The past of Mars

Mars, the enigmatic red planet, has been the subject of fascination and study for decades. Thanks to advances in technology and recent space missions, we have begun to unravel the mysteries of its past.

A Wet and Hot Planet

Evidence of Liquid Water

One of the most significant findings is the evidence of liquid water on the surface of Mars in its distant past. Missions such as NASA’s Curiosity and Perseverance rovers have found minerals that only form in the presence of water, such as clays and sulfates. These geological formations suggest that Mars was home to rivers, lakes and even oceans billions of years ago.

Valley and Delta Networks

Images captured by orbiters such as the Mars Reconnaissance Orbiter (MRO) show networks of valleys and deltas that indicate an active hydrological system. These channels and formations suggest that water flowed across the Martian surface, sculpting the landscape in a similar way to how rivers do on Earth.

A Dense Atmosphere and Warm Climate

Primitive Atmosphere

Mars’ past also includes a much denser atmosphere than it has today. The MAVEN (Mars Atmosphere and Volatile Evolution) mission has provided data suggesting that Mars had an atmosphere rich in carbon dioxide, which would have allowed the existence of a greenhouse effect, keeping the planet warm enough for liquid water to exist in the surface.

Erosion and Climate Effects

Studies of erosion in Martian rocks and soil indicate that Mars experienced a warmer, wetter climate for millions of years. The existence of hydrated minerals and water-eroded geological structures point to a prolonged period of climatic conditions favorable for life as we know it.

(Photo: NASA/JPL)

Mars and the Possibility of Life

Biosignatures and Proof of Life

The search for life on Mars is one of the main objectives of current missions. Rover missions have found organic compounds in Martian soil, which could be signs of past life. Although no direct evidence of living organisms has been found, these discoveries suggest that Mars could have been habitable at some point in its history.

Current Experiments

The Perseverance rover, currently exploring Jezero Crater, is equipped with advanced instruments to search for biosignatures, or chemical signatures left by life. The data collected will help determine whether Mars had conditions suitable for microbial life.

Geological Transformations

Volcanic activity

Mars also experienced intense volcanic activity in the past. Olympus Mons, the largest volcano in the solar system, and other Martian volcanoes suggest that the planet was geologically active. This volcanic activity could have contributed to the creation of a dense atmosphere and the warming of the planet, facilitating the presence of liquid water.

Magnetic Fields and Core

Recent research has revealed that Mars had a global magnetic field in its past. This magnetic field would have protected the Martian atmosphere from the solar wind, allowing liquid water and habitable conditions to persist longer. However, the disappearance of this magnetic field allowed the solar wind to erode the atmosphere, transforming Mars into the cold desert we know today.

Mars Today and in the Future

The Martian Desert

Today, Mars is a cold, dry planet, with a thin atmosphere composed mainly of carbon dioxide. Temperatures can vary drastically, and the surface is covered in dust and rocks. However, evidence from Mars’ wet past continues to motivate scientists to search for signs of life and better understand planetary evolution.

Exploration and Colonization

Knowledge of Mars’ past is crucial for future exploration and colonization missions. Understanding the ancient climate and geology of Mars may provide clues about how to terraform the planet to make it habitable for humans. Future missions, such as those planned by NASA and SpaceX, aim not only to explore Mars, but also to establish bases that can one day house humans.