we need more lab tests to understand how DMS behaves in these unusual conditions.
One scientist reminded everyone that we’re just beginning to understand these distant, exotic planets. More research is needed, and new data from the Webb telescope will help.
NASA is working on building even more powerful telescopes to look for signs of life on other planets, including K2-18b. Even though this research takes a long time, scientists believe it’s worth the wait.
One scientist joked, “I’m not shouting ‘aliens!’—but I reserve the right to shout ‘aliens!’ later.” However, there’s concern that U.S. funding for space research might get cut in the future. If that happens, the search for alien life could slow down or stop. See less