Mars Derives Its Name from the Roman God of War

If you've ever wondered why our neighbor to the north is called Mars, it's because the Roman god of battle was known by this moniker. Reasonably, it is assumed that this has something to do with Mars' startlingly red color when viewed from Earth. In truth, the planet Ares was given that name by the ancient Greeks, who also used it to refer to their own battle deity.

What's more intriguing is that this custom did not just exist in ancient Europe. The hue of Mars has inspired other ancient cultures; Chinese astronomers named Mars "The Fire Star." The planet was known as "Her Desher" by the ancient Egyptians, who connected it to the god Horus (or "The Red One"). Her Desher Vallis is the current name of an old river valley on Mars.

The abundance of iron-rich dust and rock that cover the planet is what gives it its color. This is derived from the significant quantities of iron oxide minerals found on the surface of the planet, including hematite (Blood Stone), the typical iron ore on Earth. However, when the planet was still molten on Earth, most of the iron sank into the core, but Mars' smaller size and weaker gravity may have allowed more iron to remain close to the surface. It is still unclear to scientists how the iron oxidized (which turns it red and requires the presence of some form of oxygen).