Since the dawn of human history, Mars has been held in the greatest fascination by man, more so than any planet in the solar system. So-called the “Red Planet” because of its characteristic red appearance, Mars has been the target of scientific inquiry, myth-making, and increasingly, technological dreams. Being the fourth planet from the Sun, Mars provides a rich amount of information for astronomers and planetary scientists, and yet, despite all that is understood, there are still unanswered questions.
This article looks at what humans have discovered about planet Mars so far, from its geology and climate to whether it can or cannot support life.
A Brief Overview of Mars
Mars is roughly half the size of Earth, with a diameter of about 6,779 kilometres. Its tenuous atmosphere, made up mostly of carbon dioxide (around 95%), is not capable of sustaining human life in its current state. Yet the planet’s surface features—polar ice caps, extinct volcanoes, and deep canyons—resemble some of Earth’s own geological formations. The Martian day, or “sol”, is just a bit longer than an Earth day at 24.6 hours, making it relatively favourable to plan for future human habitation.
The Martian surface temperature averages around -63 degrees Celsius, although this can vary hugely according to region and season. The low gravity, roughly 38% that of Earth’s, also has various ramifications for human physiology and engineering considerations.
Geological Discoveries and Surface Features
The Martian surface has a complicated geological history. The huge valleys like Valles Marineris cover more than 4,000 kilometres, and Olympus Mons, the highest volcano in the solar system, stands at around 22 kilometres tall. All these points to a formerly active interior and strong volcanic activity on the planet’s past.
Perhaps most visually striking has been the visibility of riverbeds and deltas that have dried up, and sedimentary layers—signs indicating the existence of liquid water in the past. Latest missions, including those conducted by the Curiosity and Perseverance rovers, have shown mineral compositions that can only be formed in liquid water, which further supports the theory that Mars once had a more Earth-like climate some billions of years ago.
Mars and the Search for Life
The key question of whether Mars had previously supported life—and might again, in the future—is at the heart of most of the work currently being pursued. Although unequivocal evidence for microbial life hasn’t been seen, there have been some provocative hints. As an example, in 2020, the NASA Curiosity rover identified organic molecules in sedimentary rocks as well as various concentrations of methane in the Martian atmosphere. Methane is special because it results from both abiotic and biological processes.
A further field of research concerns subsurface water. European Space Agency Mars Express mission radar data indicate the possibility of liquid water reservoirs beneath the south polar ice cap. These, if true, would represent potential habitats for microbial life, protected from the hostile surface conditions on the planet.
Technological Milestones in Mars Exploration
Humanity’s understanding of Mars has grown immensely thanks to a succession of robotic missions. The Viking landers in the 1970s provided the first images of the Martian surface. Later, the Spirit and Opportunity rovers expanded knowledge about the geology and climate, while Curiosity and Perseverance have brought advanced instrumentation to explore signs of ancient life.
Moreover, the Mars Reconnaissance Orbiter and the European Space Agency’s Trace Gas Orbiter have supplied critical data about the planet’s atmosphere and topography. In 2021, China’s Tianwen-1 mission successfully deployed a rover, demonstrating global interest and collaboration in Martian exploration.
The ambition to send humans to Mars is no longer confined to science fiction. NASA’s Artemis programme, while focused on the Moon, is seen as a precursor to Mars missions. SpaceX, led by Elon Musk, has also made public its plans to facilitate human settlement on Mars using its Starship spacecraft.
Conclusion
Despite decades of study and repeated missions, Mars remains shrouded in mystery. Scientists have accumulated vast information regarding its surface, climate, and geological past, establishing the fact that the planet had liquid water and probably conditions hospitable to life in the past. Nonetheless, several questions remain to be answered, for example, whether microbial life ever existed or whether Mars would be fit for human colonisation in the future. With continued rovers’ explorations and future human missions, our knowledge of Mars only grows, drawing us closer to the discovery of the planet’s secrets.
