NEW DELHI: Nasa has identified 17
distant exolanets
that might have
large oceans
beneath their frozen surfaces, similar to the icy moons of Jupiter. These planets are considered promising for the search for biosignatures—chemical indicators of life.
Although the exact composition of these planets remains uncertain, previous studies suggest that their surface temperatures are much colder than Earth.
Despite being similar in size to Earth, they are less dense.
Lynnae Quick from Nasa's
Goddard Space Flight Center
explained that their analysis suggests these 17 planets may have icy surfaces but receive enough internal heating from the decay of radioactive elements and tidal forces from their host stars to maintain internal oceans.
In simpler terms, even though their host stars don't provide warm enough conditions for liquid water on the surface, these planets may have processes generating heat beneath their surfaces. For example, gravitational interactions with their stars and the decay of heavy elements in their cores could produce sufficient internal heat to sustain subsurface oceans.
Quick mentioned that due to the significant internal heating, all planets in the study could exhibit cryovolcanic eruptions, similar to ice volcanoes. The study drew inspiration from geyser activity on Jupiter's moons, Europa and Enceladus.
Two of the researched exoplanets, Proxima Centauri b and LHS1140 b, are particularly promising for having oceans relatively close to the surface. Quick suggested that telescopes are likely to detect geological activity on these planets, as their models predict oceans near the surface and geyser activity exceeding that of Europa by hundreds to thousands of times.
Future observations of these planets may involve astronomers capturing the emission spectra of light passing through their atmospheres. Chemicals and molecules released into the atmosphere from cryovolcanic activity could provide clues about the potential existence of life in the cold depths of these distant worlds.
English (US) ·