Geophysicists at the University of Rochester announce in today's issue of Nature that the Earth's magnetic field was nearly as strong 3.2 billion years ago as it is today.

Identification of the oldest preserved pieces of Earth's crust in southern Greenland has provided evidence of active plate tectonics as early as 3.8 billion years ago, according to a report by an international team of geoscientists in the March 23 edition of Science magazine.