The English name for the planet comes from the Romans, who named it after their god of war because its color reminded them of blood. In reality, the reddish color of Mars comes from iron oxide in the rocks and dust covering its surface. Your blood is also red because of a mixture of iron and oxygen in a molecule called hemoglobin. So in a way, the ancient connection between the planet Mars and blood wasn't completely wrong. Rust, which is a common form of iron oxide found here on Earth, also often has a reddish color. In my current research on exoplanets, I observe different types of signals from planets beyond Earth. Lots of interesting physics goes into how researchers perceive the colors of planets and stars through different types of telescopes. Probes sent from Earth have taken pictures showing rocks with a rusty color. A 1976 picture from the Viking lander, the very first spacecraft to land on Mars, shows the Martian ground covered with a layer of rusty orange dust. Not all of...
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