The inner and outer core make up about 15 percent of the Earth by volume and 32 percent by mass. The outer core extends to the Gutenberg discontinuity, the border between the mantle and the outer core. The pressures within the inner core reach about 3 million atmospheres; temperatures are in the range 4,000–5,000°C (7,200–9,000°F). The heat comes from the radioactive decay of uranium.
Related category GEOLOGY AND PLANETARY SCIENCE
Home • About • Copyright © The Worlds of David Darling • Encyclopedia of Alternative Energy • Contact