A new paper suggests the same conditions that created the cracks could have been favorable to microbial life. 

Scientists aren't certain how life began on Earth, but one prevailing theory says persistent cycles of wet and dry conditions on land helped assemble the complex chemical building blocks necessary to start life.

This is why a patchwork of well-preserved ancient mud cracks found by NASA's Curiosity Mars rover is exciting to the mission's team.

The paper in Nature details how the distinctive hexagonal pattern of these mud cracks offers the first evidence of wet-dry cycles occurring on early Mars.

'These particular mud cracks form when wet-dry conditions occur repeatedly – perhaps seasonally,' said the paper's lead author, William Rapin of France's Institut de Recherche en Astrophysique et Planétologie.

Curiosity is gradually ascending the sedimentary layers of Mount Sharp, which stands 3 miles (5 kilometres) high in Gale Crater. 

The rover spotted the mud cracks in 2021 after drilling a sample from a rock target nicknamed 'Pontours,' found within a transitional zone between a clay-rich layer and one higher up that is enriched with salty minerals called sulfates. 

While clay minerals usually form in water, sulfates tend to form as water dries up.

The minerals prevalent in each area reflect different eras in Gale Crater's history. The transitional zone between them offers a record of a period when long dry spells became prevalent and the lakes and rivers that once filled the crater began to recede.