Evidence suggests that Mars was once rich in water, with ancient river valleys, flood channels, and minerals that form in the presence of liquid water pointing to a wetter past. How the planet transitioned into its current arid state remains a subject of scientific debate. Recent research has put forward the idea that vast amounts of water may still be stored beneath the surface, but a counterargument has now been presented, questioning the validity of that conclusion. The findings highlight the complexity of Mars’ water history, with different interpretations emerging based on seismic data.

Alternative Explanations for Subsurface Water

According to a study published in Proceedings of the National Academy of Sciences (PNAS), Bruce Jakosky, Senior Research Scientist at the University of Colorado Boulder and former Principal Investigator of NASA’s MAVEN mission, has reportedly raised concerns about a previous theory suggesting that Mars’ mid-crust is saturated with water. The earlier research which was led by Vaughan Wright of the Scripps Institution of Oceanography, University of California San Diego, analysed data from NASA’s InSight mission and concluded that fractured igneous rock deep beneath Mars’ surface could contain significant water reserves.

Jakosky, however, suggests that the seismic data used in the study could be interpreted differently. He argues that the pore spaces in the Martian crust may not necessarily be filled with liquid water, as previously proposed. In a statement to PNAS, he noted that while detecting water or ice in the crust is expected, accurately determining its abundance remains a challenge.

Disputing the Extent of Water Storage

In Wright’s study, it was estimated that the Martian crust could hold between 1 to 2 kilometres of water if spread evenly across the planet. This estimate was based on the assumption that the majority of pore spaces in the mid-crust were filled with liquid water. Jakosky’s reanalysis suggests that these spaces could instead contain solid ice or remain empty, significantly altering the potential water volume. His findings point that the range could extend from zero to 2 kilometres, widening the uncertainty.

Future Exploration Needed

While the data does not rule out the presence of liquid water, it also does not confirm it, making future missions critical in resolving the question. According to Jakosky, more precise spacecraft measurements will be necessary to determine the true water content of Mars’ crust. Until then, the debate over Mars’ lost water remains unresolved.