Since that time, geologists have learned to study the strata, or the thousands of layers of sedimentary rock that make up the Earth's crust.
Over the course of history, the natural weathering of Earth's surface created sediments (rock debris) that settled in layers on the surface.
Dating techniques are procedures used by scientists to determine the age of an object or a series of events.
The two main types of dating methods are relative and absolute.
Everything that existed on Earth was the same as it had been in the beginning.