ocr: HE EARTH is the only planet in the universe known to support life. The Earth's atmosphere, made up mainly of nitrogen and oxygen, acts as a protective layer, blocking out harmful rays from the sun. The Earth'si interior is made up ofrock and metal. Water covers about 70 percent ofits surface. FACTS ABOUT THE EARTH Diameter at 7,926 miles the equator (12,755 km) Average distance 93 million miles from the sun (149.66 million km) Speed of orbit 18.51 miles (29.79 km) around the sun per second Time taken to orbit the sun 365.26 days Time taken for one rotation on its axis 23.93 hours Surface tempe ...