Which planet is known as the Red Planet?

Mars is known as the Red Planet due to its distinctive reddish appearance, which is primarily the result of iron oxide, commonly known as rust, on its surface. This characteristic color has made Mars easily recognizable in the night sky and has led to its association with the color red. The naming also ties into various historical perspectives, where Mars was linked to the Roman god of war, further emphasizing its striking hue. The geologic composition and the presence of iron minerals contribute to this unique visual trait, making Mars a focal point in both astronomy and popular culture.

The other options do not share this reddish characteristic. Earth is referred to as the Blue Planet due to its vast oceans, Venus is often called Earth's twin but is known for its thick, yellowish atmosphere, and Jupiter, while striking with its gaseous bands and large size, appears mostly as brownish and orange, lacking the distinctive red hue of Mars.