Which planet is known as the Red Planet?

Mars is known as the Red Planet due to its distinct reddish appearance, which is caused by iron oxide, commonly known as rust, on its surface. This characteristic color has made Mars a focal point of study in astronomy and popular culture. The reddish hue is particularly visible when observing Mars from Earth, leading to its nickname.

In contrast, Earth is known as the Blue Planet due to its abundant water, Jupiter is recognized for its massive size and Great Red Spot, and Venus is often referred to as Earth's “sister planet” due to its similar size and composition, but it has a thick, toxic atmosphere and is covered in clouds, giving it a different color and appearance. Mars stands out among these options specifically for its red coloration, securing its title as the Red Planet.