Mars: The Rusty Planet
The God of War
Look at Mars in the night sky. It glows with a distinct reddish-orange color. The Romans named it after their God of War because it looked like drops of blood. But it isn't blood. It is Rust. The surface of Mars is covered in Iron Oxide ($Fe_2O_3$)—the same reddish crusted metal that forms on an old bike left in the rain. Mars is essentially a planet-sized rusty nail floating in space. To rust, you need Iron and Oxygen. Mars has iron in the rocks. But where did the oxygen come from? Billions of years ago, Mars likely had water and oxygen. That oxygen reacted with the iron rocks, turning the whole planet red. Now, the oxygen is locked away in the rocks, leaving the air unbreathable ($95% CO_2$).
The Lost Atmosphere
Mars wasn't always a desert. We see dry riverbeds, canyons, and ancient lake bottoms. 4 Billion years ago, Mars was warm and wet. It was a twin of Earth. What happened? Core Death. Earth has a molten iron core that spins, creating a magnetic field (The Magnetosphere). This shield protects our air from the Sun. Mars is smaller than Earth (half the size). Because it was small, its core cooled down faster. Eventually, the core froze solid. The dynamo stopped. The magnetic shield turned off. Then came the Solar Wind. Without a shield, the sun's radiation blasted Mars for millions of years, stripping away the atmosphere and boiling the oceans into space. Mars died because its heart stopped beating.
The Pink Sky & Blue Sunsets
On Earth, the sky is Blue (Rayleigh Scattering) and sunsets are Red. On Mars, it is the opposite. The Martian sky is usually Salmon Pink or Butterscotch. This is because the air is full of fine red dust. However, if you watch a sunset on Mars (as the Curiosity rover did), it is Blue. The dust particles are exactly the right size to absorb red light near the sun, leaving a cool blue halo. It is an alien inversion of our world.
Farming on Mars: Toxic Dirt
In the movie The Martian (2015), Matt Damon grows potatoes in Mars soil using poop. Could we do this? It would be hard. Mars soil isn't just rusty; it is Toxic. It contains high levels of Perchlorates. These are salts used in rocket fuel and bleach. They are poisonous to humans. They attack the Thyroid gland. If you ate a Martian potato without washing the soil chemically first, you would die. Any future colony will have to run "soil washing factories" before they can plant a single seed.
Terraforming: Can We Fix It?
Can we turn Mars Green? This is Terraforming. The goal is to warm the planet and build an atmosphere. Elon Musk suggested "Nuking the Poles." Why? The polar ice caps of Mars are made of Dry Ice (Frozen Carbon Dioxide). If we melt them using nukes or mirrors, the $CO_2$ would be released into the air. $CO_2$ is a Greenhouse Gas. It would trap heat, warming the planet. As it warms, more ice melts, creating a feedback loop. Eventually, liquid water could flow again. But creating a breathable atmosphere (Oxygen) would take thousands of years of planting algae and trees. It is a project for the year 3000, not 2030.
The Doomed Moons
Mars has two moons: Phobos and Deimos. They are not round like our Moon. They are lumpy potatoes. They are likely captured asteroids from the asteroid belt. Phobos is doomed. It is spiraling inward towards Mars. Every 100 years, it gets 6 feet closer. In about 50 million years, it will reach the "Roche Limit." Mars' gravity will rip the moon apart. The debris will form a Ring around Mars. So, in the future, Mars will look like a miniature Saturn.
Fast Facts
- Gravity: Mars gravity is 38% of Earth's. If you weigh 100 lbs here, you weigh 38 lbs there. You could dunk a basketball easily.
- Olympus Mons: Mars has the largest volcano in the Solar System. It is 3 Times taller than Mt. Everest. It is so wide it covers the entire state of Arizona. It grew so big because Mars has no Tectonic Plates, so the volcano sat over the same "lava hotspot" for billions of years.
- Valles Marineris: A canyon system that makes the Grand Canyon look like a crack in the sidewalk. It is as long as the entire United States (NY to LA).
Diagram Prompts
- Mars vs Earth Layers: Comparison. Earth: Liquid Core (Spinning), Large Magnetosphere (Shield), Atmosphere (Blue). Mars: Solid Core (Dead), No Shield, Solar Wind stripping air away (Red). Label: "The Death of a Planet."
- Olympus Mons Scale: A silhouette of Olympus Mons. Superimposed in front of it: Mt. Everest (Tiny) and Mauna Kea (Small). Map outline of Arizona underneath. Label: "The Mega Volcano."
- Blue Sunset: An alien landscape. Red jagged rocks. Dusty pink sky. The sun is setting, and the light around it is a glowing cool Blue halo.