The main component of the planet's atmosphere is carbon dioxide, which constitutes slightly more than 95.3 percent of the atmosphere by weight. Therefore, the possibility of emigrating en masse to our neighboring planet is minimal, as the percentage of carbon dioxide in Earth's atmosphere by weight is just 0.046 percent. In addition, molecular nitrogen, which accounts for 75.47 percent of the Earth's atmosphere by weight, constitutes only 2.7 percent of Mars' atmosphere.
Argon accounts for 1.6 percent of the Martian atmosphere by weight, followed by molecular oxygen -- the second most abundant element of Earth's atmosphere -- at 0.13 percent. Other elements in the planet's atmosphere include carbon monoxide, 0.7 percent; water vapor, 0.03 percent; and tiny concentrations of noble gases neon, krypton and xenon, accounting for 0.00025, 0.00003 and 0.000008 percent of the atmosphere by weight, respectively.
From the observations of the Mars Exploration Rover robotic vehicles, scientists are now aware that rocks in different parts of the planet have a distinct composition. Volcanic rocks on the plains are rich in iron and magnesium, with certain alteration rinds -- a stone decay feature -- with high concentrations of sulfur and chlorine. Throughout the planet, the plains feature mainly basaltic minerals such as olivine and pyroxene, while on cratered terrain, alteration minerals -- namely clays -- make their appearance.
As professor Philip R. Christensen of Arizona State University stated in the "Elements" journal, water in ice caps is abundant at the planet's poles and mid-latitudes. The volume of the total water reserves of the planet is approximately 1.2 million cubic miles, and if it was spread throughout the planet, it would create a layer 115 feet deep. However, the temperature and pressure of Mars are very low, meaning that water molecules can only exist as ice or vapor.