What is Mars Made Of?
Written by Fraser Cain
The radius of Mars is actually about half the size of the Earth. Put next to each other, Earth seems huge compared to the Red Planet. And because of its smaller size, the composition of Mars is different from Earth.
The outer surface of Mars is mostly basalt, brought to the surface by volcanoes in the planet's early history. This volcanic activity ceased many years ago, and now much of the surface is covered by fine iron oxide dust with the consistency of talcum powder. Huge dust storms on Mars can blow this Martian dust around, slowly wearing down features on the surface.
Unlike the Earth, Mars has no magnetic field. It's possible that the Red Planet had an internally rotating core billions of years ago. Because of its small size and lack of water, these seized up billions of years ago. NASA's Mars Global Surveyor discovered magnetic bands on the planet, similar to deep ocean bands on Earth, which indicate that it might have had plate tectonics billions of years ago. But without water to lubricate, they would have seized up long ago.
Planetary scientists think that Mars has a core region of about 1,480 km in radius. It consists mostly of iron, with up to 17% sulfur.
The core is surrounded by a mantle that once was active, but is now dormant. The mantle of Mars is made of silicates. If the core is liquid, the mantle is more like a soft rock paste – less dense than the core.
It's then surrounded by a crust that varies in thickness between 50 km and 125 km. This is much thicker than the Earth's more dynamic crust, which averages only 40 km.
Here's an article from Universe Today about how Mars has been cold for billions of years.
Ask a Scientist answered the question about the composition of Mars, and here's some general information about Mars from Nine Planets.
Finally, if you'd like to learn more about Mars in general, we have done several podcast episodes about the Red Planet at Astronomy Cast. Episode 52: Mars, and Episode 91: The Search for Water on Mars.
Filed under: Astronomy
