Mars Facts For Kids

The planet Mars is named after the Roman God of War. It is the fourth planet from the sun, and our next-door neighbour in the solar system (Earth is the third planet from the sun).

Nasa has recently found evidence of flowing water on Mars, which raises the likelihood that life may exist on the planet! We’ll investigate their findings further down the page.

This article contains Mars facts for kids (and adults!). Let’s find out more about the Red Planet ...

(See more Science Articles.)

Introduction: Mars In The Solar System

You can often see Mars in the night sky without a telescope or binoculars. It looks like a bright red star. Named after the Roman God of War, Mars is often called the ‘Red Planet’ due to its red colour.

The video below shows actual views of Mars taken by Nasa's Curiosity Rover:

Our Next-Door Neighbour

Mars is one of our ‘next-door neighbours’ in the solar system. Our other neighbour is Venus, the second planet from the sun, which is nearer to Earth than Mars.

The diagram below shows the order of the planets in the solar system and their relative sizes. Mars is planet 4, Earth is 3.

As you can see, Earth is bigger than Mars: around twice the size, in fact.

However, they're both small compared to Uranus and Neptune, and tiny compared to Jupiter and Saturn!

Uranus and Neptune are also known as the 'Ice Giants' and Jupiter and Saturn are known as the 'Gas Giants'.

Planets Of The Solar System Showing Their Relative Sizes
Planets Of The Solar System Showing Their Relative Sizes. Mars is planet no. 4. Earth is no. 3.

Planets of the Solar System:

  1. Mercury
  2. Venus
  3. Earth
  4. Mars
  5. Jupiter
  6. Saturn
  7. Uranus
  8. Neptune
  9. (Pluto: not on the diagram)

How To Remember The Order Of The Planets

Here are two useful mnemonics to remember the order of the planets (a mnemonic is a way of remembering something). The first one includes Pluto*, the second does not.

My Very Educated Mother Just Showed Us Nine Planets

My Very Excellent Mother Just Served Up Nachos

* Many scientists regard Pluto not as a planet, but as a 'dwarf planet'. Since the discovery of Pluto, several more dwarf planets have been discovered, so the mnemonic should be even longer!

Would You Want To Live On Mars?

The Surface Of Mars
The Surface Of Mars: View from the mast camera (Mastcam) on NASA's Curiosity Mars rover.

Mars is a cold, inhospitable place. Its surface is pitted with impact craters. If you could breathe there, you might have fun jumping around in the low gravity, but you’d be in danger of being blown away: huge dust storms with winds reaching speeds of over 100 km/h (62 mph) occasionally blow across the surface. The dust can take months to settle down again.

The low gravity might help as you made your way across the rocky, desert-like terrain but you wouldn't survive the cold, at least not for most of the year.

Mars Surface
Mars' surface is a cold, rocky desert.

Because Mars is further from the Sun than Earth, its atmosphere is colder. Although during the summer the temperature at the equator of Mars can rise to a habitable 30 °C (86 °F), most of the time it’s much lower. The average temperature on Mars is -63° C (-81°F).

In the winter the temperature can fall as low as −143 °C (−225 °F) at the polar ice caps.

The wide temperature range is caused in part by the thin atmosphere, which doesn’t retain much heat.

Mars Landscape
Another incredible view of the Martian landscape from Nasa.

Mars distance from the Sun

When you're talking about space, distances tend to be very, very big! The figures below are rough approximations, because the planets don't orbit the sun in perfect circles.

Mars distance from the Sun: 141,600,000 miles (227,940,000 kilometers)

Earth distance from the Sun: 92,900,000 miles (149,600,000 kilometers)

(Data from

More Mars facts

The diameter of Mars is approximately half that of Earth's. Mars is also a much less dense planet, and is only one-tenth of the Earth’s weight. This means that gravitational pull on the surface of Mars is significantly weaker than that on Earth.

Mars Years Are Longer; Mars Days Are Around The Same

Mars has seasons, just like Earth. However, seasons last about twice as long on Mars. Mars takes almost twice as long to go round the sun, so a Martian year is equal to almost two Earth years.

That means fewer birthdays in the same amount of time!

However, a day on Mars is almost the same length as a day on Earth. Mars rotates on its axis in 24.617 hours, so a day on Mars is only a little longer.

Mars Atmosphere

The atmosphere of Mars is mainly carbon dioxide, with small amounts of argon and nitrogen, and only traces of oxygen and water vapour.

You certainly wouldn’t be able to breathe on Mars!

Mars has a very thin atmosphere, which is also caused by the planet’s low density. Mars’ atmospheric pressure is less than one-hundredth of Earth’s.

Why Is Mars Red?

Mars is red because it is covered in a layer of iron-rich dust. The rusty red colour of the planet is caused by just that: iron oxide, also known as rust!

Dust in the atmosphere causes Mars to have red skies.

Mars: A Visitor's Guide

So despite the deadly atmosphere, the cold, and the dust storms, you still want to visit Mars? Here are some of the attractions:

Polar Ice Caps

Mars's polar ice caps are made of frozen carbon dioxide, which turns to gas in the summer (when a substance turns directly from a solid to a gas it is said to ‘sublime’). When this happens, large geysers of carbon dioxide and dust erupt from the surface. Don’t forget your camera!

Olympus Mons

Be sure to visit Tharsis, the volcanic plateau in the planet's western hemisphere. Here you will find three huge volcanoes, including Olympus Mons: the biggest volcano in the solar system. It’s almost as tall as three Mount Everests!

Olympus Mons
Olympus Mons is the biggest volcano in the system. It is almost 25 km high!

The reason such a huge mountain can exist is because of the low gravity on Mars. If the volcano was moved to Earth it would sink into the ground.

Valles Marineris

If you like hiking, and think that the Grand Canyon is a bit too crowded, then why not visit the Valles Marineris? This system of canyons is over 4,000 km (2,500 miles) long, up to 200 km (120 miles) wide and up to 7 km (4.35 miles) deep.

Mars Canals

If you were hoping to see canals on Mars then you might end up disappointed. In the 19th century an Italian astronomer named Giovanni Schiaparelli found what he thought were long grooves on the surface of Mars. An American astronomer, Percival Lowell, was influenced by this discovery, and claimed that the grooves were canals, built by aliens to irrigate farmland. It was later found that the canals were optical illusions.

Mars Moons

Phobos Mars Moon
Phobos, one of Mars' two moons.

Mars has two moons, Phobos and Deimos. In Greek mythology, Phobos and Deimos are the sons of Ares, the God of war. The two moons are cratered and irregular in shape. They cannot be seen by the naked eye from Earth.

Spacecraft On Mars

Mariner 4, launched in 1967, was the first spacecraft to successfully perform a flyby of Mars. Since then, several more spacecraft have reached Mars, and there are currently 7 operational spacecraft at the planet. Five of these are in orbit, and two are on the ground.

Click on the names of the craft to go to their official sites.

In orbit:

2001 Mars Odyssey

Mars Reconnaissance Orbiter


Mars Orbiter Mission

On the planet surface:

Mars Exploration Rover Opportunity

Mars Science Laboratory Curiosity

Mars Facts

Is There Life On Mars?

Because Mars is close to Earth, and the most ‘Earth-like’ of the other planets in the solar system, man has always wondered if there could be life there.

The word ‘Martian’, which means ‘of, or relating to Mars’, has come to mean an alien invader, usually intent on the destruction of Earth!

The presence of water is used as an indicator of whether a planet could support life. There is evidence that there was once a large amount of water on Mars, which suggests that life may once have existed on the planet, even if it no longer does.

Nasa Mars Announcement

Nasa Mars Announcement
This photo from the recent Nasa Mars Announcement shows lines of water running down the mountain.

There have been a number of signs that water stills exists on Mars, and on 28th September 2015, Nasa announced that they had found evidence of liquid water on Mars. The presence of flowing water means that the planet is more likely to be able to support life.

Watch the video below to see highlights of the Nasa announcement:

If there is anything living on Mars, then it's more likely to be microbes than little green men. However, Nasa's discovery means that we are one step closer to finding out.

Flowing Water On Mars
Photo from Nasa showing flowing water on Mars

Mars Facts For Kids

Planet Mars Facts
Mars Facts For Kids

  • Mars is the fourth planet from the sun (Earth is the 3rd, so we’re neighbours).
  • Mars is visible with the naked eye.
  • Mars has a red colour, caused by iron oxide on the surface and in the atmosphere of the planet.
  • Mars is around half the size of Earth.
  • A Martian year is equal to 687 days: almost two Earth years. A Martian day is 24.617 hours long.
  • Mars has polar ice caps made of frozen carbon dioxide. The carbon dioxide turns into gas in the summer.
  • The word ‘Martian’ means anything from, or related to, Mars. It doesn’t mean an alien … unless the alien is from Mars!
  • Mars is home to the biggest volcano in the solar system. Called Olympus Mons, it is almost as tall as three Mount Everests!
  • Mariner 4 was the first spacecraft to successfully perform a flyby of Mars. It took the first pictures of the planet’s surface.
  • Mars has two moons, Phobos and Deimos.
  • In September 2015, Nasa confirmed that it had discovered liquid water on Mars, raising the likelihood that life could exist on the planet.

See more science articles here.