A new study confirms that Hycean planets – ocean planets with hydrogen-rich atmospheres outside our Solar System – are a promising frontier for extraterrestrial life.
The research led by astronomer Nikku Madhusudhan from the Institute of Astronomy at the University of Cambridge (UK) indicates that Hycean planets are much more common than Earth-like rocky planets and possess excellent conditions that allow them to sustain life, even if they are located outside the traditional “Goldilocks zone.”
View on a Hycean planet – (Graphic by Amanda Smith/Nikku Madhusudhan)
According to the publication in The Astrophysical Journal, Hycean planets – characterized by vast global oceans and hydrogen-rich atmospheres, with an average size 2.6 times that of Earth and an average mass 10 times greater – can be found either very close to or very far from their parent stars.
However, this does not create a “hellish” world on many Hycean planets. The target for the search for extraterrestrial life will be “cold” Hycean planets, which benefit from a greenhouse effect due to abundant molecular hydrogen in their atmospheres, warming the entire planet and allowing for warm oceans despite being distant from their parent stars. Some conditions in the superocean of Hycean planets closely resemble those that support life in Earth’s oceans.
Dr. Madhusudhan further explained to Science Alert that after identifying these types of Hycean planets, the next step is to search for compounds that represent life, such as ozone, oxygen, and methane. However, the study particularly emphasizes two other lesser-known compounds that could also indicate life: methyl chloride and dimethyl sulfide.
These biosignatures can be detected through their light wavelengths when telescopes collect spectral data from the planet. The authors suggest that the upcoming James Webb Space Telescope (NASA/ESA), nearing completion and preparation for launch, will be a powerful tool capable of providing definitive answers.
