Origin of the Earth

The Origins Lecture Series continues on Wednesday, Feb. 6 at 7 p.m. in the Chapel with Ray Freeman-Lynde from the department of geography:

In the early 19th Century, geologists, using simple principles to determine the relative ages of rocks, came to understand the great age of the earth and to establish a relative geologic time scale. Following the discovery of radioactivity at the end of the 19th Century, geochronologists developed techniques for radiometrically-dating rocks and then established a numerical geologic time scale by the middle 20th Century.  Also in the 20th Century, the development of plate tectonics theory based on continental drift enabled us to better understand earthquakes, volcanic eruptions and tsunamis.  In the past these "Acts of God" were attributed to a variety of causes, but we now know them to be the result of seafloor spreading and rearrangements of the earth's crust and upper mantle.

See you there.