Section 1.1: The Discovery of a Waterworld

A distant exoplanet, potentially surrounded by a vast ocean, has recently piqued the interest of astronomers. Observations from NASA's JWST revealed water vapor along with chemical signatures of methane and carbon dioxide in the exoplanet's atmosphere.

Located around 70 light-years away and measuring twice the radius of Earth, this planet displays a chemical structure suggesting it is a water world, with an ocean that might cover its entire surface and an atmosphere rich in hydrogen. Researchers from the University of Cambridge indicate that while this discovery hints at a water-dominated world, it does not necessarily suggest a welcoming environment for life.

Subsection 1.1.1: The Hycean World Hypothesis

One interpretation of these findings suggests that the exoplanet could be a "hycean world," characterized by a water ocean beneath a hydrogen-rich atmosphere.

However, this hypothesis is met with skepticism by a Canadian research team that conducted further studies on the same exoplanet, designated TOI-270 d. Although they also detected similar atmospheric chemicals, they argue that the planet's extreme temperatures could prevent the existence of liquid water, potentially reaching a staggering 4,000°C. They propose an alternative scenario where the planet has a rocky surface covered by a highly dense atmosphere made up of hydrogen and water vapor.

Section 1.2: The Unique Characteristics of Hycean Worlds

A "hycean" world blends features of both Earth and Neptune, making it a potential candidate for hosting life. The term "hycean" merges "hydrogen" and "ocean," emphasizing its dual nature of having a substantial atmosphere like Neptune while also possessing liquid water oceans akin to Earth. Typically larger than Earth, hycean worlds may orbit within the habitable zones of their stars, where conditions could allow for liquid water to exist.

The ongoing debates surrounding these observations highlight the valuable insights provided by the JWST into the properties of exoplanets outside our solar system. By analyzing starlight that passes through the atmospheres of these distant planets, JWST allows astronomers to gain a clearer understanding of their chemical compositions.

The first video titled "James Webb Telescope Discovers Atmosphere on Distant Super-Earth!" explores the recent findings regarding the chemical makeup of exoplanets and their potential for supporting life.

The evidence suggesting an ocean on TOI-270 d arises from the absence of ammonia, a compound that would typically be present in a hydrogen-rich atmosphere. Since ammonia is highly soluble in water, its depletion in the atmosphere would imply the existence of an ocean beneath.

Conditions on TOI-270 d starkly contrast those on Earth. The planet is tidally locked, meaning one side is constantly facing its star, while the other remains in perpetual darkness, resulting in extreme temperature variations. Moreover, TOI-270 d likely possesses a dense atmosphere, leading to pressures far exceeding those found on Earth's surface, with steam likely rising from its vast ocean. The ocean's depths could reach tens to hundreds of kilometers, featuring a seabed composed of high-pressure ice, under which lies a rocky core.

Both research teams identified carbon disulfide, a compound linked to biological processes on Earth, although it can also arise from non-biological sources. Notably, the absence of dimethyl sulfide (DMS), another potential biosignature, was observed. Future observations aimed at measuring the concentration of water vapor in the atmosphere may yield further insights into the possibility of an ocean on this distant planet.

Complete research findings were published in the Journal of Astronomy & Astrophysics.