The mystery of life’s origins on Earth has long puzzled scientists, but a recent discovery on Mars might be shedding new light on this profound question, while also inching closer to finding life on Mars.
NASA’s Curiosity Mars rover has uncovered a patchwork of well-preserved ancient mud cracks, forming a distinctive hexagonal pattern, signaling the presence of wet-dry cycles on early Mars. These cycles could be key to the assembly of complex chemical building blocks necessary for microbial life.
A study published in Nature elaborates on the importance of this discovery. The lead author, William Rapin of France’s Institut de Recherche en Astrophysique et Planétologie, expressed his excitement, stating, “These particular mud cracks form when wet-dry conditions occur repeatedly – perhaps seasonally.”
Mud cracks named “Pontours”
Curiosity’s ongoing exploration of Mount Sharp, which stands 5 kilometers high in Gale Crater, has brought about this groundbreaking revelation. In 2021, after drilling a sample from a rock target nicknamed “Pontours,” located in a transitional zone between a clay-rich layer and a layer enriched with salty minerals called sulfates, the rover spotted these telling mud cracks.
This transitional zone in Gale Crater’s history has offered scientists valuable insights into the Martian past. It represents a time when long dry spells were prevalent, and the lakes and rivers that once filled the crater began to recede.
Mud, as it dries, shrinks and fractures into T-shaped junctions, something Curiosity discovered earlier at a location known as “Old Soaker.” However, the persistent exposure to water that created the Pontours mud allowed the junctions to soften and become Y-shaped, forming the fascinating hexagonal pattern.
The continuous formation of these hexagonal cracks, even as new sediment was deposited, indicates that the wet-dry conditions persisted over long time spans. Curiosity’s precision laser instrument, ChemCam, further confirmed a hardy crust of sulfates along the cracks’ edges, preserving them for billions of years. This crust also illustrates the connection with the sulfate-rich region of Mars.
The right conditions for life
According to Rapin, “This is the first tangible evidence we’ve seen that the ancient climate of Mars had such regular, Earth-like wet-dry cycles.”
He emphasized the importance of this discovery, adding, “But even more important is that wet-dry cycles are helpful – maybe even required – for the molecular evolution that could lead to life.”
The conditions supporting life are intricate. While water is vital, equilibrium is necessary. The right balance can promote the essential chemical reactions leading to life, controlling the concentration of chemicals feeding the formation of polymers like nucleic acids, considered as life’s building blocks.
The mission’s project scientist, Ashwin Vasavada of NASA’s Jet Propulsion Laboratory, reflected on the significance of the discovery. He stated, “This paper expands the kind of discoveries Curiosity has made. Over 11 years, we’ve found ample evidence that ancient Mars could have supported microbial life. Now, the mission has found evidence of conditions that may have promoted the origin of life, too.”
Pontours may be the birthplace of life on Mars
The Pontours mud cracks represent more than just an intriguing geological find. They offer the first opportunity to study what may be the remnants of the environment that gave birth to life. Unlike Earth, where tectonic plates continually reshape and bury its surface, Mars’s lack of tectonic activity has preserved much older periods of the planet’s history.
Rapin concluded with an appreciative note. He said, “It’s pretty lucky of us to have a planet like Mars nearby that still holds a memory of the natural processes which may have led to life.”
This discovery serves as a compelling reminder that Mars still holds secrets that could unlock some of the greatest mysteries of life itself. This new finding reinforces the importance of continued exploration and study of our neighboring planet.
More about the Curiosity Mars rover mission
NASA’s Jet Propulsion Laboratory developed the Curiosity Mars rover mission, officially known as the Mars Science Laboratory (MSL)
The mission’s main goal is to investigate the Martian climate and geology, assess whether the selected field site inside Gale Crater has ever offered environmental conditions favorable for microbial life, and conduct planetary habitability studies in preparation for future human exploration. Here are some key aspects of the mission:
Launch and landing
Curiosity launched on November 26, 2011, and landed on Mars on August 6, 2012.
Curiosity Rover design
The car-sized Curiosity rover weighs about 1,982 pounds (899 kilograms). Various scientific instruments and tools equip it to analyze the Martian surface.
A radioisotope thermoelectric generator (RTG) powers it, turning heat from the decay of radioactive isotopes into electric power.
Curiosity’s mission is designed to answer several questions, such as whether Mars could ever have supported small life forms, known as microbes. The rover investigates the geology and climate of Mars, helping to understand the planet’s history, including why it underwent such drastic changes.
The rover carries a variety of scientific instruments to achieve its goals, including cameras, spectrometers, radiation detectors, and environmental sensors.
Discovery of Gale Crater
Curiosity’s primary target, Gale Crater, was chosen because it appears to be a site where water once existed. The central peak of the crater, Mount Sharp, contains layered rocks that may preserve the geological history of Mars.
Although initially intended to last two years, Curiosity’s mission has been extended multiple times, and the rover continues to operate and send back valuable data.
Key findings from the Curiosity rover
Some of the major discoveries of the mission include the detection of organic compounds in Martian rocks, evidence of past lake environments that could have supported microbial life, insights into the planet’s climate and atmosphere, and ongoing observations of the Martian weather and other environmental conditions.
The Curiosity mission has been a significant step in the exploration of the Red Planet, contributing valuable knowledge that will likely aid future human exploration of Mars.
More about Mars
Mars is the fourth planet from the Sun in our solar system. It is often referred to as the “Red Planet” because of its reddish appearance. This is due to iron oxide (rust) on its surface. Here are some key facts and characteristics about Mars:
Diameter: About half the size of Earth.
Mass: About 10% of Earth’s mass.
Surface: Features both the largest volcano and the deepest, longest canyon in the solar system.
Mars has a thin atmosphere composed mostly of carbon dioxide (about 95%), with minor amounts of nitrogen and argon.
The planet has a cold desert climate, with average temperatures around minus 80 degrees Fahrenheit (minus 62 degrees Celsius). There are, however, temperature variations throughout the Martian year. It can get as warm as 70°F (20°C) or as cold as about -195°F (-125°C).
Liquid water cannot persist on the surface of Mars due to the planet’s thin atmosphere. However, there are signs of liquid flow in the past, as well as vast frozen water reserves beneath the surface and at the polar ice caps.
Mars has two small, irregularly-shaped moons, Phobos and Deimos. They are thought to be captured asteroids.
Several robotic missions have been sent to Mars by various space agencies, including rovers such as NASA’s Curiosity and Perseverance. These rovers have been conducting experiments, taking photos, and providing a wealth of information about the planet’s geology, climate, and potential to support life.
Potential for life
There’s significant interest in determining whether Mars ever supported life. Some evidence suggests that it may have had conditions suitable for life in its distant past, such as the new findings presented in this article. The search for past or present life forms or signatures on Mars remains one of the primary objectives of Martian exploration.
There are plans for future missions to Mars, including potential human missions. These endeavors aim to learn more about the planet and possibly prepare for human colonization in the future.
In pop culture, Mars often serves as a backdrop for science fiction stories, given its relative proximity to Earth and the intrigue surrounding the possibility of past or present life.