All About Mars

Mars is a cold desert world. It is half the size of Earth. Mars is sometimes called the Red Planet. It's red because of rusty iron in the ground.


Explore Mars! Click and drag to rotate the planet. Scroll or pinch to zoom in and out. Credit: NASA Visualization Technology Applications and Development (VTAD)

Like Earth, Mars has seasons, polar ice caps, volcanoes, canyons, and weather. It has a very thin atmosphere made of carbon dioxide, nitrogen, and argon.

There are signs of ancient floods on Mars, but now water mostly exists in icy dirt and thin clouds. On some Martian hillsides, there is evidence of liquid salty water in the ground.

Scientists want to know if Mars may have had living things in the past. They also want to know if Mars could support life now or in the future.

a cartoon of Mars smiling, saying, I love having visitors!

Structure and Surface

  • Mars is a terrestrial planet. It is small and rocky.
  • Mars has a thin atmosphere.
  • Mars has an active atmosphere, but the surface of the planet is not active. Its volcanoes are dead.

Time on Mars

  • One day on Mars lasts 24.6 hours. It is just a little longer than a day on Earth.
  • One year on Mars is 687 Earth days. It is almost twice as long as one year on Earth.

Mars’ Neighbors

  • Mars has two moons. Their names are Phobos and Deimos.
  • Mars is the fourth planet from the Sun. That means Earth and Jupiter are Mars’ neighboring planets.

Quick History

  • Mars has been known since ancient times because it can be seen without advanced telescopes.
  • Several missions have visited Mars. And Mars is the only planet we have sent rovers to. They drive around Mars, taking pictures and measurements.

What does Mars look like?

A photo of one full lit side of Mars, showing the reddish brown color of its surface and a white spot on the southern side.

NASA's Hubble Space Telescope took this picture of Mars as it was making its closest approach to Earth in 60,000 years!

A photo of one full lit side of Mars showing several white splotches that are water-ice clouds and ice on the ground.

In this picture of Mars, you can see water-ice clouds, polar ice, and some rocky features.

A photo of the Mars surface with a hill in the background and lots of small rocks in the foreground.

NASA's Mars Exploration Rover Opportunity took this picture with its panoramic camera near "Solander Point" on Mars.


For more information visit:

NASA's Mars Exploration Program

NASA Solar System Exploration

article last updated July 25, 2019

If you liked this, you may like:

More Less
More Less