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Bill Nye and the Discovery Channel give you the greatest discoveries in science. Earth is always changing, and Earth's species must continually adapt. Host Bill Nye gives an inside look at planet Earth, from its inner core to its protective magnetic field. Discover how earthquakes and volcanoes help explain plate tectonics and the dynamic geology of oceans and continents. Learn how the Earth's atmosphere gives scientific insight about weather and climate, and look at forms of radiation and the potential dangers from harmful gases and geologic changes.

Arctic temperatures are now higher than at any time in the last 2,000 years, research reveals. Changes to the Earth's orbit drove centuries of cooling, but temperatures rose fast in the last 100 years as human greenhouse gas emissions rose. Scientists took evidence from ice cores, tree rings and lake sediments.

"A team at the Carnegie Institution for Science subjected the material to pressures up to 1.4 million times atmospheric pressure at sea level, and temperatures up to 2,200C. They found that it pulls off the trick of changing its electrical properties without any shifting of shape - it can be an insulator or conductor depending just on temperature and pressure. Combined with computer simulations of just what was going on with the material's electrons, the group claim that the results show a new type of metallisation. "At high temperatures, the atoms in iron oxide crystals are arranged with the same structure as common table salt," said Ronald Cohen, a co-author of the study. "Just like table salt, iron oxide at ambient conditions is a good insulator-it does not conduct electricity.""