Key Facts About Mars and Its Moons

Mars is known as the red planet because it looks red from Earth. The reddish color comes from the high concentration of iron oxide compounds—that is, rust—in the rocks of the Martian surface. Some key facts about Mars are as follows:

• Martian year is of 687 days and Martian day is 24h 37m.
• Martian atmosphere is very thin—only about 7000^th the density of Earth’s atmosphere. The atmosphere is mostly carbon dioxide, with tiny fractions of oxygen, nitrogen, and other gases.
• At the equator, during the warmest times of the Martian summer, the temperature can reach nearly –18°C at the poles, during the coldest times of the Martian winter, temperatures drop to -85°C and beyond.
• Mars is known for fascinating geologic features on its surface; it is covered with all sorts of mountains, craters, channels, canyons, highlands, lowlands, and even polar ice caps.
• Scientific evidence strongly suggests that once, billions of years ago, Mars was much warmer than it is now, and was an active, dynamic planet.

Polar Ice Caps on Mars

• Polar Ice Caps were first observed by Italian astronomer Gian Domenico Cassini, who is known for many important discoveries, including a gap in Saturn’s rings (This is called Cassini division).
• He made detailed observations of Mars, and discovered light-colored patches at the Martian north and south poles. These polar caps showed seasonal variations, spreading during the Martian winter and shrinking during the summer.
• Martian polar ice caps are made up mostly of frozen carbon dioxide {dry ice.}. Some frozen water, or just plain ice, may also be embedded within the polar caps.
• Due to the atmospheric conditions on the surface of Mars, however, neither the ice nor the dry ice would melt to make water or liquid carbon dioxide when the temperatures go up; rather, they would sublimate, or turn directly into gas. Thus, polar ice caps on Mars are not a source of liquid water.

Geological features of Mars

• Mars has a rich variety of geological features: huge craters, broad plains, tall mountains, deep canyons, and much more, all with colorful names.
• The tallest mountain in the solar system, the extinct volcano Olympus Mons, rises 24 kilometers above the Martian surface.
• A massive canyon called the Vallis Marineris (Mariner Valley) cuts across the northern hemisphere of Mars for more than 3,200 kilometers; it is three times deeper than the Grand Canyon, here on Earth.
• On the southern hemisphere of Mars is Hellas, an ancient canyon that was probably filled with lava long ago and is now a large, light area covered with dust.

Martian meteorite ALH84001

• ALH84001 was so named because it was found in the Allan Hills region of Antarctica in 1984 . It is the most famous of a number of meteorites that are thought to have been pieces of the Martian surface millions of years ago.
• They were probably knocked loose by a powerful collision from a comet or asteroid, which sent pieces of rock into orbit around the Sun that later landed on Earth.
• Mars Exploration Rovers, Spirit and Opportunity, are geological robots that have explored several areas of Mars. Among the many discoveries made with them are minerals that form only in the long term presence of water; microscopic mineral structures nicknamed “blueberries” that only form when moisture is present, along with chemical and isotopic ratios in Martian rocks that would have formed only if liquid water were in the environment.
• The strong scientific conclusion is that Mars is currently dry on its surface, but that this was not always the case. It may even have been awash with liquid water billions of years ago.

Moons of Mars – Phobos and Deimos

Phobos and Deimos are irregularly shaped rocky objects. They look very much like asteroids. Phobos is about 10 miles across, and Deimos is about half that size.

Phobos and Deimos look like small asteroids. The proximity of Mars to the asteroid main belt, suggests that they were indeed once asteroids whose orbits took them close to Mars. The orbital conditions were just right for Mars to capture them with its gravity, causing them to enter into stable orbits around Mars.