American scientists first measured out the core magnetic of field intensity

University of California, Berkeley, geophysicists measure the ground first 1,800 miles (about 2900 kilometers) deep in the core areas of the magnetic field strength, to prove the Earth's core heat source provides an important parameter, is the core cause of the internal heat source to maintain current the magnetic field. Related papers published in the December 16 issue of "Nature" magazine.
 
Thesis, University of California, Berkeley professor of Earth and Planetary Sciences, said Bruce Buffett, this is the first observation and not based on inferences from real data, the results do not dispute the core internal magnetic field strength to quell the dispute. Here they are calculated based on observation of 25 gauss magnetic field strength core is 50 times the Earth's surface. Geophysicists predict that the data is only moderate levels.
Strong magnetic field within the core means a strong heat source, the scientists assume that the energy source before the 40 billion years ago, state of the earth left behind by the melting of the heat, heavy element deposition and longer life expectancy occurring radioactive decay of elements. About 60% of Earth's internal energy may come from expansion of solid core cooling when the discharge of lighter elements, if only a very weak magnetic field of 5 Gauss, indicating that the supply from the radioactive decay very little heat, if the magnetic field of 100 gauss , then the strong radioactive decay.
Earth's core, including liquid outer core and solid core. Earth's liquid outer core contains 2 / 3 of the iron and nickel, about 1,400 miles (2,300 km) thick, formed Earth's magnetic field; core is the radius of 800 miles (1,300 kilometers) of solidified iron-nickel ball, about the size of the moon . Earth's core is hot thick hard layer of the mantle and crust surrounded.