Life beyond the stars: Traces of alien microbes found on 盗U系统前端伪装页面制作an exoplanet 124 light-years away

April 17, 2025  22:23

Astronomers have taken a bold step toward answering humanity’s greatest question: is there life beyond Earth? On the exoplanet K2-18b, located 124 light-years away, scientists have detected chemical signatures that, on our planet, are produced solely by living organisms. This discovery, made possible by the James Webb Space Telescope, has researchers wondering: could we finally have company in the cosmos?

What Was Found on K2-18b?

In K2-18b’s atmosphere, scientists identified two organic compounds—dimethyl sulfide (DMS) and dimethyl disulfide (DMDS). On Earth, these molecules are byproducts of microbial life, particularly ocean-dwelling phytoplankton. Their presence in space is like a cosmic fingerprint, hinting at possible biological activity.

“This isn’t proof of life, but it’s the strongest clue we’ve ever found,” says lead researcher Professor Nikku Madhusudhan. He notes that K2-18b, a “Hycean” world—characterized by a hydrogen-rich atmosphere and vast oceans—is an ideal candidate for life as we understand it.

A Portrait of the Exoplanet

Orbiting a red dwarf star in the Leo constellation, K2-18b is smaller and cooler than our Sun. The planet is 2.6 times Earth’s diameter and 8.6 times its mass, with a year lasting just 33 days due to its close orbit. Surface temperatures are Earth-like, and scientists believe K2-18b is cloaked in a global ocean beneath a dense hydrogen atmosphere. A hybrid of Earth and Neptune, it’s a world where life might have sparked in salty seas under an alien sky.

How Was It Detected?

The James Webb Space Telescope was the key. Its infrared spectrometers captured chemical “signatures” in K2-18b’s atmosphere as the planet passed in front of its star, a technique known as the transit method. The starlight, filtered through the atmosphere, revealed DMS and DMDS, alongside methane and carbon dioxide—clues to watery conditions. This marks the first time biomarkers tied to life have been spotted so far from Earth.

Why This Discovery Matters

The finding reshapes the hunt for alien life:

• Biomarkers: DMS and DMDS are rare molecules, produced on Earth only by living organisms. Their presence on K2-18b suggests possible microbial ecosystems, not mere coincidence.
• Hycean Worlds: K2-18b validates these ocean-bearing, hydrogen-shrouded planets as prime targets for life. Such worlds may be common across the galaxy.
• Astronomy’s Future: The discovery fuels exploration of other exoplanets. With 5,000 exoplanets already found in habitable zones, K2-18b is just the beginning.

Yet questions linger. DMS could, in rare cases, form through non-biological chemistry, though this seems less likely. Scientists are planning further observations to rule out false positives.

What Else to Know?

Madhusudhan’s team is scheduling more Webb sessions to confirm the findings and hunt for other biomarkers, like oxygen or ozone. Future telescopes, such as Ariel (set to launch in 2029), will probe hundreds of exoplanet atmospheres, refining the search for life. For now, K2-18b stands as the top contender for a “second Earth”—or perhaps the “first ocean.”

Traces of life 124 light-years away aren’t science fiction but a reality unveiled by Webb. K2-18b, with its oceans and microbial hints, sparks dreams of waves teeming with alien life. This discovery is a stride toward answering whether we’re alone in the Universe.