Mars Facts for Kids
Diameter: 6,779 km (4,212 miles)
Mean distance from Sun: 227,943,824 km (141,637,725 miles)
Orbital period (year): 687 Earth days
Rotation period (day): 24.6 hours
Atmosphere: 95.3% carbon dioxide, 2.7% nitrogen, 1.6% argon,
tiny amounts of oxygen, carbon monoxide and water vapor
Mars was named for the Roman god of war.
Mars was the Roman god of war. The Greeks called him Ares, and he always went into battle with his sons Phobos (panic) and Deimos (terror). When American astronomer Asaph Hall discovered the two small Martian moons in 1877, he named them Phobos and Deimos.
Mars isn't bloody, it's rusty.
For a god of war, a planet the color of blood sounds just right. But the color comes from a layer of iron oxide – that's the chemical name for rust.
Mars doesn't have liquid water on the surface.
There isn't enough air pressure from the thin Martian atmosphere to keep water liquid on the planet's surface. Long ago, Mars flowed with water, but it had a thick atmosphere then. There is still lots of water frozen on Mars. If the southern polar icecap melted, there could be enough water to cover the whole planet with 11 meters (36 feet) of water.
Mars is much smaller than Earth.
Mars is only half as big across as Earth, and the pull of gravity on Mars is only 38% of what we're used to. So a person weighing 100 lbs (45.5 kg) on Earth would weigh 38 lbs (17 kg) on Mars. This might sound like fun, but the low gravity is one reason why Mars lost most of its atmosphere. You could run and jump, but not breathe.
Seasons on Mars are the most Earth-like of all the planets.
A planet has seasons because its axis of rotation is tilted. (For an explanation, click on the link below this article “Why Planets Have Seasons”.) Earth's axis is tilted 23 degrees, and the Martian axis 25 degrees, so we have a similar pattern of seasons. Of course, Mars is a lot colder and its seasons are longer. It's farther away from the Sun than we are, and its years are two Earth years long. If Mars still had a thick atmosphere, it would be warmer than it is, because an atmosphere acts like a blanket.
The highest mountain in the Solar System is on Mars.
Olympus Mons is 27 km (17 miles) high, which is more than three times higher than Mount Everest. Mars also has the largest known canyon. Valles Marineris is about 4000 km (2500 miles) long. Even if the Grand Canyon in Arizona went all the way to Florida, it still wouldn't be as long as Valles Marineris.
There weren't ever any giant canals on Mars.
Nineteenth-century Italian astronomer Giovanni Schiaparelli thought he saw long channels (canali in Italian) on Mars. This sounded like the English “canals”, which are always man-made. A prominent American, Percival Lowell, was enchanted by the idea of a great Martian civilization that had built canals. So he built Lowell Observatory in Arizona to observe them. As telescopes got better, it was obvious that the canals were an illusion. However Clyde Tombaugh did discover Pluto at Lowell Observatory. So even though we lost a Martian civilization, we gained an interesting dwarf planet.
Mars has the biggest dust storms in the Solar System.
The storms can be local and last a few days, but others cover the whole planet for months. Amateur astronomers can see really big ones through their telescopes. The Martian Rovers Spirit and Opportunity were caught in such a big storm in 2007 that NASA was afraid they'd be permanently damaged. Both rovers survived to continue their exploration, but sadly, Spirit stopped communicating on March 22, 2010 and her mission was formally ended on May 25, 2011. And Opportunity was finally lost in 2018 in the biggest dust storm ever seen on Mars.
The “stone face” in Cydonia is a natural rock formation.
In 1976 the Viking orbiter took a picture of the Cydonia area of Mars that included something that looked like a giant face. This was a trick of the light and shadows. You can see a more recent high-resolution picture of the same rock formation, along with the original Viking photograph.
We haven't found any life on Mars yet.
Many people still hope to find life on Mars even though ultraviolet radiation from the Sun would be fatal to any living thing at the planet's surface. Earth is protected from most of the dangerous radiation by a thick atmosphere and a magnetic field, but Mars doesn't have either of these. Future missions looking for life will be designed to dig deeply into the soil to take samples. If there is still bacterial life – or evidence of past bacterial life – we'll be most likely to find it underground.
You Should Also Read:
Absolute Beginners - Seeing Mars and beyond
Why Planets Have Seasons
Editor's Picks Articles
Top Ten Articles
Content copyright © 2019 by Mona Evans. All rights reserved.
This content was written by Mona Evans. If you wish to use this content in any manner, you need written permission. Contact Mona Evans for details.