INTERIOR STRUCTURE of the Earth is made up of THREE main shells the very thin and brittle crust the mantle and the core.The earth s radius is 6,370 km.Earth is moving about our sun in a very nearly circular orbit. It covers this route at a speed of nearly 30 kilometres per second or 67,000 miles per hour.The circumference of a circle is equal to 2 x π x r. So in ONE year, Earth travels about 584 million miles.Earth travels about 1.6 million miles a DAY. Structure of the Earth.