The quest finds life beyond our solar system with the discovery of an exoplanet named K2-18b. It lies 120 light-years from Earth. Scientists and enthusiasts cheer this world because it might hold alien life. This marks a big moment in astrobiology.

What Makes K2-18b Special?

K2-18b is not Earth. It is a "super-Earth" that is 2.6 times the size and almost nine times the mass of our planet. It carries a thick, hydrogen-rich atmosphere. It likely wraps a vast liquid ocean around itself. That ocean may mix methane, ammonia, or acidic compounds instead of water. It recalls the lakes of methane and ethane on some Saturn moons.

Gases fill the atmosphere. Methane and carbon dioxide make it hard for humans to breathe without a suit. Yet, dimethyl sulfide appears there too. On Earth, life makes dimethyl sulfide. Its presence may point to microbes or simple aquatic life.

The Challenges of Studying Distant Exoplanets

Studying planets so far is hard work. Scientists relied on the James Webb Space Telescope to gather data on K2-18b. The telescope watched the planet move in front of its star. Starlight filters through the atmosphere. This light shows clues about the gases there. Still, the surface stays hidden because of the great distance.

It would take about 1.3 million years to travel to K2-18b at current rocket speeds. Human travel is not possible with our technology today.

Some astronomers may not see K2-18b as a super-Earth. They label it a mini-Neptune. Its thick air and missing hard surface could cut the chance for life as we know it.

Looking Closer to Home: Proxima Centauri b and Ross 128 b

K2-18b fires our curiosity. Other nearby worlds may hold life too.

Proxima Centauri b

Proxima Centauri b sits 4.2 light-years away. It circles Proxima Centauri, the star closest to our Sun. This planet is a bit larger than Earth. It orbits a cool red dwarf star and gets less heat than a planet near a sun-like star. Its temperature hovers near -39°C. That cold may still allow some forms of life. Still, scientists worry about the planet’s air, gravity, and flares that fire harmful radiation.

Ross 128 b

Ross 128 b lies 11 light-years away. Its star stays quiet with low bursts of energy. This calm light makes the place more stable. Still, the planet orbits very close to its star, about 20 times nearer than Earth is to the Sun. The cooler star helps Ross 128 b keep a spot where liquids can exist. Its average temperature may be near 23°C. This is warmer than Earth. Yet, questions cover its air and the radiation it gets. Life here might be very different from what we expect.

The Bigger Picture: A Universe of Possibilities

Over 5,000 exoplanets have now been confirmed by astronomers. About 63 might have chances for life. Most of these worlds have harsh conditions. Some have toxic air, extreme heat or cold, or suffer from strong bursts of star energy.

The sign of dimethyl sulfide on K2-18b is an exciting clue. It is not proof of life. New telescope tools, space probes, and ideas for travel will bring more clues soon. For now, planets like Proxima Centauri b, Ross 128 b, and K2-18b keep our minds active. They remind us of the great unknown that lies beyond our solar system.

Conclusion

The hunt for life beyond Earth stays one of our boldest quests. K2-18b shows hints of life with the gases in its air. Big challenges exist. Distances are huge, and planets can be harsh. Yet, each new measure and tool shapes our view of the universe and our place in it. Who knows what surprise waits close by, turning a distant idea into a real world?