🌍 What Is K2-18b?
- K2-18b is an exoplanet, meaning it orbits a star outside our solar system.
- It is located about 124 light-years away in the Leo constellation, orbiting a red dwarf star called K2-18 1.
- It’s classified as a Hycean planet—a type of world with a hydrogen-rich atmosphere and possibly deep oceans 2.
🪐 Why It Can’t Be the 9th Planet
To be considered a planet in our solar system, a body must:
- Orbit the Sun (not another star),
- Be massive enough to be spherical,
- Clear its orbit of other debris.
K2-18b fails the first criterion—it orbits a different star, not the Sun. So, no matter how Earth-like or fascinating it is, it cannot be counted among the planets of our solar system.
🔭 Why It’s Still Important
K2-18b is scientifically exciting because:
- It lies in the habitable zone of its star.
- It may have liquid water and a hydrogen-rich atmosphere.
- In 2023–2025, scientists detected methane, carbon dioxide, and possibly dimethyl sulfide (DMS)—a potential biosignature gas associated with life on Earth 2.
