Fifteen Facts about Mars
Mars is the fourth planet from the Sun, a rusty red world of giant volcanoes, enormous canyons, frozen poles and dusty deserts. Here are fifteen facts about the Red Planet.
Mars is the fourth planet from the Sun
Mars orbits the Sun at an average distance of about 228 million kilometres, or 142 million miles. This means it is about one and a half times farther from the Sun than Earth is. Mars sits between Earth and Jupiter, making it the outermost of the four rocky inner planets: Mercury, Venus, Earth and Mars
Mars is known as the Red Planet
Mars gets its famous red colour from iron-rich minerals in its soil and dust. The iron has effectively rusted, giving much of the planet its reddish-orange appearance. Its sky is also red. Well, a orangey-pinky-salmony-red.
Mars is smaller than Earth
Mars has a diameter of about 6,779 kilometres, or 4,212 miles, making it roughly half the width of Earth. It is the second smallest planet in the Solar System, larger only than Mercury. Despite being smaller than Earth, Mars still has some of the biggest landscape features anywhere in the Solar System.
Mars has two tiny moons
Mars has two moons called Phobos and Deimos. They are much smaller than Earth’s Moon and are irregularly shaped, looking more like captured space potatoes than elegant glowing worlds. Phobos is the larger of the two and orbits very close to Mars, while Deimos is smaller and farther away. Both may be captured asteroids, or leftover debris from the early Solar System.
Phobos is slowly falling towards Mars
Phobos orbits Mars closer than any other known moon orbits its planet. It is gradually spiralling inwards, getting about 1.8 metres closer to Mars every hundred years. Eventually, it will either crash into Mars or be torn apart by the planet’s gravity, possibly forming a ring around Mars. Don’t panic though. This is expected to happen in about 50 million years.
Mars has the largest volcano in the Solar System
Olympus Mons is the largest volcano in the Solar System. It is about 600 kilometres wide and around 22 kilometres high, making it nearly three times taller than Mount Everest. It is a shield volcano, meaning it was built up by lava flowing over long distances rather than exploding violently like some volcanoes on Earth.
Mars has the largest canyon in the Solar System
Valles Marineris is an enormous canyon system stretching across Mars. It is more than 4,000 kilometres long, up to 200 kilometres wide in places, and several kilometres deep. If it were on Earth, it would stretch across a huge chunk of a continent. It makes the Grand Canyon look like a small scratch on Earth's surface.
Mars once had rivers, lakes and flowing water
Today, Mars is cold and dry, but there is strong evidence that liquid water once flowed across its surface. Spacecraft have found dry river valleys, ancient lakebeds, deltas and minerals that formed in water. This means Mars may once have been much warmer and wetter than it is today, although probably still not the sort of place where you’d want to forget your coat.
Mars has polar ice caps
Mars has polar caps at its north and south poles. These contain water ice and frozen carbon dioxide, also known as dry ice. The polar caps grow and shrink with the seasons as carbon dioxide freezes out of the atmosphere and then turns back into gas again.
Mars has seasons like Earth
Mars has seasons because its axis is tilted, just like Earth’s. Earth is tilted by about 23.5 degrees, while Mars is tilted by about 25 degrees. This means different parts of Mars receive more or less sunlight during the Martian year. However, because a year on Mars lasts 687 Earth days, each season lasts much longer than a season on Earth.
The Sun appears smaller from Mars
Mars is farther from the Sun than Earth, so the Sun appears smaller in the Martian sky. From Mars, the Sun looks about two-thirds the size it appears from Earth, and sunlight is weaker too. Martian sunsets can also look bluish because of the way fine dust in the atmosphere scatters sunlight.
Mars has a very thin atmosphere
Mars has an atmosphere, but it is much thinner than Earth’s. It is mostly made of carbon dioxide, with much smaller amounts of nitrogen and argon. The thin atmosphere means Mars cannot trap much heat, which is one reason the planet is so cold. It also means liquid water cannot easily remain on the surface today.
Mars is very cold
Even though Mars can sometimes reach mild temperatures near the equator during the day, it is generally a freezing cold world. Temperatures can drop far below zero, especially at night and near the poles. So, if you're planning on visiting Mars, bring a jumper, and then bring another jumper to wear on top of it.
Robots have explored Mars for decades
Mars is the most explored planet beyond Earth. Orbiters, landers and rovers have studied it from above and on the ground. NASA’s Curiosity rover landed in 2012, and Perseverance landed in 2021 to explore Jezero Crater and collect rock samples. Other countries and space agencies have also sent missions to Mars, making it the busiest world in the Solar System after Earth. No humans have yet visited Mars.
Pieces of Mars have landed on Earth
Some meteorites found on Earth originally came from Mars. Large impacts on Mars blasted rocks off its surface and into space. After travelling around the Solar System, a few of those rocks eventually fell to Earth. This means scientists can study real pieces of Mars without having to go all the way there, which is handy. Future missions are expected to collect rocks from Mars and fly them back to Earth.
