Thorium is a chemical element in actinide group. It is a weakly radioactive metal. It has a shiny, silvery white color. It has the chemical symbol Th and the atomic number 90. Natural thorium has an atomic weight of 232. Thorium is named after Thor, the Norse god of thunder. Its ores are found in nature, especially in India, the United States, and Australia. Many scientists believe thorium would make a good source of nuclear fuel because it makes much less waste and is four times as common as uranium. It makes 3,200,000 times as much energy as coal and 200 times as much energy as uranium, because natural uranium is mostly non-fissile isotopes. Scientists believe that there is enough of it to power the world for thousands of years.