History
Extrapolations on the observations of core cooling estimate that the inner core formed approximately 2-4 billion years ago, from what was previously an entirely molten core. If true, this would mean that the Earth's inner core is not a primordial feature inherited during the planet's formation, since it would be younger than the age of Earth (about 4.5 billion years).
Read more about this topic: Inner Core
Famous quotes containing the word history:
“If you look at history you’ll find that no state has been so plagued by its rulers as when power has fallen into the hands of some dabbler in philosophy or literary addict.”
—Desiderius Erasmus (c. 1466–1536)
“It would be naive to think that peace and justice can be achieved easily. No set of rules or study of history will automatically resolve the problems.... However, with faith and perseverance,... complex problems in the past have been resolved in our search for justice and peace. They can be resolved in the future, provided, of course, that we can think of five new ways to measure the height of a tall building by using a barometer.”
—Jimmy Carter (James Earl Carter, Jr.)
“the future is simply nothing at all. Nothing has happened to the present by becoming past except that fresh slices of existence have been added to the total history of the world. The past is thus as real as the present.”
—Charlie Dunbar Broad (1887–1971)