Mars

Mars: The Rust-Red Frontier

Mars has captivated human imagination for centuries, first as a blood-red omen in the night sky and now as the most likely candidate for humanity’s first interplanetary outpost. While it is only half the size of Earth, its surface area is nearly equal to all of Earth’s continents combined. For the readers of Ad Astra, Mars represents a window into the deep past—a world that was once blue and wet, now frozen in a state of oxidized "rust."

The Alchemy of Red

The most striking feature of Mars is its color. This distinctive hue isn't just surface deep; it is the result of iron-rich minerals in the Martian regolith (the loose dust and rock) that have oxidized, or rusted. This fine dust is everywhere, kicked up by "dust devils" and massive storms that can occasionally engulf the entire planet for weeks at a time. Beneath this rusty veneer, however, Mars is a complex terrestrial world of basaltic rock and ancient volcanic history.

A Land of Superlatives

Mars is home to geological features that dwarf anything found on Earth.

• Olympus Mons: This is the undisputed king of volcanoes in the solar system. A shield volcano roughly the size of the state of Arizona, it stands 25 kilometers (15 miles) high—nearly three times the height of Mount Everest. Because Mars lacks plate tectonics, this volcanic "hotspot" remained under the same spot for billions of years, allowing the mountain to grow to such impossible proportions.

• Valles Marineris: If you were to place this canyon system on Earth, it would stretch from New York City to Los Angeles. Reaching depths of 7 kilometers (4 miles), it is a vast tectonic crack in the crust, likely formed as the planet cooled and the nearby Tharsis volcanic bulge pushed the ground upward.

The Ghost of an Ocean

Perhaps the greatest mystery of Mars is its lost water. The surface is scarred by ancient riverbeds, sprawling deltas, and flood channels that suggest a much thicker, warmer atmosphere once existed. Today, the atmospheric pressure is less than 1% of Earth’s, consisting mostly of carbon dioxide. In these "hyper-continental" conditions, liquid water would instantly boil away or freeze.

However, the water hasn't entirely vanished. It is locked away as ice in the polar caps and hidden in vast permafrost layers beneath the soil. If all the Martian ice were melted, it is estimated that the entire planet would be covered in an ocean over 20 meters deep.

The Martian Rhythm

A "day" on Mars, known as a Sol, is remarkably similar to ours, lasting about 24 hours and 40 minutes. Because Mars is tilted on its axis at 25 degrees (very close to Earth’s 23.5), it experiences four distinct seasons. However, because its orbit is much farther from the Sun, a Martian year lasts 687 Earth days, meaning each season is nearly twice as long as ours. During the winter, it gets so cold at the poles (reaching -153°C) that the atmosphere itself freezes, with carbon dioxide falling as "dry ice" snow.

The New Age of Exploration

Mars is currently the most inhabited planet in the solar system—by robots. From the Curiosity and Perseverance rovers currently trekking across its craters to the legacy of the Ingenuity helicopter, we have more data on Mars than any other world besides Earth. As of 2026, international eyes are turning toward "Sample Return" missions, aiming to bring Martian rocks back to Earth to search for microscopic fossils of ancient life.

The Moons: Phobos and Deimos

Mars is orbited by two tiny, lumpy moons that look more like captured asteroids than true satellites. Phobos (Fear) and Deimos (Dread) are small and dark. Phobos is actually spiraling inward; in about 50 million years, it will either crash into Mars or be torn apart by gravity to form a temporary ring around the planet.

Mars at a Glance for Ad Astra

• Distance from Sun: ~228 million km (1.5 AU)

• Surface Gravity: 38% of Earth’s (you could jump nearly 3x higher!)

• Atmosphere: 95% Carbon Dioxide

• Moons: 2 (Phobos and Deimos)

• Key Feature: Olympus Mons and the potential for past life.