Relative time permits scientists to tell the story of Earth events, however doesn’t present specific numeric ages, and thus, the speed at which geologic processes operate. Based on Hutton’s precept of uniformitarianism (see Chapter 1), early geologists surmised geological processes work slowly and the Earth could be very outdated. Relative courting principles was how scientists interpreted Earth history until the end of the nineteenth Century. Because science advances as technology advances, the discovery of radioactivity within the late 1800s supplied scientists with a new scientific software known as radioisotopic relationship. Using this new expertise, they might assign particular time units, in this case years, to mineral grains within a rock. More info These numerical values are not dependent on comparisons with different rocks such as with relative courting, so this relationship technique is known as absolute relationship [5].