What is Ringworld? Ringworld is a huge disk 180 million miles in diameter, with a G2 star at the center. It revolves around the star for gravity. It's a million miles across, has a circumference of 565 million miles, and an area of 2 trillion,544 billion,690 million miles. By comparison, the total surface area of the earth is only 149 million square miles, of which only about 30% is land.
Having a hard time getting a grasp on the scale? Check this out: