Red Planet Day is observed every year on November 28 to commemorate a turning point in humanity's quest to understand Mars. On this day in 1964, NASA launched the Mariner 4 spacecraft, the first mission to successfully perform a close flyby of the planet. The spacecraft transmitted the first-ever close-up images of Mars, offering a glimpse of its barren, cratered surface and laying the foundation for all future Mars exploration.
Why Red Planet Day Matters
The day honours decades of scientific progress and highlights the continued global effort to study Mars. From rovers and landers to orbiters and future sample-return plans, Mariner 4's success continues to inspire missions aimed at uncovering the planet's history, climate, geology, and potential for past life.
Why Mars Is Called The Red Planet
Mars gets its distinctive red colour from iron oxide, essentially rust, that coats its soil and dust. The iron-rich particles interact with the atmosphere, giving the planet its widely recognised reddish tint. This unique appearance is the reason ancient Romans named it after their god of war. Civilisations across history made similar associations; Egyptians called the planet "Her Desher," or "the red one."
A Planet Of Extremes
Mars is the fourth planet from the Sun and around half the size of Earth, with a radius of 3,390 km. Although it is one of Earth's closest planetary neighbours, conditions there are far from hospitable. Its landscape is cold, dry, and rocky, with temperatures ranging from a relatively mild 20°C to as low as -153°C. Because the atmosphere is extremely thin - composed mainly of carbon dioxide, nitrogen, and argon - the planet offers little protection from meteorite impacts and allows heat to escape quickly.
Despite these harsh conditions, Mars is home to the only robots that operate independently on another world, including rovers, landers, and orbiters.
Orbit, Seasons, and Martian Days
A day on Mars, known as a sol, lasts 24.6 hours, slightly longer than an Earth day. But a Martian year spans 687 Earth days because of the planet's greater distance from the Sun. Mars also experiences seasons due to its tilted axis (25 degrees), though their lengths vary because of its elliptical orbit. Northern spring lasts 194 sols, while the shortest season, northern autumn, lasts 142 sols.
Mars' Twin Moons
The planet is orbited by two small moons, Phobos and Deimos, which scientists believe may be captured asteroids. Because of their uneven shapes, they resemble large space rocks rather than spherical moons. Their names come from Greek mythology - representing fear and terror, companions of the god of war.
Water On Mars: A Clue To Ancient Life
Evidence suggests Mars once had rivers, lakes, and possibly even oceans. Features like dried valley networks and minerals formed by water point to a wetter past. Today, liquid water cannot survive at the surface for long, but ice deposits exist beneath the polar regions, and briny water occasionally seeps down slopes during warmer seasons. These clues fuel ongoing research to determine whether Mars ever supported life when its environment was more suitable.
Red Planet Day reminds us how a single spacecraft, Mariner 4, transformed humanity's understanding of Mars and opened a new era of planetary exploration. As space agencies plan crewed missions and sample-return projects, November 28 continues to symbolise both scientific achievement and the curiosity driving humanity toward the Red Planet.
