While climbing the slope of a sedimentary mountain in 2021, Curiosity found salt deposits forming a hexagonal pattern in the soil from about four billion years ago.
According to the study published in the journal Nature, the rover’s instruments identified patterns in the form of cracks in the dry soil.
“When the lake dries up the soil cracks, and when it fills back in, the cracks heal,” Rapin explained.
Repeat this process enough times, and the cracks will arrange themselves into hexagons.
Rapin said, therefore, that this is “the first solid evidence that Mars had a cyclical climate.”
Regular wet and dry seasons on Earth may have provided the conditions necessary for life to form, the researchers said.