Scientists from The University of Texas at Austin have made a significant discovery that sheds light on the ancient water cycle of Mars. Their study, published in Geophysical Research Letters, reveals that billions of years ago, water on the Red Planet seeped into its subsurface at a rate tens of times slower than on Earth, forming vast underground reservoirs. This finding explains why Mars transformed into a dry desert.

How Did Mars’ Water Cycle Work?

A computer model developed by the researchers shows that 3–4 billion years ago, water on Mars infiltrated deep aquifers over 50–200 years. In contrast, similar processes on Earth take just a few days. This slow seepage caused a significant portion of the water to become “trapped” in the planet’s crust.

The total volume of underground water, scientists estimate, could have covered Mars’ entire surface in a layer about 90 meters thick. However, unlike Earth, where water actively returns to the atmosphere through evaporation and precipitation, Mars’ water cycle was severely limited. Moisture either remained locked in the subsurface or escaped into space due to the planet’s thin atmosphere.

Why Did Mars Dry Up?

The model explains the rapid drying of Mars’ surface. Since water that entered the ground rarely returned to the atmosphere, evaporation and precipitation processes were minimal. This disrupted the water cycle, rendering Mars incapable of sustaining rivers, lakes, and oceans believed to have existed in its distant past.

Prospects for Research

The discovery not only reveals the reason for Mars’ aridity but also offers hope for finding hidden water resources. Underground reservoirs formed billions of years ago may still hold significant amounts of water as ice or liquid. This opens new possibilities for future missions aimed at searching for signs of life or resources for colonization.

Significance for Science and Space Exploration

The study confirms that Mars was once a much wetter planet than it is today, but its unique water cycle led to the loss of surface water. Understanding these processes helps scientists better reconstruct the Red Planet’s history and assess its potential for supporting life. Moreover, knowledge of underground water reserves could be crucial for planning future expeditions and establishing bases on Mars.