The Red Planet’s Peculiarities
Mars looms large in the human imagination. It’s the “Red Planet,” our planetary neighbor, and the most accessible next step for human exploration beyond the Moon. From a distance, it appears as a rusty, dusty, and perhaps somewhat simple world. It looks like a cold, cratered desert. But a closer look, provided by decades of robotic exploration, reveals a planet that is anything but simple. Mars isn’t just a static ball of rock; it’s a world of bizarre extremes, unsolved mysteries, and geological oddities that challenge our understanding of how planets work. Its “facts” are often strange, counter-intuitive, and deeply weird.
This article explores the peculiarities of Mars, moving beyond the common knowledge of “it’s red” and “it’s cold” to examine the truly strange features of its geology, atmosphere, history, and its place in the solar system.
A World of Superlatives
Part of what makes Mars so strange is its scale. For a planet that is only about half the diameter of Earth, it holds some of the most dramatic and oversized records in the entire solar system. These aren’t just large features; they are so colossally large that they point to a planet with a very different geological history than our own.
The Tallest Volcano in the Solar System
Earth has impressive volcanoes, but they are dwarfed by Olympus Mons. This single mountain is the largest known volcano in the solar system. Its numbers are difficult to comprehend. It stands nearly 13.6 miles (22 kilometers) high, making it almost three times the height of Mount Everest above sea level. Its base is so wide, at about 370 miles (600 kilometers) across, that it would cover an area roughly the size of Arizona.
The strangeness isn’t just its size, but its shape. Olympus Mons is a shield volcano, meaning it was built up slowly by countless lava flows over millions, or even billions, of years. On Earth, plate tectonics keep the crust moving. A “hotspot” of magma in the mantle might punch through the crust to form a volcano, but as the plate moves, that volcano is carried away from the source, and a new one forms. This is what created the Hawaiian island chain.
Mars, it seems, lacks active plate tectonics. Its crust is static. So, a massive hotspot of magma could just sit in one place, erupting and building upon the same spot for eons. This, combined with Mars’s lower gravity – which is only about 38% of Earth’s – allowed Olympus Mons to grow to its staggering height without collapsing under its own weight. Standing on the surface of Mars, you wouldn’t even be able to “see” the mountain in the traditional sense. Its base is so wide and its slopes so gentle that it would simply appear as a long, gradual incline, like a planetary-scale hill, its peak far beyond the horizon.
The Grandest Canyon
Just as it holds the record for the tallest high point, Mars also boasts the most spectacular low point. Valles Marineris, or the Mariner Valley, is a system of canyons that stretches for more than 2,500 miles (4,000 kilometers). If Valles Marineris were on Earth, it would span the entire continental United States, from New York to Los Angeles.
It’s not just long; it’s incredibly deep. In places, the canyon floor is more than 4 miles (7 kilometers) below the surrounding plateau. Earth’s Grand Canyon is a mile deep at its deepest, but Valles Marineris is a scar on a completely different scale.
The strangest part about this canyon system is its origin. Earth’s Grand Canyon was carved slowly over millions of years by the Colorado River. Valles Marineris was not. While water has certainly flowed through parts of the canyon and modified its features, the canyon itself wasn’t created by erosion. It’s a massive tectonic crack. It’s believed that the canyon system is a gigantic “stretch mark” in the Martian crust, formed billions of years ago during the creation of the Tharsis bulge, a massive volcanic plateau that includes Olympus Mons. The sheer weight of the Tharsis volcanoes was so great that it caused the planet’s crust to split open nearby. It’s a wound that dwarfs any geological feature on Earth.
The Global Dust Storms
Dust is a defining feature of Mars, but Martian dust storms are a bizarre and violent phenomenon. While Earth has large dust storms, they are typically regional. On Mars, these storms can grow to become truly global events.
These storms can start in a small, localized area, often in the southern hemisphere during its summer. But under the right conditions, they can grow and merge, feeding off the energy of sunlight warming the dust. The dust in the air absorbs sunlight, heating the thin atmosphere, which in turn lifts more dust, creating a runaway feedback loop.
Within weeks, a single storm can balloon into a planet-encircling event, shrouding the entire surface of Mars in a thick, dusty haze. This is what happened in 2018, famously leading to the demise of the Opportunity rover. The rover, powered by solar panels, couldn’t get enough sunlight through the thick dust to recharge its batteries. These global storms can last for months, dramatically changing the planet’s temperature and visibility. They are a powerful reminder that Mars, despite its thin air, is not a dead world; it’s a dynamic one.
The Curious Case of Martian Water
Perhaps the greatest Martian paradox is its relationship with water. Today, the surface of Mars is a bone-dry, freezing desert. The atmospheric pressure is so low that liquid water is unstable; it will either freeze solid or boil away into vapor almost instantly. Yet, everywhere we look on Mars, we see the ghosts of water.
The Water That Isn’t There (Anymore)
The evidence for a wet past is overwhelming. Robotic explorers have found features that are unmistakably ancinet. Orbiters have photographed vast, dried-up river valleys, deltas, and even shorelines of what appear to be ancient oceans. Rovers on the ground have driven through dry lakebeds. The Curiosity rover explored Gale Crater, finding finely layered mudstones that could only have formed at the bottom of a lake that existed for millions of years.
The Perseverance rover is currently exploring Jezero Crater, which was chosen as a landing site specifically because it contains a perfectly preserved river delta. This is a fan-shaped deposit of sediment that forms when a river flows into a larger, standing body of water, like a lake. Rovers have also found minerals like hematite (in the form of “blueberries”) and gypsum, which, on Earth, form almost exclusively in the presence of water.
The strangeness is this significant discrepancy. Billions of years ago, Mars was a world with lakes, rivers, and possibly even a northern ocean. Today, it’s a barren desert.
Where Did the Water Go?
This is one of the biggest unsolved questions in planetary science. The water clearly went somewhere, and there are several answers.
First, a lot of it is still there, just frozen. The Martian polar ice caps are not just “dry ice.” The northern polar cap, in particular, contains a massive amount of water ice, enough to cover the entire planet in a shallow ocean if it all melted. There is also a huge amount of water ice locked away underground as permafrost, similar to Earth’s arctic regions.
Second, a large amount of water was lost to space. Mars once had a protective global magnetic field, just like Earth does. But for reasons not fully understood, this field died billions of years ago. Without this magnetic shield, the solar wind – a stream of charged particles from the Sun – blew directly onto the Martian atmosphere. This process, called “sputtering,” slowly but surely stripped away Mars’s thicker, warmer atmosphere. As the atmosphere thinned and the pressure dropped, the water on the surface boiled away and was also lost to space.
The Mysterious Subglacial Lakes
While water can’t exist as a liquid on the surface, scientists have found tantalizing evidence that it might exist underground. In 2018, data from the MARSIS radar instrument on the European Space Agency’s Mars Express orbiter suggested the presence of a large body of liquid water, a lake, buried a mile beneath the ice of the south polar cap.
This is extremely strange. It’s incredibly cold at the Martian poles, far below the freezing point of water. For a lake to remain liquid, it would need some source of heat, perhaps from geothermal activity deep within Mars. An alternative and more widely accepted explanation is that the water is an extremely salty brine. Just as we put salt on roads to melt ice, a very high concentration of salts (like perchlorates, which are common on Mars) could lower the freezing point of water dramatically, allowing it to stay liquid even at -70°C (-94°F) or lower.
More recent research has complicated this picture, suggesting some of these radar reflections might be from clay or other minerals, not liquid water. The debate continues, but the possibility of hidden, briny lakes deep beneath the ice remains one of Mars’s most compelling and strangest possibilities.
A Bizarre Atmosphere and Sky
The Martian atmosphere is a study in oddities. It’s the reason for the planet’s strange weather, its unique appearance, and one of its most fascinating chemical mysteries.
The Thin, Toxic Air
The first “strange fact” about Mars’s air is that there is barely any of it. The atmospheric pressure on the surface of Mars is, on average, less than 1% of Earth’s pressure at sea level. This thin blanket of air is also completely unbreathable. It’s composed of about 95% carbon dioxide, with small amounts of nitrogen and argon.
This thin CO2 atmosphere is a poor insulator. While Earth’s atmosphere traps heat in the greenhouse effect, Mars’s thin air lets heat escape back into space. This leads to wild temperature swings. On a summer day at the equator, the temperature might reach a comfortable 20°C (70°F). But on that very same night, the temperature will plummet to a frigid -73°C (-100°F).
Blue Sunsets and Pink Skies
On Earth, we have blue skies and red sunsets. On Mars, it’s the exact opposite.
The Martian daytime sky is not blue. Because the atmosphere is so full of fine, red dust particles, it has a pale, butterscotch or pinkish-red color. This is because these particles are the right size to scatter red light across the sky.
But at sunrise and sunset, the light from the Sun has to travel through more of the thin atmosphere to reach an observer (or a rover’s camera). As it does, this same red dust scatters the red light away, allowing the blue light to pass through more directly. The result is a surreal and beautiful blue-hued glow around the setting or rising Sun. A blue sunset is one of the most famously strange and iconic features of Mars.
The Methane Mystery
One of the most significant and puzzling Martian mysteries involves methane. Methane is a simple organic molecule. On Earth, over 90% of atmospheric methane is produced by living organisms, from microbes to cows. It can also be produced by geological processes, such as the interaction of water and certain types of rock (a process called serpentinization).
The strange part isn’t just that methane exists on Mars. The strange part is that it shouldn’t. Sunlight and chemical reactions in the Martian atmosphere should destroy any methane molecule in just a few hundred years. This means that any methane detected today must have been released very, very recently.
And it has been detected. Both orbiters and, more notably, the Curiosity rover have detected small “puffs” of methane in the air. What’s even stranger is that these puffs are seasonal. They seem to appear and disappear, peaking in the Martian summer.
This implies there is an active source of methane on Mars today. Is it geology, or is it biology? Are there pockets of deep, geologically-produced methane being released as the ground warms in the summer? Or – the more exciting possibility – is this a signature of subsurface microbial life, microbes that are alive and releasing methane as a waste product right now? Scientists at NASA and other agencies are actively debating this, and the answer remains unknown.
Snowing Dry Ice
Mars gets so cold, especially at its poles during winter, that the atmosphere itself freezes. With temperatures dropping below -125°C (-195°F), the carbon dioxide gas in the air condenses and falls as snow. This isn’t the fluffy water-ice snow we know on Earth; it’s “dry ice” snow.
This CO2 snow, along with CO2 frost, builds up the seasonal polar caps. Each winter, a significant portion of the entire Martian atmosphere freezes out of the sky and gets deposited at the poles, only to turn back into gas (sublimate) in the spring. This is a bizarre seasonal cycle that causes massive swings in the planet’s atmospheric pressure.
The Lopsided Planet: A Tale of Two Hemispheres
From orbit, one of Mars’s strangest features is immediately obvious. The planet is dramatically lopsided. This “Martian dichotomy” is a stark division between its two hemispheres, as if two different planets were crudely stitched together.
The Great Dichotomy
The southern hemisphere of Mars is ancient, heavily cratered, and has a high elevation. It’s a rugged, old landscape that has seen billions of years of impacts.
The northern hemisphere is the complete opposite. It’s young, smooth, and has a much lower elevation. It’s a vast lowland plain with far fewer craters. The difference in elevation between the two hemispheres is stark, with the northern plains sitting several miles lower than the southern highlands.
Why is Mars like this? This question has puzzled scientists for decades.
What Caused the Dichotomy?
There are two main theories for this bizarre split. The first involves internal geological processes, perhaps an ancient and long-dead form of plate tectonics or a massive mantle plume that reshaped one side of the planet.
But a more dramatic and widely-discussed theory is the “Borealis Basin” hypothesis. This theory suggests that, very early in its history, Mars was struck by a massive object, something the size of Pluto or larger. This colossal giant impact would have effectively blasted away the entire crust of the northern hemisphere, creating one enormous impact basin that covers 40% of the planet’s surface. This would be, by far, the largest impact basin in the solar system. The smooth lowlands we see today would be the floor of that ancient, planet-sized crater, which was later partially filled in by lava flows.
The “Ghost” Magnetic Field
Earth is protected from harmful solar radiation by a strong, global magnetic field, generated by the swirling of its molten iron outer core. This is the “dynamo” effect. Mars, today, has no such global field. Its core is thought to have cooled and solidified, or at least stopped convecting, causing its dynamo to die billions of years ago. This was a catastrophic event for Mars, as it allowed the solar wind to strip away its atmosphere and water.
The strange part is the “ghost” of the field that was left behind. In the 1990s, the Mars Global Surveyor orbiter discovered that Mars doesn’t have no magnetic field – it just doesn’t have a global one. Instead, it has “fossil” magnetism.
Specifically, in the ancient southern highlands, there are stripes of magnetized rock on the surface. These stripes have alternating magnetic polarity, pointing north, then south, then north again. This pattern is an unmistakable signature of plate tectonics and a reversing global magnetic field. On Earth, these “magnetic stripes” are found on the seafloor, and they were the key evidence that confirmed the theory of continental drift.
Finding them on Mars is astounding. It suggests that, billions of years ago, Mars was a very different world. It not only had a magnetic field, but it may also have had plate tectonics, just like Earth. Then, for some reason, it all just stopped. The southern highlands are a frozen record, a magnetic ghost, of a more active and Earth-like planet that died.
The Oddball Moons
Mars has two moons, Phobos and Deimos. But they aren’t like our Moon. They are tiny, lumpy, potato-shaped objects that look more like asteroids than traditional moons. And their properties and fates are just as strange as their appearance.
Phobos: The Doomed Moon
Phobos is the larger and inner moon, but it’s still tiny, only about 14 miles (22 km) across. It orbits Mars incredibly closely, just 3,700 miles (6,000 km) above the surface. This is so close that it whips around the planet faster than Mars rotates. It completes an orbit in just 7.5 hours, meaning it rises and sets twice in a single Martian day.
But this close proximity has sealed its fate. Phobos is so close that it’s inside the “Roche limit,” the point at which a planet’s tidal forces are stronger than the moon’s own gravity holding it together. Mars is actively pulling Phobos apart. This gravitational stress means Phobos is in a death spiral. It’s drawing closer to Mars by about 6 feet (1.8 meters) every century.
In about 30 to 50 million years – a short time in cosmic terms – Phobos will meet a violent end. It will either be ripped to shreds by Mars’s gravity, its fragments spreading out to form a small, dusty ring around the planet, or it will spiral all the way in and crash into the Martian surface in a cataclysmic impact.
The Strange Grooves
Phobos itself is covered in a series of bizarre, parallel grooves or “striae.” For a long time, the origin of these grooves was a mystery. One leading theory today is that they are, quite literally, stretch marks. As Mars’s gravity relentlessly pulls on Phobos, the small moon is beginning to break apart, and these grooves are the first signs of the structural failure. They are cracks and fissures opening up as the moon is deformed by tidal forces. Another theory suggests they are chains of craters formed by material blasted off Mars from a large impact, which then peppered the small moon.
Captured Asteroids? Or Something Else?
The long-standing theory for the origin of Phobos and Deimos was that they are captured asteroids. Their small size, irregular shape, and dark, carbon-rich composition are very similar to asteroids found in the outer asteroid belt. It seemed simple: they wandered too close to Mars and were caught by its gravity.
But there is a major problem with this theory. Their orbits are the strange part. Both Phobos and Deimos have very stable, very circular orbits that lie almost perfectly along Mars’s equator. This is extremely unlikely for captured objects. A captured asteroid would almost certainly have a more eccentric, tilted, and unstable orbit.
This has led to a newer, stranger theory. Phobos and Deimos may not be captured asteroids at all. Instead, they may be “second-generation” objects, formed from Martian material. Like the Borealis Basin impact hypothesis, this theory suggests Mars was struck by a large body. The resulting debris would have been blasted into orbit, forming a ring around the planet. Phobos and Deimos would have then coalesced from this ring. This would make them, in a sense, tiny moons made from the same stuff as Mars itself, a bit like a miniature version of how Earth’s Moon is thought to have formed.
Anomalies and Illusions on the Surface
Mars is a grainy, windswept place. Its combination of alien geology, strange lighting, and low-resolution images from early missions has made it a hotbed for optical illusions and apparent anomalies.
The “Face on Mars”
The most famous “strange fact” about Mars is one that isn’t a fact at all. In 1976, NASA’s Viking 1 orbiter snapped a photograph of a region called Cydonia. One of the images showed a mile-long mesa that, in the grainy, low-resolution photo with its specific shadows, looked uncannily like a humanoid face, complete with eyes, a nose, and a mouth.
This “Face on Mars” became a cultural phenomenon, fueling speculation about lost Martian civilizations. The feature was a perfect example of a psychological effect called pareidolia – the human brain’s hard-wired tendency to find familiar patterns, especially faces, in random or ambiguous stimuli.
The mystery was definitively solved decades later when new missions, like the Mars Global Surveyor and the Mars Reconnaissance Orbiter (MRO), imaged the Cydonia region in stunning high resolution. These new images showed the “Face” for what it truly is: a large, heavily eroded, natural rock formation. From different angles and in better light, it looks nothing like a face.
Martian “Spiders”
One Martian feature that looks biological but isn’t is the “araneiforms,” more commonly known as Martian spiders. These are seen from orbit in the spring near the planet’s south pole. They are bizarre, web-like patterns of dark channels that radiate outward from a central point, looking just like giant, spidery legs carved into the ground.
These are not life. They are the result of a uniquely Martian process. During the winter, a layer of translucent “dry ice” (frozen CO2) forms over the ground. In the spring, sunlight penetrates this ice layer, warming the dark ground underneath it. This causes the frozen CO2 at the bottom of the ice sheet to turn directly into gas (sublimate).
This pressurized CO2 gas gets trapped under the ice. Eventually, the pressure builds until it finds a weak spot and erupts in a violent, geyser-like plume, shooting hundreds of feet into the air. This gas jet carries dark sand and dust from below. The dust settles on top of the ice in a dark fan shape, and the escaping gas carves the spidery channels in the ground beneath. It’s an exotic form of erosion found nowhere on Earth.
The Strangeness of Time and Space on Mars
Even the fundamental concepts of time and distance are skewed on Mars, creating a world that is uncannily similar to Earth in some ways and significantly alien in others.
A Day Just a Little Too Long
This is one of the most remarkable coincidences in the solar system. A day on Earth is 24 hours. A day on Mars, known as a “sol,” is 24 hours, 39 minutes, and 35 seconds. This similarity is a complete cosmic accident.
It’s close enough to feel familiar, but it’s just different enough to be a logistical nightmare. For the scientists and engineers at NASA’s Jet Propulsion Laboratory (JPL) who operate the rovers, they must “live on Mars time.” This means their workday starts 39 minutes later each Earth day. After just two weeks, their “morning” on Mars time has become “midnight” on Earth time. This “jet lag” is a constant challenge for mission operations.
Wildly Eccentric Seasons
A Martian year is much longer than Earth’s, lasting 687 Earth days (or 668 sols). Like Earth, Mars has seasons. This isn’t because of its distance from the Sun, but because, like Earth, it’s tilted on its axis (Mars’s tilt is 25.2 degrees; Earth’s is 23.5 degrees).
But Mars’s seasons are far more extreme, and that’s because its orbit is strange. Earth’s orbit is nearly a perfect circle. Mars’s orbit is highly “eccentric,” or elliptical. This means its distance from the Sun varies dramatically. At its closest point (perihelion), it’s 128 million miles away. At its farthest (aphelion), it’s 155 million miles away.
This has a huge effect on its seasons. When the southern hemisphere is tilted toward the Sun (its summer), Mars also happens to be at its closest point to the Sun. This makes southern summers intensely hot and short. Conversely, southern winters are long and punishingly cold. This imbalance is a major driver of the planet’s climate and is one of the engines that powers the global dust storms.
Lower Gravity, Higher Jumps
Mars is a smaller planet with less mass than Earth. Its surface gravity is only about 38% of Earth’s. This has all sorts of strange consequences. If you weigh 150 pounds on Earth, you would weigh only 57 pounds on Mars. You could jump nearly three times as high.
This lower gravity is why Martian volcanoes like Olympus Mons could grow so tall without collapsing. It’s why dust, once kicked up, can stay suspended in the thin atmosphere for much longer. And it would have significant effects on any future human explorers, whose muscles and bones would weaken without the constant pull of Earth’s gravity.
Summary
Mars is a planet of significant contradictions. It’s a world that is dead but also dynamic. It’s a place that is bone-dry but shows undeniable evidence of ancient oceans and may hide liquid lakes today. It has a sky with blue sunsets, an atmosphere that snows, and a history of planet-shattering impacts. It boasts the solar system’s largest volcano and canyon, yet it’s a fraction of Earth’s size. Its lopsided geology hints at a violent birth, and its “fossil” magnetism tells of an Earth-like past that was mysteriously cut short.
The strangeness of Mars is what makes it so compelling. It’s not just a simpler, redder version of Earth. It’s a complex world with its own unique and bizarre rules. Each new mission that lands on its surface or orbits above it doesn’t just answer old questions; it invariably uncovers new ones, revealing a planet far more peculiar and fascinating than we ever imagined.
