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Mars – Planet · Rocky
Image: Kevin Gill from Los Angeles, CA, United States · CC BY 2.0
🪐 Planets · The Rocky Worlds

Mars

Planet · Rocky

Mars is a cold desert world, red because its dust is full of iron oxide (rust). It has the tallest volcano in the Solar System, ancient dry riverbeds, and ice at its poles. Billions of years ago it had lakes – maybe even life.

  • 6,779 kmYou could line up 2 of them across Earth.
  • 24 h 37 minDay
  • 687 daysYear
🔭 Find it in the sky

Take a closer look

A canyon across a continent

Mars has a giant canyon system called Valles Marineris, about 4,000 km long and up to 7 km deep. On Earth it would stretch right across the United States. Next to it, the Grand Canyon would look like a small scratch.

Planet-wide dust storms

Martian air is very thin – less than 1% as thick as Earth’s – and mostly carbon dioxide. Even so, dust storms sometimes grow until they wrap the entire planet for weeks. In 2018 one blocked the sunlight that powered the Opportunity rover, ending its mission after nearly 15 years.

Pieces of Mars on Earth

Some rocks found on Earth actually come from Mars. Long ago, big impacts blasted them off the Martian surface, and they drifted through space until they fell here as meteorites. Scientists know where they came from because tiny bubbles of gas trapped inside match the Martian air measured by spacecraft.

Size it up

EarthMars

You could line up 2 of them across Earth. Both are drawn to the same scale.

How we found out

  1. 1877

    Asaph Hall discovers Mars’ two small moons, Phobos and Deimos.

  2. 1965

    Mariner 4 sends the first close-up pictures: a cratered, Moon-like world.

  3. 1976

    Viking 1 lands and photographs the surface.

  4. 2014

    India’s Mangalyaan reaches Mars orbit on its very first try.

  5. 2021

    Perseverance lands and the Ingenuity helicopter makes the first powered flight on another planet. China’s Zhurong rover lands too.

🤔 Something to wonder about

On Mars, what colour is the sunset?

See it yourself

A reddish-orange “star” that shines with a steady light. It’s brightest around “opposition”, about every 26 months.

Got it?

Mark Mars as explored to earn 10 XP.