Lesson Four: 

Mars

This planet, the fiftn for the sun, is named for the Roman God of War.  This planet has always been studied as a "second home" for humans, but it is only half Earth's size. It's core is made of iron sulphide, which it much heavier than Earth's core. Mars rotates once on its axis every 24.6 hours, so a Martian Day is nearly identical to an day and Earth. The planet's equator also leans to one side, so they experience seasonal cycles as well. Southern Hemisphere summer occurs during at something called the Martian perihelion, which is Mars is as close to the sun as it can get. Summer in the Northern Hemisphere occurs during the Martian aphelion, which is the time when the planet is has far from the sun as it gets. Mars also had polar caps made of frozen carbon dioxide (dry ice) and not water ice. The only water on the planet, however, is permanently frozen. The Mariner 9 visited Mars, and experienced a planet wide dust storm, which obscures the entire planet. The strong winds can often reach hurricane proportions (hundreds of kilometers per hour). The GAC (German Aerospace Centre) has done extensive tests to simulate the temperatures, atmosphere, minerals and light conditions of the planet’s surface based on data collected by Mariner 9. The Curiosity Rover has also landed on the planet, and took readings of air circulation patterns, and localized weather systems. 

Northern Hemisphere vs Southern Hemisphere 

Mars Northern Hemisphere is made up of mostly rolling volcanic plains-like the Moon- and extensive lava plains. These were formed following eruptions of enormous volumes of material. It is also covered in blocks of volcanic rock and boulders, as Martian atmosphere is too thin to resist much to debris. 

The Southern Hemisphere consists of heavily cratered highlands. They are also very mountainous. 

The Tharsis Bulge and company: This is a major geographical feature of the planet, about the size of North America. It lies on the equator and rises about 10 kilometres higher than the rest of the Martian landscape. To the east the Chryse Planitia is found, which features wide depressions measuring up to three kilometres deep. Diagonal to Tharsis is the Hellas Basin, which is the lowest point on Mars. This feature is some 3000 kilometers across, the floor of the basin lying nearly 9 kilometres below the basin’s rim and over 6 kilometers below the average level of the planet’s surface. This was created by a heavy bombardment of space debris. The Borealis Basin is found around the Martian north pole, and may be caused by one of space's largest known impact. There is also the Valles Marineris, which is a water formed canyon accompanying Tharsis. It runs for almost 4000 kilometers along the Martian equator, about 1/5^th of the way around the planet. At its widest point, it is some 120 kilometres across, and it is as deep as 7 kilometers in places.  The Grand Canyon is nothing compared to it. It also has water formed canals running through it.

Moons: Mars has two small moons in orbit around it, both visible from the Earth, and they are named Phobos, for the greek god of fear, and Deimos, for the greek god of panic. They were the two sons of Ares, god of chaotic war, and Aphrodite, goddess of love, representing that fear and panic is found in both war and love. However, this "moons" are little more than large rocks trapped in its atmosphere. They were discovered in 1877 by Muggle astronomer Asaph Hall. They were studied in detail by Mariner and Viking orbiters.