Traces of a giant ocean hidden beneath the surface of Mars discovered

New seismic studies have provided compelling evidence that a colossal water ocean may be hidden beneath the surface of Mars, reports Space.com. According to modeling results, significant volumes of water may be located in the depths of the Red Planet at a depth of 10 to 20 kilometers.

The hypothesis about the existence of a subsurface ocean was first proposed by scientists in 2024 after careful analysis of seismic data obtained from the InSight lander.

Researchers then suggested that the deep layers of Mars, especially at depths from 11.5 to 20 kilometers, may be saturated with liquid water. This conclusion was made based on a detailed study of the velocities of seismic waves recorded during Martian earthquakes.

As part of a new study, Japanese scientists Ikuo Katayama from Hiroshima University and Yuya Akamatsu from the Research Institute for Marine Geodynamics conducted a re-analysis of data from the InSight lander and concluded that the original hypotheses were correct.

"Many studies suggest the presence of water on ancient Mars billions of years ago," notes Katayama. "But our model indicates the presence of liquid water on modern Mars."

The authors of the work analyzed seismic data collected using the SEIS instrument. This instrument was a key element of the InSight mission, which operated on the surface of the Red Planet from 2018 to 2022. SEIS became the first seismometer ever to work directly on the Martian surface.

During Martian quakes, the instrument recorded various types of waves, and in their new study, scientists focused on analyzing the fastest underground P-waves and slower S-waves. Studying the speed of their propagation made it possible to determine the density and composition of the underground environment through which these waves passed.

As a result, two transition regions were identified in the seismic data, where sharp changes in the wave velocity were observed, indicating equally significant changes in the properties of the interior. The most noticeable changes were recorded at depths of 10 and 20 kilometers - exactly where previous studies suggested the presence of a significant volume of liquid water.

However, not all of the scientific community shares the confidence in the existence of a huge subsurface ocean on the Red Planet. For example, Bruce Jakosky, former principal investigator of the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission, in his letter to the editor of PNAS journal, challenged the conclusions of the mentioned studies.

According to Jakosky, the presence of an ocean on Mars is just one of the possible interpretations, but not the only one, since "the data on which the studies are based do not necessarily require the presence of a water-saturated crust."