Definition of "red planet" []

• A small reddish planet that is the 4th from the sun and is periodically visible to the naked eye; minerals rich in iron cover its surface and are responsible for its characteristic color (noun)

WordNet. Princeton University. 2010.

• "NASAs Mars landers, Viking 1 and Viking 2, which touched down on the red planet in 1976, gave us our first pictures from the surface of the planet, which had intrigued people on Earth for millennia."