Mars is the fourth planet from the Sun and the second smallest planet in the Solar System. It is often described as the “Red Planet”.
The red-orange appearance of the Martian surface is caused by iron(III) oxide, more commonly known as hematite, or rust. It can also look butterscotch, and other common surface colors include golden, brown, tan, and greenish, depending on minerals.
The Red Planet (Mars)
This rocky planet’s surface has been volcanoes, meteor impacts, shifting tectonic plates, and huge dust storms. Its seasonal temperature fluctuations are visible in its ever growing and receding polar ice caps.
Distance From Sun 141,633,260 miles (227,936,640 kilometers)
Length of Year 24 hours, 37 minutes
-125°F to 23°F (-87°C to -5°C)
Size of the Mars
Mars has a diameter of 4,222 miles (6,795 kilometers).
Orbit Size Around Sun (semi-major axis):
Metric: 227,943,824 km
English: 141,637,725 miles
Scientific Notation: 2.2794382 x 108 km (1.523662 A.U.)
By Comparison: 1.524 x Earth
Moons of Mars
Mars has two moons, Phobos and Deimos which are among the smallest in the solar system. They are made of carbon-rich rock mixed with ico. Scientists believe they could also be trapped asteroids.
Only a bit larger then Deimos, this moon orbits closer to its planet than any other known moon (3,700 miles/6,000 kilometers). It is slowly spiraling toward Mars and is expected to either crash or break up and form a ring around the planet in about 50 million years. Phobos has a six-mile-wide (ten-kilometer-wide) crater, nearly half the width of the moon itself.
The smaller of the Mars’s moons, Deimos circles the red planet every 30 hours. Its surface is smoother than that of Phobos, probably because the majority of its craters are covered in dusty regolith, a powdery soil created from earlier impacts.
Water on Mars?
Scientists believe that 3.5 billion years ago, Mars experienced the largest known floods in the solar system. This water may even have pooled into lakes or shallow oceans. But where did the ancient floodwater come from, how long did it last, and where did it go?
At present, Mars is too cold and its atmosphere is too thin to allow liquid water to exist at the surface for long. There’s water ice close to the surface and more water frozen in the polar ice caps, but the quantity of water required to carve Mars’s great channels and flood plains is not evident on—or near—the surface today. Images from NASA’s Mars Global Surveyor spacecraft suggest that underground reserves of water may break through the surface as springs. The answers may lie deep beneath Mars’s red soil.
Unraveling the story of water on Mars is important to unlocking its past climate history, which will help us understand the evolution of all planets, including our own. Water is also believed to be a central ingredient for the initiation of life; the evidence of past or present water on Mars is expected to hold clues about past or present life on Mars, as well as the potential for life elsewhere in the universe. And, before humans can safely go to Mars, we need to know much more about the planet’s environment, including the availability of resources such as water.
Mountains, Moons, and More
Mars has some remarkable geological characteristics, including the largest volcanic mountain in the solar system, Olympus Mons; volcanoes in the northern Tharsis region that are so huge they deform the planet’s roundness; and a gigantic equatorial rift valley, the Valles Marineris. This canyon system stretches a distance equivalent to the distance from New York to Los Angeles; Arizona’s Grand Canyon could easily fit into one of the side canyons of this great chasm.