K2-18b
K2-18b is a notable exoplanet.[1] It orbits a red dwarf star, K2-18, 125 lightyears from the Solar system.[2] Its mass is believed to be 8.92 times that of Planet Earth, and at 0.1429 astronomical units from its primary, its year is 32.9 days long.
K2-18b orbits in its primary's habitable zone.[1][2] In 2025 Astronomers proposed it was an hycean planet -- a planet with a deep liquid water Ocean, and an atmosphere much thicker and denser than Earth's composed largely of Hydrogen. Scientists speculate marine life could evolve in the oceans of hycean worlds.
In April, 2025, it was reportedm the planet's atmosphere contains dimethyl sulfide (DMS) and dimethyl disulfide (DMDS), chemicals that might be signs of life.[3]
A study reporting in June 2025 raised doubts over whether K2-18b is a hycean world.[4] If K2-18b was a hycean world, its atmosphere should have, and did not, contain a large amounts of Ammonia.[5]
Radio Astronomers have listened for radio signals from the exoplanet.[6]
References
[edit | edit source]- ↑ 1.0 1.1
Paul Brackley (2021-09-02). "Hycean planets: Cambridge astronomers say our best hope for finding extraterrestrial life may have been hiding in plain sight". The Cambridge Independent. Archived from the original on 2021-10-15. Retrieved 2022-02-13.
Their discovery came when Dr Madhusudhan’s team at the Institute of Astronomy studied a mini-Neptune called K2-18b.
- ↑ 2.0 2.1
Pallab Ghosh (2025-04-17). "Scientists find 'strongest evidence yet' of life on distant planet". Archived from the original on 2025-04-17. Retrieved 2026-06-15.
The Cambridge group has found that the atmosphere seems to contain the chemical signature of at least one of two molecules that are associated with life: dimethyl sulphide (DMS) and dimethyl disulphide (DMDS). On Earth, these gases are produced by marine phytoplankton and bacteria.
- ↑
"Astronomers Say They Have Found the Strongest Signs of Life on K2-18b, 120 Light-Years from Earth". Territory (YouTube). 2026-04-17. Retrieved 2026-07-06 – via YouTube.
Now, in 2025, JWST has provided even more compelling data. Scientists have identified chemical signatures of dimethyl sulfide (DMS) and dimethyl disulfide (DMDS) in K2-18b's atmosphere. On Earth, these gases are predominantly produced by marine microorganisms, making them strong candidates as biosignatures.
- ↑
Anton Petrov (2025-05-11). "Study Suggests Hycean Worlds Probably Don't Exist and There's no Life on K2-18b". What da Math. Retrieved 2026-06-18 – via YouTube.
My name is Anton and in this video, we will talk about new updates about Hycean planets and K2-18b life claims
- ↑
Anton Petrov (2025-06-02). "Let's Talk About Claims of Alien Life on Planet K2-18b (New Studies)". What da Math. Retrieved 2026-06-18 – via YouTube.
My name is Anton and in this video, we will talk about recent studies about the claim of alien life on K2-18b
- ↑ Anton Petrov (2026-06-17). "SETI Listened to Planet K2-18b for Alien Radio Signals. Here's What They Found". What da Math. Archived from the original on 2026-06-17. Retrieved 2026-06-18 – via YouTube.