A continuous attack with bombs, shells, or other missiles. In astronomy it means a
bombardment of meteors or asteroids
Geological Time scale
The geologic time scale (GTS) is a system of chronological dating that relates geological strata (stratigraphy) to
time.
The four layers of the earth
The Four Layers. The Crust. The Mantle. Convection Currents. Outer Core. Inner Core.
Stratigraphy
The branch of geology concerned with the order and relative position of strata and their
relationship to the geological time scale, the analysis of the order and position of layers of
archaeological remains, the structure of a particular set of strata.
Fossil Record
Fossil record, history of life as documented by fossils, the remains or imprints of the organisms from
earlier geological periods preserved in sedimentary rock.
Relative Dating
Relative dating is the science of determining the relative order of past events (i.e., the age of an object in
comparison to another), without necessarily determining their absolute age, (i.e. estimated age).
Absolute Dating
Absolute dating is the process of determining an age on a specified chronology in archaeology and
geology. Some scientists prefer the terms chronometric or calendar dating, as use of the word "absolute"
implies an unwarranted certainty of accuracy.