The characteristic red Martian surface is a result of the high concentration of iron-oxide in its soil and rocks. The surface of Mars is covered by the types of volcanic and impact craters that have been observed on Mercury, but there are also vast cratered plains throughout the northern hemisphere. While there are no active volcanoes on Mars at the present time, the existing dormant volcanoes are some of the tallest observed in the solar system.
The currently dormant shield type volcano, Olympus Mons, is the tallest known mountain on Mars, soaring 25 kilometers above the Martian surface. It stands approximately 16 kilometers higher than Mount Everest and can hold more than 50 times the volume of the largest shield type volcano on Earth, Mauna Loa in Hawaii. Ancient lava flows from the Martian volcanoes helped to form Mars’ vast wide plains.
Rifts and Fracture Zones
Another surface feature common to other inner solar system bodies are rifts and fracture zones. One such fracture is the Valles Marineris (Mariner Valley), a large canyon stretching east by southeast across the Martian equator. More than 4,828 kilometers in length, the Valles Marineris is the single largest surface feature on Mars. It is a network four times deeper than the Grand Canyon on earth and consists of roughly parallel rift canyons with an overall width of 640 kilometers and a main canyon200 kilometers at its widest.
Signs of Liquid Water
In addition to craters and rift canyons, the Martian surface is also marked by vast networks of dried up riverbeds, huge channels forged by running water. These features seemingly defy explanation as its water is either frozen in polar ice caps or trapped deep below its surface as permafrost. There is no liquid water visible anywhere on the surface, nor is the pressure on the Martian atmosphere high enough to permit it to exist.
These channels can be divided into three categories:
- wide, flat floored channels or flood plains
- out-flow channels that originated from underground sources
- run-off channels
While there are very few clues as to where the water disappeared to, existing evidence suggests widespread flooding as there are riverbeds that cut across craters, as well as craters layered upon them which would indicate that flooding took place over a prolonged period of time.
Beneath and Above the Martian Surface
A rigid crust 49 kilometers thick beneath the Martian surface most likely contains water icepermafrost. The 200 kilometer thick Martian mantle is composed of basalt rock and beneath it exists a partially molten transition zone leading to a core between 1,287 and 2,092 kilometers thick that was previously molten.
While the majority of the Martian cloud cover is composed of water vapor like earth’s atmosphere, carbon dioxide clouds do exist, but at high altitudes during the winter throughout the polar regions. Whilst the carbon dioxide present in the ice caps as dry ice vaporizes and circulates within the planet’s atmosphere, the temperatures at the poles are such that even during the summer, the icecaps remain frozen.
Facts for Kids About Mars
- Mars is the fourth planet from the Sun and the second smallest planet in the Solar System, after Mercury.
- Named after the Roman god of war, it is often referred to as the “Red Planet” because the ironoxide prevalent on its surface gives it a reddish appearance.
- Mars is a terrestrial planet with a thin atmosphere, having surface features reminiscent both of the impact craters of the Moon and the volcanoes, valleys, deserts, and polar ice caps of Earth.
- Mars is the site of Olympus Mons, the largest volcano and second-highest known mountain in the Solar System, and of Valles Marineris, one of the largest canyons in the Solar System.
- The smooth Borealis basin in the northern hemisphere covers 40% of the planet and may be a giant impact feature.
- Mars is host to seven functioning spacecraft: five in orbit—2001 Mars Odyssey, Mars Express, Mars Reconnaissance Orbiter, MAVEN and Mars Orbiter Mission—and two on the surface—Mars Exploration Rover Opportunity and the Mars Science Laboratory Curiosity.
- In 2013, NASA’s Curiosity rover discovered that Mars’s soil contains between 1.5% and 3% water by mass (albeit attached to other compounds and thus not freely accessible).
- Liquid water cannot exist on the surface of Mars due to low atmospheric pressure, which is about 100 times thinner than Earth’s, except at the lowest elevations for short periods.
- Map of quadrangles For mapping purposes, the United States Geological Survey divides the surface of Mars into thirty “quadrangles”, each named for a prominent physiographic feature within that quadrangle.
- In 1994 the European Space Agency’s Mars Express found an ultraviolet glow coming from “magnetic umbrellas” in the southern hemisphere.
- As Mars approaches opposition, it begins a period of retrograde motion, which means it will appear to move backwards in a looping motion with respect to the background stars.