In the early days of Mars, approximately 4 billion years ago, the planet experienced conditions favorable for the formation of lakes and river systems. According to researcher Kite, Mars had large bodies of water, with some seas comparable in size to the Caspian Sea or even larger. However, this period of wetness was relatively brief and insufficient to significantly weather or erode the landscape.
Kite’s research team utilized a model to investigate the changes that occurred as Mars transitioned to a colder climate, leading to the formation of salt deposits. “Extensive areas of snowmelt resulted in the creation of vast salt flats, which gradually accumulated into thick layers of sediment that the Curiosity rover is currently examining,” Kite explained. Despite the emergence of these salt formations, liquid water did not completely disappear from the Martian surface.
Intermittent Habitability
About 3.5 billion years ago, Mars became increasingly arid, at least by Earth’s standards. “There were prolonged phases during which the planet was completely dry,” Kite noted. During these arid spells, temperatures on Mars closely resembled its current state. Nevertheless, brief moments of liquid water emerged across the surface, resembling isolated oases in an otherwise inhospitable landscape. This suggests that while Mars was largely sterile, there existed fleeting patches that could have harbored life, with water sourced from melted snow.
Such a somber narrative regarding the evolution of Mars raises complex questions about the potential for discovering evidence of past life on the planet.
Kite posed a hypothetical scenario in which a cup of water from Earth’s ocean is poured into one of these transient Martian lakes. “Some microbes from that cup would likely thrive in those circumstances,” he stated. However, he emphasized the more profound inquiry: whether life could have originated on ancient Mars, particularly before the salt era began when conditions were wetter and warmer. There is also the critical question of whether any such life might have persisted in the intermittent oases described in their model.
Unfortunately, the outlook seems grim, as the likelihood of that occurring is probably very low.
