With a common scenario in the background – the presence of liquid water in the past and a climate transition in the periods in Noachian and Hesperian in Marte – Two recent studies offer conflicting perspectives on the old climate of the red planet.
The first of these, an orbital geomorphological analysis, was presented by Adam Losekoot of Open University ,. The other, a computational climate modeling ,.
The work of Losekoot maps extensive fossilized river systems, focusing on the Noachian-Hesperian border 3.7 billion years ago, while Kite, from the University of Chicago, has developed an unprecedented climate model, covering the last 3.5 billion years, based on Rover Curiosity data.
Both studies share some fundamental points: there was surface liquid water in the old, billion years agowith river activity and sediment deposition. The two works agree that Mars has undergone a climate transition in the Noachian-Hesperian period, from hot to cold.
But the two climate models differ frontally. Losekoot defends long stages of mild and damp climate, with lasting rivers and accumulated sediments. Kite proposes a cold and arid Mars, where liquid water emerged only into rare oasis, separated by wide drought eras.
These disparate views have deep implications for Martian habitability. The environments described in the Losekoot model are stable and favorable to life development and persistence. Kite’s scenario is more extreme and limits any biological possibility to underground niches.
Network of rivers reveals a wetter and hotter Mars in the “Noah’s Times”
When the Italian astronomer Giovanni Schiaparelli called the highlands of the southern Mars de Noachis Earth (Land of Noah) in the 19th century, he was unknowingly making a kind of prophecy. Now a team of researchers have discovered over 15,000 kilometers of fossilized channels on the red planet.
Adam Losekoot and his colleagues mapped winding crests that form when sediments deposited by ancient rivers hardens as the surrounding ground is eroded. This high resolution data, obtained through NASA instruments ,.
The extensive river system discovered indicates a hydrological cycle fueled by constant rainfallnot just for sporadic melting of ice. According to the research, water must have fallen from the sky regularly and accumulated in streams that flowed enough to form these “cemented” sediments.
This frontally contradicts the theories that Mars was dry during the Noachian. In his talk, Losekoot states that the rivers persisted for geologically significant periods, demanding a thick atmosphere and a temperate climate, ideal for life development.
The new map contradicts the models that see Mars as a fundamentally cold planet that only occasionally “defailed” due to events such as volcanic eruptions or asteroid impacts. “Mars has been a much more complex and active planet than it is now,” concludes Losekoot.
The newest Martian climate model: cold and hostile environment
Using data from Rover Curiosity, a team of scientists led by Edwin Kite, from the University of Chicago, developed a Martian climate model showing a “carbon kidnapping” from the Martian atmosphere. Dissolved in existing water, CO₂ reacted with minerals to form carbonates.
This “arrest” of the greenhouse gas created a self -destructive cycle: although there was enough water to retain CO₂, it cooled the planet, eliminating the conditions that allow the existence of liquid water. Comprehensive, this unique model captured the evolution of the Marcian landscape and climate for long periods.
Very early in the history of Mars, “perhaps 4 billion years ago,” says the leader researcher, Mars was hot enough to support lakes and river networks ,. However, this damp period was very brief. Soon, snow melting areas created huge salines.
3.5 billion years ago, the landscape became arid with long dry periods where Mars was almost as cold as today. From time to time, small areas with liquid water appeared as transient oasis, lasting only about one hundred thousand years, geologically very short periods to support life.
However, based on recent discoveries of Curiosity, long chain alkanes (molecules similar to those produced by living beings), Kite states in a statement: “I think we cannot completely close the door to Martian life.”
