Mars has been a source of curiosity for thousands of years. For many of those years, humans wondered if the planet could possibly harbor life. A logical outbranching of that wonder was, what is Mars made of ?
Mars composition is similar to Earth in its basic composition. It has a core that is mainly iron and sulfur, wrapped in a mantle that is silicates, all of which is cocooned by a crust that is made of basalt and just enough iron oxide to give the planet it characteristic reddish hue. Knowing the basic components of Mars is just brushing the surface.
The core, like Earth’s, has a major iron component. That is where the similarities stop. The core here on Earth is molten and in constant motion. The inner core rotates in a different direction than the outer core and the interaction of the two creates our magnetic field, which protects the surface from solar radiation. The Martian core is solid and does not move. It is thought to be about 2,960 km in diameter. The planet lacks a magnetic field because of this and is constantly bombarded by radiation that killed an potential life forms millenia ago.
The mantle is as dormant as the core. There is no tectonic plate action to reshape the surface or to assist in removing carbon from the atmosphere. The mantle is believed to be fairly soft, kind of like a rock paste. There are no numbers for the thickness of the mantle available at this time.
The crust is mainly basalt from volcanic activity billions of years ago. It varies between 50 and 125 km thick. A large portion of the outer edges of the crust is compromised of iron oxide dust. Given the lightness of the dust and the high speed of the Martian winds, features on the surface can be obliterated in a relatively short time frame.
Past exploration of the Martian environs has proven that the planet had a magnetic field billions of years ago along with active tectonic plate action. It has also revealed the possibility of a a huge impact crater. The suspected crater is thought to be 10,600 km by 8,500 km. That seems to infer an impactor the size of Pluto hitting the surface about 4 billion years ago during the Late Bombardment period of the Solar System. It would be interesting to know if the core and tectonic action ceased as a result of the huge impact.
As you can see, just knowing the answer to ”what is Mars made of?” only gives you a small picture of the planet. Do not hesitate to explore the files that NASA has on the Red Planet as well as look deeper into our website.
Here’s an article from Universe Today about how Mars has been cold for billions of years.
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.