Mars: The Red Dream of Worlds

Mars, the fourth planet from the Sun, is a world of stark and beautiful desolation. A terrestrial planet with a thin atmosphere composed primarily of carbon dioxide, its most defining feature is the rusty iron oxide dust that covers its surface, earning it the enduring moniker, the “Red Planet.” It is a world of extremes, home to the tallest volcano in the Solar System, Olympus Mons, and the deepest canyon, Valles Marineris. Yet, Mars is more than a collection of geological superlatives. In the grand tapestry of human thought, it has been a god of war, a celestial omen, a canvas for our wildest fantasies of alien life, and, most recently, a tangible destination. Its story is our story, a reflection of our evolving capacity to see beyond our own world. From a flickering light in the ancient night sky to the dusty ground beneath the wheels of robotic emissaries, the brief history of Mars is a journey through mythology, science, delusion, and discovery—a chronicle of how we came to know our planetary neighbour and, in doing so, came to better understand our own place in the cosmos.

Some 4.6 billion years ago, in the swirling disc of gas and dust that would become our Solar System, a new world was taking shape. Through the chaotic process of accretion, countless planetesimals—small, rocky bodies—collided and merged, their gravity pulling in ever more material. From this violent cosmic ballet, Mars was born. Smaller than its neighbours, Earth and Venus, it was a molten sphere, a hellscape of magma oceans and relentless bombardment from the debris still cluttering the young solar system. This period, known as the Late Heavy Bombardment, scarred the infant planet, leaving behind the massive craters that still pockmark its southern highlands today, ancient wounds from a turbulent youth. But as the bombardment subsided and the planet began to cool, a remarkable transformation occurred. Volcanoes, gargantuan in scale, erupted across its surface, spewing gases like water vapour, carbon dioxide, and nitrogen into the sky. These gases, held in place by the planet's gravity, formed a thick, protective atmosphere, far denser than the tenuous envelope that exists today. Under this primordial sky, the water vapour condensed and fell as rain. For millions of years, rain filled the vast craters and deep basins, giving rise to sprawling oceans, shimmering lakes, and meandering river systems. For a time, Mars was not a red world, but a blue one. It was a warmer, wetter, and more dynamic planet, a world with cloudy skies and perhaps, just perhaps, the right conditions for life to emerge. Evidence of this lost paradise is etched into the very rock of the planet. Orbital probes have mapped the ghostly outlines of ancient shorelines and the intricate, branching patterns of dried-up river valleys. Rovers on the ground have driven across the beds of long-gone lakes, analysing mudstones and discovering minerals that could only have formed in the presence of liquid water. This was the climax of Mars's planetary life: a vibrant, water-rich world, a cosmic sibling to early Earth. But this paradise was not to last. Mars's tragic flaw was its size. Being only about half the diameter of Earth, its internal furnace—the molten iron core that generates a protective magnetic field—cooled and solidified much more quickly. Without a strong global magnetic field, Mars was left defenseless against the solar wind, a relentless stream of charged particles flowing from the Sun. This solar wind stripped away the planet's thick atmosphere over hundreds of millions of years, molecule by molecule. As the atmospheric pressure plummeted, the liquid water on the surface either boiled away into space or froze solid, retreating into the polar ice caps and underground reservoirs where it remains locked away today. The planet's lifeblood drained away, the blue faded to ochre, and Mars began its long, slow transformation into the cold, arid desert we see today—a planetary ghost story written in rust and rock.

Long before humans knew Mars as a world, they knew it as a light. As our earliest ancestors tracked the predictable procession of the stars, a few “wanderers”—the planetes of the ancient Greeks—refused to conform. Among them, one stood out for its distinct and ominous reddish hue. This was Mars, and its colour, so reminiscent of blood and fire, would define its character in the human imagination for millennia. The ancient Egyptians, masters of celestial observation, were among the first to record its movements. They called it Her Desher, meaning “the Red One,” and associated it with their god Horus. Its retrograde motion—an optical illusion where the planet appears to temporarily reverse its course in the sky—was seen as a powerful and often unsettling omen. The Babylonians, who developed one of the world's first sophisticated systems of Astronomy, tracked its path with mathematical precision. They named it Nergal, after their god of fire, plague, and the underworld. For them, Mars was a harbinger of doom, its appearance in certain constellations foretelling war, famine, and the death of kings. It was the Greco-Roman world that cemented the planet's martial identity in the bedrock of Western culture. For the Greeks, it was Ares, the volatile and brutal god of war, a figure more feared than revered. But it was the Romans who gave the planet its modern name and its most enduring persona. Their god, Mars, was a more dignified figure than his Greek counterpart. He was not just a god of chaotic battle but also a guardian of the Roman state, a symbol of military power, and an agricultural deity who protected the fields. This duality—of destruction and protection, of violence and virility—perfectly captured the awe and anxiety the blood-red wanderer inspired. For thousands of years, this was the totality of Mars. It was not a place of canyons and craters, but a symbolic entity, a character in a cosmic drama. Its brightness and position were consulted by priests and astrologers, its influence believed to tug at the strings of human destiny. It was a point of light that carried the weight of our deepest fears about conflict and chaos. It would take a revolution in technology, a simple combination of ground glass and human ingenuity, to begin the long process of stripping away the myth and revealing the physical world beneath.

The story of Mars as a physical place begins in the early 17th century, with a new and miraculous instrument: the Telescope. When Galileo Galilei turned his crude spyglass to the heavens in 1610, he shattered the ancient distinction between the perfect, unchanging heavens and the terrestrial Earth. He saw mountains on the Moon and moons orbiting Jupiter. When he looked at Mars, he saw not just a point of light, but a tiny, distinct disc. It was a revelation. Mars was not a metaphysical influence; it was a world, subject to the same physical laws as our own. As the quality of lenses improved, so too did our view of Mars. In the 1650s, the Dutch astronomer Christiaan Huygens, using a vastly superior Telescope, was able to sketch the first discernible feature on another planet's surface: a large, dark area on Mars that would later be named Syrtis Major Planum. By meticulously tracking this feature as it rotated in and out of view, Huygens made a staggering calculation. He determined that a day on Mars was roughly 24 hours and 40 minutes long, remarkably close to Earth's own day. This discovery was profound. It gave Mars a familiar rhythm, a terrestrial tempo. It was a world with days and nights, just like ours. A few years later, in 1666, the Italian astronomer Giovanni Cassini observed the planet's bright white polar caps. He correctly hypothesized that, like Earth's, they might be composed of snow and ice. He also noted that they appeared to grow and shrink with the Martian seasons, providing the first evidence of seasonal change on another world. The picture was becoming clearer. Mars was a dynamic, rotating planet with an Earth-like day, polar caps, and seasons. Throughout the 18th and 19th centuries, astronomers armed with ever-larger and more powerful telescopes continued to fill in the details. They drew increasingly intricate maps, naming the dark and light regions, or albedo features, after terrestrial lands and seas from classical antiquity. They observed clouds and dust storms, further cementing the idea of Mars as a world with weather and an atmosphere. The planet was slowly being stripped of its divine terror and clothed in the familiar garb of geology and meteorology. It was becoming less a god of war and more a sibling world, a slightly smaller, colder, redder version of Earth. This growing familiarity, however, was about to set the stage for one of the most spectacular and widespread delusions in the history of science.

The late 19th century was an age of colossal engineering. Humanity was crisscrossing continents with Railroads and connecting oceans with grand canals like the Suez. It was an era of unbridled optimism in the power of technology to tame nature. It was in this cultural climate that Mars underwent its most famous and fantastical transformation. The story begins in 1877, during a particularly favourable opposition when Mars was unusually close to Earth. An Italian astronomer named Giovanni Schiaparelli, using a powerful new Telescope in Milan, peered at the Red Planet and saw something astonishing. He observed a network of fine, linear streaks crisscrossing the planet's lighter-coloured regions. He called them canali, an Italian word that simply means “channels,” a term that could refer to natural formations like a riverbed. However, when his discovery was reported in English, canali was translated as “canals.” The difference was monumental. A channel is a work of nature; a canal is a work of intelligence. The idea electrified the public, but it found its true champion in a wealthy, charismatic Bostonian named Percival Lowell. A man of immense passion and persuasive power, Lowell became obsessed with the Martian canals. He dedicated his personal fortune to the cause, establishing a state-of-the-art Observatory under the clear, steady skies of Flagstaff, Arizona, for the sole purpose of studying Mars. From 1894 until his death in 1916, Lowell and his assistants produced breathtakingly intricate maps of Mars, depicting hundreds of canals. They were shown as impossibly straight lines, converging on nodes or “oases,” connecting the planet's polar caps to its arid equatorial regions. Lowell did not just map these features; he wove a compelling and romantic narrative around them. In a series of popular books—Mars (1895), Mars and Its Canals (1906), and Mars as the Abode of Life (1908)—he argued that Mars was a dying world. Its ancient oceans had dried up, and its inhabitants, a race of intelligent, ancient beings, were engaged in a desperate, planet-wide struggle for survival. The canals, he claimed, were a colossal irrigation system, an engineering marvel built to carry precious water from the melting polar caps to the thirsty cities of the equator. It was a powerful and poignant story, a planetary epic of ingenuity and decay that captured the public imagination. For decades, the “canal debate” raged in scientific and popular circles. While many astronomers remained skeptical, unable to see the canals with their own instruments, Lowell's vision was too captivating to dismiss. It bled into the culture, seeding a new genre of fiction. In 1898, H.G. Wells inverted Lowell's narrative of a dying, noble race. In his seminal novel, The War of the Worlds, the Martians were not tragic engineers but ruthless invaders, casting their envious eyes upon our own lush, water-rich planet. The book gave birth to the archetype of the hostile alien and forever linked Mars with the idea of invasion. The Red Planet was once again a source of fear, but this time it was not a mythological omen, but a technological threat from a neighbouring world. The canals, of course, were an illusion—a combination of wishful thinking, optical tricks of the human eye and brain struggling to find patterns in faint, blurry details, and the immense cultural weight of an industrializing world. It would take a new kind of explorer, a robotic one, to finally lay the ghost of the canals to rest.

The second half of the 20th century saw the dawn of the Space Age, and Mars was a primary target. The burgeoning Space Race between the United States and the Soviet Union provided the political will and financial fuel to transform the planet from a distant object of astronomical study into a tangible destination for robotic emissaries. The goal was to finally see Mars up close, to bypass the distorting veil of Earth's atmosphere and settle the debate about canals and life once and for all. The initial attempts were fraught with failure. The Soviet Union, though first in many early space milestones, suffered a string of heartbreaking losses in its Mars program throughout the 1960s. Probes failed to leave Earth's orbit, lost communication mid-journey, or missed the planet entirely. Mars, it seemed, was a “great galactic ghoul,” actively devouring the machines sent to study it. The breakthrough came on July 15, 1965. After a journey of more than 200 days, NASA's Mariner 4 spacecraft flew past Mars, snapping the first 22 close-up photographs of another planet in human history. As the grainy black-and-white images were slowly transmitted back to an anxious mission control at the Jet Propulsion Laboratory, a profound sense of anticlimax, and even disappointment, set in. There were no canals. No cities. No signs of a dying civilization. There were only craters. Countless craters, large and small, revealing a surface that looked disturbingly like the Moon: ancient, battered, and seemingly lifeless. The romantic vision of Percival Lowell, which had held sway for over half a century, was shattered in a matter of hours. Mars was not a world of tragic engineers; it was a geologically quiet, cratered desert. Later missions in the Mariner series, Mariner 6, 7, and especially the orbiter Mariner 9 in 1971, painted a more nuanced and complex picture. Mariner 9 arrived during a global dust storm, and as the dust settled, it revealed the colossal volcanoes of the Tharsis region, the vast Valles Marineris canyon system, and, most tantalizingly, features that looked unmistakably like dried-up riverbeds. The canals were an illusion, but the water, it seemed, had been real after all. The culmination of this first wave of exploration came in 1976 with the arrival of NASA's two Viking landers. These were the most sophisticated robotic probes ever built, each carrying a miniature biological laboratory designed to perform experiments on Martian soil and search directly for signs of life. The landers sent back the first stunning, panoramic color images from the surface: a rocky, rust-colored landscape under a pale pink sky. The biology experiments, however, produced bewildering results. They showed unexpected chemical reactivity in the soil but failed to find the organic molecules—the building blocks of life as we know it—that scientists had expected to accompany any biological activity. The results were ambiguous, tantalizing, and ultimately inconclusive. The Viking mission answered many questions about Mars, but it left the biggest one of all—are we alone?—hanging in the thin, cold air.

After the ambiguous results of the Viking mission, crewed and robotic exploration of Mars entered a period of relative quiet. It took two decades and a new generation of engineers and scientists to reignite the public's passion and begin a new, more systematic campaign of exploration. The new mantra was simple: “follow the water.” If life ever existed on Mars, it would have needed liquid water. The key to finding past life was to find past habitable environments. This new era began with a bounce. On July 4, 1997, the Mars Pathfinder mission landed, cocooned in a cluster of giant airbags. It deployed the first successful Rover, a microwave-sized vehicle named Sojourner. For 83 days, the little Rover crept across the rocks, its journey broadcast to the world via the burgeoning Internet. The mission was a cultural phenomenon, re-engaging the public with the sheer excitement of interplanetary exploration. Sojourner proved that the roving-geologist concept could work, paving the way for its much larger and more ambitious successors. In January 2004, this promise was realized with the spectacular arrival of two twin rovers, Spirit and Opportunity. Designed for a 90-day mission, these golf-cart-sized explorers embarked on one of the greatest odysseys in the history of exploration.

• Spirit landed in Gusev Crater, a place that looked like a dry lakebed from orbit. It spent years traversing the crater floor and climbing the nearby Columbia Hills, finding abundant evidence of rock altered by water in Mars's distant, volcanic past.
• Opportunity landed on the other side of the planet, in Meridiani Planum, and hit the geological jackpot. It rolled right into a small crater exposing layers of sedimentary rock. Within weeks, it had found “blueberries”—small, hematite-rich spherules—and sulfate minerals that provided definitive proof of a past environment that was not just wet, but was likely a salty, standing body of water.

Spirit's mission ended in 2010 after it became stuck in soft soil, but Opportunity roved on and on, a lonely titan of endurance, surviving dust storms and brutal winters. It traversed more than a marathon's distance (26.2 miles) across the Martian plains, continuing to send back invaluable data until a planet-encircling dust storm finally silenced it in 2018. The twin rovers had fundamentally rewritten the story of water on Mars, transforming it from a theoretical possibility to a documented certainty. The next generation of rovers were not just geologists; they were mobile, nuclear-powered laboratories. In 2012, the one-ton Rover Curiosity, a vehicle the size of a small Car, landed in Gale Crater using a daring and unprecedented “sky crane” maneuver. Its mission was to assess past habitability. It soon discovered the bed of an ancient, freshwater lake containing all the key chemical ingredients necessary for life, along with complex organic molecules preserved in 3-billion-year-old mudstone. In 2021, it was joined by Perseverance, which landed in Jezero Crater, the site of an ancient river delta. Perseverance is not just studying the rocks; it is the first leg of a multi-mission relay race. It is drilling and caching the most promising rock samples in sealed tubes, leaving them on the surface for a future mission to collect and return to Earth, where our most powerful instruments can finally search them for the ultimate prize: definitive biosignatures.

The story of Mars, which began as a flicker of light in a prehistoric sky, now stands at a profound threshold. The robotic vanguard—the orbiters, landers, and rovers—has done its work magnificently. It has peeled back the layers of myth and illusion, replacing them with a complex and compelling portrait of a world that was once much like our own and may, in its subsurface brine or ancient rocks, still hold secrets of life. Now, the human imagination is turning toward the next logical, and most audacious, chapter: sending ourselves. The prospect of a human mission to Mars represents arguably the greatest technological challenge humanity has ever contemplated. It is a quantum leap beyond the Apollo Moon landings.

• The Journey: A round trip could take up to three years, exposing astronauts to the long-term effects of weightlessness and dangerous levels of cosmic radiation far outside the protection of Earth's magnetic field.
• The Landing: Mars's atmosphere is thick enough to cause significant frictional heating but too thin to be of much help in slowing a heavy crewed spacecraft for a soft landing, a problem engineers call the “seven minutes of terror.”
• The Stay: Once on the surface, pioneers would have to be entirely self-sufficient, generating their own power, water, and breathable air from Martian resources, all while contending with the corrosive, toxic dust and frigid temperatures.

Despite these colossal hurdles, the dream of a human footprint on the Red Planet is more potent than ever. It is being pursued by national space agencies like NASA and by a new generation of private companies, sparking a modern Space Race driven not just by national prestige, but by commercial ambition and a shared humanistic vision. The motivations are as multifaceted as the challenges. For scientists, it is the chance to conduct investigations with a geologist's intuition and a biologist's dexterity, exponentially accelerating the search for life. For engineers, it is the ultimate proving ground for technologies like advanced life support, in-situ resource utilization, and closed-loop habitats. But the deepest driver may be philosophical. Setting foot on Mars would be a profound statement about the resilience and reach of life. It would be a hedge against the existential risks that threaten humanity on our single planetary home. It would fulfill a primal urge for exploration that has defined our species since we first walked out of Africa. To see a sunrise over Olympus Mons, to stand on the precipice of Valles Marineris, to sift the red sand through a gloved hand—these are the experiences that could redefine what it means to be human. Mars, the ancient god of war and the fantasized home of aliens, is being recast in its final and most important role: as humanity's next horizon, a second cradle for life, and a stepping stone on an unimaginable journey to the stars. The Red Dream of Worlds awaits.