Mars is the 4th planets from the sun, and is named after the Roman God of War, due to the planets red colouring it is known for. Mars has been the subject of space exploration for quite some time, particularly in the field of of extra terrestrial life. Planetary scientists have long studied this world as possibly being a second home to the population of Earth. It is a relatively smaller planet, being only about half of the Earth’s size itself. Though for being such a large body, its density is surprising in that it is only slightly greater than that of the Moon. However, this suggests a secret that lays deep within the center of Mars: the core is suspected to be comprised largely of iron sulfide. Iron sulfide is a compound that is twice as dense as the rock that composes the surface of Mars, and is nearly two thirds the size of the entire planet.


The New Land

* The surface of Mars has many distinguishable features that allow astronomers to track the planet’s rotation very clearly.
* Mars rotates once on its axis every 24.6 hours, so one Martian day is nearly identical to one Earth day.
* Interestingly enough, the planet’s equator leans to one side, at nearly the same amount as the Earth’s. Thus, as Mars orbits the Sun, the planet experiences both daily and season cycles, just like our home.
* The seasons are complicated somewhat by differences in solar heating due to the planet’s very strange orbit – Southern Hemisphere summer occurs around the time of Martian perihelion (the time when Mars is closest to the Sun) and so is significantly warmer than summer in the Northern Hemisphere which occurs at the aphelion (the time when Mars is furthest from the sun).
* Spectroscope observations from Earth and from Earth’s Orbit have revealed that the polar caps, which are visible through telescopes, are actually frozen carbon dioxide (dry ice) and not water ice.
* Though the polar caps do contain water, but it remains permanently frozen, and the dark markings that were previously thought to be a network of canals, are actually highly cratered and eroded areas around which surface dust occasionally blows viciously into the atmosphere

What We Need is A... Lava Flow?

- The northern hemisphere is made up largely of rolling volcanic plains not unlike the Moon – indeed, this similarity was key to their identification as lava-flow features. Much larger than their counterparts on the Earth or Moon, these extensive lava plains were formed by eruptions involving enormous volumes of material. They are strewn with blocks of volcanic rock, as well as with boulders blasted out of impact areas by infalling meteoroids, as the Martian atmosphere is too thin to offer much resistance to incoming debris.
- The southern hemisphere consists of heavily cratered highlands lying some 5 kilometres above the level of the lowland north. Most of the dark regions visible from Earth are mountainous regions in the south. It is suggested that because of the cratering in the south that the northern hemisphere’s surface is much younger: 3 billion years, compared to the 4 billion year old surface of the south. In places, the boundary between the southern highlands and northern plains is very sharp – the surface level can drop by as much as 4 kilometers in height with only 100 kilometers of distance from one side to the other. It is assumed that the southern hemisphere is the original crust of the planet. How most of the northern hemisphere could have been lowered in elevation and subsequently flooded with lava remains a mystery.

Now Featuring

- The major geological feature on the planet is the Tharsis bulge.
- Roughly the size of North America, Tharsis lies on the equator and rises some 10 kilometers higher than the rest of the Martian surface.
- To its east lies the Chryse Planitia (the “Plains of Isis,” an Egyptian Goddess).
- These features are wide depressions, hundreds of kilometers across and up to 3 kilometers deep.
-  If we wished to extend the idea of ‘continents’ from Earth and Venus to Mars, we would conclude that Tharsis is the only continent on the Martian surface.
- There is no sign of plate tectonics on Mars – the absence of fault lines or other evidence of plate motion tells geologists that the ‘continent’ of Tharsis is not drifting as its Earthly counterparts are.
- Almost diagonally opposite Tharsis, in the southern hemisphere, lies the Hellas Basin which, paradoxically, contains the lowest point on Mars.
- This feature is some 3000 kilometers across, the floor lies nearly 9 kilometers below the basin’s rim and over 6 kilometers below the average level of the planet’s surface.
- Its shape and structure identify the Hellas Basin as an impact feature. The formation of the Hellas Basin must have caused a major change to the Martian crust
- The giant Borealis Basin around the Martian north pole may be the result of one of the largest known impacts in the solar system.
- Recent research, based on simulations of the collision and detailed data from Muggle spacecraft missions (Mars Global Surveyor and Mars Reconnaissance Orbiter) suggests that the basin could have formed when a giant celestial object some 2000 kilometers across – twice the size of the largest known asteroid Ceres – struck the planet a grazing blow during the formation stages.
- The collision could also explain why the northern hemisphere of Mars is so much lower than and differs so radically from the south.

Well Thats Just Grand!


- A particularly prominent feature associated with the Tharsis bulge is a great “canyon” known as Valles Marineris (the Mariner Valley).
- This feature is not really a canyon in the terrestrial sense because running water played no part in its formation.
- It is theorized that it was formed by the same crustal forces that caused the entire Tharsis region to bulge outward, making the surface split and crack. The resulting cracks, called tectonic fractures, are found all around the Tharsis bulge.
- Valles Marineris is the largest of them, and studies suggest that the cracks are at least 2 billion years old with the Valles Marineris range being estimated at around 35 billion years old.
- Valles Marineris runs for almost 4000 kilometers along the Martian equator, about 1/5th of the way around the planet.
- The Grand Canyon in Arizona, USA, Earth, would easily fit into one of its side “tributary” cracks. Valles Marineris is so large hat it can even be seen from Earth. In fact, it was one of the few “canals” observed by 19th-century astronomers that actually corresponded to a real feature on the planet’s surface. It was then known as the Coprates canal.

The Brothers


Mars has two small moons in orbit around it, both visible (through telescopes of course) from Earth. They are named Phobos (Fear) and Deimos (Panic) for the sons of Ares (the Greek name of the God of War known to the Romans as Mars) and Aphrodite (the Greek name for Venus, Goddess of Love). These moons are little more than large rocks trapped by the planet’s gravity.
Discovered by American Muggle astronomer Asaph Hall in 1877, these two tiny moons orbit very closely to Mars, and are only a few tens of kilometers across. Their composition is quite unlike that of the planet. They are quite difficult to study from Earth because their proximity to Mars makes it hard to distinguish them from their much brighter parent. The Mariner and Viking orbiters, however, studied them both in greater detail.
Phobos and Deimos are both quite irregularly shaped and heavily cratered. The larger of the two is Phobos, which is about 28 kilometers long and 20 kilometers wide and is dominated by an enormous 10-kilometer-wide crater named Stickney (after Angelina Stickney, Asaph Hall’s wife, who encouraged him to persevere in his observations). The smaller Deimos is only 16 kilometers long by 10 kilometers wide. Its largest crater is 2.3 kilometers in diameter. The fact that both moons have quite dark surfaces, reflecting no more than 6% of the light falling on them, contributes to the difficulty in observing them from Earth.
Astronomers estimated the masses of the two moons on the basis of measurements of their gravitational effect on the Viking orbiters. The density of the Martian moons is around 2000 kg per square meter, far less than that of any world we have yet encountered in our outward journey through the solar system. This is one reason that astronomers think it unlikely that Phobos and Deimos formed along with Mars. Instead, it is more probable that they are asteroids that were slowed and captured by the outer fringes of the early Martian atmosphere (which, was probably much denser back then than it is today). It is even possible that they are remnants of a single object that broke up during capture.
Phobos, on its low-altitude orbit, continues to interact with the planet’s upper atmosphere. Its orbit is expected to decay, plunging the moon into the surface in just a few tens of millions of years.
If they are indeed captured asteroids, Phobos and Deimos represent material left over the from the earliest days of the solar system. Astronomers study them not to gain insight into Martin evolution, but rather because the moons contain information about the young solar system, before the major planets had formed