Mars Facts for Kids: Rust, Blue Sunsets & Robot Explorers

Nova: Buckle up, Explorers.

Cosmo: Brains in!

Nova: Wheels up!

Nova & Cosmo: Brain Bus, let's GO!

Nova: Welcome to The Brain Bus - I'm Nova, your driver, and right now this car you're sitting in has just phased into the most breathtaking place in the solar system. Cosmo, my trusty robot co-pilot, say hello.

Cosmo: Hello! I have been waiting ALL week for this one.

Nova: Here's your first brain-flip for today, Explorers. You know how sunsets on Earth are orange and pink and red? On Mars - the planet that is already red - the sunset turns blue. Blue. While the daytime sky stays butterscotch red. Everything backwards. Everything reversed. We are going to Mars.

Cosmo: I've had butterscotch! The planet is delicious already!

Nova: We'll get to that. Strap in, Explorers - The Brain Bus is taking us to the Red Planet.

Nova: Okay, first things first. Why is Mars red? Cosmo, I know you have a theory.

Cosmo: Oh, I have several. My leading hypothesis is that Mars is red because it is extremely hot. Like lava. Lava planet!

Nova: Oooh, that is such a satisfying guess - and so completely wrong.

Cosmo: It's not lava?

Nova: Mars is freezing. Average temperature: minus sixty degrees Celsius. Colder than anywhere people actually live on Earth. The red comes from rust.

Cosmo: The whole planet is rusty?

Nova: The whole planet is rusty. The dust covering Mars is packed with iron, and long ago that iron reacted with oxygen and turned to rust - exactly the same reaction that turns an old bike orange when you leave it in the rain. Except here, it's a whole planet. A planet-sized rusty bike.

Cosmo: So Mars is... a giant bike someone forgot to bring inside.

Nova: Essentially, yes. And the dust is everywhere - which brings us to the storms. Dust storms on Mars can grow so enormous they wrap around the entire planet and last for months. Imagine every grain of that rusty dust being hurled into the sky until you can't see the Sun at all.

Cosmo: Wait, wait, wait. Can I just say - this is exactly like when someone shakes a cinnamon jar too hard over their toast and suddenly it's in their hair and on the ceiling and everywhere.

Nova: That is - actually that is exactly what a Martian dust storm is. Planetary cinnamon chaos.

Cosmo: Mars is a planet someone dusted with cinnamon sugar, and the storms are just someone overenthusiastic at breakfast.

Nova: I'm going to stop arguing with that.

Cosmo: Wise.

Nova: Now - how big is Mars? Because this is where things get properly enormous. Mars has the biggest volcano in the entire solar system. It's called Olympus Mons - and it's about two and a half times taller than Mount Everest, the tallest mountain on Earth. And so wide at the base that it would nearly cover the entire country of Italy.

Cosmo: Italy is a whole country.

Nova: It is a whole country. Olympus Mons got that enormous for an interesting reason - on Earth, the ground is split into massive plates that slowly move around, sliding over hot spots, so volcanoes pop up in chains. But Mars's surface doesn't slide. It stays put. So lava piled up in exactly the same spot for millions and millions of years, just stacking higher and higher until you get the most enormous volcano in the solar system.

Cosmo: Ooh, Data Log - I actually have an entry on this from our last volcano episode. Filing it now. "Olympus Mons: what happens when a planet builds one volcano without moving the furniture around. Same spot. Forever. Mountains happen."

Nova: Perfect Data Log entry. And right next to those epic scales, Mars also has a canyon called Valles Marineris - nearly as long as Australia is wide, and in places four times deeper than the Grand Canyon. If you fell into it, you'd be falling for a very long time.

Cosmo: Please don't fall into it.

Nova: Agreed. Now, Cosmo - people have been looking at Mars for thousands of years. Ancient Egyptians called it Her Desher - meaning "the red one." Simple, accurate. Ancient Chinese astronomers called it Huo Xing - "fire star" - because of that red glow. And the Romans named it Mars after their god of war, the Babylonians before them linked it to Nergal, their god of war and fire. What's remarkable is that all these cultures, across completely different parts of the world, who never spoke to each other - they all looked at the same red dot in the sky and reached for the same idea. Red means fire. Red means battle. All from rust, in the end.

Cosmo: They weren't wrong about the red part.

Nova: They absolutely nailed the red part. Now - the moons. Mars has two moons, named Phobos and Deimos, meaning "Fear" and "Dread."

Cosmo: Okay, those names are incredible.

Nova: They are dramatic. But here's the thing - Phobos and Deimos look nothing like their names. They are tiny and lumpy and potato-shaped. Scientists think Mars's gravity probably grabbed them out of the nearby asteroid belt.

Cosmo: Small. Lumpy. Potato-shaped. Orbiting above a planet. Explorers, Mars is keeping two tater tots in orbit for later.

Nova: For a snack. For when it gets peckish.

Cosmo: Smart. Very smart planet.

Nova: Here's the wild thing about Phobos specifically. It races around Mars so fast it crosses the sky about twice in a single Martian day - rising in the west and setting in the east, because it's zooming around faster than Mars itself spins. And it's slowly, very slowly, spiralling inward. In tens of millions of years, it'll either break apart or crash into Mars - and if it breaks apart, it might even form a ring around the planet. Like Saturn.

Cosmo: That's not terrifying at all.

Nova: Tens of millions of years, Explorers - nothing to worry about from this car. And a ring around Mars would be beautiful.

Cosmo: Okay I'm choosing to focus on the beautiful ring.

Nova: Good choice. Now, a Martian day is almost identical to ours - 24 hours and 37 minutes. The morning would feel familiar. But a Martian year lasts almost two of our Earth years, because Mars takes much longer to travel all the way around the Sun. And if you stood on Mars, you'd weigh about a third of what you do here - the planet is smaller, gravity is weaker, and you could jump more than twice as high as you can right now.

Cosmo: I want to jump twice as high immediately.

Nova: And at the poles, Mars has ice caps - but they're partly made of frozen carbon dioxide. That's dry ice - the same stuff that makes the smoky fog you see at science demonstrations. So the polar caps aren't just frozen water. They're partly frozen fog.

Cosmo: Are they... fizzy?

Nova: They are not fizzy. But I understand why you'd hope.

Cosmo: The research department will be hearing about this.

Nova: And here is where I want everyone to go quiet for a second. All of this - the rust, the cold, the dried-up riverbeds - because Mars had rivers once, Explorers. Long ago. We can still see the dried channels in the rock. Mars had water. Mars might once have had conditions where something could live. And then it changed. The reason it changed is worth sitting with.

Nova: Imagine a bed on a freezing cold night. You've got a thick warm blanket, and you're perfectly comfortable. Earth is like that - it has a thick blanket of air wrapped all the way around it, holding warmth in and keeping water liquid. Mars used to have a blanket too. But it lost it. Its air became so thin that the warmth just drifted away into space. And without warmth, the water froze, or dried up, or disappeared. Mars went cold and dry because it lost almost all of its air. A planet needs that blanket to stay warm - and to keep its water. Earth still has its blanket. Mars lost it. And here we are - one planet alive, and one turned quiet and rust-red and cold.

Nova: The scientists exploring Mars aren't just looking at a dead world. They're trying to understand how two planets that started in the same solar system ended up so different - and what that means for us.

Cosmo: That question is enormous.

Nova: It really is. And it's one of the best reasons we keep going back.

Nova: Now - robots. No people have ever set foot on Mars yet. But robots have been exploring it for decades. Including a small helicopter called Ingenuity, which became the first machine in history to fly through the air of another planet. Flying on Mars is incredibly hard because the air is so thin - Ingenuity's blades had to spin many times faster than a helicopter on Earth just to push against that wisp of atmosphere.

Cosmo: Wait wait wait - no humans on Mars yet? I was sure astronauts were living there!

Nova: No humans, ever, so far. Robots yes. People, not yet.

Cosmo: My Space Guidebook said there was a colony.

Nova: Your Space Guidebook has let you down again. But here's the thing - a little device called MOXIE was sent to Mars, and it actually turned the Martian air into breathable oxygen. The air on Mars is mostly carbon dioxide - not something you can breathe - but MOXIE pulled oxygen out of it. That's a first step. Making oxygen from the air that's already there. Which means the path to humans on Mars is being built, one experiment at a time.

Cosmo: Okay. The robots are setting up the planet for us. I'm into this plan.

Nova: It's a very good plan. And when those robots phone home - when they send signals back to Earth - those signals are sometimes caught by an antenna dish at a place called Tidbinbilla, near Canberra in Australia. It's called the Canberra Deep Space Communication Complex, and it's one of only three stations on the entire planet that can talk to spacecraft across the solar system. The only one in the Southern Hemisphere. So when Ingenuity flew for the first time on another world, part of that message came home through Australia.

Cosmo: That is extremely cool.

Nova: Extremely cool.

Nova: Quiz time, Explorers! Cosmo is going to keep score - on himself - and we are asking four questions. No pressure, just brain-flexing. Ready?

Cosmo: I am ready. I have already gotten one wrong in this episode so statistically things can only improve.

Nova: That's not how statistics work, but I love your confidence. Question one!

Nova: Why is Mars red? Is it (a) it's on fire, (b) rusty iron in its dust, or (c) someone painted it?

Cosmo: Answer: (b) - rusty iron! Iron in the soil reacted with oxygen long ago and turned to rust. Same chemistry as an old bike. Just - you know. Planet-sized.

Nova: Question two!

Nova: True or false - a day on Mars is almost exactly the same length as a day on Earth.

Cosmo: True! Twenty-four hours and thirty-seven minutes. Mars spins at nearly the same speed we do - so the days feel familiar, even if the years don't.

Nova: Question three!

Nova: How many moons does Mars have - give us your best estimate.

Cosmo: Two! Phobos and Deimos - Fear and Dread - small, lumpy, potato-shaped, and probably stolen from the asteroid belt.

Nova: Last one - and this is the question I personally love most. True or false: sunsets on Mars look blue.

Cosmo: True - absolutely, weirdly, beautifully true! The fine dust in Mars's air scatters light the opposite way our air does, so the daytime sky is red, and the sunset glows blue. Everything flipped.

Nova: Explorers, however many of those landed for you - four or one or anywhere in between - what matters is you sat with those questions and your brain did something. That's what we're here for. The thinking is the point.

Cosmo: Agreed. And I'm giving myself a personal score of "improving."

Nova: Fun Fact Blast - five facts, fast. Things we haven't told you yet. Cosmo, hit it.

Cosmo: Fact one! Sending a signal from Earth to Mars takes somewhere between five and twenty minutes one way - because even radio waves, travelling at the speed of light, have an enormous distance to cross. You cannot have a real-time conversation with Mars. Every sentence arrives late.

Nova: Fact two! Mars's ice caps are partly made of frozen carbon dioxide - dry ice - the same stuff that makes the foggy smoke in stage shows. The poles of Mars are partly made of the same material as a science classroom demonstration.

Cosmo: Fact three! The name for the study of Mars is "areology" - because the Greeks called the god of war Ares instead of Mars. So Mars scientists sometimes call themselves areologists. Which is a very good job title.

Nova: Fact four! Valles Marineris - that enormous canyon on Mars - is nearly as long as Australia is wide. If you drove a car from one end of it to the other without stopping, it would take many days.

Cosmo: Fact five! When a rover on Mars recorded sounds, they came out quieter and more muffled than they would on Earth - because the thin carbon dioxide air carries sound differently. The same shout on Mars would reach your ears smaller, stranger, quieter. Your voice, but not quite your voice.

Nova: That one never stops being extraordinary to me. The same sounds - just muffled by a different sky.

Nova: Okay, Explorers - this one is for the whole car, and you need absolutely nothing except your voice and your patience. Ready? This is called The Mars Phone Call.

Nova: Here's the thing about talking to Mars - a signal takes between five and twenty minutes just to get there. One way. So if you ask a question and the answer comes back, you've been waiting up to forty minutes for that whole exchange. You can't chat. You can't joke back and forth. Every sentence arrives late.

Cosmo: Which sounds like a very frustrating game of chess.

Nova: So here's your challenge. Pick one person in the car to say one short sentence. Then everyone - everyone - counts silently to ten. Don't rush it. One... two... all the way to ten. Then the next person can respond. One sentence. Count again. Keep going.

Nova: Notice how strange it feels. The gap. The waiting. The way a joke lands ten counts after you've almost forgotten it was coming.

Cosmo: On real Mars time that ten-count is standing in for actual minutes. Real robots wait real minutes for real answers.

Nova: And here's your wondering question, Explorers - for the whole car, no right answer needed. If every message took that long, how would you even tell a joke to someone on Mars? How would you play a game together? What would change about how you talked to each other - if every word took that long to travel?

Nova: Before we phase back, Explorers - a riddle. And this one is pointing somewhere new.

Nova: I rise in the west and set in the east. I zoom across the sky a couple of times a day. Far, far in the future, I'm going to crash into the very planet I circle. What am I?

Nova: Now - some of you might have an answer forming. Hold it. Keep it. Because here is the thing about this riddle: we are not solving it today. The answer is waiting for you somewhere you can actually go looking - somewhere closer than you might think. Wonder about it on the rest of this journey. Ask your grown-up. See what you come up with together.

Cosmo: I have thoughts. I am not sharing them.

Nova: Smart robot.

Nova: The Brain Bus is phasing back. Mars is shrinking in the window - all that rust-red dust, those frozen cinnamon storms, Phobos tumbling overhead like a lost tater tot - fading back into the night sky where it lives.

Cosmo: I will miss it. And also I want a snack.

Nova: You always want a snack. Explorers, if anyone in the car asks what you learned today - you can tell them: Mars lost its blanket. Its air got too thin to hold the warmth, and the water disappeared, and the whole planet went cold. Earth kept its blanket. That's why we're here and not there. And the robots we sent are making oxygen out of that thin Martian air, one small breath at a time, getting ready for whenever we follow.

Nova: Stay curious, stay clever, and keep that brain working!

Nova: Until the next stop, Explorers...

Cosmo: ...keep wondering.