ABSTRACT
This chapter discusses concept of deep time. It also discusses radiometric age dating which is an absolute dating technique that uses radioactive elements such as uranium that decay at a known rate. By measuring the amounts and determining the ratio of parent to daughter, the chapter determines the age of the mineral or rock. Some scientists in the 1800s felt that, if one could find the thickness of all rocks ever deposited, and determine the rate of deposition through time, then the age of the earth could be calculated. Earth is thought to have formed by collision and accretion of small dust and rock-sized particles in the interstellar dust cloud that also formed the sun and solar system. The chapter further discusses fission track dating which counts the number of tracks produced in certain minerals, usually apatite or zircon, by the splitting nuclei of U-238.
