Around 3.6 to 3 billion years ago, Mars' climate was at least warm enough for rivers and lakes to exist. Allegedly, at that time, Mars was habitable.
But the surface of Mars today is a cold barren desert. Scientists are exploring whether Mars could support life or not. They're trying to find answers that could help investigate the potential for human settlement on the Red Planet, and what it might look like.
In an attempt to investigate something that seems very unrealistic, scientists take on several spacecraft missions related to the planet Mars, such as orbiters and rovers.
From Mariner 4 (1964) to Mars 2020 (2020), missions to Mars have unraveled several mysteries and yielded incredible discoveries. Mars is a major focus for scientists when it comes to extraterrestrial life.
Quoted from Wio News, scientists have noted that Mars once had rivers because there are traces of rivers and lakes, which apparently dried up about three billion years ago.
A new study, published May 25 in Science Advances, investigates changes in the spatial distribution of water flows on Mars. It has been revealed that this maps to a major shift in the Martian greenhouse effect.
The study notes that analysis of the greenhouse effect in the global climate model simulation ensemble shows that this shift is driven primarily by reduced non-CO2 radiation forces, and not changes in CO2 radiation forces.
The findings highlight that the loss of fluids was triggered by a thin, icy cloud high in the Martian atmosphere. This traps heat and warms the planet, which acts like a translucent greenhouse.
"People have come up with different ideas, but we're not sure what caused the climate to change so dramatically. We really wanted to understand it, especially since it's the only planet we know for sure going from habitable to uninhabitable." said Edwin Kite, a geophysicist at the University of Chicago.
Kite is the first author of the new study conducted in collaboration with Bowen Fan, who is a graduate student at the University of Chicago, scientists from the Smithsonian Institution, Planetary Science Institute, California Institute of Technology Jet Propulsion Laboratory, and Aeolis Research.
For the study, scientists analyzed maps based on thousands of images of Mars taken from orbit by satellites to create a timeline of how river activity changes in altitude and latitude. After that, they can combine it with simulations of different climatic conditions.
The study notes that past climates on Mars can be investigated using the spatial distribution of climate-sensitive landscapes.
"We analyzed a global database of water-treated landscapes and identified changes in the spatial distribution of rivers over time. These changes are only explained by comparison with simplified meltwater models driven by global climate model simulation ensembles," the study wrote.