How much of the earth is unexplored? July 12, 2020 by Pamela Landy What is left of the earth that is unexplored is approximately 140 million square miles of ocean floor. This is equal to two and a half times the surface area of the earth’s islands and continents. Related Answers What is the definition of everyone’s favorite Scrabble word syzygy? How thick is the crust of the earth? How hot is the sun? How long is a cosmic year? How much of the earth’s surface is permanently frozen? What’s the smallest country on earth?