So far scientists have not found a way to decide the exact age of Earth directly from Earth rocks because Earth's oldest rocks have been recycled and destroyed by the process of plate tectonics. If there are any of Earth's primordial rocks left in their original state, they have not yet been found.

Nevertheless, scientists have been able to determine the probable age of the Solar System and to calculate an age for the Earth by assuming that the Earth and the rest of the solid bodies in the Solar System formed at the same time and are, therefore, of the same age.

The Earth is at least 4.6 billion years old. Ancient rocks exceeding 3.5 billion years in age are found on all of Earth's continents. Scientists have also dated meteorites that have fallen from space, and must have formed at the same time as the Earth.

© 2008 Al Bawaba (www.albawaba.com)