Summary:

- The article discusses a new study published in Nature that reveals the existence of a massive, previously undiscovered ocean on Mars, located beneath the planet's surface.
- The study used radar data from the European Space Agency's Mars Express orbiter to detect the presence of a large, stable body of liquid water, estimated to be about 12 miles (20 kilometers) wide and located approximately 1 mile (1.5 kilometers) beneath the Martian surface.
- This discovery has significant implications for the potential habitability of Mars, as the presence of a stable, subsurface body of liquid water suggests that Mars may have been more geologically and hydrologically active in the past, increasing the likelihood of past or present microbial life on the planet.