Mars, also known as the Red Planet, has intrigued and fascinated for centuries with its mysterious water history. NASA scientists made an amazing discovery when the Curiosity rover stumbled upon ancient cracks in the mud that suggest regular wet-dry cycles on this planet. The series may have favored prebiotic processes. But what does it mean?
This unusual pattern of hexagonal cracks in the mud may be the first evidence of conditions that could have supported the origin of life on this distant planet. It has long been speculated that constant climate cycles, similar to those on Earth, may have supported microbial growth on Mars. Scientists believe that these specific patterns in the mud may support this theory.
Curiosity discovery – wet and dry cycles on Mars
Gale Crater, located on the surface of Mars, has become the site of important discoveries thanks to the mission of the Curiosity rover, which is systematically traversing the sedimentary layers of Mount Sharp, which rises to an altitude of 5,000 meters. The car-sized robot, which reached the surface in 2012, spotted cracks in the mud in 2021. These particular molds are formed when wet-dry conditions occur repeatedly, one after the other. Moreover, these cycles were likely seasonal, suggesting that the climate of the planet Mars at the time was more variable and dynamic than previously thought.
According to William Rapin of the French Institute for Astrophysical and Planetary Research, author of a study recently published inNature, “This is the first tangible evidence that the ancient climate of Mars had regular Earth-like wet-dry cycles.”
Although Mars is currently cool and devoid of moisture, for years researchers have been uncovering traces indicating that its surface was once cut by rivers, streams and full of lakes and perhaps even seas. When we consider that life on Earth appears almost everywhere there is water, these signs suggest that Mars may have once been a habitat for life – and perhaps still is.
Mars – mysterious cracks in the mud
The cracks were noticed after a sample was taken from a stone called Pontours, located in the transition zone between a layer rich in clay, which usually forms in the presence of water, and a layer rich in salt minerals called sulfates, which usually form in the evaporation of water.
The minerals present in each area of the crater reflect different eras in Gale’s history. The transition zone where the cracks were found provides information about the period of long droughts , during which the crater-filling lakes and rivers began to recede. The mud, when it dries, cracks into a T shape, but softens and takes on a Y shape when repeatedly exposed to water, eventually forming a hexagonal pattern that has been preserved for billions of years.
Scientists surmise that these formations are fossilized traces of cracks from ancient mud in the lake bed, which regularly experienced changes – moving from wet to dry periods, probably on a seasonal basis. “This formation had a certain depth, which tells us that the cycle persisted for a long time, even for millions of years,” – Rapin said.
Significance for astrobiology
Wet-dry cycles are of great importance to astrobiologists. They can promote prebiotic polymerization, a process considered a key step in the evolution of life. Under the right conditions, such as those observed in Gale Crater, such cycles could accelerate the chemical reactions that lead to the formation of the first life forms. The discovery of cracks in the mud at Pontours may provide scientists with an opportunity to study the remains of life.
Mars is not built of plates, as is the case with Earth, so much older periods of the planet’s history have been preserved there. “It’s quite fortunate for us that we have a planet like Mars nearby that still holds memories of natural processes that may have led to the origin of life,” Rapin said.
Do fossilized cracks in the mud hide the answer to the existence of life beyond Earth?
The discovery of unexpected cracks in Martian mud sheds new light on our understanding of the history of Mars and the potential for life to exist there. These fossilized traces, which have survived for billions of years, provide us with valuable information about the conditions that prevailed on the Red Planet in the past.
With each new discovery on Mars, we get closer and closer to answering one of the most pressing questions in science: did life ever exist beyond Earth? Or does it still exist? Thanks to advanced technology and ongoing research by NASA and other researchers from around the world, we are getting closer to solving this mystery.
Image source: NASA/JPL-Caltech/MSSS/IRAP